Credit: NASA. 22,784 bytes. 336 x 281 pixels.
| astronautix.com | Robot Planetary Explorers |
|
| Phobos 1 - Credit: NASA. 22,784 bytes. 336 x 281 pixels. |
Near Earth Asteroid Rendezvous (NEAR) mission was the first of NASA's Discovery missions, a series of small-scale spacecraft designed to proceed from development to flight in under three years for a cost of less than $150 million. The spacecraft's mission was to rendezvous with and achieve orbit around the asteroid Eros in January, 1999, and study the asteroid for one year. Prior to its encounter with Eros NEAR flew within 1200 km of the C-class asteroid Mathilde on 27 June 1997. It then flew by the Earth on 23 January 1998. A problem caused an abort of the first encounter burn and the mission had to be rescoped for a later encounter. NEAR finally entered orbit around Eros on February 14, 2000. Orbit insertion was at 15:34 GMT into a 323 x 370 km initial orbit with a period of 27 days. The renamed NEAR-Shoemaker probe moved into a 100 x 200 km orbit around Eros on April 2 at 0200 GMT. NEAR returned spectacular detailed pictures of the surface over the next several months. Studies were made of the asteroid's size, shape, mass, magnetic field, composition, and surface and internal structure. Periapsis of the orbit would be as low as 24 km above the surface of the asteroid during the final days of the mission.
The primary mission of Deep Space 1 probe was to test new technology for future interplanetary spacecraft, the main experiment being an ion propulsion engine using xenon propellant. It had an initial mass of 486.3 kg, including 81.5 kg of Xenon and 31.1 kg of hydrazine propellants. Deep Space 1 successfully started its ion engine on November 24 after an initial attempt failed after four minutes on November 10. From its initial solar orbit of 0.99 AU x 1.32 AU x 0.4 degree, Deep Space 1 was to fly past the 3 km diameter asteroid 1992 KD at its perihelion of 1.33 AU. An additional 2001 flyby of Comet 19P/Borrelly was also planned, by which time Deep Space 1 was to have manoeuvred to an orbit of 1.12 x 1.42 AU.
The Delta 7326 used three Alliant GEM-40 solid strap-on motors, the standard Delta II core vehicle, and a Thiokol Star 37FM solid motor as the third stage. The Delta second stage entered a 185 km parking orbit, then fired again to enter a 174 km x 2744 km x 28.5 degree orbit. The Star 37FM then separated and accelerated to place Deep Space 1 to escape velocity.
Encountered comet Halley March 13, 1986. The Giotto mission was designed to study Comet P/Halley, and also studied Comet P/Grigg-Skjellerup during its extended mission. The spacecraft encountered Halley on March 13, 1986, at a distance of 0.89 AU from the sun and 0.98 AU from the Earth and an angle of 107 degrees from the comet-sun line. The actual closest approach was measured at 596 km. All experiments performed well and returned a wealth of new scientific results, of which perhaps the most important was the clear identification of the cometary nucleus. Fourteen seconds before closest approach, Giotto was hit by a `large' dust particle. The impact caused the spacecraft angular momentum vector to shift 0.9 degrees. Scientific data were received intermittently for the next 32 minutes. Some experiment sensors suffered damage during this 32-minute interval. Other experiments (the camera baffle and deflecting mirror, the dust detector sensors on the front sheet of the bumper shield, and most experiment apertures) were exposed to dust particles regardless of the accident and also suffered damage. Many of the sensors survived the encounter with little or no damage. Questionable or partially damaged sensors included the camera (later proved to not be functional) and one of the plasma analyzers (RPA). Inoperable experiments included the neutral and ion mass spectrometers and one sensor each on the dust detector and the other plasma analyzer (JPA). During the Giotto extended mission, the spacecraft successfully encountered Comet P/Grigg-Skjellerup on July 10, 1992. The closest approach was approximately 200 km. The heliocentric distance of the spacecraft was 1.01 AU, and the geocentric distance, 1.43 AU at the time of the encounter. The payload was switched-on in the evening of July 9. Eight experiments were operated and provided a surprising wealth of data. The Johnstone Plasma Analyser detected the first presence of cometary ions 600,000 km from the nucleus at 12 hours before the closest approach. The Dust Impact Detectors reported the first impact of a fairly large particle at 15:30:56. Bow shocks/waves and acceleration regions were also detected. After the P/Grigg-Skjellerup encounter operation were terminated on 23 July 1992. The spacecraft will fly by the Earth on 1 July 1999.
Stardust was to fly within 100 km of comet 81P/Wild-2 in January 2004 and recover cometary material using an aerogel substance. A return capsule would land on a lake bed in Utah in January 2006, returning the material to earth. The launch went as planned. The second stage ignited at 21:08 GMT and its first burn put the vehicle into a 185 km x 185 km x 28 degree parking orbit at 21:14 GMT. The second stage second burn at 21:25 changed the orbit to planned values of 178 km x 7184 km x 28.5 degrees. The Star 37FM solid third stage ignited at 21:29 GMT and placed the spacecraft into a 2 year period solar orbit. The spacecraft separated at 21:31 GMT. Meanwhile, the Delta 266 second stage burned a third time on its own, until its propellants were depleted, entering a final orbit of 294 km x 6818 km x 22.5 degrees.
First US lunar attempt. The first US Air Force lunar probe, using a Thor-Able booster. An explosion ripped it apart 77 seconds after launch.
This was the start of an acrimonious debated between Glushko and Korolev design bureaux over the fault and fix for the problem.
Pioneer 2 was launched from the Atlantic Missile Range, using a Thor-Able booster, the Air Force acting as executive agent to NASA. The 86.3-pound instrumented payload, intended as a lunar probe, failed to reach escape velocity.
Failed to reach moon; provided radiation data. Pioneer III, the third U.S.-IGY intended lunar probe under the direction of NASA with the Army acting as executive agent, was launched from the Atlantic Missile Range by a Juno II rocket. The primary objective, to place the 12.95 pound scientific payload in the vicinity of the moon, failed. Pioneer III reached an altitude of approximately 70,000 miles and revealed that the earth's radiation belt comprised at least two distinct bands.
Lunar probe; passed within 5.995 km of moon but did not hit it as planned due to a failure of the launch vehicle control system. Went into solar orbit. First manmade object to attain of escape velocity. Also known as Mechta ("Dream"), popularly called Lunik I. Because of its high velocity and its announced package of various metallic emblems with the Soviet coat of arms, it was concluded that Luna 1 was intended to impact the Moon. After reaching escape velocity, Luna 1 separated from its 1472 kg third stage. The third stage, 5.2 m long and 2.4 m in diameter, travelled along with Luna 1. On 3 January, at a distance of 113,000 km from Earth, a large (1 kg) cloud of sodium gas was released by the spacecraft. This glowing orange trail of gas, visible over the Indian Ocean with the brightness of a sixth-magnitude star, allowed astronomers to track the spacecraft. It also served as an experiment on the behavior of gas in outer space. Luna 1 passed within 5,995 km of the Moon's surface on 4 January after 34 hours of flight. It went into orbit around the Sun, between the orbits of Earth and Mars. The measurements obtained during this mission provided new data on the Earth's radiation belt and outer space, including the discovery that the Moon had no magnetic field and that a solar wind, a strong flow of ionized plasma emmanating from the Sun, streamed through interplanetary space.
The fourth U.S.-IGY lunar probe effort, Pioneer IV, a joint project of the Army Ballistic Missile Agency and Jet Propulsion Laboratory under the direction of NASA, was launched by a Juno II rocket from the Atlantic Missile Range. Intended to impact on the lunar surface, Pioneer IV achieved earth-moon trajectory, passing within 60,200 km of the moon before going into permanent orbit around the sun.
First probe to impact lunar surface. Delivered a pennant to the surface of the Moon and conducted research during flight to the Moon. Impacted Moon 13 Sep 1959 at 22:02:04 UT, Latitude 29.10 N, Longitude 0.00 - Palus Putredinis, east of Mare Serenitatis near the Aristides, Archimedes, and Autolycus craters. After launch and attainment of escape velocity, Luna 2 separated from its third stage, which travelled along with it towards the Moon. On 13 September the spacecraft released a bright orange cloud of sodium gas which aided in spacecraft tracking and acted as an experiment on the behavior of gas in space. On 14 September, after 33.5 hours of flight, radio signals from Luna 2 abruptly ceased, indicating it had impacted on the Moon. Some 30 minutes after Luna 2, the third stage of its rocket also impacted the Moon. The mission confirmed that the Moon had no appreciable magnetic field, and found no evidence of radiation belts at the Moon.
Luna 3 was the third spacecraft successfully launched to the Moon and the first to return images of the lunar far side. It was launched on a figure-eight trajectory which brought it over the Moon (closest approach to the Moon was 6200 km) and around the far side, which was sunlit at the time. It was stabilized while in optical view of the far side of the Moon. On October 7, 1959, the television system obtained a series of 29 photographs over 40 minutes, covering 70% of the surface, that were developed on-board the spacecraft. The photographs were scanned and 17 were radio transmitted to ground stations in facsimile form on October 18, 1959, as the spacecraft, in a barycentric orbit, returned near the Earth. The photographs were to be retransmitted at another point close to Earth but were not received. The spacecraft returned very indistinct pictures, but, through computer enhancement, a tentative atlas of the lunar farside was produced. These first views of the lunar far side showed mountainous terrain, very different from the near side, and two dark regions which were named Mare Moscovrae (Sea of Moscow) and Mare Desiderii (Sea of Dreams).
An intended lunar probe launched from the Atlantic Missile Range by an Atlas-Able booster disintegrated about 45 seconds later when the protective sheath covering the payload detached prematurely. The probe was sponsored by NASA, developed by the Jet Propulsion Laboratory, and launched by the Air Force Ballistic Missile Division.
Reached an altitude of 200,000 km before plunging back to earth.
This dramatic failure resulted in a loss of thrust, and the lateral strap-on units separated and flew over the tracking stations and living areas. The core continued on its trajectory.
An attempt to launch a Pioneer satellite into lunar orbit failed when one of the upper stages of the Atlas- Able rocket malfunctioned.
The final launch in the Pioneer lunar probe program was unsuccessful; the Atlas-Able booster rocket went out of control and exploded at an altitude of 12,200 m off Cape Canaveral.
Atlas booster 111-D, to be used for Ranger I, was erected on the launch pad at Cape Canaveral.
Lunar probe; failed to leave Earth orbit. Ranger 1, a test version of the spacecraft which would attempt an unmanned crash landing on the moon, was launched from the Atlantic Missile Range by an Atlas-Agena B booster. The 306 kg spacecraft did not attain the scheduled extremely elongated orbit because of the misfiring of the Agena B rocket. Although the spacecraft systems were tested successfully, only part of the eight project experiments could be carried out. Ranger 1 reentered on August 29 after 111 orbits. Ranger 1's primary mission was to test the performance of those functions and parts that are necessary for carrying out subsequent lunar and planetary missions using essentially the same spacecraft design.
This was a flight test of the Ranger spacecraft system designed for future lunar and interplanetary missions. The spacecraft was launched into a low earth parking orbit, but an inoperative roll gyro prevented Agena restart resulting in Ranger 2 being stranded in low earth orbit. The orbit decayed and the spacecraft reentered Earth's atmosphere on 20 November 1961.
Lunar impact probe; missed the moon by 36,874 km and went into solar orbit. A malfunction in the booster guidance system resulted in excessive spacecraft speed. Reversed command signals caused the telemetry antenna to lose earth acquisition, and mid-course correction was not possible. Some useful data were obtained from the flight. Of four scientific experiments only one was partially completed: gamma-ray readings of the lunar surface. Attempts to relay television pictures of the moon and to bounce radar signals off the moon at close range were unsuccessful.
Ranger IV was launched by an Atlas-Agena B booster from the Atlantic Missile Range, attained a parking orbit, and was fired into the proper lunar trajectory by the restart of the Agena B engine. Failure of a timer in the spacecraft payload caused loss of both internal and ground control over the vehicle. The Goldstone Tracking Station maintained contact with the spacecraft until it passed behind the left edge of the moon on April 26. It impacted at a speed of 9,617 km per hour, the first American spacecraft to land on the lunar surface. The Agena B second stage passed to the right of the moon and later went into orbit around the sun. Lunar photography objectives were not achieved.
The Ranger V lunar probe was launched from Atlantic Missile Range by an Atlas-Agena B launch vehicle. The Agena B stage attained parking orbit and 25 minutes later reignited to send Ranger V toward the moon. A malfunction in the Agena B guidance system resulted in excessive spacecraft velocity. The spacecraft's solar cells did not provide power and reversed command signals caused the telemetry antenna to lose earth acquisition. This made reception of the flight-path correction signal impossible and rendering its television cameras useless. Reversed command signals caused the telemetry antenna to lose earth acquisition, and mid-course correction was not possible. The spacecraft missed the Moon by 725 km and went into solar orbit. Gamma-ray data were collected for 4 hours prior to the loss of power. Ranger V was to have relayed television pictures of the lunar surface and rough-landed an instrumented capsule containing a seismometer. The spacecraft was tracked for 8 hours, 44 minutes, before its small reserve battery went dead.
On October 29, Homer E. Newell, NASA Director of the Office of Space Sciences, established a Board of Inquiry to review the entire Ranger program. The Board, headed by Albert J. Kelley of NASA Headquarters, submitted its report on December 4 and found that, while the Ranger design concept was basically sound, improvements could be made to increase flight reliability.
Apparent causes were instabilities in the torque sensor circuit and the pitch-free floating gyro device. The upper stages and payload broke up on re-entry into the atmosphere over the Pacific.
Luna 4 was the second attempted Soviet unmanned lunar soft lander probe. The spacecraft, rather than being sent on a straight trajectory toward the Moon, was placed first in an earth parking orbit. The rocket stage then reignited and put the spaccecraft on a translunar trajectory. Failure of Luna 4 to make a required midcourse correction resulted in it missing the Moon by 8336.2 km on April 6, at 4:26 a.m. Moscow time. It thereafter entered a barycentric Earth orbit. The Soviet news agency, Tass, reported that data had been received from the spacecraft throughout its flight and that radio communication would continue for a few more days.
Launch vehicle test. Launch vehicle put payload into geosynchronous transfer orbit
Impacted Moon but TV camera malfunctioned. A midcourse trajectory correction was accomplished early in the flight by ground control. On February 2, 1964, 65.5 hours after launch, Ranger 6 impacted the Moon on the eastern edge of Mare Tranquillitatis (Sea of Tranquility). No camera data were obtained, probably because of failure due to an arc-over in the TV power system when it inadvertently turned on during the period of booster-engine separation.
The upper stages burnt on re-entry into the atmosphere.
The upper stages broke up on re-entry into the atmosphere..
First successful Ranger; returned 4,308 photos before lunar impact. The Atlas- Agena B inserted the Agena and Ranger into a 192 km altitude Earth parking orbit. Half an hour after launch a second burn of the Agena engine injected the spacecraft into a lunar intercept trajectory. After separation from the Agena, the solar panels were deployed, attitude control activated, and spacecraft transmissions switched from the omniantenna to the high-gain antenna. The next day the planned mid-course maneuver was successfully initiated at 10:27 GMT. The only anomaly during flight was a brief loss of two-way lock on the spacecraft by the DSIF tracking station at Cape Kennedy following launch.
Ranger 7 reached the Moon on 31 July. The F-channel began its one minute warm up 18 minutes before impact. The first image was taken at 13:08:45 GMT at an altitude of 2110 km. Transmission of 4,308 photographs of excellent quality occurred over the final 17 minutes of flight. The final image taken before impact had a resolution of 0.5 meters. The spacecraft encountered the lunar surface in direct motion along a hyperbolic trajectory, with an incoming asymptotic direction at an angle of -5.57 degrees from the lunar equator. The orbit plane was inclined 26.84 degrees to the lunar equator. After 68.6 hours of flight, Ranger 7 impacted in an area between Mare Nubium and Oceanus Procellarum (subsequently named Mare Cognitum) at approximately 10.35 S latitude, 339.42 E longitude. Impact occurred at 13:25:48.82 GMT at a velocity of 2.62 km/s.
Launch vehicle test. Launch vehicle put dummy Surveyor payload into geosynchronous transfer orbit
Returned 7137 photos before lunar impact. The Atlas- Agena B booster injected the Agena and Ranger 8 into an Earth parking orbit at 185 km altitude 7 minutes after launch. Fourteen minutes later a 90 second burn of the Agena put the spacecraft into lunar transfer trajectory, and several minutes later the Ranger and Agena separated. The Ranger solar panels were deployed, attitude control activated, and spacecraft transmissions switched from the omni-directional antenna to the high-gain antenna by 21:30 GMT. On 18 February at a distance of 160,000 km from Earth the planned mid-course manoeuvre took place, involving reorientation and a 59 second rocket burn. During the 27 minute manoeuvre, spacecraft transmitter power dropped severely, so that lock was lost on all telemetry channels. This continued intermittently until the rocket burn, at which time power returned to normal. The telemetry dropout had no serious effects on the mission. A planned terminal sequence to point the cameras more in the direction of flight just before reaching the Moon was cancelled to allow the cameras to cover a greater area of the Moon's surface.
Ranger 8 reached the Moon on 20 February 1965. The first image was taken at 9:34:32 GMT at an altitude of 2510 km. Transmission of 7,137 photographs of good quality occurred over the final 23 minutes of flight. The final image taken before impact has a resolution of 1.5 meters. The spacecraft encountered the lunar surface in a direct hyperbolic trajectory, with incoming asymptotic direction at an angle of -13.6 degrees from the lunar equator. The orbit plane was inclined 16.5 degrees to the lunar equator. After 64.9 hours of flight, impact occurred at 09:57:36.756 GMT on 20 February 1965 in Mare Tranquillitatis at approximately 2.67 degrees N, 24.65 degrees E. Impact velocity was slightly less than 2.68 km/s.
The stage with the payload remained in Earth orbit as Kosmos-60.
Ranger 9, last of the series, returned 5814 images before lunar impact. The target was Alphonsus, a large crater about 12 degrees south of the lunar equator. The probe was timed to arrive when lighting conditions would be at their best. The Atlas- Agena B booster injected the Agena and Ranger 9 into an Earth parking orbit at 185 km altitude. A 90 second Agena 2nd burn put the spacecraft into lunar transfer trajectory. This was followed by the separation of the Agena and Ranger. The initial trajectory was highly accurate; uncorrected, the craft would have landed only 650 km north of Alphonsus. 70 minutes after launch the command was given to deploy solar panels, activate attitude control, and switch from the omni-directional antenna to the high-gain antenna. The accuracy of the initial trajectory enabled delay of the planned mid-course correction from 22 March to 23 March when the manoeuvre was initiated at 12:03 GMT. After orientation, a 31 second rocket burn at 12:30 GMT, and reorientation, the manoeuvre was completed at 13:30 GMT. Ranger 9 reached the Moon on 24 March 1965. At 13:31 GMT a terminal manoeuvre was executed to orient the spacecraft so the cameras were more in line with the flight direction to improve the resolution of the pictures. Twenty minutes before impact the one-minute camera system warm-up began. The first image was taken at 13:49:41 at an altitude of 2363 km. Transmission of 5,814 good contrast photographs was made during the final 19 minutes of flight. The final image taken before impact has a resolution of 0.3 meters. The spacecraft encountered the lunar surface with an incoming asymptotic direction at an angle of -5.6 degrees from the lunar equator. The orbit plane was inclined 15.6 degrees to the lunar equator. After 64.5 hours of flight, impact occurred at 14:08:19.994 GMT at approximately 12.83 S latitude, 357.63 E longitude in the crater Alphonsus. Impact velocity was 2.67 km/s. Millions of Americans followed the spacecraft's descent via real time television coverage provided to the three networks of many of the F-channel images (primarily camera B but also some camera A pictures) were provided for this flight.
The pictures showed the rim and floor of the crater in fine detail: in those just prior to impact, objects less than a foot in size were discernible.
A panel of scientists presented some preliminary conclusions from Ranger IX at a press conference that same afternoon. Crater rims and ridges inside the walls, they believed, were harder and smoother than the moon's dusty plains, and therefore were considered likely sites for future manned landings. Generally, the panel was dubious about landing on crater floors however. Apparently, the floors were solidified volcanic material incapable of supporting a spacecraft. Investigators believed several types of craters were seen that were of nonmeteoric origin. These findings reinforced arguments that the moon at one time had experienced volcanic activity. Later the images were shown to the press as a continuous-motion movie, leading astronaut Wally Schirra to yell �bail out you fool!� just before the final frame.
The upper stages fell apart on re-entry into the atmosphere..
Soft lunar landing attempt. The retrorocket system failed, and the spacecraft impacted the lunar surface at the Sea of Clouds. Western observers, among them England's Sir Bernard Lovell, correctly speculated that the craft's mission was a soft landing.
Attempted unmanned lunar soft lander. Tass reported that all onboard equipment was functioning normally. Two days into the flight, however, the spacecraft's engine failed to shut down following a midcourse correction. This failure caused Luna 6 to miss its target by 159,612.8 Km.
Surveyor model launched dummy Surveyor payload into a barycentric / translunar orbit.
The launch was delayed due to malfunction of the RKS system of the Stages 1/2's control system during pre-launch service.
Lunar soft landing attempt. The Luna 7 spacecraft was intended to achieve a soft landing on the Moon. However, due to premature retrofire and cutoff of the retrorockets, the spacecraft impacted the lunar surface in the Sea of Storms.
Lunar soft landing attempt failed. Luna 8's objectives were to test a soft lunar landing system and scientific research. Weighing 1,552 kg (3,422 lbs), the spacecraft was following a trajectory close to the calculated one and the equipment was functioning normally. However, the retrofire was late, and the spacecraft impacted the lunar surface in the Sea of Storms. Tass reported that "the systems were functioning normally at all stages of the landing except the final touchdown." The mission did complete the experimental development of the star-orientation system and ground control of radio equipment, flight trajectory, and other instrumentation.
Soft landed on Moon; photographed surface for 3 days. Landed on Moon 3 February 1966 at 18:44:52 GMT, Latitude 7.08 N, Longitude 295.63 E - Oceanus Procellarum. The Luna 9 spacecraft was the first spacecraft to achieve a lunar soft landing and to transmit photographic data to Earth. Seven radio sessions, totaling 8 hours and 5 minutes, were transmitted as were three series of TV pictures. When assembled, the photographs provided a panoramic view of the nearby lunar surface. The pictures included views of nearby rocks and of the horizon 1.4 Km away from the spacecraft.
Lunar Orbit (Selenocentric). Development of system to permit the creation of an artificial lunar satellite for the investigation of circumlunar space; development of onboard systems for putting a station into a selenocentric (circumlunar) orbit. Orbit: Lunar Orbiter. The Luna 10 spacecraft was launched towards the Moon from an Earth orbiting platform. The spacecraft entered lunar orbit 3 50 x 1017 km, inclination 71.9 deg to plane of the lunar equator. on April 4, 1966. Scientific instruments included a gamma-ray spectrometer for energies between 0.3--3 MeV, a triaxial magnetometer, a meteorite detector, instruments for solar-plasma studies, and devices for measuring infrared emissions from the Moon and radiation conditions of the lunar environment. Gravitational studies were also conducted. The spacecraft played back to Earth the `Internationale' during the Twenty-third Congress of the Communist Party of the Soviet Union. Luna 10 was battery powered and operated for 460 lunar orbits and 219 active data transmissions before radio signals were discontinued on May 30, 1966.
Launch vehicle test. Payload was dummy Surveyor spacecraft.
Surveyor 1 soft landed on the moon in the Ocean of Storms and began transmitting the first of more than 11,150 clear, detailed television pictures to Jet Propulsion Laboratory's Deep Space Facility, Goldstone, Calif. The landing sequence began 3,200 kilometers above the moon with the spacecraft traveling at a speed of 9,700 kilometers per hour. The spacecraft was successfully slowed to 5.6 kilometers per hour by the time it reached 4-meter altitude and then free-fell to the surface at 13 kilometers per hour. The landing was so precise that the three footpads touched the surface within 19 milliseconds of each other, and it confirmed that the lunar surface could support the LM. It was the first U.S. attempt to soft land on the moon.
Lunar Orbiter I was launched from Cape Kennedy Launch Complex 13 at 3:26 p.m. EDT August 10 to photograph possible Apollo landing sites from lunar orbit. The Atlas-Agena D launch vehicle injected the spacecraft into its planned 90-hour trajectory to the moon. A midcourse correction maneuver was made at 8 p.m. the next day; a planned second midcourse maneuver was not necessary. A faultless deboost maneuver on August 14 achieved the desired initial elliptic orbit around the moon, and one week later the spacecraft was commanded to make a transfer maneuver to place it in a final close-in elliptic orbit of the moon.
During the spacecraft's stay in the final close-in orbit, the gravitational fields of the earth and the moon were expected to influence the orbital elements. The influence was verified by spacecraft tracking data, which showed that the perilune altitude varied with time. From an initial perilune altitude of 58 kilometers, the perilune decreased to 49 kilometers. At this time an orbit adjustment maneuver began an increase in the altitude, which was expected to reach a maximum after three months and then begin to decrease again. The spacecraft was expected to impact on the lunar surface about six months after the orbit adjustment.
During the photo-acquisition phase of the flight, August 18 to 29, Lunar Orbiter I photographed the 9 selected primary potential Apollo landing sites, including the one in which Surveyor I landed; 7 other potential Apollo landing sites; the east limb of the moon; and 11 areas on the far side of the moon. Lunar Orbiter I also took photos of the earth, giving man the first view of the earth from the vicinity of the moon (this particular view has been widely publicized). A total of 207 frames (sets of medium- and high-resolution pictures) were taken, 38 while the spacecraft was in initial orbit, the remainder while it was in the final close-in orbit. Lunar Orbiter I achieved its mission objectives, and, with the exception of the high-resolution camera, the performance of the photo subsystem and other spacecraft subsystems was outstanding. At the completion of the photo readouts, the spacecraft had responded to about 5,000 discrete commands from the earth and had made about 700 maneuvers.
Photographs obtained during the mission were assessed and screened by representatives of the Lunar Orbiter Project Office, U.S. Geological Survey, DOD mapping agencies, MSC, and Jet Propulsion Laboratory. The spacecraft was deliberately crashed into moon after the mission was completed.
Automatic station Luna 11. Further development of artificial lunar satellite systems and conduct of scientific experiments in circumlunar space. Lunar orbit 160 km x 1200 km x 27 degrees. Luna 11 was launched towards the Moon from an earth-orbiting platform and entered lunar orbit on August 28, 1966. The objectives of the mission included the study of: (1) lunar gamma- and X-ray emissions in order to determine the Moon's chemical composition; (2) lunar gravitational anomalies; (3) the concentration of meteorite streams near the Moon; and, (4) the intensity of hard corpuscular radiation near the Moon. A total of 137 radio transmissions and 277 orbits of the Moon were completed before the batteries failed on October 1, 1966.
Soft lunar landing attempt failed. Surveyor II was launched from Cape Kennedy at 8:32 a.m. EDT. The Atlas-Centaur launch vehicle placed the spacecraft on a nearly perfect lunar intercept trajectory that would have missed the aim point by about 130 kilometers. Following injection, the spacecraft successfully accomplished all required sequences up to the midcourse thrust phase. This phase was not successful because of the failure of one of the three vernier engines to ignite, causing eventual loss of the mission. Contact with the spacecraft was lost at 5:35 a.m. EDT, September 22, and impact on the lunar surface was predicted at 11:18 p.m. on that day.
Lunar Orbiter, further development of artificial lunar satellite systems and conduct of scientific experiments in circumlunar space. Luna 12 was launched towards the Moon from an earth-orbiting platform and achieved a lunar orbit of of 100 km x 1740 km on October 25, 1966. The spacecraft was equipped with a television system that obtained and transmitted photographs of the lunar surface. The photographs contained 1100 scan lines with a maximum resolution of 14.9--19.8 m. Pictures of the lunar surface were returned on October 27, 1966. The number of photographs is not known. Radio transmissions from Luna 12 ceased on January 19, 1967, after 602 lunar orbits and 302 radio transmissions.
Launch vehicle test. Launch vehicle put Surveyor spacecraft payload into geosynchronous transfer orbit
Lunar Orbiter II was launched at 6:21 p.m. EST from Launch Complex 13 at Cape Kennedy, to photograph possible landing sites on the moon for the Apollo program. The Atlas-Agena D booster placed the spacecraft in an earth-parking orbit and, after a 14-minute coast, injected it into its 94-hour trajectory toward the moon. A midcourse correction maneuver on November 8 increased the velocity from 3,051 to 3,133 kilometers per hour. At that time the spacecraft was 265,485 kilometers from the earth.
The spacecraft executed a deboost maneuver at 3:26 p.m., November 10, while 352,370 kilometers from the earth and 1,260 kilometers from the moon and traveling at a speed of 5,028 kilometers per hour. The maneuver permitted the lunar gravitational field to pull the spacecraft into the planned initial orbit around the moon. On November 15, a micrometeoroid hit was detected by one of the 20 thin-walled pressurized sensors.
The spacecraft was transferred into its final close-in orbit around the moon at 5:58 p.m. November 15 and the photo-acquisition phase of Lunar Orbiter II's mission began November 18. Thirteen selected primary potential landing sites and a number of secondary sites were to be photographed. By the morning of November 25, the spacecraft had taken 208 of the 211 photographs planned and pictures of all 13 selected potential landing sites. It also made 205 attitude change maneuvers and responded to 2,421 commands.
The status report of the Lunar Orbiter II mission as of November 28 indicated that the first phase of the photographic mission was completed when the final photo was taken on the afternoon of November 25. On November 26, the developing web was cut with a hot wire in response to a command from the earth. Failure to achieve the cut would have prevented the final readout of all 211 photos. Readout began immediately after the cut was made. One day early, December 6, the readout terminated when a transmitter failed, and three medium-resolution and two high-resolution photos of primary site 1 were lost. Full low-resolution coverage of the site had been provided, however, and other data continued to be transmitted. Three meteoroid hits had been detected.
Soft landed on Moon 24 December 1966 at 18:01:00 GMT, Latitude 18.87 N, 297.95 E - Oceanus Procellarum. The petal encasement of the spacecraft was opened, antennas were erected, and radio transmissions to Earth began four minutes after the landing. On December 25 and 26, 1966, the spacecraft television system transmitted panoramas of the nearby lunar landscape at different sun angles. Each panorama required approximately 100 minutes to transmit. The spacecraft was equipped with a mechanical soil-measuring penetrometer, a dynamograph, and a radiation densitometer for obtaining data on the mechanical and physical properties and the cosmic-ray reflectivity of the lunar surface. It is believed that transmissions from the spacecraft ceased before the end of December 1966.
Crashed into Moon; returned 182 photos of lunar surface. Selenocentric orbit. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).
Soft landed on Moon; perrformed soil sample tests and imaged lunar surface.
Returned 163 photos of lunar surface before impacting Moon. Selenocentric orbit. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).
The E-6LS was a radio-equipped version of the E-6 used to test tracking and communications networks for the Soviet manned lunar program. The payload entered the desired orbit as Kosmos-159.
Soft lunar landing attempt failed.
Lunar Orbiter V was launched from the Eastern Test Range at 6:33 p.m. EDT August 1. The Deep Space Net Tracking Station at Woomera, Australia, acquired the spacecraft about 50 minutes after liftoff. Signals indicated that all systems were performing normally and that temperatures were within acceptable limits. At 12:48 p.m. EDT August 5, Lunar Orbiter V executed a deboost maneuver that placed it in orbit around the moon. The spacecraft took its first photograph of the moon at 7:22 a.m. EDT August 6. Before it landed on the lunar surface on January 31, 1968, Lunar Orbiter V had photographed 23 previously unphotographed areas of the moon's far side, the first photo of the full earth, 36 sites of scientific interest, and 5 Apollo sites for a total of 425 photos.
Soft lunar landing; returned 19,000 photos, soil data.
Soft landed on lunar Moon; photographed lunar surface; sampled lunar soil; used propulsion system to briefly lift off of lunar surface.
Soft landed on lunar Moon; photographed lunar surface; sampled lunar soil.
Failed launch of an E-6LS radio-equipped version of the E-6 used to test tracking and communications networks for the Soviet manned lunar program. Suggestions for the abnormal consumption included the seizing up of a pintle valve for controlling fuel supply into the regulator or the seizing up of the fuel inlet control. The upper stages broke up in the atmosphere.
Lunar Orbiter; studied lunar gravitational field, Earth-Moon gravitational relationship, and conducted further scientific experiments in circumlunar space. Not revealed until years later was that the E-6LS was primarily intended to test tracking and communications networks for the Soviet manned lunar program. The Luna 14 spacecraft entered a 140 x 870 km x 42 degree lunar orbit on April 10, 1966. The spacecraft instrumentation was similar to that of Luna 10 and provided data for studies of the interaction of the earth and lunar masses, the lunar gravitational field, the propagation and stability of radio communications to the spacecraft at different orbital positions, solar charged particles and cosmic rays, and the motion of the Moon. This flight was the final flight of the second generation of the Luna series.
Unmanned soil return mission launched coincident with Apollo 11 mission in last ditch attempt to return lunar soil to earth before United States. After completing 86 communications sessions and 52 orbits of the Moon at various inclinations and altitudes, crashed on the moon on 20 July in an attempted landing. Altitude data used in programming inaccurate or guidance system unable to cope with effect of lunar mascons.
Officially: Testing of on-board systems of the automatic station and further scientific investigation of the moon and circumlunar space. Parameters are for lunar orbit.
Robotic lunar soil return mission. Failed to leave low earth orbit due to Block D stage failure.
Robotic lunar soil return mission. Failed to leave low earth orbit due to Block D stage failure.
Robotic lunar soil return mission. Launch vehicle failure.
Lunar Sample Return. Landed on Moon 20 September 1970 at 05:18:00 GMT, Latitude 0.68 S, Longitude 56.30 E - Mare Fecunditatis. Luna 16 was launched toward the Moon from a preliminary earth orbit and entered a lunar orbit on September 17, 1970. On September 20, the spacecraft soft landed on the lunar surface as planned. The spacecraft was equipped with an extendable arm with a drilling rig for the collection of a lunar soil sample. After 26 hours and 25 minutes on the lunar surface, the ascent stage, with a hermetically sealed soil sample container, left the lunar surface carrying 100 grams of collected material. It landed in the Soviet Union on September 24, 1970. The lower stage of Luna 16 remained on the lunar surface and continued transmission of lunar temperature and radiation data. Parameters are for lunar orbit.
Luna 17 was launched from an earth parking orbit towards the Moon and entered lunar orbit on November 15, 1970. Luna 17 landed on Moon 17 November 1970 at 03:47:00 GMT, Latitude 38.28 N, Longitude 325.00 E - Mare Imbrium (Sea of Rains). The payload, the Lunokhod 1 unmanned rover, rolled down a ramp from the landing stage and began exploring the surface. Lunokhod was intended to operate through three lunar days but actually operated for eleven lunar days (earth months). The operations of Lunokhod officially ceased on October 4, 1971, the anniversary of Sputnik 1. By then it had traveled 10,540 m and had transmitted more than 20,000 TV pictures and more than 200 TV panoramas. It had also conducted more than 500 lunar soil tests. Parameters are for lunar orbit.
Released from Apollo 15 into lunar orbit on 4 August 1971; studied lunar particles and included fields experiments.
Attempted lunar soil return mission; crashed while attempting to soft land at Latitude 3.57 N, Longitude 50.50 E - Mare Fecunditatis. Luna 18 used a new method of navigation in lunar orbit and for landing. The spacecraft's designer, Babakhin, had died at age 56 only the month before. Luna 18 successfully reached earth parking orbit before being put on a translunar trajectory. On September 7, 1971, it entered lunar orbit. The spacecraft completed 85 communications sessions and 54 lunar orbits before it was sent towards the lunar surface by use of braking rockets. It impacted the Moon on September 11, 1971, in a rugged mountainous terrain. Signals ceased at the moment of impact. Parameters are for lunar orbit.
Heavy lunar Orbiter; conducted lunar surface mapping. Luna 19 entered an intermediate earth parking orbit and was then put on a translunar trajectory by the Proton Block D stage. It entered lunar orbit on October 3, 1971. Luna 19 extended the systematic study of lunar gravitational fields and location of mascons (mass concentrations). It also studied the lunar radiation environment, the gamma-active lunar surface, and the solar wind. Photographic coverage via a television system was also obtained. Parameters are for lunar orbit.
Soft landed on Moon; returned soil samples to Earth. Landed on Moon 21 February 1972 at 19:19:00 GMT, Latitude 3.57 N, Longitude 56.50 E - Mare Fecunditatis. Luna 20 was placed in an intermediate earth parking orbit and from this orbit was sent towards the Moon. It entered lunar orbit on February 18, 1972. On 21 February 1972, Luna 20 soft landed on the Moon in a mountainous area known as the Apollonius highlands, 120 km from where Luna 18 had crashed. While on the lunar surface, the panoramic television system was operated. Lunar samples were obtained by means of an extendable drilling apparatus. The ascent stage of Luna 20 was launched from the lunar surface on 22 February 1972 carrying 30 grams of collected lunar samples in a sealed capsule. It landed in the Soviet Union on 25 February 1972. The lunar samples were recovered the following day.
Released from Apollo 16 into lunar orbit on 24 April 1972; fields and particles data; impacted lunar surface.
The Proton / Block D launcher put the spacecraft into Earth parking orbit followed by translunar injection. On 12 January 1973, Luna 21 braked into a 90 x 100 km orbit about the Moon. On 13 and 14 January, the perilune was lowered to 16 km altitude. On 15 January after 40 orbits, the braking rocket was fired at 16 km altitude, and the craft went into free fall. At an altitude of 750 meters the main thrusters began firing, slowing the fall until a height of 22 meters was reached. At this point the main thrusters shut down and the secondary thrusters ignited, slowing the fall until the lander was 1.5 meters above the surface, where the engine was cut off. Landing occurred at 23:35 GMT in LeMonnier crater at 25.85 degrees N, 30.45 degrees E. The lander carried a bas relief of Lenin and the Soviet coat-of-arms. After landing, Lunokhod 2 took TV images of the surrounding area, then rolled down a ramp to the surface at 01:14 GMT on 16 January and took pictures of the Luna 21 lander and landing site. It stopped and charged batteries until 18 January, took more images of the lander and landing site, and then set out over the Moon. The rover would run during the lunar day, stopping occasionally to recharge its batteries via the solar panels. At night the rover would hibernate until the next sunrise, heated by the radioactive source. Lunokhod 2 operated for about 4 months, covered 37 km of terrain including hilly upland areas and rilles, and sent back 86 panoramic images and over 80,000 TV pictures. Many mechanical tests of the surface, laser ranging measurements, and other experiments were completed during this time. On June 4 it was announced that the program was completed, leading to speculation that the vehicle probably failed in mid-May or could not be revived after the lunar night of May-June. The Lunokhod was not left in a position such that the laser retroreflector could be used, indicating that the failure may have happened suddenly.
Heavy lunar orbiter. Scientific investigation of the moon and circumlunar space from the orbit of an artificial satellite of the Moon, which was begun by the Luna 19 automatic station. The spacecraft carried imaging cameras and also had the objectives of studying the Moon's magnetic field, surface gamma ray emissions and composition of lunar surface rocks, and the gravitational field, as well as micrometeoroids and cosmic rays. Luna 22 braked into a circular lunar orbit on 2 June 1974. The spacecraft made many orbit adjustments over its 18 month lifetime in order to optimise the operation of various experiments, lowering the perilune to as low as 25 km. Manoeuvring fuel was exhausted on 2 September and the mission was ended in early November. Parameters are for lunar orbit.
Failed lunar soil return mission. After successfully entering earth orbit, flying to the moon, entering lunar orbit, and descending toward the surface, the spacecraft was damaged during landing in Mare Crisium (Sea of Crises). The sample collecting apparatus could not operate and no samples were returned. The lander continued transmissions for three days after landing. In 1976, Luna 24 landed several hundred meters away and successfully returned samples. Parameters are for lunar orbit.
Attempted robotic lunar soil return mission. Block D stage failed.
MUSES-A was renamed Hiten after launch. It developed of lunar swingby techniques for future missions and ejected a lunar orbiter. Launching organization ISAS. On 1990 Jan 25: Period 6.665 days, inclination 30.63 deg, 262.49 x 286182.72 km. On 1992 Feb 17: Period 4.53 days, inclination 38.90 deg, perilune 2289.67 km, apolune 49013.93 km.
SDIO sensor technology demonstration; mapped lunar surface; planned asteroid flyby cancelled due to spacecraft failure. After two Earth flybys, lunar insertion was achieved on February 21. Lunar mapping took place over approximately two months, in two parts. The first part consisted of a 5 hour elliptical polar orbit with a perilune of about 400 km at 28 degrees S latitude. After one month of mapping the orbit was rotated to a perilune of 29 degrees N latitude, where it remained for one more month. This allowed global imaging as well as altimetry coverage from 60 degrees S to 60 degrees N. After leaving lunar orbit, a malfunction in one of the on-board computers on May 7 at 14:39 UTC (9:39 AM EST) caused a thruster to fire until it had used up all of its fuel, leaving the spacecraft spinning at about 80 RPM with no spin control. This made the planned continuation of the mission, a flyby of the near-Earth asteroid Geographos, impossible. The spacecraft remained in geocentric orbit and continued testing the spacecraft components until the end of mission.
Clementine was a joint project between the Strategic Defense Initiative Organization and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon and the near-Earth asteroid 1620 Geographos. The observations included imaging at various wavelengths including ultraviolet and infrared, laser ranging altimetry, and charged particle measurements. These observations were originally for the purposes of assessing the surface mineralogy of the Moon and Geographos, obtaining lunar altimetry from 60N to 60S latitude, and determining the size, shape, rotational characteristics, surface properties, and cratering statistics of Geographos.
The Lunar Prospector was designed for a low polar orbit investigation of the Moon, including mapping of surface composition and possible polar ice deposits, measurements of magnetic and gravity fields, and study of lunar outgassing events. Data from the 1 to 3 year mission will allow construction of a detailed map of the surface composition of the Moon, and will improve understanding of the origin, evolution, current state, and resources of the Moon. After launch, the Lunar Prospector had a 105 hour cruise to the Moon, followed by insertion into a near-circular 100 km altitude lunar polar orbit with a period of 118 minutes. The nominal mission duration was one year. A two year extended mission following this was possible, during which the orbit was to be lowered to 50 km and then 10 km altitude to obtain higher resolution measurements.
This was the Soviet Union's first attempt at a planetary probe. Mars probe intended to photograph Mars on a flyby trajectory. The possible cause lay in resonance vibrations of upper stages during Stage 2 burning, which led to break of contact in the command potentiometer of the gyrohorizon. As a result a pitch control malfunctioned and the launcher began to veer off the desired ascent profile. On exceeding 7 degrees of veering in pitch, the control system failed. The upper stage with the payload reached an altitude of 120 km before burning up on re-entry into the atmosphere above East Siberia.
Mars probe intended to photograph Mars on a flyby trajectory. This was the Soviet Union's second attempt at a planetary probe. The upper stages and payload broke up on re-entry into the atmosphere.
Mars probe intended to photograph Mars on a flyby trajectory. The spacecraft broke into many pieces, some of which apparently remained in Earth orbit for a few days. This occurred during the Cuban missile crisis and was picked up by U.S. military radar installations, who originally feared it might by the start of a Soviet nuclear attack.
Mars probe intended to photograph Mars on a flyby trajectory. Sixty-one radio transmissions were held in which a large amount of data was collected. On March 21, 1963, when the spacecraft was at a distance of 106 million km communications ceased, possibly due to a malfunction in the spacecraft orientation system. Mars 1 closest approach to Mars occurred on June 19, 1963 at a distance of approximately 193,000 km, after which the spacecraft entered a heliocentric orbit. Announced mission: Prolonged exploration of outer space during flight to the planet Mars; establishment of inter-planetary radio communications; photgraphing of the planet Mars and subsquent radio-transmission to Earth of the photographs of the surface of Mars thus obtained.
Mars probe; launch fairing failure prevented Mars flyby. Solar Orbit (Heliocentric). Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).
Mariner 4 provided the first up close pictures of Mars. The protective shroud covering Mariner 4 was jettisoned and the Agena D/Mariner 4 combination separated from the Atlas D booster at 14:27:23 GMT on 28 November 1964. The Agena D first burn from 14:28:14 to 14:30:38 put the spacecraft into an Earth parking orbit and the second burn from 15:02:53 to 15:04:28 injected the craft into a Mars transfer orbit. Mariner 4 separated from the Agena D at 15:07:09 and began cruise mode operations. The solar panels deployed and the scan platform was unlatched at 15:15:00 and Sun acquisition occurred 16 minutes later. A midcourse maneuver made on 5 December 1964.
After a 228 day cruise, the spacecraft flew by Mars on July 14 and 15, 1965. Planetary science mode was turned on at 15:41:49 GMT on 14 July. The camera sequence started at 00:18:36 GMT on July 15 and 21 pictures plus 21 lines of a 22nd picture were taken. The images covered a discontinuous swath of Mars starting near 40 N, 170 E, down to about 35 S, 200 E, and then across to the terminator at 50 S, 255 E, representing about 1% of the planet's surface. The closest approach was 9,846 km from the Martian surface at 01:00:57 GMT 15 July 1965. The images taken during the flyby were stored in the onboard tape recorder. At 02:19:11 GMT Mariner 4 passed behind Mars as seen from Earth and the radio signal ceased. The signal was reacquired at 03:13:04 GMT when the spacecraft reappeared. Cruise mode was then re-established. Transmission of the taped images to Earth began about 8.5 hours after signal reacquisition and continued until 3 August. All images were transmitted twice to insure no data was missing or corrupt.
The spacecraft performed all programmed activities successfully and returned useful data from launch until 22:05:07 GMT on 1 October 1965, when the distance from Earth (309.2 million km) and the antenna orientation temporarily halted signal acquisition. In 1967 Mariner 4 returned to the vicinity of Earth again and engineers decided to use the ageing craft for a series of operational and telemetry tests to improve their knowledge of the technologies that would be needed for future interplanetary spacecraft. The cosmic dust detector registered 17 hits in a 15 minute span on 15 September, part of an apparent micrometeoroid shower which temporarily changed the spacecraft attitude and probably slightly damaged the thermal shield. On 7 December the gas supply in the attitude control system was exhausted, and on December 10 and 11 a total of 83 micrometeoroid hits were recorded which caused perturbation of the attitude and degradation of the signal strength. On 21 December 1967 communications with Mariner 4 were terminated.
Results
The total data returned by the mission was 5.2 million bits. All experiments operated successfully with the exception of the ionization chamber/Geiger counter which failed in February, 1965 and the plasma probe, which had its performance degraded by a resistor failure on 6 December 1964. The images returned showed a Moon-like cratered terrain (which later missions showed was not typical for Mars, but only for the more ancient region imaged by Mariner 4). A surface atmospheric pressure of 4.1 to 7.0 mb was estimated and no magnetic field was detected.
Mars probe intended to photograph Mars on a flyby trajectory. Zond 2 was launched from an earth parking orbit towards Mars to test space-borne systems and to carry out scientific investigations. Zond 2 carried six electric rocket engines of plasma type that served as actuators of the attitude control system. The communications system failed during April 1965. The spacecraft flew by Mars on August 6, 1965, at a distance of 1500 km.
Zond 3 was towards the moon and interplanetary space. The spacecraft was equipped with a TV system that provided automatic inflight film processing. On July 20, during lunar flyby, 25 pictures of very good quality were taken of the lunar farside from distances of 11,570 to 9960 km. The photos covered 19,000,000 km square of the lunar surface. Photo transmissions by facsimile were returned to earth from a distance of 2,200,000 km on July 29 and were retransmitted later from a distance of 31,500,000 km, thus proving the ability of the communications system. After the lunar flyby, Zond 3 continued space exploration in a heliocentric orbit. Those pictures showed clearly the heavily cratered nature of the surface. This mission dramatized the advances in space photography that the U.S.S.R. had made since its first far-side effort six years earlier.
Mars flyby 31 July 1969; returned 75 images of Martian surface. Ten days before the scheduled launch, a faulty switch opened the main valves on the Atlas stage. This released the pressure which supported the Atlas structure, and as the booster deflated it began to crumple. Two ground crewman started pressurizing pumps, saving the structure from further collapse. The two ground crewman, who had acted at risk of the 12-story rocket collapsing on them, were awarded Exceptional Bravery Medals from NASA.
The Mariner 6 spacecraft was removed, put on another Atlas/Centaur, and launched on schedule. The main booster was jettisoned 4 min. 38 sec. after launch, followed by a 7.5 minute Centaur burn to inject the spacecraft into Mars direct trajectory. After Mariner 6 separated from the Centaur the solar panels were deployed. A midcourse correction involving a 5.35 second burn of the hydrazine rocket occurred on 1 March 1969. A few days later explosive valves were deployed to unlatch the scan platform. Some bright particles released during the explosion distracted the Canopus sensor, and attitude lock was lost temporarily. It was decided to place the spacecraft on inertial guidance for the Mars flyby to prevent a similar occurrence.
On 29 July, 50 hours before closest approach, the scan platform was pointed to Mars and the scientific instruments turned on. Imaging of Mars began 2 hours later. For the next 41 hours, 49 approach images (plus a 50th fractional image) of Mars were taken through the narrow-angle camera. At 05:03 UT on 31 July the near-encounter phase began, including collection of 26 close-up images. Due to a cooling system failure, channel 1 of the IR spectrometer did not cool sufficiently to allow measurements from 6 to 14 micrometers so no infrared data were obtained over this range. Closest approach occurred at 05:19:07 UT at a distance of 3431 km from the martian surface. Eleven minutes later Mariner 6 passed behind Mars and reappeared after 25 minutes. X-band occultation data were taken during the entrance and exit phases. Science and imaging data were played back and transmitted over the next few days. The spacecraft was then returned to cruise mode which included engineering and communications tests, star photography TV tests, and UV scans of the Milky Way and an area containing comet 1969-B. Periodic tracking of the spacecraft in its heliocentric orbit was also done.
Science Results
Mariner 6 returned 49 far encounter and 26 near encounter images of Mars. Close-ups from the near encounter phases covered 20% of the surface. The spacecraft instruments measured UV and IR emissions and radio refractivity of the Martian atmosphere. Images showed the surface of Mars to be very different from that of the Moon, in some contrast to the results from Mariner 4. The south polar cap was identified as being composed predominantly of carbon dioxide. Atmospheric surface pressure was estimated at between 6 and 7 mb. Radio science refined estimates of the mass, radius and shape of Mars.
Mars probe intended to enter Martian orbit and comprehensively photograph Mars, together with a landing probe.
Mars probe intended to enter Martian orbit and comprehensively photograph Mars, together with a landing probe. Further Mars launches during the 1969 launch window were cancelled when this attempt resulted in a major accident, which almost wiped out all of the leaders of the space industry. The Proton rocket lifted off, but one engine failed. The vehicle flew at an altitude of 50 m horizontally, finally exploding only a few dozen metres from the launch pad, spraying the whole complex with poisonous propellants that were quickly spread by the wind. Everyone took off in their autos to escape, but which direction to go? Finally it was decided that the launch point was the safest, but this proved to be even more dangerous - the second stage was still intact and liable to explode. The contamination was so bad that there was no way to clean up - the only possibility was just had to wait for rain to wash it away. This didn't happen until the Mars launch window was closed, so the first such probe was not put into space until 1971.
Intended Mars flyby.
Mars probe intended to enter Martian orbit and comprehensively photograph Mars. Rocket block failed to reignite in Earth Orbit. It is widely believed this spacecraft was launched with the primary purpose of overtaking Mariner 8, which had been launched (unsuccessfully, as it turned out) two days earlier, and becoming the first Mars orbiter. The Proton booster successfully put the spacecraft into low (174 km x 159 km) Earth parking orbit with an inclination of 51.4 degrees, but the Block D stage 4 failed to function due to a bad ignition timer setting (the timer, which was supposed to start ignition 1.5 hours after orbit was erroneously set for 1.5 years.) The orbit decayed and the spacecraft re-entered Earth's atmosphere 2 days later on 12 May 1971. The mission was designated Cosmos 419.
Soft landed on Mars 11/27/71.
Soft landed on Mars 12/2/71.
The first spacecraft to orbit another planet. The Mariner Mars 71 mission was planned to consist of two spacecraft on complementary missions. Mariner 8 was to map 70 % of the Martian surface and Mariner 9 was to study temporal changes in the Martian atmosphere and on the Martian surface. The launch failure of Mariner 8 forced Mariner 9 to combine the mission objectives of both. For the survey portion of the mission, the planetary surface was to be mapped with the same resolution as planned for the original mission, although the resolution of pictures of the polar regions would be decreased due to the increased slant range. The variable features experiments were changed from studies of six given areas every 5 days to studies of smaller regions every 17 days. Mariner 9 was launched on a direct trajectory to Mars. Separation from the booster occurred at 22:36 GMT. The four solar panels were deployed at 22:40 GMT. The sensors locked onto the Sun at 23:16, shortly after the spacecraft left the Earth's shadow and Canopus acquisition was achieved at 02:26 GMT 31 May. A planned midcourse maneuver was executed on 5 June. Mariner 9 arrived at Mars on 14 November 1971 after a 167 day flight. A 15 minute 23 second rocket burn put the spacecraft into Mars orbit. The insertion orbit had a periapsis of 1398 km and a period of 12 hr, 34 min. Two days later a 6 second rocket burn changed the orbital period to just under 12 hours with a periapsis of 1387 km. A correction trim maneuver was made on 30 December on the 94th orbit which raised the periapsis to 1650 km and changed the orbital period to 11:59:28 so that synchronous data transmissions could be made to the Goldstone 64-m DSN antenna.
Imaging of the surface of Mars by Mariner 9 was delayed by a dust storm which started on 22 September 1971 in the Noachis region. The storm quickly grew into one of the largest global storms ever observed on Mars. By the time the spacecraft arrived at Mars no surface details could be seen except the summits of Olympus Mons and the three Tharsis volcanoes. The storm abated through November and December and normal mapping operations began. The spacecraft gathered data on the atmospheric composition, density, pressure, and temperature and also the surface composition, temperature, gravity, and topography of Mars. A total of 54 billion bits of scientific data were returned, including 7329 images covering the entire planet. After depleting its supply of attitude control gas, the spacecraft was turned off on 27 October 1972. Mariner 9 was left in an orbit which should not decay for at least 50 years, after which the spacecraft will enter the Martian atmosphere.
The Mariner 9 mission resulted in a global mapping of the surface of Mars, including the first detailed views of the martian volcanoes, Valles Marineris, the polar caps, and the satellites Phobos and Deimos. It also provided information on global dust storms, the gravity field as well as evidence for surface aeolian activity.
Failed; did not enter Martian orbit as planned; intended to be a Mars orbiter mission. Mars 4 reached Mars on 10 February 1974. Due to use of helium in preflight tests of the computer chips, which resulted in degradation of the chips during the voyage to Mars, the retro-rockets never fired to slow the craft into Mars orbit. Mars 4 flew by the planet at a range of 2,200 km. It returned one swath of pictures and some radio occultation data. Final heliocentric orbit 1.02 x 1.63 AU, 2.2 degree inclination, 556 day period.
Mars probe intended to enter Martian orbit and comprehensively photograph Mars. Parameters are for Mars orbit. Mars 5 reached Mars on 12 February 1974 and was inserted into a 1760 km x 32,586 km orbit. Due to computer chip failures the orbiter operated only a few days and returned atmospheric data and images of a small portion of the Martian southern hemisphere.
Soft landed on Mars 3/12/74.
Mars probe intended to make a soft landing on Mars. Mars 7 reached Mars on 9 March 1974. Due to a problem in the operation of one of the onboard systems (attitude control or retro-rockets) the landing probe separated prematurely and missed the planet by 1,300 km. The early separation was probably due to a computer chip error which resulted in degradation of the systems during the trip to Mars. Ended up in a final heliocentric orbit 1.01 x 1.69 AU, 2.2 degree inclination, 574 day period.
Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).
Combined Mars orbiter and lander mission; orbiter inserted in Mars orbit 8/7/76; lander soft landed on Martian surface 9/3/76Mars. Mars Orbit. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).
Second of two missions to Mars' moon Phobos; carried 2 landers; planned to enter Mars orbit. Phobos 1 operated nominally until an expected communications session on 2 September 1988 failed to occur. The failure of controllers to regain contact with the spacecraft was traced to an error in the software uploaded on 29/30 August which had deactivated the attitude thrusters. This resulted in a loss of lock on the Sun, resulting in the spacecraft orienting the solar arrays away from the Sun, thus depleting the batteries. Left in solar Orbit (Heliocentric).
First of two Mars missions to Mars' moon Phobos; carried two landers; entered Mars orbit 1/29/89; failed 3/27/89; extremely limited science data. Phobos 2 operated nominally throughout its cruise and Mars orbital insertion phases, gathering data on the Sun, interplanetary medium, Mars, and Phobos. Shortly before the final phase of the mission, during which the spacecraft was to approach within 50 m of Phobos' surface and release two landers, one a mobile 'hopper', the other a stationary platform, contact with Phobos 2 was lost. The mission ended when the spacecraft signal failed to be successfully reacquired on 27 March 1989. The cause of the failure was determined to be a malfunction of the on-board computer.
Planned Mars orbiter; lost contact during orbit insertion burn. Solar Orbit (Heliocentric). Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).
En route Mars
The Mars 96 spacecraft was launched into Earth orbit, but failed to achieve insertion into Mars cruise trajectory and re-entered the Earth's atmosphere at about 00:45 to 01:30 GMT on 17 November 1996 and crashed within a presumed 320 km by 80 km area which includes parts of the Pacific Ocean, Chile, and Bolivia. The Russian Mars 96 mission was designed to send an orbiter, two small autonomous stations, and two surface penetrators to Mars.
En route Mars
Originally known as Planet-B; renamed Nozomi ('Hope') after launch. The third stage and payload entered a 146 x 417 km x 31.1 deg parking orbit. The KM-V1 kick (fourth) stage then fired to place the spacecraft into a circumlunar 359 x 401491 km x 28.6 deg orbit. Nozomi made multiple lunar and Earth gravity assist passes to increase its energy for solar orbit insertion and the cruise to Mars.. The spacecraft used a lunar swingby on 24 September and another on 18 December 1998 to increase the apogee of its orbit. It swung by Earth on 20 December at a perigee of about 1000 km. The gravitational assist from the swingby coupled with a 7 minute burn of the bipropellant engine put Nozomi into an escape trajectory towards Mars. It was scheduled to arrive at Mars on 11 October 1999 at 7:45:14 UT, but the Earth swingby left the spacecraft with insufficient acceleration and two course correction burns on 21 December used more propellant than planned, leaving the spacecraft short of fuel. The new plan is for Nozomi to remain in heliocentric orbit for an additional four years and encounter Mars at a slower relative velocity in December 2003.
The Mars Climate Orbiter was the second flight of the Mars Surveyor Program. The probe was to enter a 160 km x 38600 km polar orbit around Mars on September 23,1999, and use aerobraking to reach a 373 km x 437 km x 92.9 degree sun-synchronous mapping orbit by November 23 1999. While the Mars Orbit Insertion burn began as planned on September 23, 1999 at 08:50 GMT, no signal was received after the spacecraft went behind the planet. Subsequent investigation showed that the spacecraft had plunged deep into the Martian atmosphere, with its closest approach to Mars being 57 km. It was concluded that the spacecraft burnt up in the atmosphere. It was later found that cutbacks in tracking, combined with incorrect values in a look-up table imbedded deep in the spacecraft software (use of pounds force instead of newtons) were to blame. This failure led to a shake-up of NASA's 'faster, better, cheaper' approach to unmanned spaceflight.
Launch had been as planned, with the Delta upper stage entered an initial 185 km x 198 km x 28.4 degree parking orbit. A second burn raised apogee to around 900 km. Then the Thiokol Star 48 third stage motor accelerated the spacecraft to a trans-Mars trajectory. The Delta stage was left in a 162 km x 857 km x 23.9 degree Earth orbit. Primary on-board propulsion for the orbit insertion manoeuvre at Mars was a 65 kgf Leros bi-propellant engine. Mars Climate Orbiter was equipped with a MARCI colour imager for mapping and weather studies; a PMIRR radiometer; and a UHF communications system which would also relay data from the (equally unsuccessful) Mars Polar Lander, scheduled for launch in January 1999. The science mission was to map the Martian surface at high resolution, and study the distribution of water vapour and ozone. It would study the transport of dust and water with latitude, the motions of weather systems and dust storms, and study the response to daily solar heating.
Mariner 10 was the first spacecraft to reach Mercury. Mariner 10 was placed in a parking orbit for 25 minutes after launch, then accelerated to a trans-Venus escape trajectory. The television and ultraviolet experiments were trained on the comet Kohoutek while the spacecraft was en route to its destination. The vehicle's first planetary encounter was with Venus on February 5, 1974, at a distance of 4200 km. Mariner 10 took 4,000 photos of Venus, which revealed a nearly round planet enveloped in smooth cloud layers. The gravity of Venus bent the orbit of the spacecraft and sent it towards Mercury. It crossed the orbit of Mercury on March 29, 1974, at 20:46 GMT, at a distance of 704 km from the surface. Photographs taken during the pass revealed an intensely cratered, Moon-like surface and a faint atmosphere of mostly helium. After the first flyby, Mariner 10 entered solar orbit, which permitted two more rendezvous with Mercury. On September 21, 1974, the second Mercury rendezvous, at an altitude of about 47,000 km, provided another opportunity to photograph the sunlit side of the planet and the south polar region. The third and final Mercury encounter on March 16, 1975, at an altitude of 327 km, yielded 300 photographs and magnetic field measurements. The vehicle was turned off March 24, 1975 when the supply of attitude-control gas was depleted.
Jupiter flyby December 1973; first man-made object to leave solar system. The spacecraft achieved its closest approach to Jupiter on December 3, 1973, when it reached approximately 2.8 Jovian radii (about 200,000 km). As of Jan. 1, 1997 Pioneer 10 was at about 67 AU from the Sun near the ecliptic plane and heading outward from the Sun at 2.6 AU/year and downstream through the heliomagnetosphere towards the tail region and interstellar space.
This solar system escape direction is unique because the Voyager 1 and 2 spacecraft (and the now terminated Pioneer 11 spacecraft mission) are heading in the opposite direction towards the nose of the heliosphere in the upstream direction relative to the inflowing interstellar gas. The spacecraft is heading generally towards the red star Aldebaran, which forms the eye of Taurus (The Bull). The journey over a distance of 68 light years to Aldebaran will require about two millions years to complete. Routine tracking and project data processing operations were terminated on March 31, 1997 for budget reasons. Occasional tracking continues under support of the Lunar Prospector project at NASA Ames Research Center with retrieval of energetic particle and radio science data; this is expected to continue at least through mid-1998. Space experiments mostly continued to operate for planetary or interplanetary measurements until failure or until insufficient spacecraft power from the RTG's was available for operation of all instruments, such that some were turned off permanently and others were cycled on and off in accordance with a power sharing plan implemented in September 1989. The Asteroid/Meteroid Detector failed in December 1973, followed by the Helium Vector Magnetometer (HVM) in November 1975 and the Infrared Radiometer in January 1974. The Meteroid Detector was turned off in October 1980 due to inactive sensors at low temperatures. The spacecraft sun sensors became inoperative in May 1986, and the Imaging Photopolarimeter (IPP) instrument was used to obtain roll phase and spin period information until being turned off in October 1993 to conserve power. The Trapped Radiation Detector (TRD) and Plasma Analyzer (PA) were respectively turned off in November 1993 and September 1995 for the same reason. As of January 1996 the final power cycling plan included part-time operations of the Charged Particle Instrument (CPI), the Cosmic Ray Telescope (CRT), the Geiger Tube Telescope (GTT), and the Ultraviolet Photometer (UV). Power availability for operation of one or more instruments was expected to continue at least through 1998. Currently, the GTT and CPI instruments are still returning data during occasional tracking intervals; GTT operates nominally, returning data whenever tracking takes place (there is no onboard tape recorder), while CPI is cycled on for about four hours every two weeks. Three-way doppler data for radio science are also obtained during some tracking intervals.
Various other spacecraft subsystems also either failed or were turned off for power or other reasons, and an account of these may be of interest for engineering design of long duration deep space missions. The primary antenna feed offset bellows failed sometime in 1976 but a redundant unit was available for use thereafter. The Program Storage and Execution (PSE) subsystem was turned off in September 1989 for power conservation, after which spacecraft maneuvers were performed by ground command sequences. A receiver problem in mid-1992 prevented uplink to the high gain antenna, after which uplink commands could only be sent with 70-meter DSN antennas which also supported the 16 bps downlink. The Backup Line Heater experienced a sticking thermostat operation in March 1993 for 30 days but the problem did not reoccur. Undervoltage Protection Logic was turned off in December 1993 to prevent loss of critical spacecraft systems in the event of a transient undervoltage condition. Duration and Steering Logic (DSL) was turned off in February 1995 to conserve power, after which it was turned on again only for spacecraft maneuvers. As of March 2, 1998 two experiments (GTT, CPI) were still active. RTG power levels are low enough that the spacecraft occasionally relies in part on battery power (accumulated during inactive periods) to run the experiments and other systems.
Jupiter flyby December 1974; Saturn flyby September 1979. Solar system escape trajectory. Pioneer 11 was the second mission to investigate Jupiter and the outer solar system and the first to explore the planet Saturn and its main rings. Pioneer 11, like Pioneer 10, used Jupiter's gravitational field to alter its trajectory radically. It passed close to Saturn and then it followed an escape trajectory from the solar system. During its closest approach, December 4, 1974, Pioneer 11 passed to within 34,000 km of Jupiter's cloud tops. It passed by Saturn on September 1, 1979, at a distance of 21,000 km from Saturn's cloud tops. The spacecraft has operated on a backup transmitter since launch. Instrument power sharing began in February 1985 due to declining RTG power output. Science operations and daily telemetry ceased on September 30, 1995 when the RTG power level was insufficient to operate any experiments. As of the end of 1995 the spacecraft was located at 44.7 AU from the Sun at a nearly asymptotic latitude of 17.4 degrees above the solar equatorial plane and was heading outward at 2.5 AU/year. Routine tracking and project data processing operations were terminated on March 31, 1997 for budget reasons.
Jupiter flyby 7/9/79, Saturn flyby 8/26/81, Uranus flyby 1/24/86, Neptune flyby 8/25/89. Solar system escape trajectory. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).
Jupiter flyby 3/5/79, Saturn flyby 11/12/80. Solar system escape trajectory. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).
Atmospheric probe; deployed from Galileo 7/13/95; entered Jupiter atmosphere 12/7/95. Entry into Jupiter Dec 7
En route Venus
The escape stage entered parking orbit but the main engine cut off just 0.8 s after ignition due to cavitation in the oxidiser pump and pump failure.. The payload attached together with escape stage remained in Earth orbit.
Launched Venera 1 from low Earth orbit.
NASA announced that instrumented Venus probe to be launched next year would be launched by an Atlas-Agena B rather than a Centaur rocket as originally planned.
Venus probe.
The motor burnt for only 45s of the planned 240s. The stage remained in Earth orbit.
Mariner 2 was the first spacecraft to successfully flyby another planet. It was a backup for the Mariner 1 mission which failed shortly after launch to Venus. After launch and termination of the Agena first burn, the Agena-Mariner was in a 118 km altitude Earth parking orbit. The Agena second burn injected the Mariner 2 spacecraft into a geocentric escape hyperbola at 26 minutes 3 seconds after lift-off. Solar panel extension was completed about 44 minutes after launch. On 29 August 1962 cruise science experiments were turned on. A midcourse maneuver was initiated at 22:49:00 GMT on 4 September and completed at 2:45:25 GMT 5 September. On 8 September at 17:50 GMT the spacecraft suddenly lost its attitude control, which was restored by the gyroscopes 3 minutes later. The cause was unknown but may have been a collision with a small object. On October 31 the output from one solar panel deteriorated abruptly, and the science cruise instruments were turned off. A week later the panel resumed normal function and instruments were turned back on. The panel permanently failed on 15 November, but Mariner 2 was close enough to the Sun that one panel could supply adequate power. On December 14 the radiometers were turned on. Mariner 2 approached Venus from 30 degrees above the dark side of the planet, and passed below the planet at its closest distance of 34,773 km at 19:59:28 GMT 14 December 1962. After encounter, cruise mode resumed. Spacecraft perihelion occurred on 27 December at a distance of 105,464,560 km. The last transmission from Mariner 2 was received on 3 January 1963 at 07:00 GMT. Mariner 2 remains in heliocentric orbit. Scientific discoveries made by Mariner 2 included a slow retrograde rotation rate for Venus, hot surface temperatures and high surface pressures, a predominantly carbon dioxide atmosphere, continuous cloud cover with a top altitude of about 60 km, and no detectable magnetic field. It was also shown that in interplanetary space the solar wind streams continuously and the cosmic dust density is much lower than the near-Earth region. Improved estimates of Venus' mass and the value of the astronomical unit were made.
The escape stage entered parking orbit but the main engine cut off just 0.8 s after ignition due to cavitation in the oxidiser pump and pump failure.
Mars probe intended to make a soft landing on Mars. Although the escape stage and payload reached orbit, the strong third stage vibrations shook a fuse loose from its mount in the main nozzle of the escape stage Block L's engine. The engine could not be ignited and remained in Earth orbit. It decayed about two months after insertion.
The stage with payload remained in Earth orbit as Cosmos-51 and burnt up on re-entry.
The launch was delayed due to malfunctions during prelaunch service.
The stage with payload remained in Earth orbit as Cosmos-27.
Failed Venus probe. Solar Orbit (Heliocentric). Elaboration of a long range space system and conduct of scientific research.
Venera 2 was launched towards the planet Venus and carried a TV system and scientific instruments. On February 27, 1966, the spacecraft passed Venus at a distance of 24,000 km and entered a heliocentric orbit. The spacecraft system had ceased to operate before the planet was reached and returned no data.
Venera 3 was launched towards the planet Venus. The mission was to land on the Venusian surface. The entry vehicle contained a radio communication system, scientific instruments, electrical power sources, and medallions bearing the coat of arms of the U.S.S.R. The station impacted Venus on March 1, 1966. However, the communications systems had failed before planetary data could be returned.
The escape stage Block L entered parking orbit tumbling and was not able to operate properly.
The launch attempt was abandoned due to a launch vehicle malfunction during pre-launch preparations.
Venera 4 was successfully launched towards the planet Venus with the announced mission of direct atmospheric studies. On October 18, 1967, the descent vehicle entered the Venusian atmosphere. Signals were returned by the spacecraft, which deployed a parachute after braking to subsonic velocity in the Venusian atmosphere, until it reached an altitude of 24.96 km.
Mariner 5 flew by Venus on October 19, 1967 at an altitude of 3,990 kilometres. With more sensitive instruments than its predecessor Mariner 2, Mariner 5 was able to shed new light on the hot, cloud-covered planet and on conditions in interplanetary space. Operations of Mariner 5 ended in November 1967. The spacecraft instruments measured both interplanetary and Venusian magnetic fields, charged particles, and plasmas, as well as the radio refractivity and UV emissions of the Venusian atmosphere.
Suggestions for the cause of the failure included incorrect soldering of wires in multiple pin plugs, wrong attachments of the plugs to the pyrotechnic connectors, or a mix-up of the pyrotechnic connectors during assembly.. Investigation of the upper atmosphere and outer space.
Venera 5 was launched from a Tyazheliy Sputnik (69-001C) towards Venus to obtain atmospheric data. The spacecraft was very similar to Venera 4 although it was of a stronger design. When the atmosphere of Venus was approached, a capsule weighing 405 kg and containing scientific instruments was jettisoned from the main spacecraft. During satellite descent towards the surface of Venus, a parachute opened to slow the rate of descent. For 53 min on May 16, 1969, while the capsule was suspended from the parachute, data from the Venusian atmosphere were returned. The spacecraft also carried a medallion bearing the coat of arms of the U.S.S.R. and a bas-relief of V.I. Lenin to the night side of Venus.
Venera 6 was launched towards Venus to obtain atmospheric data. When the atmosphere of Venus was approached, a capsule weighing 405 kg was jettisoned from the main spacecraft. This capsule contained scientific instruments. During descent towards the surface of Venus, a parachute opened to slow the rate of descent. For 51 min on May 17, 1969, while the capsule was suspended from the parachute, data from the Venusian atmosphere were returned. The spacecraft also carried a medallion bearing the coat of arms of the U.S.S.R. and a bas-relief of V.I. Lenin to the night side of Venus.
Venera 7 was launched from an earth parking orbit towards Venus to study the Venusian atmosphere and other phenomena of the planet. Venera 7 entered the atmosphere of Venus on December 15, 1970, and a landing capsule was jettisoned. After aerodynamic braking, a parachute system was deployed. The capsule antenna was extended, and signals were returned for 35 min. Another 23 min of very weak signals were received after the spacecraft landed on Venus. The capsule was the first man-made object to return data after landing on another planet.
Probable Venus probe failure.
Venus atmospheric probe. The spacecraft took 117 days to reach Venus, entering the atmosphere on 22 July 1972. Descent speed was reduced from 41,696 km/hr to about 900 km/hr by aerobraking. The 2.5 meter diameter parachute opened at an altitude of 60 km, and a refrigeration system was used to cool the interior components. Venera 8 transmitted data during the descent and continued to send back data for 50 minutes after landing. The probe confirmed the earlier data on the high Venus surface temperature and pressure returned by Venera 7, and also measured the light level as being suitable for surface photography, finding it to be similar to the amount of light on Earth on an overcast day.
Combined Venus orbiter/lander mission. After separation of the lander, the orbiter spacecraft entered Venus orbit and acted as a communications relay for the lander and explored cloud layers and atmospheric parameters. On October 20, 1975, the Descent Craft was separated from the Orbiter, and landing was made with the sun near zenith at 05:13 GMT on October 22. The Descent Craft included a system of circulating fluid to distribute the heat load. This system, plus precooling prior to entry, permitted operation of the spacecraft for 53 min after landing. The landing was about 2,200 km from the Venera 10 landing site. Preliminary results indicated: (A) clouds 30-40 km thick with bases at 30-35 km altitude, (B) atmospheric constituents including HCl, HF, Br, and I, (C) surface pressure about 90 (earth) atmospheres, (D) surface temperature 485 deg C, (E) light levels comparable to those at earth midlatitudes on a cloudy summer day, and (F) successful TV photography showing shadows, no apparent dust in the air, and a variety of 30-40 cm rocks which were not eroded. Venera 9 and 10 were the first probes to send back black and white pictures from the Venusian surface. They were supposed to make 360 degree panoramic shots, but on both landers one of two camera covers failed to come off, restricting their field of view to 180 degrees. Parameters are for Venus orbit.
The orbiter spacecraft entered Venus orbit and was separated from the lander on October 23, 1975. The lander touched down with the sun near zenith, at 05:17 GMT, on October 25. A system of circulating fluid was used to distribute the heat load. This system, plus precooling prior to entry, permitted operation of the spacecraft for 65 min after landing. During descent, heat dissipation and deceleration were accomplished sequentially by protective hemispheric shells, three parachutes, a disk-shaped drag brake, and a compressible, metal, doughnut-shaped, landing cushion. The landing was about 2,200 km distant from Venera 9. Preliminary results provided: (A) profile of altitude (km)/pressure (earth atmospheres) / temperature (deg C) of 42/3.3/158, 15/37/363, and 0/92/465, (B) successful TV photography showing large pancake rocks with lava or other weathered rocks in between, and (C) surface wind speed of 3.5 m/s. Venera 9 and 10 were the first probes to send back black and white pictures from the Venusian surface. They were supposed to make 360 degree panoramic shots, but on both landers one of two camera covers failed to come off, restricting their field of view to 180 degrees.
The Pioneer Venus Orbiter was inserted into an elliptical orbit around Venus on December 4, 1978. After entering orbit around Venus in 1978, the spacecraft returned global maps of the planet's clouds, atmosphere and ionosphere, measurements of the atmosphere-solar wind interaction, and radar maps of 93 percent of the planet's surface. Additionally, the vehicle made use of several opportunities to make systematic UV observations of several comets. From Venus orbit insertion to July 1980, periapsis was held between 142 and 253 km (at 17 degrees north latitude) to facilitate radar and ionospheric measurements. The spacecraft was in a 24 hour orbit with an apoapsis of 66,900 km. Thereafter, the periapsis was allowed to rise (to 2290 km at maximum) and then fall, to conserve fuel. In 1991 the Radar Mapper was reactivated to investigate previously inaccessible southern portions of the planet. In May 1992 Pioneer Venus began the final phase of its mission, in which the periapsis was held between 150 and 250 km until the fuel ran out and atmospheric entry destroyed the spacecraft. With a planned primary mission duration of only eight months, the spacecraft remained in operation until October 8, 1992 when it finally burned up in Venus' atmosphere after running out of propellant.
Venera 13 and 14 were identical spacecraft built to take advantage of the 1981 Venus launch opportunity and launched 5 days apart. After launch and a four month cruise to Venus, the descent vehicle separated and plunged into the Venus atmosphere on 1 March 1982. As it flew by Venus the bus acted as a data relay for the brief life of the descent vehicle, and then continued on into a heliocentric orbit. After the descent vehicle braked to subsonic speed a parachute was deployed. At an altitude of 47 km the parachute was released and simple airbraking was used the rest of the way to the surface. Venera 13 landed about 950 km northeast of Venera 14 at 7 deg 30 min S, 303 E, just east of the eastern extension of an elevated region known as Phoebe Regio. The area was composed of bedrock outcrops surrounded by dark, fine-grained soil. After landing an imaging panorama was started and a mechanical drilling arm reached to the surface and obtained a sample, which was deposited in a hermetically sealed chamber, maintained at 30 degrees C and a pressure of about .05 atmospheres. The composition of the sample, as determined by the X-ray flourescence spectrometer, put it in the class of weakly differentiated melanocratic alkaline gabbroids. The lander survived for 127 minutes (the planned design life was 32 minutes) in an environment with a temperature of 457 degrees C and a pressure of 84 Earth atmospheres. The bus carried instruments built by Austrian and French specialists, as well as Soviet scientific equipment.
Venera 15 was part of a two spacecraft mission (along with Venera 16) designed to use side-looking radar mappers to study the surface properties of Venus. The two spacecraft were inserted into Venus orbit a day apart with their orbital planes shifted by an angle of approximately 4 degrees relative to one another. This made it possible to reimage an area if necessary. Each spacecraft was in a nearly polar orbit with a periapsis at 62 N latitude. Together, the two spacecraft imaged the area from the north pole down to about 30 degrees N latitude over the 8 months of mapping operations. Data is for Venus orbit.
Venus radar mapper; entered Venus orbit 10/14/83. Venera 16 was part of a two spacecraft mission (along with Venera 15) designed to use side-looking radar mappers to study the surface properties of Venus. The two spacecraft were inserted into Venus orbit a day apart with their orbital planes shifted by an angle of approximately 4 degrees relative to one another. This made it possible to reimage an area if necessary. Each spacecraft was in a nearly polar orbit with a periapsis at 62 N latitude. Together, the two spacecraft imaged the area from the north pole down to about 30 degrees N latitude over the 8 months of mapping operations.
Investigations of the planet Venus and Halley's Comet. The APV-V plasma antenna did not deploy until the first mid-course correction burn. Deployed lander and balloon at Venus on June 14, 1985. The surface experiments of the lander failed to send back data because they were inadvertently switched on at an altitude of 20 km. Apparently high winds activated a G-force sensor that was to automatically switch on the surface package after the jolt of touchdown. The bus continued in heliocentric orbit and rendezvoused with comet Halley on March 9, 1986. The images of the comet were nearly lost when a television sensor failed shortly before the flyby. A back-up sensor was activated just in time. Fitted with scientific apparatus and equipment built in the USSR, Austria, Bulgaria, Hungary, German Democratic Republic, Poland, France, Federal Republic of Germany and C zechoslovakia.
SAR radar imaging of the Venusian surface, gravitational field mapping. The Magellan spacecraft was deployed from shuttle STS-30 on May 5, 1989, arrived at Venus on August 10, 1990 and was inserted into a near-polar elliptical orbit with a periapsis altitude of 294 km at 9.5 deg. N. The primary objectives of the Magellan mission were to map the surface of Venus with a synthetic aperture radar (SAR) and to determine the topographic relief of the planet. At the completion of radar mapping 98% of the surface was imaged at resolutions better than 100 m, and many areas were imaged multiple times. The mission was divided up into 'cycles', each cycle lasted 243 days (the time necessary for Venus to rotate once under the Magellan orbit - i.e. the time necessary for Magellan to 'see' the entire surface once.) The mission proceeded as follows: 10 Aug 1990 - Venus orbit insertion and spacecraft checkout;15 Sep 1990 - Cycle 1: Radar mapping (left-looking); 15 May 1991 - Cycle 2: Radar mapping (right-looking); 15 Jan 1992 - Cycle 3: Radar mapping (left-looking); 14 Sep 1992 - Cycle 4: Gravity data acquisition; 24 May 1993 - Aerobraking to circular orbit; 3 Aug 1993 - Cycle 5: Gravity data acquisition; 30 Aug 1994 - Windmill experiment; 12 Oct 1994 - Loss of radio signal; 13 Oct 1994 - Loss of spacecraft. A total of 4225 usable SAR imaging orbits was obtained by Magellan. Magellan showed an Earth-sized planet with no evidence of Earth-like plate tectonics. At least 85% of the surface is covered with volcanic flows, the remainder by highly deformed mountain belts. Even with the high surface temperature (475 C) and high atmospheric pressure (92 bars), the complete lack of water makes erosion a negligibly slow process, and surface features can persist for hundreds of millions of years. Some surface modification in the form of wind streaks was observed. Over 80% of Venus lies within 1 km of the mean radius of 6051.84 km. The mean surface age is estimated to be about 500 million years. A major unanswered question concerns whether the entire surface was covered in a series of large events 500 million years ago, or if it has been covered slowly over time. The gravity field of Venus is highly correlated with the surface topography, which indicates the mechanism of topographic support is unlike the Earth, and may be controlled by processes deep in the interior. Details of the global tectonics on Venus were still unresolved.