Cruise stage tanks 2 and 3 were filled with water, the engine feed tank was filled with propellant, and tanks 1 and 4 were empty. Mass was reduced by 30% from that of a fully fueled stage. The boosters were fully fueled. A slightly different turbopump was installed on the engines in comparison to earlier flights. The flight was to demonstrate simultaneous control of the missile using both aerodynamic surfaces and exhaust vanes after T+50 seconds. The flight continued to T+81 seconds, when failure of an electric circuit led to premature cutoff of the boosters

NASA announced the signing of a $24 million contract with Douglas Aircraft Co., Inc., for a three-stage Thor-Vanguard launching rocket called Delta. References: 17 .

Final NASA report on the study proposed for Saturn for use as Dyna-Soar booster was presented to the Air Force. References: 18 .

Little Joe 5B (LJ-5B) was launched from Wallops Island to test the Mercury escape system under maximum dynamic pressure conditions. At the time of lift-off, one of the launch vehicle rocket motors did not ignite until after 4 seconds had elapsed. This delay caused the launch vehicle to pitch into a lower trajectory than had been planned, with a result that the abort maneuver experienced greater dynamic pressures than had been specified in the flight test plan. Other than this, all other sequential systems operated according to plan, and after landing, a normal helicopter recovery was accomplished. Thus, all test objectives were met and were actually exceeded because the spacecraft withstood the higher dynamic pressures. References: 16 , 18 .

First successfull silo launch

Program partially completed. Part of the information lost due to failure of engine block stabilization system. Area survey photo reconnaissance satellite. Also performed radiation measurements. References: 1 , 2 , 5 , 6 , 93 .

Joseph F. Shea, ASPO Manager, approved Crew Systems Division's recommendation to retain the "shirtsleeve" environment for the CM. The design was simpler and promised greater overall mission reliability; also, it would be more comfortable for the crewmen. Additional Details: Shirtsleeve environment in the Apollo CM. References: 16 .

Maximum Speed - 5266 kph. Maximum Altitude - 28224 m. First star tracker checkout. References: 38 , 49 , 97 .

KH-7 type satellite. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A). References: 1 , 2 , 5 , 6 , 278 .

Radar monitoring. References: 1 , 2 , 5 , 6 , 172 , 278 .

Maximum Speed - 5985 kph. Maximum Altitude - 50900 m. References: 38 , 49 , 97 .

Materials research; deployed ERS 27. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A). References: 1 , 2 , 5 , 6 .

Radiation research; deployed ERS 20. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A). References: 1 , 2 , 5 , 6 .

Radiation research. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A). References: 1 , 2 , 5 , 6 .

Space craft engaged in investigation of spaceflight techniques and technology (US Cat A). References: 1 , 2 , 5 , 6 .

Space craft engaged in investigation of spaceflight techniques and technology (US Cat A). References: 1 , 2 , 5 , 6 .

Acquisition of meteorological information needed for use by the weather service. References: 1 , 2 , 5 , 6 .

Investigation of the upper atmosphere and outer space. References: 1 , 2 , 5 , 6 .

High resolution photo reconnaissance satellite; returned film capsule; maneuverable. References: 1 , 2 , 6 .

Released 24 Romb radar calibration subsatellites. References: 1 , 2 , 5 , 6 .

Continued operation of the long-range telephone and telegraph radio-communication system within the Soviet Union and transmission of USSR central television programmes to stations in the Orbita and participating international networks (international coope ration scheme). References: 1 , 2 , 5 , 6 .

Forward payload bay doors on dock, Palmdale, Columbia (OV-102) References: 15 .

Photo surveillance; returned film capsule; maneuverable. References: 1 , 2 , 6 .

Replaced Cosmos 1190. References: 1 , 2 , 5 , 6 .

Investigation of the natural resources of the earth in the interests of various branches of the national economy of the USSR and international cooperation. References: 1 , 2 , 6 , 103 .

Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). References: 1 , 2 , 5 , 6 .

Covered Oko constellation plane 1 - 277 degree longitude of ascending node. References: 1 , 2 , 5 , 6 , 100 .

Shuttle Pallet Satellite-II (SPAS-II) experiments were carried out on this classified mission. No details on whether SPAS was released or nature of experiments. References: 1 , 2 , 5 , 6 , 7 .

Chemical Release Observation; deployed 5/2/91; released gases for observation by IBSS. Spent boosters, spent maneuvering stages, shrouds and other non-functional objects (US Cat D). References: 1 , 2 , 5 , 6 .

Infrared Background Signature Survey; sensor technology test; retrieved 5/2/91. Spent boosters, spent maneuvering stages, shrouds and other non-functional objects (US Cat D). References: 1 , 2 , 5 , 6 .

Classified subsatellite released from shuttle. References: 1 , 2 , 5 , 6 .

Chemical Release Observation; deployed 5/3/91; released gases for observation by IBSS. Spent boosters, spent maneuvering stages, shrouds and other non-functional objects (US Cat D). References: 1 , 2 , 5 , 6 .

Chemical Release Observation; deployed 5/2/91; released gases for observation by IBSS. Spent boosters, spent maneuvering stages, shrouds and other non-functional objects (US Cat D). References: 1 , 2 , 5 , 6 .

Manned seven crew. Deployed USA 70, CRO A, CRO B, CRO C; deployed and retrieved IBSS. Payloads: Infrared Background Signature Survey (lBSS), Air Force Program (AFP)-675, Space Test Payload (STP)-I, Multi-Purpose Experiment Canister (MPEC), Cloud Logic to Optimize Use of Defense Systems (CLOUDS)-1A, Radiation Monitoring Equipment (RME)-lll. Additional Details: STS-39. References: 1 , 2 , 5 , 6 , 7 .

Second launch of new EORSAT, second of three stationed at 120 degree intervals on the same orbit with a 0 degree ascending node. References: 1 , 2 , 5 , 6 , 69 .

Photo/digital surveillance. References: 1 , 2 , 6 , 276 .

Geostationary at 109.9 degrees E.

Egypt's first satellite. Geostationary at 7.0 degrees W.

A small technology satellite which carried an experimental high rate data transmission payload.

X-ray astronomy satellite with the mission to carry out an all-sky survey in the 1-10 keV band. The satellite's battery failed and contact was lost on May 1.