First aircraft takeoff in United States with permanently installed JATO rocket powerplant, an A-20A at Muroc Army Air Base, Calif. References: 17 .

The rocket failed in flight. References: 17 .

Bell flight 7. Buffet boundary investigation. Mach 0.80 at 10675 m. References: 49 , 97 .

NACA flight 4. Turns and pull-ups to buffet. Mach 0.83. References: 49 , 97 .

NASA requested eight Redstone-type launch vehicles from the Army to be used in Project Mercury development flights. References: 17 .

In an interview for Space Business Daily, Edward Z. Gray, Director of Advanced Studies in NASA's Office of Manned Space Flight, predicted that NASA's manned space station would be more sophisticated than the Defense Department's Manned Orbiting Laboratory. NASA had more than a dozen study projects under way, Gray said, that when completed would enable the agency to appraise requirements and pursue the best approach to developing such a space station.

Maximum Speed - 5818 kph. Maximum Altitude - 42642 m. References: 38 , 49 , 97 .

Defense Meteorological Satellite Program. References: 5 , 126 .

Central Committee of the Communist Party and Council of Soviet Ministers Decree 19-10 'On Work on Research of the Moon, Venus and Mars by Automatic Stations--work on automated lunar and interplanetary spacecraft' was issued. References: 474 .

Dale D. Myers was appointed NASA Associate Administrator for Manned Space Flight with an effective date of 12 January. He succeeded George E. Mueller, who left NASA on 10 December 1969 to become a vice president of General Dynamics Corporation. Prior to his acceptance of the NASA position, Myers was Vice President and General Manager of the Space Shuttle Program at North American Rockwell.

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. References: 1 , 2 , 5 , 6 , 67 , 274 , 296 .

Development of the military nuclear powered communications satellite was approved by the Soviet VPK Military-Industrial Commission. The satellite would have used the 5 kW nuclear reactor originally planned for the Ekran satellite and used secure uninterceptable laser and radio inter-satellite and space-to-ground communications links. Did not reach flight status before the collapse of the Soviet Union.

Military cartographic satellite; returned film capsule. References: 1 , 2 , 6 .

Installed star tracker. References: 66 .

NATO communications; 18 deg W. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C). References: 1 , 2 , 5 , 6 .

Mir Expedition EO-15. Docked at the Kvant module on January 10 at 11:15 GMT. Transported to the Mir orbital station of a crew comprising the cosmonauts V M Afanasev, Y V Usachev, and V V Polyakov for the fifteenth main expedition. The Soyuz TM-18 descent module landed 110 km north of Arkalyk in Kazakhstan at 10:32:35 GMT on July 9. References: 1 , 2 , 6 , 51 .