NACA flight 43. Pilot familiarization. Reached mach 1.07.

Missile test failure. Missed aimpoint by 7,000 m.

Douglas Thor IRBM (XSM-75) was launched at Cape Canaveral, Fla., destroyed by range safety officer. The missile was actually on course throughout its flight. The console wiring error led the range safety officer to believe it was headed inland rather than out to sea, so he hit the destruct button.

NASA announced acceptance of proposals by the Canadian Defense Research Telecommunications Establishment for continuing joint rocket and satellite ionospheric experiments of a nonmilitary nature.

A conference was held at NASA Headquarters on the relationship between the Prospector and Apollo programs. Representatives of the Jet Propulsion Laboratory (JPL) and STG discussed the possible redirection of Prospector planning to support more directly the manned space program. The Prospector spacecraft was intended to soft-land about 2,500 pounds on the lunar surface with an accuracy of +/-1 kilometer anywhere on the visible side of the moon. An essential feature of Prospector was the development of an automatic roving vehicle weighing about 1500 pounds which would permit detailed reconnaissance of the lunar surface over a wide area. - Additional details.

Korolev’s fantastic ‘Orbitalniy Poyas’ (OP -Orbital Belt) scheme anticipated Ronald Reagan’s Strategic Defence Initiative by 25 years. Two to three large N-I launched military manned stations would control a constellation of strategic assets. Geosynchronous nuclear-powered satellites would provide secure communications. Piloted reconnaissance spacecraft would surprise the enemy, observing military preparations without warning. The orbital stations would provide continuous observations of the territory of the imperialist block.

Maximum Speed - 6097 kph. Maximum Altitude - 63250 m.

NASA selected IBM, Federal Systems Division, to develop and build the instrument units (IU) for the Saturn IB and Saturn V launch vehicles. (IBM had been chosen by NASA in October 1963 to design and build the IU data adapters and digital guidance computers and to integrate and check out the IUs.) Under this new contract, expected to be worth over $175 million, IBM would supply the structure and the environmental control system. NASA would furnish the telemetry system and the stabilized platform (ST-124M) of the guidance system. MSFC would manage the contract.

The upper stages broke up on re-entry into the atmosphere..

. Program partially completed. Abnormal operation of SA-10 camera.

150 people attend. The readiness of the spacecraft and launch vehicles are confirmed. The final responsibilities and schedule are approved. Everything is go. Afterwards there is a meeting with Mishin. He is mainly worried about two things that could cause them to scrub the launch of the second Soyuz: a failure of the Igla automatic docking system or the solar panels on Soyuz 1.

The full design 1145 km cross range was demonstrated, and the X-23A SV-5D lifting body vehicle was successfully snatched at 3700 m altitude, 8 km from the target point. With this success the rest of the project was cancelled, and the two remaining unflown X-22A's were sent to the USAF Museum at Wright Patterson Air Force Base.

Replaced ESSA 3. Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C).

Unfuelled tests of the Proton rocket on the pad are completed successfully. The K-100 star sensor on the L1 is a special concern.

Area survey photo reconnaissance satellite. Unsuccessful mission. Spacecraft landed in River Volga 1 km from shore and sank after 42 minutes. 85% of the data was ruined.

Six of eight fans in the ECS have failed. There are only two back-ups, which are not enough for the 90-day active mission life planed. But it is decided the problem could actually be failed sensors, and in any case the first crew can easily repair the fans. At 17:00 the State Commission meets publicly (radio and television coverage) to approve the launch of Soyuz 10. Launch is set for 22 April at 03:30.

Anik I and Anik II also registered as United States objects. .The satellites, act as space repeaters capable of receiving transmissions from earth stations and retransmitting them to other earth stations in Canada. The antenna coverage of the satellite pr ovides the capability of serving virtually all of Canada. Anik I and II had weights of 1240.59 lb and 1246.48 lb. Each satellite has 12 RF channels each capable of transmitting a color television signal or up to 900 one-way voice channels. Positioned in geosynchronous orbit over the Americas at 109 deg W in 1973-1979; over the Americas at 106 deg W in 1979-1981; over the Americas at 114 deg W in 1981-1982 As of 26 August 2001 located at 0.59 deg E drifting at 1.690 deg W per day. As of 2007 Mar 9 located at 150.94E drifting at 1.684W degrees per day.

Uncertain if Molniya-1T model was Molniya-1 or Molniya-1T. Operation of a system of long range telephone-telegraph radiocommunication, and transmission of USSR Central Television programmes to the stations of the Orbita network.

Area survey photo reconnaissance satellite; returned film capsule.

Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

High resolution photo reconnaissance satellite; returned film capsule; maneuverable.

On 20 April 1979 LVI-4 VA (VA s/n 103 and s/n 008) was awaiting launch. The booster ignited, but then shut down on the pad. This triggered the launch escape system, which pulled the top capsule away from the booster. The parachute system failed and the capsule crashed to the ground. The lower capsule remained in the rocket. The top capsule was to have been manned, but the inability to demonstrate two consecutive failure-free launches of the Proton/TKS-VA combination made that (luckily) impossible.

Photo surveillance; returned film capsule.

Manned three crew. Unsuccessful mission. Failed to rendezvous with Salyut 7. Recovered April 22, 1983 13:29 GMT. Landed 113 km SE Arkalyk.

Investigation of the natural resources of the earth in the interests of various branches of the national economy of the USSR and international cooperation. Stayed in operation for six years, six months, far beyond its rated life of 3 to 5 years.

High resolution photo reconnaissance; returned film in two small SpK capsules during the mission and with the main capsule at completion of the mission.

Military navigation satellite. Positioned in plane 2 of constellation.

STS-59 landed at 16:54 GMT.

Geostationary at 106.5W. Positioned in geosynchronous orbit at 106 deg W in 1996-1999 As of 3 September 2001 located at 106.55 deg W drifting at 0.004 deg W per day. As of 2007 Mar 11 located at 106.48W drifting at 0.004W degrees per day.

Repeated rumours appeared that a Chinese military satellite was launched or suffered a failure on this date. The story was first carried by Reuters in May 1997. In December 2000 it was again reported in a Chinese professional magazine that China launched its last recoverable satellite on April 20, 1997. The last official launch of the series was in October 1996.

At 0916 UTC on April 20 Soyuz TM-33 undocked from the Zarya nadir port carrying the Expedition-4 crew. It redocked with the Pirs nadir port at 0937 UTC. This cleared the port Zarya port for the pending Soyuz TM-34 launch.

Gravity Probe B's mission was to confirm a prediction of Einstein's theory of relativity. The physics experiment, developed by Stanford University and Lockheed Martin, was to observe the magnitude 5 star IM Pegasi for over a year, attempting to measure the tiny shifts in the spacecraft gyroscopes' orientation caused by the Lense-Thirring gravitomagnetic (or `frame-dragging') effect. To accomplish this the spacecraft carried four gyroscopes kept at 1.8 deg Kelvin by a liquid helium dewar, laser retroreflectors and two GPS receivers for orbit determination, a drag compensation system, and a 14 cm aperture quartz telescope. The satellite was also to make an accurate measurement of the already-established gravitostatic warping of spacetime due to the Earth's mass.

The first Centaur upper stage burn placed the stack into a 167 km x 22442 km x 24.8 deg transfer orbit. After a second burn the Centaur released the satellite into a 6470 km x 36240 km x 23.8 deg orbit, from which it would use its own engine to achieve final geosynchronous orbit. As of 2007 Mar 10 located at 19.18E drifting at 0.022W degrees per day.