Pioneer P-3
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Mission type | Lunar orbiter |
---|---|
Operator | NASA |
Mission duration | Failed to orbit |
Spacecraft properties | |
Manufacturer | TRW Space Technology Laboratories |
Launch mass | 168.70 kilograms (371.9 lb) |
Start of mission | |
Launch date | 26 November 1959, 07:26:00 | UTC
Rocket | LC-14 |
Pioneer P-3 (also known as Atlas-Able 4 or Pioneer X) was intended to be a lunar orbiter probe, but the mission failed shortly after launch. The objectives were to place a highly instrumented probe in lunar orbit, to investigate the environment between the
Mission
The probe was originally intended for launch on Atlas 9C in October, but the launch vehicle was destroyed in a static firing accident on 24 September, so it was decided to use the Atlas D (an operational version of the Atlas ICBM) rather than the Atlas C, which was still a test model. The launch took place on Thanksgiving, 26 November 1959 from LC-14 at Cape Canaveral Air Station using Atlas vehicle 20D, which had originally been the backup booster for the Mercury
Spacecraft design
Pioneer P-3 was a 1-meter diameter sphere with a propulsion system mounted on the bottom giving a total length of 1.4 meters. The mass of the structure and aluminum alloy shell was 25.3 kg and the propulsion units 88.4 kg. Four solar panels, each 60 x 60 cm and containing 2200 solar cells in 22 100-cell nodules, extended from the sides of the spherical shell in a "paddle-wheel" configuration with a total span of about 2.7 meters. The solar panels charged chemical batteries. Inside the shell, a large spherical hydrazine tank made up most of the volume, topped by two smaller spherical nitrogen tanks and a 90 N injection rocket to slow the spacecraft down to go into lunar orbit, which was designed to be capable of firing twice during the mission. Attached to the bottom of the sphere was a 90 N vernier rocket for mid-course propulsion and lunar orbit maneuvers which could be fired four times. This space engine was designed and built under contract with NASA by the Space Technology Laboratories (STL) of TRW.
Around the upper hemisphere of the hydrazine tank was a ring-shaped instrument platform which held the batteries in two packs, two 5 W UHF transmitters and diplexers, logic modules for scientific instruments, two command receivers, decoders, a buffer/amplifier, three converters, a telebit, a command box, and most of the scientific instruments. Two dipole UHF antennas protruded from the top of the sphere on either side of the injection rocket nozzle. Two dipole UHF antennas and a long VLF antenna protruded from the bottom of the sphere.
Thermal control was planned to be achieved by a large number of small "propeller blade" devices on the surface of the sphere. The blades themselves were made of reflective material and consist of four vanes that were flush against the surface, covering a black heat-absorbing pattern painted on the sphere. A thermally sensitive coil was attached to the blades in such a way that low temperatures within the satellite would cause the coil to contract and rotate the blades and expose the heat-absorbing surface, and high temperatures would cause the blades to cover the black patterns. Square heat-sink units were also mounted on the surface of the sphere to help dissipate heat from the interior.
On-board equipment
The scientific instruments consisted of an