||24 Sep 1959|
||Atlas-C Able (#9C)|
Failure: First launch Atlas-Able rocket.
The whole vehicle was destroyed in an explosion on Launch Pad 12, after a static test of the Atlas engines.
|Mass at launch
|| 1 m dia, long 1.4 m|
|| Hydrazine thruster|
|| see below||
The Pioneer P-1, -3, -30 and -31 series 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 Earth and Moon, and to develop technology for controlling and
maneuvering spacecraft from Earth. It was equipped to take images of the lunar
surface with a television-like system, estimate the Moon's mass and topography
of the poles, record the distribution and velocity of micrometeorites, and study
radiation, magnetic fields, and low frequency electromagnetic waves in space. A
mid-course propulsion system and injection rocket would have been the first U.S.
self-contained propulsion system capable of operation many months after launch
at great distances from Earth and the first U.S. tests of maneuvering a
satellite in space.
All probes were 1 meter diameter spheres 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.
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. The transmitters operated on a frequency of 378 MHz.
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 which 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
The scientific instruments consisted of an ion chamber and Geiger-Mueller
tube to measure total radiation flux, a proportional radiation counter telescope
to measure high energy radiation, a scintillation counter to monitor low-energy
radiation, a VLF receiver for natural radio waves, a transponder to study
electron density, and part of the television facsimile system and flux-gate and
search coil magnetometers mounted on the instrument platform. The television
camera pointed through a small hole in the sphere between two of the solar panel
mounts. The micrometeorite detector was mounted on the sphere as well. The total
mass of the science package including electronics and power supply was 55 kg.