Ranger 5 was designed to transmit pictures of the lunar surface to Earth stations during a period of 10 minutes of flight prior to impacting on the Moon, to rough-land a seismometer capsule on the Moon, to collect
gamma-ray data in flight, to study radar reflectivity of the lunar
surface, and to continue testing of the Ranger program for development of
lunar and interplanetary spacecraft. Due to an unknown malfunction, the
spacecraft ran out of power and ceased operation. It passed within 725 km
of the Moon.
Spacecraft and Subsystems
Ranger 5 was a Block II Ranger spacecraft similar to Rangers 3 and 4.
The basic vehicle was 3.1 m high and consisted of a lunar capsule covered
with a balsawood impact-limiter, 65 cm in diameter, a mono-propellant
mid-course motor, a 5080-pound thrust retrorocket, and a gold- and
chrome-plated hexagonal base 1.5 m in diameter. A large high-gain dish
antenna was attached to the base. Two wing-like solar panels (5.2 m
across) were attached to the base and deployed early in the flight. Power
was generated by 8680 solar cells contained in the solar panels which
charged a 11.5 kg 1000 W-hour capacity AgZn launching and backup battery.
Spacecraft control was provided by a solid-state digital computer and sequencer
and an earth-controlled command system. Attitude control was provided by
six Sun and one Earth sensor, gyroscopes, and pitch and roll cold nitrogen gas jets. The telemetry
system aboard the spacecraft consisted of two 960 MHz transmitters, one at
3 W power output and the other at 50 mW power output, the high-gain antenna,
and an omnidirectional antenna. White paint, gold and chrome plating, and
a silvered plastic sheet encasing the retrorocket furnished thermal control.
The experimental apparatus included: (1) a vidicon television camera, which employed a scan mechanism that yielded one complete frame in 10 s; (2) a gamma-ray spectrometer in a 30 cm sphere mounted on a 1.8 m boom;
(3) a radar altimeter; and (4) a seismometer to be rough-landed on the lunar
surface. The seismometer was encased in the lunar capsule along with an
amplifier, a 50-milliwatt transmitter, voltage control, a turnstile antenna,
and 6 silver-cadmium batteries capable of operating the lunar capsule
transmitter for 30 days, all designed to land on the Moon at 130 to
160 km/hr (80 -100 mph). The instrument package floated in a layer of freon
within the balsawood sphere. The radar altimeter would be used for reflectivity
studies, but was also designed to initiate capsule separation and ignite the
The mission was designed to boosted towards the Moon by an Atlas/Agena, undergo one mid-course correction, and impact the lunar surface. At the appropriate altitude the capsule was to separate and the retrorockets ignite to cushion the landing. Due to an unknown malfunction after injection into lunar trajectory from Earth parking orbit, the spacecraft failed to receive power. The batteries ran down after 8 hours, 44 minutes, rendering the spacecraft inoperable. Ranger 5 missed the Moon by 725 km. It is now in a heliocentric orbit. Gamma-ray data were collected for 4 hours prior to the loss of power.
Total research, development, launch, and support costs for
the Ranger series of spacecraft (Rangers 1 through 9) was
approximately $170 million.