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Surveyor 2



This spacecraft was the second of a series designed to achieve a soft landing on the moon and to return lunar surface photography for determining characteristics of the lunar terrain for Apollo lunar landing missions. It was also equipped to return data on radar reflectivity of the lunar surface, bearing strength of the lunar surface, and spacecraft temperatures for use in the analysis of lunar surface temperatures. The target area proposed was within Sinus Medii at 0 latitude and 0.67 W longitude. However, an engine failure resulted in the spacecraft tumbling uncontrollably, and the mission failed.

Spacecraft and Subsystems

The basic Surveyor spacecraft structure consisted of a tripod of thin-walled aluminum tubing and interconnecting braces providing mounting surfaces and attachments for the power, communications, propulsion, flight control, and payload systems. A central mast extended about one meter above the apex of the tripod. Three hinged landing legs were attached to the lower corners of the structure. The legs held shock absorbers, crushable, honeycomb aluminum blocks, and the deployment locking mechanism and terminated in footpads with crushable bottoms. The three footpads extended out 4.3 meters from the center of the Surveyor. The spacecraft was about 3 meters tall. The legs folded to fit into a nose shroud for launch.

A 0.855 square meter array of 792 solar cells was mounted on a positioner on top of the mast and generated up to 85 Watts of power which was stored in rechargeable silver-zinc batteries. Communications were achieved via a movable large planar array high gain antenna mounted near the top of the central mast to transmit television images, two omnidirectional conical antennas mounted on the ends of folding booms for uplink and downlink, two receivers and two transmitters. Thermal control was achieved by a combination of white paint, high IR-emittance thermal finish, polished aluminum underside. Two thermally controlled compartments, equipped with superinsulating blankets, conductive heat paths, thermal switches and small electric heaters, were mounted on the spacecraft structure. One compartment, held at 5 - 50 degrees C, housed communications and power supply electronics. The other, held between -20 and 50 degrees C, housed the command and signal processing components. The TV survey camera was mounted near the top of the tripod and strain gauges, temperature sensors, and other engineering instruments are incorporated throughout the spacecraft. One photometric targets was mounted near the end of a landing leg and one on a short boom extending from the bottom of the structure. Other payload packages, which differed from mission to mission, were mounted on various parts of the structure depending on their function.

A Sun sensor, Canopus tracker and rate gyros on three axes provided attitude knowledge. Propulsion and attitude control were provided by cold-gas (nitrogen) attitude control jets during cruise phases, three throttlable vernier rocket engines during powered phases, including the landing, and the solid-propellant retrorocket engine during terminal descent. The retrorocket was a spherical steel case mounted in the bottom center of the spacecraft. The vernier engines used monomethyl hydrazine hydrate fuel and MON-10 (90% N2O2, 10% NO) oxidizer. Each thrust chamber could produce 130 N to 460 N of thrust on command, one engine could swivel for roll control. The fuel was stored in spherical tanks mounted to the tripod structure. For the landing sequence, an altitude marking radar initiated the firing of the main retrorocket for primary braking. After firing was complete, the retrorocket and radar were jettisoned and the doppler and altimeter radars were activated. These provided information to the autopilot which controlled the vernier propulsion system to touchdown.

Mission Profile

Surveyor 2 launched on an an Atlas/Centaur from launch site 36A at Cape Kennedy, Florida. Liftoff took place at 12:31:59.824 UT on 20 September 1966. Surveyor separation from the Centaur took place at 12:44:32.4 UT. During the 9.8 s midcourse maneuver firing at 5:00 UT on 21 September, one of the three vernier engine failed to ignite, resulting in an unbalanced thrust that caused the spacecraft to tumble at roughly 1.22 rev/s. The nitrogen gas system operated to stabilize the spacecraft, but could only marginally reduce the spin rate. Multiple attempts to fire the no. 3 engine, and other attempts to reduce the spin rate and salvage the mission, were unsuccessful. At terminal descent the vernier engines and retrorockets were fired at 9:34:17 UT on 22 September. Signals ceased abruptly roughly 30 seconds later, at about 9:35 UT, indicating Surveyor 2 had impacted the Moon, at a point estimated to be roughly 5.5 N, 12 W. The Surveyor program involved building and launching 7 Surveyor spacecraft to the Moon at a total cost of $469 million.

Alternate Names

  • 02425
  • AC 7
  • Surveyor2

Facts in Brief

Launch Date: 1966-09-20
Launch Vehicle: Atlas-Centaur
Launch Site: Cape Canaveral, United States
Mass: 292 kg

Funding Agency

  • NASA-Office of Space Science Applications (United States)


  • Planetary Science

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Mr. Benjamin MilwitzkyProgram ManagerNASA Headquarters
Dr. Leonard D. JaffeProject ScientistNASA Jet Propulsion Laboratory

Selected References

  • Surveyor II mission report, mission description and performance, JPL, Calif. Inst. Technol., TR 32-1086, Pasadena, CA, Apr. 1967.

Surveyor at National Air and Space Museum

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