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Luna 5

NSSDCA/COSPAR ID: 1965-036A

Description

The Luna 5 (Ye-6 no.10) automatic interplanetary station was designed to continue investigations of a lunar soft landing. The spacecraft carried an imaging system and a radiation detector. After launch fom Baikonur on 9 May 1965 at 7:49:37 UT and 5 successful communications sessions the spacecraft performed a midcourse correction maneuver on 10 May. Unfortunately a problem developed in a flotation gyroscope (it did not have enough time to warm up properly) in the I-100 guidance control unit and control was lost so the spacecraft began spinning around its main axis. It was brought back under control, but at the time of the next maneuver, the main retrorocket system failed due to a ground control error in calculating the setpoints, and the spacecraft, though still headed for the Moon, was far off its intended landing site. Problems again cropped up with the I-100 unit so a retrorocket burn could not take place and Luna 5 impacted the lunar surface some 700 km from the target point at about 19:10 UT on 12 May 1965, becoming the second Soviet probe to hit the Moon. A Soviet announcement gave the impact point as the Sea of Clouds at roughly 31 degrees S, 8 degrees W. Later analysis gives a location of 1.35 S, 25.48 W, but the impact point is very uncertain. (Other analyses and reports give a wide range of possible impact sites: 1.6 S, 25 W; 8.17 N, 23.43 W; 30 S, 8 W; and 31 S, 8 W.) An unconfirmed report from the astronomical observatory at Rodeswisch in Germany took photographs of the area which showed a cloud of dust. The cloud was 80 km by 203 km in extent at 19:15:24.7 UT and the center was estimated at 31 S, 8 E.

Spacecraft and Subsystems

The spacecraft was built by design bureau OKB-1 based on the Soviet Ye-6 design, which consisted of a stack of three cylindrical modules. The first module was the Isayev rocket module, which held the main engine, used for midcourse correction and the descent to landing, four thrusters for attitude control, and two cruise modules. The main engine propellant was hypergolic nitric acid and amine, and could produce a thrust of about 45,000 N. The four thrusters were mounted on outriggers and could produce 245 N each. A 5-meter boom would be deployed from the bottom of the spacecraft, used to trigger the final landing sequence. The second module was a hermetically sealed pressurized compartment that contained communication, attitude orientation, an altimeter, and the I-100 control system. It also held the propellant and oxygen.

The third module was the lunar lander, a 58 cm diameter sphere protected by two hemispherical airbags. The 105 kg sphere had a hermetically sealed compartment that held communications apparatus, batteries, thermal control systems, a timer, and the science experiments. The top of the sphere had four petals, which would open up on landing, allowing deployment of four 75 cm whip antennas and the lander camera turret. Control of the lander was done by the timing device onboard or by communication from Earth. The batteries were designed to operate for a total of 5 hours over about 4 days. The scientific payload contained an imaging system and an SBM-10 radiation detector. The three sections had a height of 2.7 meters and a launch mass of 1476 kg.

The mission plan was to initialize the landing sequence at an altitude of about 8300 km. At 70 - 75 km altitude the cruise modules would be jettisoned, the main engine would start, the radar altimeter would be activated, and the lander airbags would inflate. At 250 to 265 meters altitude the main engine would shut off and the four thrusters would ignite. The 5 meter boom would touch the surface first, causing the ejection of the lander, which would hit the surface, cushioned by the airbags, at about 15 m/s. The airbags would deflate, the petals would open, causing the sphere to be oriented correctly, and the antennas and instruments could be deployed.

Alternate Names

  • Lunik 5
  • 01366
  • Luna5
  • Ye-6 no.10

Facts in Brief

Launch Date: 1965-05-09
Launch Vehicle: Modified SS-6 (Sapwood) with 2nd Generation Upper Stage + Escape Stage
Launch Site: Tyuratam (Baikonur Cosmodrome), U.S.S.R
Mass: 1476 kg

Funding Agency

  • Unknown (U.S.S.R)

Disciplines

  • Planetary Science
  • Space Physics

Additional Information

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

 

Personnel

NameRoleOriginal AffiliationE-mail

Selected References

  • Lyubimov, G. P., Measurement of the intensity of cosmic radiation during the flights of automatic interplanetary stations Zond 1, Zond 2, Zond 3, Luna 5, Luna 6, NASA, ST-CR-IS-10655, Oct. 1967.
  • Lunik 5 and 6, TRW Space Log, TRW Systems, 5, No. 2, 55, Redondo Beach, Calif., 1965.
  • Shelton, W., Soviet space exploration - the first decade, Arthur Barker Ltd., Unnumbered, London, England, 1969.
  • Johnson, N. L., Handbook of soviet lunar and planetary exploration - volume 47 science and technology series, Amer. Astronau. Soc. Publ., 1979.
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