Surveyor 7

Surveyor 7

Surveyor 7, sitting on the ejecta blanket of Tycho Crater (image width is 500 m). Inset is zoomed 4x [NASA/GSFC/Arizona State University].
Mission type	Lunar lander
Operator	NASA
COSPAR ID	1968-001A
SATCAT no.	03091
Mission duration	45 days (launch to last contact)
Spacecraft properties
Manufacturer	Hughes Aircraft
Launch mass	1,040.1 kilograms (2,293 lb)[1]
Landing mass	305.7 kilograms (674 lb) after landing
Start of mission
Launch date	January 7, 1968, 06:30:00 (1968-01-07UTC06:30Z) UTC [1]
Rocket	Atlas SLV-3C Centaur-D AC-15
Launch site	Cape Canaveral LC-36A
End of mission
Last contact	February 21, 1968 (1968-02-22)
Lunar lander
Landing date	January 10, 1968, 01:05:36 UTC
Landing site	41°01′S 11°25′W / 41.01°S 11.41°W / -41.01; -11.41
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Surveyor 7 was sent to the Moon in 1968 on a scientific and photographic mission as the seventh and last lunar lander of the American uncrewed Surveyor program. With two previous unsuccessful missions in the Surveyor series, and with Surveyor 7's landing success, Surveyor 7 became the fifth and final spacecraft in the series to achieve a lunar soft landing. A total of 21,091 pictures were transmitted from Surveyor 7 back to Earth.

The objectives for this mission were to perform a lunar soft landing (in an area well removed from the maria to provide a type of terrain photography and lunar sample significantly different from those of other Surveyor missions); obtain postlanding TV pictures; determine the relative abundances of chemical elements; manipulate the lunar material; obtain touchdown dynamics data; and obtain thermal and radar reflectivity data.

This spacecraft was similar in design to the previous Surveyors, but it carried more scientific equipment including a television camera with polarizing filters, a surface sampler, bar magnets on two footpads, two horseshoe magnets on the surface scoop, and auxiliary mirrors. Of the auxiliary mirrors, three were used to observe areas below the spacecraft, one to provide stereoscopic views of the surface sampler area, and seven to show lunar material deposited on the spacecraft. The spacecraft landed on the lunar surface on January 10, 1968, on the outer rim of the crater Tycho.

Operations of the spacecraft began shortly after the soft landing and were terminated on January 26, 1968, 80 hours after sunset. On January 20, while the craft was still in daylight, the TV camera clearly saw two laser beams aimed at it from the night side of the crescent Earth, one from Kitt Peak National Observatory, Tucson, Arizona, and the other at Table Mountain at Wrightwood, California.^[2][3]

Operations on the second lunar day occurred from February 12 to 21, 1968. The mission objectives were fully satisfied by the spacecraft operations. Battery damage was suffered during the first lunar night and transmission contact was subsequently sporadic. Contact with Surveyor 7 was lost on February 21, 1968.^[4]

NASA and Bellcom mission planners considered the Surveyor 7 site as a potential target for a crewed late Apollo mission, perhaps Apollo 20, though a combination of operational constraints, including the high latitude of the site and its rough terrain, and the early cancellation of post-Apollo 17 lunar missions, contributed to the site's elimination.^[5][6]

Surveyor 7 was the first probe to detect the faint glow on the lunar horizon after dark that is now thought to be light reflected from electrostatically levitated Moon dust, a phenomenon known as Lunar horizon glow^[7]