The Surveyor Block II spacecraft was imagined as an unmanned scout that could reconnoiter a specific lunar landing site for Apollo and assist the manned Lunar Module in making a precise touch down. A number of possible active and passive landing aids were considered, including: a Surveyor deployed transponder; an active radio homing device; a passive radar device (corner reflector); visual markers. In the end the concept, similar to one using the LK and Lunokhod in the Soviet Union, was abandoned.

Associated Launch Vehicle: Atlas Centaur SLV-3C.

• 1964 October 23 - Surveyor Block II study related to the Apollo landing aid problem - Program: Apollo.

  Jet Propulsion Laboratory proposed a meeting on October 29 between representatives of NASA Headquarters, Bellcomm, MSC, MIT, and JPL to present the requirements and status of projects underway as they related to the landing aid problem. The Surveyor Block II study effort was concentrating on determining needs of obtaining data on the lunar surface and environment for Apollo.Additional Details: Surveyor Block II study related to the Apollo landing aid problem (16701).

• Ertel , Ivan D; Morse , Mary Louise; et al, The Apollo Spacecraft Chronology Vol I - IV NASA SP-4009, NASA, 1966-1974. Accessed at: http://www.hq.nasa.gov/office/pao/History/SP-4009/cover.htm.