Surveyor 5 was the third spacecraft in the Surveyor series to achieve a successful lunar soft landing and the first mission to obtain in-situ compositional data on the Moon. The primary objectives of the Surveyor program, a series of seven robotic lunar softlanding flights, were to support the coming crewed Apollo landings by: (1) developing and validating the technology for landing softly on the Moon; (2) providing data on the compatibility of the Apollo design with conditions encountered on the lunar surface; and (3) adding to the scientific knowledge of the Moon. The specific objectives for this mission were to perform a soft landing on the Moon in Mare Tranquillitatis and obtain postlanding television pictures of the lunar surface. The secondary objectives were to conduct a vernier engine erosion experiment, determine the relative abundances of the chemical elements in the lunar soil by operation of the alpha-scattering instrument, obtain touchdown dynamics data, and obtain thermal and radar reflectivity data.

References
http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1967-084A