Mission Summary
Surveyor 5 returned the first direct chemical analysis of soil on another world, and it did so only after engineers saved it from a crippling fuel leak. Launched September 8, 1967, it replaced the digging scoop of earlier flights with an alpha-backscatter instrument designed to measure the composition of the lunar surface.
On the way to the Moon, a helium leak in a pressure regulator nearly doomed the mission. Controllers at JPL and Hughes Aircraft devised a new descent plan on the fly and brought Surveyor 5 down safely in Mare Tranquillitatis on September 11, 1967, though about 29 kilometers off target on the sloping wall of a small crater.
It proved the most productive Surveyor yet, returning some 20,000 images across several lunar days. Its alpha-backscatter instrument found the soil to be more than half oxygen, with silicon and aluminum, the first such measurement made on the Moon. Controllers even briefly fired the main engine against the surface to study the effect, finding that it raised no crater or dust cloud. Contact was lost on December 16, 1967.
Sources and notes can be found on the Sources page.
