Knowledge from the Moon

Abstract

Having made a precision landing with Apollo 12, the flight dynamics team felt sufficiently confident to further reduce the target ellipse to enable the next mission to aim for a more confined site in rougher terrain. To escape the confinement of the equatorial zone, it was necessary to relax the propellant margins. The requirement for a backup site was also deleted, and a launch delay of up to three days would be accommodated by making the landing at the higher Sun angle. This relaxation of the constraints did not ‘open up’ the Moon, because high-latitude sites were still out bounds, but it was a welcome degree of flexibility. It was the contraction of the ellipse, and the elimination of the rule that the general area be free of terrain relief, which allowed more interesting sites to be considered. In anticipation of a successful landing by Apollo 11, the site selectors had met on 10 June 1969 to plan Apollo 13. Some geologists were eager to visit a large crater. Hipparchus and Censorinus would have met the projected operational constraints, but the consensus was in favour of the terrain to the north of the crater Fra Mauro.

Information pertaining to each sample is given on page 369.