Apollo Mission mode selection Lunar orbit rendezvous
apollo 11 lunar module rendezvousing command module in lunar orbit when apollo moon landing program started in 1961, assumed three-man command , service module combination (csm) used takeoff lunar surface, , return earth. therefore have landed on moon larger rocket stage landing gear legs, resulting in large spacecraft (in excess of 100,000 pounds (45,000 kg)) sent moon. if done direct ascent (on single launch vehicle), rocket required have extremely large, in nova class. alternative have been earth orbit rendezvous, in 2 or more rockets in saturn class launch parts of complete spacecraft, rendezvous in earth orbit before departing moon. possibly include separately launched earth departure stage, or require on-orbit refueling of empty departure stage. tom dolan proposed alternative of lunar orbit rendezvous, had been studied , promoted jim chamberlin , owen maynard @ space task group in 1960 apollo feasibility studies. mode allowed single saturn v launch csm moon smaller lunar excu...