Rendezvous and docking

Getting off the Moon and returning to the relative safety of the command module was a feat that literally defined the mission plan. NASA even named it lunar orbit rendezvous (LOR) in view of the important benefits the technique promised in overall weight savings, including that of the launch vehicle. Yet, to many in NASA in the early 1960s, it seemed suicidal for one tiny spacecraft to launch and attempt to pull up alongside another tiny spacecraft, each whizzing along at some 5,800 kilometres per hour, around another world nearly half a million kilometres away. At that time, no one had even attempted rendezvous in the relative safety of Earth orbit in spacecraft that could at least return to the ground if things went awry. Space navigation techniques were rudimentry at best. There were no GPS satellites around Earth and even spaceborne radar techniques were merely theoretical. It was a measure of the managers’ faith in their engineers and scientists that they felt confident to march ahead with an apparently hare-brained scheme which, if it were to go wrong, would doom two men to certain death in lunar orbit.

Once LOR had been chosen as the preferred mission mode, NASA needed to practise the techniques of rendezvous around Earth. Through 1965 and 1966, the ten missions of the Gemini programme turned rendezvous from a frightening unknown manoeuvre into a routine operation. Appropriate procedures were learned through successive flights beginning with simple tasks:

• Could the manoeuvrable Gemini spacecraft station-keep with its spent upper rocket stage?

• Could two independently launched spacecraft rendezvous and station-keep?

• Could a spacecraft rendezvous and then dock with an unmanned target?

• Could it achieve the same feat within a single orbit?

All these lessons built NASA’s confidence in its procedures, and were directly applicable to Apollo’s need to rendezvous and dock around the Moon. The Gemini programme is often overlooked by writers eager to tell the story of how NASA prepared to venture to the Moon. But without it, Apollo could never have succeeded within President Kennedy’s deadline. Years later, David Scott, Gemini 8 pilot and veteran of Apollos 9 and 15, reflected: "You go away back, it was a big mystery

W. D. Woods, How Apollo Flew to the Moon, Springer Praxis Books,

DOI 10.1007/978-1-4419-7179-1 13. © Springer Science+Business Media. LLC 2011
doing a rendezvous. Magic mysterious stuff! Now it’s just straight off – choof, bang.”