 The proper technique requires changing the tracking vehicle's orbit to allow the rendezvous target to either catch up or be caught up with, and then at the correct moment changing to the same orbit as the target with no relative motion between the vehicles (for example, putting the tracker into a lower orbit, which has a shorter orbital period allowing it to catch up, then executing a Hohmann transfer back to the original orbital height).Rendezvous was first successfully accomplished by US astronaut Wally Schirra on December 15, 1965.Schirra maneuvered the Gemini 6 spacecraft within of its sister craft Gemini 7.