Word: gemini
(lookup in dictionary)
(lookup stats)
Dates: during 1960-1969
Sort By: most recent first
(reverse)
Calculating with split-second exactitude, NASA scientists had determined the proper time of Gemini 6's launch by the position and orbit of Gemini 7. Because the earth rotates on its axis once every 24 hours, while Gemini 7 was circling around it once every 96 minutes, there were only one or two brief periods a day when the launch pad for Gemini 6 was located approximately under Gemini 7's orbit and when the orbiting ship was close by-the proper launch "window" for a rendezvous attempt. For Wednesday, ideal launch time had been calculated...
...powerful Titan II rocket swiftly shoved Gemini 6 into an elliptical orbit that dipped as close to earth as 100 miles (perigee) and swung as far away as 161 miles (apogee). The average velocity was 17,535 m.p.h., only 8 m.p.h. slower than planned. Even more important, a maneuver of Gemini 6's second-stage launch rocket had placed the capsule in an orbital plane that nearly coincided with Gemini 7's; its path was almost directly below that of Gemini 7, slanting away at an angle of less than one-tenth...
Some 1,200 miles ahead, Gemini 7 sailed along at 17,290 m.p.h. The strategy of rendezvous, painstakingly plotted by NASA scientists and computers, called for Gemini 6 to catch up by taking advantage of orbital mechanics-the physical laws that govern the motion of orbiting bodies. Those laws state that an orbital path is determined by a delicate balance between gravity, which tries to pull a satellite down, and centrifugal force, which is proportional to the satellite's speed and tends to shove it farther away from the earth. A satellite orbiting close to earth, where the pull...
During the first three orbits of Gemini 6, Command Pilot Schirra made a number of ground-computed corrective maneuvers. To change his elliptical orbit into a circle that reached up closer to Gemini 7, he made several "posigrade" burns-bursts from his forward-thrusting rockets. At two hours and 18 minutes after launch, for instance, Schirra made a posigrade burn when Gemini 6 reached its second apogee over the Indian Ocean. That thrust helped the change from ellipse to circle by increasing the perigee from 100 to 140 miles above the earth; following the laws of orbital mechanics, though...
...information about Gemini 6 and Gemini 7 was fed back from NASA's worldwide tracking stations, the computer was ready to deliver, in microseconds, answers that its human tutors would take too long to supply. Its orders constantly changed Gemini 6's flight plan, pumped out new burn times, duration of burn, power of burn, direction of thrust. It was the computer, for example, that noticed the apogee was half a mile low and called for a tiny "tweak" burn at the second perigee. "During the rendezvous," says NASA Flight Director Chris Kraft proudly, "it gave...