Page 18 - Intro to Space Sciences Spacecraft Applications

5
Introduction and History
unmanned satellites for a variety of military and scientific purposes, but it
was apparent that efforts were also being made to place a man into space.

Manned Spaceflight

Once again, the Soviets were first in the manned spaceflight effort with
the launch of Air Force Major Yuri A. Gagarin in the 4,706-kg (10,400-lb)
Vosfok 1 (“East”) spacecraft on April 12, 1961, for a single orbit. The
recovery area, unlike the later U.S. manned flights, was back in the Soviet
homeland, and, after the spacecraft reentered and was on its way down by
parachute, Gagarin exited the capsule and used his own parachute to land!
Three weeks later on May 5, 1961, the United States launched Navy
Commander Alan B. Shepard, Jr., into space. The successful 15-minute
suborbital flight reached an altitude of 187.6 km (116.5 mi) and went
489.1 km (303.8 mi) downrange to recovery in the South Atlantic.
Although successful, this flight showed, once again, that America was
lagging behind the Soviet Union in what was now being called the “Space
Race.” In an effort to turn this tide, President John E Kennedy, during a
major speech before Congress only three weeks later, publicly committed
the United States to landing a man on the moon, and returning him safely
to earth, before the decade was out. With this clear objective in mind, the
U.S. manned space program took shape, evolving from the existing Mer-
cury program, through Gemini, to Apollo.

Mercury. The purpose behind the Mercury program was to gain basic
data on the effects of spaceflight on human beings. To gain preliminary
physical data as well as test the launcher and spacecraft systems, a rhesus
monkey (Sam, December 1959) and a chimpanzee (Ham, December
1960) were launched on suborbital flights, and another chimp (Enos,
November 1961) was launched into orbit before these same flights were
attempted by astronauts.
Alan Shepard’s flight was followed by a second suborbital flight carry-
ing Virgil “Gus” Grissom in July 1961. John Glenn became the first
American to orbit the earth on February 20, 1962. Three additional orbital
Mercury flights followed, the longest by Gordon Cooper who spent more
than 34 hours alone in orbit.

Gemini. Gemini flights were designed to evaluate the ability of perform-
ing the tasks in space required for a manned lunar landing. Three methods