Page 33 - Curriculum Visions Dynamic Book

gravity The force of attraction between bodies. The larger an object, the more its gravitational pull on other objects.
heat shield A protective device on the outside of a space vehicle that absorbs the heat during reentry and protects it from burning up.
retrorocket A rocket that fires against the direction of travel in order to slow down a space vehicle.
Vostok
The Soviet Union was again first to launch a man into orbit around the Earth. Yuri Gagarin will be one of the most remembered people in history for his epic journey on April 12, 1961.
The spacecraft that the Soviet Union used was so primitive that Gagarin had no control over it at all—he was more like a passenger than a pilot. His Vostok spacecraft was nearly 4.5 m long. The reentry capsule was a sphere just bigger than the height of the pilot, a mere 2.3 m across.
The reentry vehicle had no way to land, even in the
sea, and so Gagarin had to press an ejector button to fire himself clear of the reentry vehicle so that he could land by parachute, while the vehicle crashed to the ground.
The heat shield of the Vostok was designed to burn away during reentry.
Inside the capsule Gagarin had food, a radio, and a porthole to see through. He also had a box containing scientific equipment for experiments.
Attached to the capsule was an instrument section containing the retrorocket that was needed to slow the capsule during reentry.
It was important to play safe, because much of the equipment was still untested or unreliable. For example, Gagarin was launched into a low orbit so that he would return by gravity if the retrorocket failed to work.
 Yuri Gagarin in the bus on the way to the launch pad on the morning of April 12, 1961. Behind him, seated, is his backup, German Titov.
On April 12, 1961, at 9:06 a.m. Gagarin lifted off in the Vostok
1 spacecraft. After a 108-minute flight of extended low gravity he parachuted safely to the ground in the Saratov region of the USSR. The first human to fly in space, he successfully completed one
orbit around the Earth. After his historic flight Gagarin became an international symbol for the Soviet space program and in 1963 was appointed deputy director of the Cosmonaut Training Centre. In 1966 he served as a backup crew member for Soyuz 1.
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