23.3 Recent Space Exploration
Lesson Objectives
- Outline the history of space stations and space shuttles.
- Describe recent developments in space exploration.
Space Shuttles and Space Stations
While the United States continued missions to the Moon in the early 1970s, the Soviets had
another goal: to build aspace station. A space station is a large spacecraft on which
humans can live for an extended period of time.
Early Space Stations
The Soviet Union put the first space station, Salyut 1, into orbit on April 19, 1971. At
first, the station had no crew. Three cosmonauts boarded the station on June 7, 1971, and
stayed for 22 days. Unfortunately, the cosmonauts died during their return to Earth, when
the return capsule lost pressure while still in the airless vacuum of space. Salyut 1 left orbit
on October 11, 1971, and burned up as a result of friction with the Earth’s atmosphere.
Between 1971 and 1982, the Soviets put a total of seven Salyut space stations into orbit.
Figure23.25shows the last of these, Salyut 7. These were all temporary stations that were
launched and later inhabited by a human crew. Three of the Salyut stations were used for
secret military purposes. The others were used to study the problems of living in space and
for a variety of experiments in astronomy, biology, and Earth science. Salyut 6 and Salyut
7 each had two docking ports, so one crew could dock a spacecraft to one end, and later a
replacement crew could dock to the other end.
The U.S. only launched one space station during this time—Skylab, shown inFigure23.26.
Skylab’s design was based on a segment of the Saturn V rockets that were used in the
Apollo missions to the Moon. Skylab was launched into low Earth orbit in May 1973. It
was damaged as it passed out of Earth’s atmosphere, but repairs were made when the first
crew arrived.
Three crews visited Skylab, all within its first year in orbit. Skylab was used to study the
effects of staying in space for long periods. It was also used for studying the Sun. Skylab
reentered Earth’s atmosphere in 1979, sooner than expected. It was so large that Skylab
did not completely burn as it reentered the Earth’s atmosphere. As a result, pieces of it fell
across a large area, including some of western Australia. News headlines read, “The Skylab
is Falling!”