•The first spacecraft was the German V-2 rocket, launched from Peenemünde, East Prussia (now Poland) in June 1944. Although other flights reached altitudes above 100 km, the International Aviation Federation considers 100 km to be the beginning of spaceflight, and calls this the Karman line. Sputnik 1, the first artificial satellite, was launched by the Soviet Union into an elliptical Low Earth orbit on 4 October 1957. The launch marked the beginning of a new political, military, technological and scientific era, although it was only one event. Sputnik 1 marked the beginning of the Space Age. By measuring changes in the satellite’s orbit, the density of the upper atmosphere was determined. Data were also obtained on the radio-signal distribution in the ionosphere. Thanks to the pressurized nitrogen in the satellite’s false body, meteoroid detection was achieved for the first time. Sputnik 1 was launched from the Tyuratam launch site, site number 5, at the Gagarin Start launch site, as part of the International Geophysical Year. The satellite traveled at a speed of 29,000 kilometers per hour, completing a full orbit in 96.2 minutes, and broadcasting radio signals at frequencies between 20.005 and 40.002 MHz.
The second human spaceflight vehicle was named Freedom 7 and carried American astronaut Alan Shepard to an altitude of about 187 km during a suborbital flight in 1961. Five more human spaceflight missions were carried out using the Mercury spacecraft.
开发过程 of Space Shuttles
The first partially reusable space vehicle, the X-15, was launched on July 19, 1963, in a suborbital trajectory. The X-15 made two manned flights to an altitude of 100 km in the 1960s. The first partially reusable orbital, non-capsule space vehicle was the Space Shuttle, launched by the United States on April 12, 1981, the 20th anniversary of Yuri Gagarin’s flight. Six shuttles were built during this period, all of which flew in the atmosphere, but only five flew in space. Columbia was the first shuttle to go into space, followed by Challenger, Discovery, Atlantis, and Endeavour. Endeavour was built to replace Challenger, which was lost in January 1986. The first fully automatic and partially reusable space vehicle, the Buran class space shuttle, was launched by the USSR on November 15, 1988. This shuttle made only one unmanned flight. The lack of funds and the chaotic situation created by the collapse of the Soviet Union prevented further flights of the Buran. Under the “Vision for Space Exploration” plan announced by George W. Bush in 2004, the Space Shuttle program was retired in 2011 due to the high cost of each flight, which exceeded one billion dollars, and the long-term use of the program.
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