<P> The U.S. Earth satellite program began in 1954 as a joint U.S. Army and U.S. Navy proposal , called Project Orbiter , to put a scientific satellite into orbit during the International Geophysical Year . The proposal , using a military Redstone missile , was rejected in 1955 by the Eisenhower administration in favor of the Navy 's Project Vanguard , using a booster advertised as more civilian in nature . Following the launch of the Soviet satellite Sputnik 1 on October 4 , 1957 , the initial Project Orbiter program was revived as the Explorer program to catch up with the Soviet Union . </P>
<P> The U.S. Earth satellite program began in 1954 as a joint U.S. Army and U.S. Navy proposal , called Project Orbiter , to put a scientific satellite into orbit during the International Geophysical Year . The proposal , using a military Redstone missile , was rejected in 1955 by the Eisenhower administration in favor of the Navy 's Project Vanguard , using a booster advertised as more civilian in nature . Following the launch of the Soviet satellite Sputnik 1 on October 4 , 1957 , the initial Project Orbiter program was revived as the Explorer program to catch up with the Soviet Union . </P>
when was the first satellite put in space
when was the first satellite put in space
October 4 , 1957
October 4 , 1957