Explorer 1: United States first space explorer.
Explorer 1 was the first satellite launched by the united states January 31, 1958. This was launched after the Soviet union (Russia) launched sputnik 1 October 2, 1957. The U.S. Army Ballistic missile agency was directed to launch a satellite using a Jupiter C rocket under direction of Dr. Wernher Von Braun. The JPL Jet propulsion laboratory received the assignment to design, operate and build the rocket . They completed this job in 3 months. The primary science instrument was a cosmic ray detector , the cosmic ray detector was to measure the radiation in earth orbit. This space experiment was created by Dr. James Van Allen. Explorer 1 traveled 354 kilometers (220 miles) It made 1 orbit every 114.8 minutes a total of 12.54 orbits per day. The satellite was 203 centimeters ( 80 inches long ) and 15.9 centimeters( 6.25 inches) in diameter. Explorer made it's final transmission May 23, 1958. It entered earths atmosphere and burned up on March 31, 1970 after 58,000 orbits . The satellite weighed 14 kilograms (38.8 pounds). A launch attempt of a similar satellite was attempted Explorer 2 was made on March 5, 1958 the fourth stage of the Jupiter C rocket failed to ignite. Explorer 3 was successfully launched on March 26, 1958. explorer 3 operated until October 6 of that year. The launch of Explorer 5 on August 24, 1958 failed when the rocket booster collided with it's second stage of separation causing the firing angle of the upper stage to be incorrect.Explorer 1 was launched in Cape Canaveral Missile Annex, Florida.