Goals: Bumper rockets were the first two-stage rockets -- a German V-2 missile coupled with an American-made WAC Corporal. They were designed to test high altitude rocket systems and study Earth's upper atmosphere.

Accomplishments: Bumper rockets were the first human-made objects to cross the boundary into outer space, although they did not orbit the Earth like Sputnik 1 (the first true spacecraft). The rocket's upper stages were able to reach then-record altitudes of up to 399 kilometers (248 miles), higher than even modern space shuttles fly. The rockets' small science payloads also sent back information on air temperatures and cosmic ray impacts.