Suborbital space flight

The first rockets to explore space flew a basic up-and-down trajectory and did not have the velocity (of 18,000 mph or 29,000 kph) to attain Earth orbit. In their plans to place a man in space first, both the Americans and the Soviets investi­gated a program of suborbital space shots, launching on smaller rockets to about 100 miles (approximately 160 km) before separating for landing several hundred miles downrange. Clearly these rockets could not attain the thrust required for orbital flight and the vehicles they carried (commonly called capsules) would not have the capacity for a controlled land landing similar to the X-15, so they were termed suborbital missions. While the Russians abandoned the suborbital program in favor of proceeding directly to orbital missions, NASA chose to send its first two astronauts on suborbital hops down the Atlantic Missile Range in 1961, ending up in the Atlantic Ocean barely 15 minutes after launch. These two mis­sions have always been accredited as America’s first two space flights, but in some more recent online listings, while the pilots Alan Shepard and Gus Grissom are accredited with their “suborbital space missions”, they are not listed under manned space flights. Instead, the three-orbit mission of John Glenn in February 1962 is credited as America’s first (orbital) flight in space, so the debate continues—and will probably do so for some time.