A shuttle takes flight bolted to a jumbo jet's back

On February 18, 1977, NASA’s prototype orbiter Enterprise left the ground for the first time, riding bolted to the back of a modified Boeing 747 known as the Shuttle Carrier Aircraft, NASA 905. No one was aboard Enterprise itself; the orbiter was inert ballast for the day.

This was the opening run of the Approach and Landing Tests, a nine-month campaign at Dryden Flight Research Center in California. The mated pair flew for 2 hours and 5 minutes, reaching about 16,000 feet and 287 mph, while engineers measured how the unusual stack handled loads, vibration, and steering.

Enterprise never flew in space, but it taught the program how to fly home.

These captive flights led to the famous free flights later in 1977, when astronaut crews released Enterprise to glide unpowered to a runway, validating the landing approach every space-flown shuttle would later use.