In this historical photo from the U.S. space agency, a Pegasus rocket is carried to altitude beneath a B-52 on Apr. 5, 1990. The Pegasus was developed as a low-cost way to put small payloads into space. It's somewhat like an oversized model rocket. An air-launched, three stage, all solid-propellant, three-axis stabilized vehicle, the Pegasus can put a 1,000 pound payload into low-Earth orbit.
To get there, a Pegasus is released from a B-52 at about 39,000 feet, freefalls for around 5 seconds, then the first stage motor fires and accelerates the rocket to over 5,000 mph. The motor burns out after about 76 seconds, and a second stage ignites at the 97-second mark. Nearly 10 minutes later, the rocket can reach an altitude of 460 miles above earth, doing nearly 17,000 mph, and the payload is released.
Each weekday, SPACE.com looks back at the history of spaceflight through photos (archive).