Launching Light Satellites: Pegasus

ISS Re-supply Contract

Orbital Sciences Corporation (OSC) recently won a contract with NASA to re-supply the International Space Station (ISS). They, along with SpaceX, will do work previously only performed by the Russian Progress unmanned spacecraft…and our Shuttles.

I don’t know how OSC will do their work. What spacecraft they have and will be using to send up supplies and how it will dock with ISS is unclear…at least to me. (OSC has other launch vehicles, called Taurus and Minotaur. They are probably going to use some version of the Taurus with a new vehicle called Cygnus.)

Dependable, Cheap Satellite Launches

But, OSC has a long history of government contracts and launching things into orbit. They created a system called Pegasus for the U.S. Defense Department back in the 1980s. And here’s how it works:

The Pegasus rocket is lifted to a height of 38,000 feet, mounted to the underside of a large jet. About 5 seconds after release, stage one of Pegasus fires and lifts the rocket to a height of 39 miles. The rocket continues to climb on its first-stage wings. At an altitude of 55 miles, the second stage fires and raises the altitude to 130 miles. At 460 miles high, a third stage accelerates the craft to orbit.

Incredibly, after only computer simulations, the very first launch of Pegasus, in 1990, was a success. It put 2 small satellites into orbit. And since late 1996, the success rate has been 100%.