NASA's Space Technology 5 Microsatellites Begin Mission
An Orbital Sciences-built Pegasus XL rocket launches NASA's Space Technology 5 satellite trio from its Stargazer L-1011 parent aircraft on March 22, 2006.
Credit: NASA.

Three microsatellites, each the size of a large cake, rocketed into space Wednesday on a NASA mission to prove new technologies and observe space weather.

NASA's Space Technology 5 satellite trio rode an Orbital Sciences-built Pegasus XL rocket into orbit in a flawless launch staged from a jet flying 39,000 feet (11,887 meters) above the Earth.

"It looks like we're three for three," NASA launch director Chuck Dovale said after the successful launch. "It followed a smoothest count as I can remember on the Pegasus program, I think we were rewarded tonight for the trouble we had the other night."

Today's successful space shot occurred one week to the day of an aborted March 15 launch attempt, during which a last minute glitch prevented ST5's Pegasus rocket from detaching from its Stargazer L-1011 parent aircraft. A March 14 launch plan was also delayed due to a poor weather outlook.

But none of those problems plagued ST5's launch today, which occurred at about 9:03 a.m. EST (1403) as its Pegasus booster fell free of its L-1011 parent craft. By 9:20 a.m. EST (1420 GMT), all three ST5 spacecraft had flung away from their launch carrier to start their planned 90-day mission.

"We saw three deployments of the ST5 spacecraft come off kind of like a Frisbee-fashion, which was kind of neat to see," Dovale said.

During their spaceflight, the ST5 spacecraft are expected to evaluate six technologies that include a new cold gas microthruster for flight orientation, an outer "skin" to maintain the proper temperature, and software tools to aid autonomous ground operations among others, NASA officials said.

Each of the round ST5 spacecraft weighs about 55 pounds (25 kilograms) and measures about 21 inches (53 centimeters) wide and 19 inches (48 centimeters) tall. Their $130 million mission is part of NASA's New Millennium program to develop and test technologies for future missions.

The ST5 probes are also equipped with a boom-mounted magnetometer, an instrument that will scan the Earth's magnetosphere to study the effects of high-energy particles from the Sun's flares and coronal mass ejections.

"My experiences have shown that missions like this are rollercoasters," said Jim Slavin, ST5 project scientist at NASA's Goddard Space Flight in Greenbelt, Maryland, before today's launch. "I think the rollercoaster ride won't be over until the last day of our 90-day mission."