Poor Weather Threatens NASA Space Technology Launch
The Pegasus XL rocket sits inside Orbital Sciences' Building 1555 at Vandenberg Air Force Base, Calif., after being mated with the Space Technology 5 satellites.
Credit: NASA.

A NASA mission to launch three small satellites on a technology-testing spaceflight Tuesday is facing a stormy start, launch officials said Sunday.

The Space Technology 5 mission, which is expected to shake down microsatellite technologies for future missions to track space weather, has just a 20 percent chance of rocketing spaceward from an air-based mothership due to poor weather conditions expected for its March 14 launch target.

Poor weather has already forced ground crews to shift their schedules during the spacecraft's weekend launch preparations, said Chuck Dovale, NASA's ST5 launch director, during a press conference at Vandenberg Air Force Base in California. On Sunday, hail at the mission's Vandenberg staging ground delayed battery charging for all three microsatellites, he added.

NASA's $130 million ST5 mission, part of the agency's New Millennium Program to develop new technologies, is currently set to launch three small microsatellites - each the size of a large cake (or 13-inch television set) and weighing 55 pounds (25 kilograms) - into orbit atop an Orbital Sciences' built Pegasus XL rocket.

An L-1011 Stargazer aircraft will haul the Pegasus booster to an altitude of about 39,000 feet (11,887 meters) before dropping the rocket into launch position at about 9:02 a.m. EST (1402 GMT). The space shot has a 77-minute launch window, Dovale said.

Technology shakedown

Each of the three ST5 spacecraft is expected to test six technologies that range from software tools for autonomous ground operations to a new cold gas micro-thruster for minute course corrections.

The microsatellites also carry a flux magnetometer to measure the effects of solar radiation and particles on the Earth's magnetic field, mission managers said.

Such interactions between particles and radiation from the Sun - such as coronal mass ejections or solar flares - and the Earth's magnetic field can interfere with satellite operations, communications - including mobile phones and pagers - and other space-based systems that society has grown dependent in the last few decades.

"ST5 is going to measure the intensity...the stability and the motion of the electrical currents moving in and out of our ionosphere," said James Slavin, the mission's project scientist at NASA's Goddard Space Flight in Greenbelt, Maryland. "We're going to demonstrate constellation level science operations, to take multiple spacecraft and operate them as a single instrument."

The ST5 mission could lead to a future space weather monitoring system and better techniques to safeguard satellites from the radiation environment, Slavin added.

"We may actually launch a space weather mission with a 100 small satellites in the future," Slavin said, adding that each of the swarm's microsatellites could be positioned in a different location to allow better forecasts, monitoring and possibly early-warning capabilities of solar events.

But first, the ST5 must begin its 90-day mission.

U.S Air Force Capt. David Bieger, the flight's launch weather officer for the 30th Weather Squadron at Vandenberg, said that while forecasts of rain, thunderstorms and thick clouds threatened ST5's planned Tuesday launch, there was an 80 percent chance of favorable conditions for a March 15.

"It's much more favorable on Wednesday," Bieger said of ST5's launch conditions.