ST5 to try again

NASA will try again Wednesday to launch Space Technology 5, a trio of beach-ball-size satellites that could pave the way for a future solar-storm warning system. They will test equipment that would enable dozens of tiny satellites to monitor space weather and do other science in orbit. The satellites will launch at 9:02 a.m. EST, on a Pegasus rocket dropped from a jet flying out of Vandenberg Air Force Base in California. Then they will spin into orbits that will take them over the Earth's poles and allow them to monitor variations in the magnetic field. The launch window ends at 10:02 a.m.

A launch attempt March 15 was aborted when a pin retractor system failed on the rocket, possibly due to ice formation. The part was replaced, and NASA says it has worked to minimize water intrusion that could lead to more ice. There's an 80 percent chance of favorable weather conditions for the launch. See our earlier preview.