Posted: Thu, Apr 26, 2007, 8:23 AM ET (1223 GMT)

A Pegasus rocket successfully launched Wednesday a small satellite designed to study clouds in the Earth's upper atmosphere. The Pegasus XL was deployed from its L-1011 carrier aircraft off the coast from Vandenberg Air Force Base, California, at 4:26 pm EDT (2026 GMT) and placed the 200-kilogram Aeronomy of Ice in the Mesosphere (AIM) spacecraft into polar orbit. AIM is designed to study high-altitude noctilucent clouds, usually only seen in polar regions at night but increasingly found at lower latitudes. The launch was the first this year for the Pegasus, a small launcher developed by Orbital Sciences Corporation.