Atlantis's astronauts Sunday released a reusable European satellite that will study the effects of weightlessness on crystals, brine shrimp eggs, and fungal spores.
European Space Agency scientists worked into the early morning to clear up communications problems that had delayed the release of the Eureca satellite by a day.
"Houston, we've got a release," pilot Andrew Allen told Mission Control, after Swiss astronaut Claude Nicollier freed the scientific satellite from the end of the shuttle's robot arm.
The astronauts succeeded on the first of five chances Sunday, the last day they could deploy the satellite. The National Aeronautics and Space Administration had said Eureca would be repacked in Atlantis's cargo bay and returned to Earth if it had not been released Sunday.
After the release, Atlantis moved about 1,000 feet behind Eureca, where it was to fly for a few hours to make sure the satellite was working. Eureca then was to be raised by on-board thrusters from an altitude of 264 miles to 320 miles.
It will orbit until next spring, when another shuttle crew isto swing by and pick it up.
Scientists plan to analyze Eureca's biological samples after months in space. In addition to those specimens, Eureca holds a gamma ray and X-ray telescope, cosmic dust catchers and solar monitors.
Trouble struck the satellite early Saturday, less than a day into Atlantis's flight. Flight controllers missed three orbital opportunities to release the satellite before giving up for the day. The satellite had suffered data dropouts when it tried to communicate with ground stations. But late Saturday, smooth contact was established between the satellite and earth stations.