Astronaut James Newman hoisted a 4,300-pound steel disc with Endeavour's robot crane Friday to test the field of ionized particles that flow over the shuttle as it zooms around Earth.
Newman, working from inside Endeavour's crew cabin, held the Wake Shield Facility amid the particle field during experiments that called for him to dangle the satellite over the side of the cargo bay and later lift the craft high overhead.The goal was to help engineers create a map of particle flow over the shuttle.
The $25 million satellite was retrieved Thursday after three problem-filled days flying free of the shuttle for semiconductor research, its principal mission.
This time, the 12-foot dish was used to examine Endeavour's atomic wake - waves of charged particles formed as the shuttle plows through atomic oxygen at 17,500 mph.
Sensors mounted on both sides of the Wake Shield were to measure the volume of ions, or charged particles, flowing around the spaceship, as well as their composition, temperature and direction of flow.
NASA has long been interested in the so-called plasma glow produced when shuttle surfaces interact with atomic oxygen. Engineers want to know more about it to be sure the particles can't interfere with spaceship communications.
The crew's last major task of the flight is a Saturday spacewalk by astronauts James Voss and Michael Gernhardt, who will spend six hours testing tools and techniques for building a space station.
Endeavour is due back in Florida on Monday with the Wake Shield and Spartan, a solar-research satellite that was released and retrieved early in the 11-day mission.