Discovery Undocks for Trip Home

The shuttle Discovery left the International Space Station on Saturday en route to a planned homecoming Monday at the Kennedy Space Center.

With Navy Cmdr. Mark Kelly piloting, the shuttle and its crew of six undocked from the station as the spacecraft flew 210 miles above the Pacific Ocean north of New Zealand. Kelly slowly eased the shuttle away before firing steering jets to separate the ships.

During Discovery’s nine-day visit, the shuttle dropped off a third resident for the station, German astronaut Thomas Reiter, along with more than 3 tons of equipment and supplies. The crew also performed three spacewalks, including one that restored mobility to a robot arm on the station critical to continuing the outpost’s construction.

After Saturday morning’s undocking, Discovery’s astronauts used a sensor-equipped boom at the end of the shuttle’s 50-foot robotic arm to inspect the nose of the orbiter and the right wing’s leading edge for damage from orbital debris or micrometeoroids. A survey of the left wing was completed Friday.

Engineers are studying the results and this morning plan to clear Discovery’s heat shield for the flight home if, as expected, no damage is detected.

Today, the crew will check out Discovery’s flight control systems to get ready for a planned Monday-morning landing at Kennedy Space Center.

Mission managers will focus on one of three auxiliary power units that operate the ship’s body flaps, brakes and steering during landing. The unit has a small leak of either hazardous hydrazine fuel or harmless nitrogen gas. Engineers have been unable to determine which.

The leaky unit will be turned on for about five minutes and if the leak rate doesn’t worsen, the plan is to use the unit during landing as usual.