WASHINGTON — NASA announced the four astronauts who will make up the crew of STS-335, the rescue mission that would fly only if needed to bring home the members of space shuttle Endeavour’s STS-134 mission, currently the final scheduled shuttle flight.

Chris Ferguson, a retired U.S. Navy captain and veteran of two previous shuttle missions, would command the flight. Astronaut and U.S. Marine Col. Doug Hurley would serve as pilot, and astronauts Sandy Magnus and retired U.S. Air Force Col. Rex Walheim would be the mission specialists.

Based on recommendations made after the loss of space shuttle Columbia in February 2003, NASA has trained a launch on need crew to be ready to fly in the event of irreparable damage to a shuttle while in orbit. Typically, the next crew to fly serves as the rescue crew for the current mission. The STS-335 crew will prepare for a potential rescue mission and preserve flexibility if another shuttle flight is added to the launch manifest.

“These astronauts will begin training immediately as a rescue crew as well as in the baseline requirements that would be needed to fly an additional shuttle flight,” said Bill Gerstenmaier, associate administrator for NASA’s Space Operations Mission Directorate in Washington. “The normal training template for a shuttle crew is about one year prior to launch, so we need to begin training now in order to maintain the flexibility of flying a rescue mission if needed, or alter course and fly an additional shuttle mission if that decision is made.”

If required, the STS-335 rescue mission would launch on shuttle Atlantis in June 2011 to bring home the STS-134 crew from the International Space Station. STS-134 currently is scheduled to lift off on Feb. 26, 2011, from NASA’s Kennedy Space Center in Florida. If converted to an additional shuttle flight, STS-335 would be redesignated STS-135 and targeted to launch in June 2011.

Ferguson, who was born in Philadelphia, flew on two prior shuttle missions, STS-115 in 2006 and STS-126 in 2008. Hurley, who was born in Endicott, N.Y., but considers Apalachin, N.Y., his hometown, served as the pilot on STS-127 in 2009. Magnus, of Belleville, Ill., flew on STS-112 in 2002 and launched to the space station in 2008 on STS-126, where she served four and a half months as a flight engineer and science officer on Expedition 18 before returning to Earth on STS-119 in 2009. Walheim was born in Redwood City, Calif., and considers San Carlos, Calif., his hometown. He flew on STS-110 in 2002 and STS-122 in 2008.

For more information on the Space Shuttle Program, visit: http://www.nasa.gov/shuttle

For complete biographies of the four astronauts, visit: http://www.jsc.nasa.gov/Bios