Discovery's crew, left to right, Nicole Stott, Mike Barratt, Tim Kopra, Alvin Drew, Eric Boe and Steve Lindsey. Astronauts arrive at Kennedy Space Center on Thursday. Photo credit/NASA

NASA will aim for an Election Day lift of the shuttle Discovery on the orbiter’s final flight, a one day delay called for on Friday to repair helium and nitrogen leaks in the spacecraft’s right Orbital Maneuvering System pod.

A Tuesday lift off would occur at 4:17 p.m., EDT, the middle of a 10 minute launching period. With the shuttle program closing in on retirement, large crowds are expected in Central Florida to witness the departure.

Discovery’s six astronauts have trained for an 11-day mission to the International Space Station for the delivery of an equipment storage module and external spare parts.

Discovery’s crew

Veteran shuttle commander Steve Lindsey’s crew includes pilot Eric Boe and mission specialists Alvin Drew, Tim Kopra, Mike Barratt and Nicole Stott.

The countdown, which was to get under way on Friday, will start instead on Saturday at 2 p.m., EDT, if the leaks in the system that pressurizes propellant tanks and opens and closes valves in the fuel line plumbing can be repaired. The shuttle has two tail mounted Orbital Maneuvering System engines that are used during space station rendezvous maneuvers as well as to carry out the braking maneuver that starts the descent to Earth at the end of the mission.

Leaks Found Overnight

 

The leaks were discovered late Thursday and early Friday as the propulsion system was being pressurized, according to NASA Test Director Jeff Spaulding.

The weather forecast for Tuesday includes a 70 percent chance of favorable conditions. There is a small chance that cloudy skies or isolated rain showers could interfere, said Kathy Winters, the shuttle launch weather officer.

Discovery’s launch period extends through Nov. 7. The mission would then face a delay until early December because of temporary excessive solar heating on the station’s orbital plane.

Favorable Weather Expected for Multiple Launch Attempts

Tuesday’s favorable weather outlook will hold through Thursday.

The mission is the 39th and final flight for Discovery, which will be retired about 26 years. NASA’s fleet leader launched the Hubble Space Telescope in 1990 and led NASA back into space following the 2003 Columbia and 1986 Challenger tragedies.

Discovery’s cargo also includes Robonaut 2, the first humanoid assigned to a space mission. The robot will become a permanent resident of the space station and under go testing to determine its suitability for spacewalks as well as internal maintenance duties.

Endeavour’s flight could be program’s final flight

 

Endeavour is scheduled to launch the shuttle program’s final mission, lifting off Feb. 27 on a two-week mission to deliver the Alpha Magnetic Spectrometer, a $2 billion astronomical observatory that will be fastened to the station’s solar power truss. The White House and Congress are evaluating the need for an additional flight of shuttle Atlantis in mid-2011.