KENNEDY SPACE CENTER, Fla. -- Eleventh-hour work to validate critical navigation and control software has forced Space Exploration Technologies to pass up a pair of launch opportunities next week, delaying the maiden flight of a commercial cargo ship bound for the International Space Station to May 19, company officials said today.
Already running about three months behind schedule, SpaceX gave up a May 7 launch slot earlier this week and during a late afternoon teleconference with senior NASA managers today, company officials decided to pass up a May 10 backup opportunity.
"SpaceX and NASA are nearing completion of the software assurance process, and SpaceX is submitting a request to the Cape Canaveral Air Force Station for a May 19 launch target with a backup on May 22," SpaceX spokeswoman Kirstin Brost Grantham said in a short statement. "Thus far, no issues have been uncovered during this process, but with a mission of this complexity we want to be extremely diligent."
May 10 was the last day the SpaceX Falcon 9 rocket and Dragon cargo capsule could have taken off and still completed a rendezvous and berthing before the planned launch of a Russian Soyuz spacecraft carrying three fresh crew members to the lab complex. The Soyuz TMA-04M spacecraft is scheduled for launch from the Baikonur Cosmodrome in Kazakhstan on May 14 U.S. time with docking at the station's upper Poisk module expected two days later.
SpaceX now hopes to launch its Falcon 9/Dragon spacecraft from pad 40 at the Cape Canaveral Air Force Station around 4:55 a.m. ET on Saturday, May 19. The flight plan calls for a series of test maneuvers during a close approach May 21 before berthing at the Earth-facing port of fhe station's forward Harmony module the next day.
"After additional reviews and discussions between the SpaceX and NASA teams, we are in a position to proceed toward this important launch," Bill Gerstenmaier, NASA's chief of space operations, said in a statement. "There are a few remaining open items but we are ready to support SpaceX for its new launch date of May 19."
The SpaceX Dragon capsule is the first commercial cargo ship to be cleared for a flight to the space station, a key element in NASA's long-range strategy to use private-sector spacecraft to help keep the lab complex supplied in the wake of the space shuttle's retirement. SpaceX of Hawthorne, Calif., holds a $1.6 billion contract to launch 12 resupply missions while Orbital Sciences of Dulles, Va., holds a contract valued at $1.9 billion for eight flights.
Both companies hold separate contracts for test flights and SpaceX is first to the launch pad with its Falcon 9/Dragon spacecraft. For this initial flight, the Dragon capsule will be carrying 1,150 pounds of non-critical equipment and supplies, including clothing and food for upcoming crews. If all goes well, Dragon will remained docked to the station for at least two weeks, depending on lighting and temperature constraints, before it is released for a splashdown off the coast of California.
"The most important thing about this first attempt is to make sure you get your hardare, your software and your operations down correctly," space station flight engineer Donald Pettit told CBS News in an interview earlier today. "They could send an empty vehicle up here from a supply point of view and the important aspect is to show that we can actually do this. The supplies are just frosting on the cake.
"However, we are on a frontier up here and we're always on the verge of (being) supply limited and you can't just run down to the local grocery store," he said. "Just as an example, we're almost out of disinfectant wipes, and without that we can't clean our hands after we go to the bathroom. We're always running low on things like that. We're getting low on garbage bag liners...There's always something that we're short on up here, and the more wagons bringing supplies to station, the better we can continue our work."
After a successful test flight of the Falcon 9/Dragon spacecraft in December 2010, SpaceX successfully lobbied NASA to combine a second and third into a single mission that would include the first Dragon berthing with the station. Launch originally was targeted for early February, but the flight has been repeatedly pushed back to give SpaceX additional time to validate its trajectory analysis and command software.