NASA, SpaceX lower expectations for historic flight to space station

George Leopold

May 18, 2012

George Leopold

WASHINGTON – On the eve of an historic launch of a commercial spacecraft to the International Space Station scheduled for Saturday (May 19), NASA and SpaceX officials again emphasized that the ambitious mission is ultimately a test flight and a “learning opportunity.”

The long delayed flight of an unmanned SpaceX Dragon spacecraft aboard a Falcon 9 rocket to the space station has a tight launch window early Saturday morning in order to catch up and dock with the space station after about 75 hours of orbital flight.

“This is a test flight [and] we want to make sure we learn something” as well as “wring out the spacecraft,” SpaceX President Gwynne Shotwell said during a briefing at the Kennedy Space Station.



The test flight is intended to show that SpaceX can launch its Dragon cargo ship into orbit and guide it to a rendezvous and docking with the space station. Only four nations have linked up with the orbiting laboratory, and SpaceX is the first commercial supplier to attempt a docking.

“This mission is extremely complicated,” stressed NASA’s Alan Lindenmoyer, manager of its commercial crew and cargo program. Given the difficulty of SpaceX achieving all of its goals on only the second test flight of the Falcon 9 and Dragon spacecraft, Lindenmoyer said unmet objectives would “roll over” to the next test flight scheduled for later this year.

Beyond that, NASA and SpaceX officials declined to define what would represent a successful mission.

SpaceX successfully launched the Dragon spacecraft to orbit and returned it to Earth in December 2010, marking the first time a commercial space company had done so.

But this weekend’s cargo mission is far more complex. The Dragon spacecraft will carry with it a “trunk” containing rendezvous and proximity sensors needed to catch up with and dock with the space station. Shortly after launch, solar panels will be deployed to generate power for onboard systems. Dragon also will carry redundant flight computers needed to guide the spacecraft to the space station’s docking hatch along with UHF communications so that space station astronauts can control Dragon’s approach and docking.

The spacecraft also will be controlled by what Shotwell called “dramatically more complex software” needed for navigation, rendezvous and docking. NASA managers and SpaceX engineers spent months examining every line of spacecraft code as part of a software assurance program. NASA officials were reportedly concerned about Dragon systems interfering with space station equipment.

Shotwell said the SpaceX team validated every code and configuration change in the flight software before NASA would sign off on the systems. The software assurance drill has delayed the Dragon launch several times.

Asked when SpaceX could begin flying U.S. astronauts to the space station, Shotwell estimated mid-2015 if NASA ultimately selects the Hawthorne, Calif., company. That ambitious schedule assumes most of the 17 scheduled test flights meet their objectives. “We have a lot of work in front of us to fly [a] crew,” Shotwell conceded.

Nevertheless, NASA managers called the transition to commercial launches to low Earth orbit “inevitable” as the space agency shifts its focuses to planetary missions. “The time is right” to turn over space station cargo and crew launches to the private sector, said Phil McAlister, acting director of NASA’s commercial spaceflight program. “We are [no longer] pushing the state of the art” with orbital missions, he added.

If SpaceX fails to launch on Saturday, NASA officials said the next launch window to reach the space station would be May 22.