SpaceX tentatively cleared for April 30 launch attempt

On Monday, NASA and SpaceX officials met for a Flight Readiness Review (FRR) for SpaceX’s upcoming Dragon mission to the International Space Station (ISS). After the FRR, NASA announced at a press conference that they had given tentative approval for that April 30 launch, pending some final tests and simulations.

“Everything looks good as we head towards the April 30th launch date, but I would caution us all that there’s quite a bit of work that needs to be done,” said Bill Gerstenmaier, NASA’s associate administrator for human exploration and operations, at the post-FRR briefing. “There’s a good chance to make the 30th.” That additional work an additional long simulation and som additional software testing, Gerstenmaier said. NASA and SpaceX will assess their progress on April 23, although not in a formal FRR-like meeting, and proceed from there.

This mission, designated “C2+”, will combine the separate C2 and C3 missions in SpaceX’s original Commercial Orbital Transportation Services (COTS) awards. Dragon will first work to achieve the C2 mission requirements of approaching and maneuvering around the station. If successful, SpaceX and NASA will proceed with the C3 milestones, capped off by berthing the Dragon spacecraft to the station, which would take place as early as May 3, assuming an on-time launch at 12:22 pm EDT (1622 GMT) on April 30. Dragon will remain berthed to the station for about two and a half weeks before undocking and returning to Earth, splashing down in the Pacific off the California coast.

Both the space agency and the company emphasized that this mission is a test mission, and any problems don’t indicate a lack of capability or other systemic problems with the vehicle or commercial cargo in general. “This is a test flight,” said SpaceX CEO Elon Musk. “If we don’t succeed in berthing on this mission, we’ve got a couple of more missions later this year and I think we’ll succeed on one of those.”

If this mission does succeed in berthing, it will supply the station with some cargo. ISS program manager Michael Suffredini said the Dragon will carry 521 kilograms of cargo, primarily consumables and other crew provisions. It also will carry a NanoRacks payload with some student experiments. Dragon will also return 660 kilograms from the station back to Earth, although Suffredini said the exact manifest of “downmass” cargo remains to be determined.

If SpaceX misses the April 30 launch (which is an instantaneous window, so no margin for error in the event of weather or technical issues), a second launch window is on May 3. The gap between launch windows is for a variety of reasons, including seeking to minimize the propellant needed to put Dragon into orbit so it has more available for ISS maneuvers. If Dragon doesn’t launch either day, it will slip until at least mid May, deferring to an Atlas launch from the Cape and a Soyuz mission to the ISS planned for early May.

At the post-FRR briefing, both NASA and SpaceX praised each other and the spirit of cooperation between the two for this flight, which departs from the tradition of NASA-managed missions. ISS mission controllers in Houston and Dragon flight controllers at SpaceX’s Hawthorne, California, headquarters are learning to work together to understand each others’ capabilities and requirements to allow for a smooth mission, in much the same way NASA already does for cargo missions by ESA’s ATV and JAXA’s HTV spacecraft. “It’s been a learning experience, I think, for NASA and SpaceX,” said Suffredini. “We’ve really grown together as two organizations.”