WASHINGTON — A Dragon cargo spacecraft SpaceX plans to launch to the International Space Station this week will be making its second trip there as the company extends its approach to reusability.
The Dragon spacecraft, on a mission designed SpX-11, is scheduled for launch on a Falcon 9 at 5:55 p.m. Eastern June 1 on what will be the 100th launch in the storied history of Launch Complex 39A at the Kennedy Space Center in Florida. Forecasts project a 70 percent chance of acceptable weather in the instantaneous launch window.
The spacecraft is carrying more than 2,700 kilograms of scientific investigations and supplies for the station, arriving there on the morning of June 4. Should the June 1 launch attempt be scrubbed, NASA and SpaceX have a backup launch date of June 3 at 5:07 p.m. Eastern.
This launch will not be the first trip to the station for this Dragon spacecraft, or at least most of it. The spacecraft first launched on the SpX-4 mission in September 2014, returning to Earth a month later. SpaceX refurbished the spacecraft and won NASA approval to fly it again on SpX-11.
“The structure itself is the same as what flew the first time,” Hans Koenigsmann, vice president of mission assurance at SpaceX, said at a pre-launch briefing May 31 at the Kennedy Space Center. “The majority of this Dragon has been in space before.”
Some components have been replaced, most notably the capsule’s heat shield, as well as those items that could have been exposed to seawater after splashdown at the end of the Dragon’s first flight, he said. The trunk section at the rear of the spacecraft, which stores external payloads, is also new, as it burns up on reentry at the end of each mission.
“SpaceX did a very thorough job in terms of certification of the Dragon and refurbing it, and NASA did a very thorough job of understanding that certification and making sure that it was safe to fly and that risk was not substantially more than a brand new Dragon capsule,” said Kirk Shireman, NASA ISS program manager. “We’ve very happy with this capsule flying again.”
Shireman didn’t specify if NASA received a discount from SpaceX by accepting a used Dragon. SpaceX’s Commercial Resupply Services (CRS) contract with NASA is a fixed-price one, he said, but one that allows for “equitable adjustments” when circumstances change either for the agency or the company. “In general, when we do things like this, we make trades,” he said.
Koenigsmann said that the next Dragon mission to the station, launching later this year, will use a new spacecraft. However, he said it may be possible to perform the remaining missions after that on its current CRS contract, which has a total of 20 missions, using refurbished capsules.
SpaceX has become famous for landing its Falcon 9 first stages, and plans to land the first stage from this mission at its Landing Zone 1 at neighboring Cape Canaveral Air Force Station. It reused one for the first time on the launch of the SES-10 communications satellite in March. A second reused Falcon 9 first stage will launch the BulgariaSat-1 satellite in mid-June. However, Shireman said NASA is not yet ready to launch Dragons, new or reused, on a previously-flown Falcon 9.
“We want to be very methodical about it,” he said. “SpaceX is certifying the Falcon 9 for multiple flights. We want to take our time and review all of those certification results.” He said he wasn’t sure when NASA would approve the use of a reused Falcon 9 for a Dragon cargo mission.
The upcoming launch, as well as all previous Falcon 9 launches from Florida this year, have taken place from Launch Complex 39A, the pad previously used by the space shuttle and the Saturn 5. Space Launch Complex 40, located several kilometers away at Cape Canaveral Air Force Station, remains unavailable after it was damaged in a Falcon 9 pad explosion last September during preparations for a static-fire test.
Koenigsmann said at the briefing that repairs to the pad are in progress. “There’s lots of construction going on,” he said. “I’m anticipating a late summer return to operations there.”