Updated at 1 p.m. Eastern with comments from the post-launch press conference.
WASHINGTON — A SpaceX Falcon 9 successfully launched a Dragon cargo spacecraft to the International Space Station Dec. 15 on the first use of a previously-flown first stage for a NASA mission.
The Falcon 9 lifted off from Space Launch Complex (SLC) 40 at Cape Canaveral Air Force Station at 10:36 a.m. Eastern. It placed the Dragon spacecraft, flying on a mission designated SpX-13, into orbit 10 minutes after liftoff. The Dragon is scheduled to arrive at the International Space Station early Dec. 17.
The launch was the first Dragon mission to use a previously-flown first stage, in this case one that first flew on a previous Dragon launch in June. As with that earlier launch, the first stage made a successful landing at SpaceX’s Landing Zone 1 at Cape Canaveral.
The launch was the fourth SpaceX mission to use a previously-flown first stage. The previous three flights were all for commercial customers, two launches for satellite operator SES and one for BulgariaSat. Iridium will also fly a reused booster on its next Falcon 9 launch of 10 Iridium Next satellites, scheduled for Dec. 22.
At a pre-launch press conference Dec. 11, Kirk Shireman, ISS program manager at NASA, said the agency concluded after months of reviews with SpaceX that the risk of using a previously-flown booster was similar to using a new one.
“We’re very comfortable that the risk posture on this vehicle is not significantly greater than a new booster,” he said at the pre-launch briefing. “The net result is about equivalent risk.”
At a post-launch press conference at the Kennedy Space Center, Ven Feng, manager of NASA’s transportation integration office for the ISS program, said that use of previously-flown first stages on future Dragon missions would be done on a case-by-case basis. “We’re considering that for the future as well, but no decisions have been made yet,” he said.
The Dragon, which itself is a reused spacecraft that first flew on a 2015 mission, is carrying 2,205 kilograms of cargo to the station, including supplies for the station’s crew and experiments. The payloads range from an experiment by the company Made In Space to test the production of high-quality optical fibers in weightlessness to a NASA sensor that will be mounted on the station’s exterior to measure minute variations in solar irradiance.
The launch marked the return to service of SLC-40, which suffered extensive damage in a September 2016 pad explosion that destroyed a Falcon 9 and its satellite payload during preparations for a static fire test. SpaceX spent about $50 million to rebuild and improve the pad.
“We really looked at this as an opportunity to not only rebuild the pad, but to make it better,” said John Muratore, director of SLC-40 at SpaceX, in a call with reporters Dec. 8. Those improvements, he said, will allow for faster turnarounds between flights, key as SpaceX seeks to further increase its launch activity in 2018 and beyond.
Jessica Jensen, director of Dragon mission management at SpaceX, said at the post-launch briefing that Muratore confirmed to her that the pad “looked great” after the launch. “All the additional work they put into this pad kept it strong, which means we’ll be able to have much faster turnarounds in the future,” she said.
The launch was the 17th for SpaceX in 2017, far and away the most it has done in a single year. The Dec. 22 Iridium launch is the company’s last scheduled mission for the year.