Falcon 9 SpX-27 launch
A Falcon 9 streaks towards orbit carrying a Dragon cargo spacecraft March 14. Credit: SpaceX

WASHINGTON — A SpaceX cargo Dragon spacecraft is on its way to the International Space Station carrying supplies and experiments after a launch March 14.

A Falcon 9 lifted off from Kennedy Space Center’s Launch Complex 39A at 8:30 p.m. Eastern. The Dragon spacecraft separated from the rocket’s upper stage about 12 minutes after liftoff and is scheduled to dock with the ISS at 7:52 a.m. Eastern March 16.

The spacecraft, flying the SpX-27 cargo mission under SpaceX’s Commercial Resupply Services 2 contract with NASA, is carrying 2,852 kilograms of cargo, more than 40% of which is science experiments for the station. Those payloads include studies of the effects of microgravity on heart tissue, tests of carbon dioxide removal techniques and one experiment to expose bacteria and spores to the space environment.

The Dragon is also carrying supplies for the crew and station hardware. The Dragon will spend about a month docked to the station before returning to Earth with completed science experiments and other hardware.

The mission is the third flight of this cargo Dragon, which previously flew the SpX-22 and SpX-24 mission. The Falcon booster, which landed on a droneship in the Atlantic, completed its seventh mission.

While NASA has previously discussed certifying boosters for up to five launches for crewed missions, there is no firm limit for cargo missions. “It’s based on the assessment of the health of the booster and to meet the requirements of a government mission,” said Phil Dempsey, NASA ISS transportation integration manager, during a pre-launch briefing March 13.

The launch of SpX-27 came just days after the docking port that spacecraft will use was freed up by the departure of the Crew-5 mission, which undocked from the station March 11 and splashed down later that day. It’s the latest in what NASA officials have described as a busy sequence of missions to the station, although the schedule of some of those upcoming missions is uncertain.

A Northrop Grumman Cygnus cargo spacecraft currently at the station is scheduled to leave this spring, concluding the NG-18 mission, while the NG-19 Cygnus would launch soon thereafter. The timing of both the NG-18 departure and NG-19 launch “is still being worked out,” Dempsey said before the Dragon launch.

While earlier schedules had indicated a launch in April of NG-19, Dempsey would only say that the NG-18 departure would take place some time in the next one to two months. The NG-19 launch would take place later in the spring. “There’s readiness that’s being worked between Northrop Grumman and NASA to understand when the vehicle is ready,” he said.

Also in flux is the launch of the first crewed mission of Boeing’s CST-100 Starliner to the ISS. At a mid-February briefing, NASA and Boeing officials said they were planning a launch in mid to late April, but at the SpX-27 briefing, Dempsey said the current planned launch date was no earlier than the end of April.

“There’s handful of open work that’s still being assessed,” he said. The current launch date of the end of April “is under review at the moment based on the readiness of the vehicle.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...