NASA gave the all-clear today for the first test flight of SpaceX’s Crew Dragon spaceship to the International Space Station in a week, setting the stage for crewed missions later this year.
There won’t be any crew aboard this first Crew Dragon, also known as the Dragon 2, but there will be an instrument-laden, spacesuit-wearing mannequin sitting in one of the seats, to provide data about the environment that astronauts will experience.
“Should I say ‘dummy,’ is that the right word?” Hans Koenigsmann, SpaceX’s vice president of mission assurance, asked during a briefing for reporters at NASA’s Kennedy Space Center in Florida.
“ATD, ATD,” said Kathy Lueders, program manager for NASA’s commercial crew program. “We prefer to not call them dummies.” (For the record, ATD stands for Anthropomorphic Test Device or Anthropomorphic Test Dummy.)
There’ll also be a load of cargo to be sent up to the station from Launch Complex 39A at NASA’s Kennedy Space Center, at 2:48 a.m. ET March 2 (11:48 p.m. PT March 1). Lueders said the total mass would be “pretty close” to what the Dragon 2 will carry when astronauts climb aboard.
The Crew Dragon is an upgraded version of SpaceX’s robotic cargo-carrying Dragon — which has been resupplying the space station since 2012, a year after NASA retired its space shuttle fleet.
Like Dragon 1, Dragon 2 is designed to be launched by SpaceX’s Falcon 9 rocket. But the upgraded Dragon has a more robust thruster system that’s meant to power the spacecraft and its crew out of harm’s way if something goes wrong during launch or ascent. It has side-mounted solar arrays and can seat up to seven spacefliers. And instead of having to be pulled in for its berthing with the space station’s robotic arm, Dragon 2 can fly directly in for its docking.
NASA and SpaceX are still working to close out some remaining issues in advance of next week’s launch of Demonstration Mission 1, or DM-1. For example, Russian space officials voiced concerns about the computer system that SpaceX will use when the Dragon approaches the station for docking early on March 3. NASA officials said their Russian counterparts registered a dissenting opinion when mission managers approved the launch date at today’s Flight Readiness Review.
Bill Gerstenmaier, NASA’s associate administrator for human exploration and operations, said the spaceships that dock with the station typically have a separate backup system that kicks in if the main computer system goes out of commission during approach. SpaceX, however, is using a single, fault-tolerant computer system.
“We think that’s acceptable,” Gerstenmaier said. But because of the Russians’ concerns, NASA engineers will take a closer look at the potential failure modes. “I don’t think it’ll be a problem once we go through the details of why it’s safe, and we can explain to them why we’re moving forward,” he said.
“I fully expect we’re going to learn something on this flight,” Gerstenmaier added. “I guarantee everything will not work exactly right, and that’s cool.”
After the Dragon is docked, the station’s spacefliers will open up the hatch, move cargo back and forth and conduct a survey to assess how the spacecraft weathered its maiden voyage. Exterior surveys will be made using the station’s camera-equipped robotic arm, to check for any dings from orbital debris.
The Dragon and its dummy … er, ATD … are due to leave the station on March 8 and splash down in the Atlantic Ocean, a couple of hundred miles off the Florida coast. A ship will recover the capsule and bring it back to shore for study.
“When we have the crewed missions, it’ll be closer in,” Lueders said.
There’s a list of issues to be resolved more fully before NASA gives the go-ahead for the crewed test flight to the station, known as Demonstration Mission 2 or DM-2. Two NASA astronauts, Robert Behnken and Doug Hurley have already been assigned to that flight and are undergoing training.
Gerstenmaier said the open issues include:
- Concerns about carbon-composite-wrapped helium tanks on the Falcon 9 rocket that were implicated in launch-pad explosion that occurred in September 2016. SpaceX says the tanks have been redesigned to solve the problem, but NASA wants to make sure they’re safe.
- A condition that could lead to parts of SpaceX’s Draco thrusters breaking free under low temperatures. “We’re totally avoiding that condition on this mission by controlling the operational parameters of the mission,” Lueders said.
- Further testing that’s required for the Crew Dragon’s parachute system. “We’re comfortable that this parachute system is perfectly good for DM-1,” Gerstenmaier said. “It could be also OK for DM-2 the way it is, but we need to get through this qualification testing and understand how much margin we have in certain areas to see if it’s the right thing to do.”
Assuming that DM-1 is a success and that all the open issues are resolved, SpaceX plans an uncrewed in-flight abort test of the Crew Dragon in June, followed by DM-2 in the July time frame.
Meanwhile, Boeing is on a separate track to get its Starliner space taxi ready for orbital test flights. The current schedule calls for sending an uncrewed Starliner to the station and back in April or so, followed by a pad abort test a month later. The first crewed Starliner flight is set for no earlier than August.
After the first crewed test flights, NASA will once again take stock of the space taxis’ performance and get any remaining issues resolved before certifying them for operational missions. That process seems certain to slop over into 2020.
To ensure continued access to the space station, even if snags develop, NASA is looking into buying more seats on Russian Soyuz spacecraft — or converting Boeing’s crewed test flight into an operational crew transfer mission if necessary. Gerstenmaier said a decision on that score would be made later this year when the test program is further advanced.