Today is a very big day for human spaceflight, NASA officials said, but it's still unclear what tomorrow will bring.
Boeing's CST-100 Starliner capsule landed safely at White Sands Missile Range in New Mexico this morning (Dec. 22), bringing an end to its truncated debut mission, the uncrewed Orbital Flight Test (OFT).
The reusable Starliner thus became the first crew vehicle to touch down on American soil after an orbital trip since the space shuttles retired in July 2011, and the first capsule ever to do so. (NASA's Apollo and Orion capsules have landed in the ocean, as has SpaceX's Crew Dragon spacecraft.)
Related: Boeing's 1st Starliner Flight Test in Photos
"It was an absolute bullseye, better than I think anybody anticipated," NASA Administrator Jim Bridenstine said of the landing during a news conference today. "That's good for the agency, it's good for Boeing; that's good for the United States of America."
But not everything went smoothly on OFT. The mission was supposed to last eight days and feature an automated rendezvous and docking with the International Space Station (ISS), demonstrating Starliner's ability to ferry astronauts to and from the orbiting lab and clearing the way for a crewed test flight next year.
But an error with Starliner's onboard timing system, which manifested shortly after liftoff on Friday morning (Dec. 20), nixed that original plan. The timing problem prevented the capsule from properly performing a pivotal engine burn, trapping Starliner in the wrong orbit, NASA and Boeing representatives have said.
So Starliner ended up circling Earth on its own for about 48 hours and then coming home, leaving some original mission objectives unachieved. But that doesn't necessarily mean the capsule will have to refly OFT before astronauts can climb aboard, NASA officials said.
Indeed, going straight to the Crew Flight Test (CFT), which will carry three astronauts to and from the ISS, is definitely still on the table, NASA Commercial Crew Program deputy manager Steve Stich said during today's news conference.
"To me, there's good data out there to suggest that, once we go through it, maybe it's acceptable to go, next step, fly the Crew Flight Test," Stich said. "But we have to go through the data first."
That good data includes a nominal launch and landing, the two most important milestones to check off on a human spaceflight, Stich and Bridenstine both said. And Starliner seems to have performed very well in orbit, Jim Chilton, senior vice president of Boeing’s Space and Launch Division, said during a news conference yesterday (Dec. 21). And today, Chilton estimated that Starliner may end up meeting about 85% of the original OFT objectives, after all data analyses are complete.
But all three men stressed that the NASA and Boeing teams need to perform those analyses before any decisions can be made about Starliner's next flight.
"I think we're into January, pretty deep into January, before everybody has a thorough understanding" of the OFT data, Chilton said today.
CFT is currently targeted for liftoff sometime next year. If it is decided that Starliner must fly another version of OFT first, the CFT timeline would probably shift to the right by at least three months. That's the estimated minimum amount of time it would take for Boeing to get ready for another OFT, Chilton said today.
(The Starliner vehicle that landed today won't fly CFT, by the way. This capsule will perform Boeing's first contracted ISS crew mission for NASA. And the crew of that mission, which will be commanded by NASA astronaut Suni Williams, has named the capsule "Calypso," after the ship of ocean explorer Jacques Cousteau.)
Boeing has been developing Starliner with funding from NASA's Commercial Crew Program, most notably a $4.2 billion contract that was announced in September 2014. That deal also pays for six operational, crew-carrying flights to and from the ISS.
SpaceX got a similar, $2.6 billion contract at the same time. The California-based company's Crew Dragon capsule aced its version of OFT, called Demo-1, this past March. SpaceX is now gearing up for a key in-flight test of Crew Dragon's emergency-escape system next month; if all goes well with that demonstration, Crew Dragon will be cleared to perform a crewed test flight to the orbiting lab.
Getting one of these private vehicles up and running will end NASA's dependence on Russian Soyuz spacecraft for crewed trips to the ISS, which has been total since the space shuttles were grounded more than eight years ago. And having both of them operational is vital to ensure stable, uninterrupted access to space, Bridenstine said.
"We need to have dissimilar redundancy for how we fly astronauts into space," he said.
NASA also wants to be just one of many customers that use private American spacecraft to get to and from low-Earth orbit, Bridenstine added.
"We want to have numerous providers that are competing against each other on cost and innovation, driving down cost and increasing access," he said. "And today was really a great milestone in that eventuality."
- Boeing's CST-100 Starliner Space Capsule (Infographic)
- Boeing in Space: The Latest News, Images and Video
- How Boeing's Starliner Orbital Flight Test Works: A Step-By-Step Guide
Mike Wall's book about the search for alien life, "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.