Boeing Starliner's two astronauts knew to expect the unexpected when they took off on the spacecraft's first crewed mission on June 5.

I learned this back in March, when NASA hosted reporters at the agency's Johnson Space Center (JSC) in Houston for two days. We used four Starliner simulators, spoke at length with senior agency and Boeing leadership, and sat down with NASA astronauts Butch Wilmore and Suni Williams.

The duo — career astronauts and veterans of long International Space Station (ISS) missions — were both U.S. Navy test pilots when they started out and knew how to build aerospace programs with big teams decades ago. This is why they were selected to put Starliner through its crewed paces for the first time.

"With an experimental spacecraft, there are things that haven't been done before. We really want to make sure that that all works and is fine," Williams said in a small-group interview at JSC on March 24. She explained that dynamic events, like docking and manual flying, would be especially tricky despite all the simulator hours: "Our hair on the back of our neck is going to stand up a little bit more when we do these things."

That prediction came true on June 6 — the day after launch — when Williams and Wilmore were asked to delay their final approach to the ISS for docking. Starliner was not only leaking helium, continuing a manageable problem that was tracked carefully before launch, but its thrusters were affected in ways that NASA and Boeing could not yet explain. The astronauts docked safely to the ISS on their second try on June 6, after demonstrating again that they could safely control the spacecraft.

Starliner has remained at the ISS. Its mission, known as Crew Flight Test (CFT), was extended beyond the 10-day nominal timeline, then extended again beyond 45 days when the batteries (the main duration-limiting factor) were behaving better than expected. Williams and Wilmore have now spent about 55 days in space, living off an existing reserve of food, oxygen and other critical items that NASA already has on hand for such scenarios.

image description NASA astronauts Suni Williams (left) and Butch Wilmore, the first people to fly on Boeing Starliner, are the two astronauts of Crew Flight Test. (Image credit: NASA/Frank Micheaux)

"We'll have a little bit more work to do to get there for the final return. But they're safe on space station," Stich said of Williams and Wilmore. "Their spacecraft is working well, and they're enjoying their time on the space station."

Boeing's Mark Nappi, who manages the commercial crew program at the company, emphasized that staying docked to the ISS is the best way to troubleshoot. "We don't understand issues enough to fix them permanently, and the only way that we can do that is take the time in this unique environment and get more data, run more tests," he said in the same press conference.

Starliner was always rated to leave the ISS in case of emergency, and that scenario was activated June 26 when pieces of Russian satellite space debris came within the miles-wide "pizza box" shape of space that surrounds the ISS. Even if the risk to astronauts is infinitesimally small, protocol dictates that the crew get ready to go home if an object intrudes into the pizza box.

As procedures dictate, NASA and the Russian space agency Roscosmos each ordered their astronauts to shelter in their return spacecraft. The Expedition 71 crew duly decamped to a SpaceX Crew Dragon, a Russian Soyuz and — in the case of Williams and Wilmore — Starliner. They waited for about an hour, and were cleared to return to ISS duties when the danger passed.