NASA astronauts revealed that the Boeing Starliner came dangerously close to failing its docking attempt at the International Space Station.

Butch Wilmore and Suni Williams described the moments before the Boeing Starliner docked to Ars Technica, revealing that they almost had to abort the docking attempt on June 5, 2024.

Wilmore said that as the Starliner approached the International Space Station, they lost the first thruster. As the Starliner got closer to the space station, a second thruster was also lost. Typically, Wilmore said, these kinds of events would trigger an abortion of the docking attempt. According to Wilmore, NASA waived the flight rules to allow the mission to continue.

In this photo provided by NASA, Boeing’s Starliner spacecraft is docked to the Harmony module of the International Space Station on July 3, 2024, seen from a window on the SpaceX Dragon Endeavour spacecraft docked to an adjacent port. (NASA via AP)

Wilmore remembered a point in the docking process when his optimism about aborting the mission and returning to Earth was dwindling.

“I don’t know that we can come back to Earth at that point. I don’t know if we can. And matter of fact, I’m thinking we probably can’t. So there we are, loss of 6DOF control, four aft thrusters down, and I’m visualizing orbital mechanics,” Wilmore said.

Eventually, NASA Mission Control decided to take control of the spacecraft for its final approach to the space station after it recovered the failed thrusters.

NASA astronauts Suni Williams and Butch Wilmore were the flight crew on Boeing’s Starliner capsule, which is recovering from a series of issues. (NASA)

“Oh, phew, let’s just take a breather and try to understand what happened,” Williams remembered thinking when the Starliner docked.

While the Starliner returned to Earth on Sept. 7, 2024, it was without astronauts inside in order to minimize risks. The astronauts finished their unexpected 9-month trip to the space station on March 18, when they returned to Earth in a SpaceX Crew Dragon Capsule.