'Degradation in our thrusters': Ex-astronaut reveals what’s needed to bring stranded pilots home

Two astronauts have been stranded at the International Space Station (ISS) for weeks. Now, a former NASA astronaut is explaining what needs to be done to get them back on solid ground.

NASA test pilots Butch Wilmore and Suni Williams, who rode the Boeing Starliner capsule to the ISS, almost didn't make it to the research outpost due to helium leaks and what they referred to as "degradation in our thrusters." Even though this was the Starliner's first manned space flight, unmanned launches and re-entries of the capsule had gone off without a hitch.

In a Wednesday interview with CNN host Boris Sanchez, Col. Terry Virts – a former NASA astronaut – explained what went wrong with Wilmore and Williams' trip to the ISS, and how they can get back to Earth safely. Virts joined the interview holding up a model Boeing Starliner. He explained that the astronauts are safe and can come home anytime, but that more research needs to be done in order to determine what caused the thruster failure so future missions won't be jeopardized.

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"They have a lot of small RCS [Reaction Control System] jets there on this back part of the capsule, and that's used to orient and point the capsule in the right direction. They also have some large OMAC [Orbital Maneuvering and Attitude Control] engines that are used to actually de-orbit the capsule to get it back to Earth," Col. Virts explained. "So when the capsule undocks, it'll turn around backwards, fire the larger thrusters, the OMAC, thrusters and come back."

"The small thrusters, the RCS, failed during the docking," he continued. "And the problem is, when it comes back to Earth, the capsule with the crew on board is going to separate from the service module. The capsule will come back safely with the heat shield and a parachute, and the service module is going to burn up. So they won't have the thrusters to look at and analyze, they won't have the helium tanks that had some leaks to look at, so they need to keep it on the space station for as long as they need, to get the data they need, before the separation in the service module burns up."

According to Virts, Boeing needs the Starliner to fly a successful manned test flight to and from the ISS in order to get the craft certified by NASA. The craft's next expedition will be an operational flight with four astronauts rather than two, in which the four scientists on board will complete a normal rotation on the ISS.

"They really want that big giant certification stamp so that they can consider the vehicle operational, so I think they're taking as long as they need to make sure they can get that certification," Virts said. "If there was an emergency, we just heard in the press conference, the crew would jump in, close the hatch and come back to Earth. And I don't think there'll be any, no one expects any problems at all, but they do want that certification stamp and so it's a lot better to take a few extra weeks now than to have to fly an entire another test mission which Boeing and NASA definitely don't want."

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The Starliner's woes are just the latest headache for Boeing, which has been reeling from numerous whistleblowers coming forward to speak out about the company's lackadaisical attitude for safety regulations. Aerospace analyst Miles O'Brien told CNN last month that the company's thirst for ever-increasing profits may have been what led to the breakdown of the Starliner.

Virts noted that one unexpected silver lining of the malfunction on Boeing's Starliner capsule is that Wilmore and Williams will be able to help other astronauts on the ISS. He explained that more hands are always needed to maintain the jointly operated outpost that the U.S. runs in conjunction with other countries.

The station astronauts are going to be happy to get some free labor," Virts said. "You can never have enough workers on the space station. So this is free free labor to knock off the honey-do list, which is always long on a space station."

Watch Virts' full segment on CNN below, or by clicking this link.

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