Three months into what was supposed to be a 10-day mission, astronauts Butch Wilmore and Sunny Williams are now preparing to close the hatch and send their Boeing Starliner home without them. Just after 6:00 PM on Friday, NASA will remotely undock the trouble spaceship from the space station, then guide it back to Earth, as Williams and Wilmore settle in for another five-month stay on the station.

They're very much engaged, asking questions. I think they're happy that a decision was made, and they understand the plan forward.

Still haunted by the Challenger and Columbia disasters that killed 14 astronauts, mission managers decided last month they will not risk putting Williams and Wilmore on a starliner with engine thrusters that could potentially malfunction on re-entry.

Nasa has decided that Butch and Sunny will return with crew 9 next February.

Ignition. Engine's full power. And lift off. The SpaceX crew nine mission will launch later this month with two astronauts rather than four. Williams and Wilmore will fill the empty seats on return. Until then, they'll continue working on the station and doing long-duration cardio and strength exercises. But NASA insists the crew is not stuck in space since they could ride Starliner home if the space station were in danger.

In my view, they're never stuck or stranded. They always had a way to depart the space station.

But that would only be if the space station had an emergency.

It copies OF1 at 170 meters, and it looks like good separation.

To send Starliner home without the astronaut NASA plans to use the troubled thrusters to gently back away from the station to avoid causing any damage.

And that is just to take the Starliner away from station and then immediately start going up and away. And eventually it'll to the top and de-orbit from above station a few orbits.

If all goes well, Starliner will land without its crew in the New Mexico desert just after 12:00 AM Saturday.

Tom Costello joins us now. Tom, or viewers at home may be following this story. They may remember about the astronauts reporting, hearing that pulsing sound coming from the Starliner that they couldn't immediately explain. Some conspiracy theorists online started going wild with that. Let's just take a listen and we can clear it up on the back end. It does sound like something from the movie Alien. What is it really? And is there any cause for alarm?

I think it's aliens, Tom. No, listen, NASA cleared this up. The bottom line is there are multiple spacecraft docked to the space station, and they are running multiple comms channels, right? And that can sometimes create feedback that runs back and forth between the station and the spacecraft, in this case, Starliner. So they were getting a feedback loop through their systems, multiple audio channels, and it took a little bit, but even NASA Mission Control wasn't quite sure first what it was.

I also got to ask you about the optics of this, right? So you're going to have SpaceX bring them home. I got to think this has got to be an embarrassment for Boeing.

Huge embarrassment. I mean, SpaceX is the arch-rival for Boeing. Boeing has now lost $1.6 billion on its Starliner program. As you know, it is years behind schedule. It is billions over budget. Now they've got to turn to Elon Musk, SpaceX, to bring those NASA astronauts home in February. Nasa is still committed to Starliner. It needs an alternative to SpaceX. It's not just relying on one spaceship. The question is now, okay, once you fix this problem, how soon might it be certified? That may be another year away now, Tom.

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