Here's NASA’s possible plan for bringing Boeing astronauts home on SpaceX

How would a plan to rescue Boeing Starliner astronauts from the ISS with a SpaceX crew vehicle work?

As of today, Suni Williams and Butch Wilmore have been at the ISS for over two months. They launched in a Boeing Starliner spacecraft on a Crewed Flight Test on June 5. We still don’t know when they’re coming back — and at this point, we don’t even know what kind of spacecraft they’ll be returning in —SpaceX Crew Dragon or Boeing Starliner.

But how would a SpaceX rescue even work? What would happen to the Starliner spacecraft attached to the ISS? And can Boeing Starliner be certified for operational flights without returning crew?

The hows and whys of all of it

• What specifically is NASA concerned about?

• How this whole SpaceX rescue mission would work

• Why is NASA taking so long to make this decision?

What specifically is NASA concerned about?

Let’s break down this complicated issue.

I did a deep dive into what might be going on behind the scenes at NASA, as well as what Boeing Starliner’s problems are, so check that out if you need to get up to speed.

Thanks to extensive testing on the ground and the ISS, Boeing thinks they have found the root cause of the helium leaks and thruster failures. But not everyone at NASA is convinced on Starliner’s safety. What the agency is focusing in on is a Teflon seal that’s deformed — bubbling is the word that’s been used to describe it — they think that’s happening because the doghouses, which is where the thrusters are located, are getting much hotter than expected when the thrusters are firing. This is vaporizing propellant, and these vapors are affecting the Teflon seals. At least that’s what they think, but NASA is struggling to find a concrete explanation as to why the Teflon is behaving this way.

The problem is they just aren’t certain. If thrusters aren’t able to hold Starliner’s attitude steady during re-entry maneuvers, and if at the same time there are catastrophic helium leaks that disable the OMAC thrusters, that could strand the astronauts. This is a serious issue. They likely can fix these thruster problems in future versions of Starliner — but is THIS one safe? These are obviously worst case scenarios, and the likelihood of them happening at the same time in this integrative way is very small. But it exists.

For any flight, NASA calculates a loss of crew statistic. It’s a standard practice. The requirement for Commercial Crew providers for these flight tests is 1/270 (for operational flights it’s more like 1/400). Boeing’s before launch of CFT was 1/295. It’s probably not that now. As a comparison, SpaceX’s loss of crew statistic for their crewed demonstration mission was 1/276.

How this whole SpaceX rescue mission would work

At a press conference yesterday, NASA acknowledged for the first time that the SpaceX Crew Dragon rescue option is one that they’re seriously considering and planning for, even going so far as to lay out what the contingency options are. Right now, I want to be clear about this — nothing has been decided. NASA would still prefer to return Boeing Starliner astronauts in Starliner. But they have acknowledged there is enough uncertainty at NASA to warrant laying out this backup option.

Here’s how a SpaceX rescue would work, if it were to happen:

Right now on the ISS, there are four Crew-8 astronauts, and the two Boeing Starliner astronauts Butch and Suni (in addition to the Russian cosmonauts). That means both docking ports capable of supporting crew vehicles on the Harmony module of the ISS are taken — one by Crew-8’s SpaceX Crew Dragon and one by Boeing Starliner.

The way having crew at the ISS works is that there always have to be enough seats to evacuate the crew on board at any time. That means that they can’t just send Suni and Butch home on the Crew-8 vehicle and leave two of those astronauts up there, without any vehicle to take them home if there’s an emergency.

This brings us to Crew-9.

NASA announced yesterday they’re delaying the launch of Crew-9, which was previously scheduled for August 18. That’s getting pushed more than a month to no earlier than Tuesday, September 24.

NASA generally likes to do what they call a “direct handover” when it comes to Space Station crews — they want the crews to overlap. That can’t happen if Boeing Starliner is still docked.

So here’s the plan, and I want to stress again that this hasn’t been greenlit. This is just an option NASA can take advantage of if they see the need to.

Boeing Starliner will autonomously undock and return to Earth. That would happen in early September — there’s basically a landing window every four days starting September 2. Then Crew-9 will launch on September 24 with two astronauts, two spacesuits, and two empty seats. NASA would put ballast in those seats to ensure that they mimic the mass of an astronaut.

Butch and Suni would become basically the two additional members of Crew-9 and fulfill those astronauts’ responsibilities for a long-duration ISS stay. It’s not clear who would get bumped from the flight (but a safe best is that the commander and pilot would be the ones to go up). Butch and Suni have trained extensively for this, because NASA has always know there is this risk with a crewed test flight that a long duration stay on the ISS will be necessary. Crew-9 is scheduled to last about 180 days, so Butch and Suni would come home in February 2025, turning an eight day mission into an eight month mission.

When does NASA have to decide this? Probably in the next week or two. They need enough time to make that Crew-9 launch date, plus there are some modifications that must be made to Boeing Starliner for autonomous undocking. That software hasn’t been used since OFT-2 in 2022, and they need to basically dust it off and update it because there have been changes in the orientation of the ISS since that flight, and they need to have time to test it out before it’s used. That’ll take time.

They also will have to modify the Crew-8 capsule to handle two extra astronauts before Boeing Starliner undocks. Why? Well, remember what I said about every astronaut having a way off the ISS? They have to have that contingency configuration for Butch and Suni until Crew-9 arrives.

Indications are that NASA is prepared to have Butch and Suni stay on the ISS for a longer period of time. Remember back when Starliner launched, and NASA put an important repair part for the urine processor on board? (If you missed it, check out my video). Well, they had to pull some of Butch and Suni’s suitcases off the spacecraft to accommodate that part. They sent those suitcases up on an uncrewed resupply mission that docked with the ISS on Tuesday.

The bottom line is that it’s possible, but not easy, to bring Butch and Suni home on a SpaceX Crew Dragon. NASA has made the plans and is just waiting for more data. They’re running every test they can think of on this Teflon, doing modeling, trying to figure out how it acts when exposed to different temperatures. They’re bringing in experts from other centers, anything they can do to get more concrete data on this bulging seal.

Why is NASA taking so long to make this decision?

So why not just bring Butch and Suni home on a Crew Dragon then? Why all this testing when there is that option? Well, there is risk built into going to space that we just have to accept. But bringing this crew home on another U.S. made vehicle is possible, which is unprecedented in NASA’s history of spaceflight. This is the first time they’ve had the option of two different U.S. made crew vehicles (there’s always the Soyuz as a backup, but given geopolitical issues and the poor funding of Russia’s own space program, it’s not without its own complications).

And that, in and of itself, is why this decision is so hard. If NASA opts to return Butch and Suni home on a SpaceX Crew Dragon, that very possibly the end of Boeing Starliner. It’s as of yet uncertain if NASA will be willing to certify Starliner for operational flight if the crew comes home on a different vehicle. Remember, Boeing likely has enough information to fix future spacecraft, but it’s this particular one, called Calypso, we’re concerned about.

If NASA declines to certify Boeing Starliner and asks for a second crewed test flight, which frankly would be warranted based on how this has gone, that will likely be the end of Boeing Starliner. That being said, is is clear that NASA wants to certify this vehicle for flight, and if they think it’s safe, they’ll do so based on the autonomous data. But again, the safety of the crew comes first.

It’s important to note, Boeing is working on a fixed-price contract for Commercial Crew. This is different than the cost-plus contracts NASA uses for vehicles it owns and operates, where it is responsible for the extra costs associated with testing, with flights, with anything that goes wrong. NASA paid Boeing a fixed amount for six operational flights. Boeing has had to absorb all of the extra costs associated with these failures and delays. And they have lost an incredible $1.6 billion on Starliner.

If they have to do another crewed test flight, they will likely just pull out of the Commercial Crew program altogether and SpaceX will be left as the only provider for flights to the ISS. And yes the ISS will be retired at the end of the decade most likely (I have a video on how that will happen and why we can’t save it, if you’re interested). So we’re only possibly talking about six years.

But NASA also has extensive experience with only one crew vehicle to service the ISS with the Space Shuttle, and didn’t like that experience. That’s why they wanted so much to have TWO crew vehicles. NASA doesn’t take that lightly — that if they show no confidence in Starliner at this point, Boeing may be out. Which would be a shame if the spacecraft is, in fact, safe.

I will update again when we have more hard news from NASA, or more credible speculation.