Starliner launches to space (but not ISS) (reached ISS in 2022)

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In summary: They might find a bug, but that's about it.In summary, Boeing's Starliner spacecraft, designed to carry astronauts, has faced new safety concerns in the wake of a parachute failure during a pad abort test. The problem is being attributed to a software bug that caused the spacecraft to enter a precise pointing mode too early, using up a lot of thruster fuel. Although both individual issues are easy to fix, it leads to the question how many of these issues are still to be discovered. The next flight is supposed to deliver crew to the ISS for a month, but NASA and Boeing are reviewing all this very thoroughly.
  • #36
Dullard said:
It's going to take some guts to go ahead with docking with 2 thrusters out, the rest suspect, and an untested system. I'm guessing that there is some serious indigestion at NASA.
Can they use one of the ISS robotic arm systems to aid in the docking if needed? I don't know if they can reach near the docking hatch at all...

https://en.wikipedia.org/wiki/Mobile_Servicing_System
 
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  • #37
No idea, however: To dock with the station, they'll have to move toward the station. They can be cute with their vector until they get close, but eventually they will be in a situation where the thrusters absolutely need to work properly (that's ON and OFF). One major problem with not knowing exactly what's wrong is that you also don't know what's right.
 
  • #38
Hmmm.

https://www.space.com/nasa-boeing-hail-starliner-launch-success-despite-glitch

"The first failed after only one second. Its backup immediately kicked on and was able to fire for another 25 seconds before it also failed."

"Nappi emphasized that the issue was not one that needed to be resolved prior to the completion of the OFT-2 mission."
 
  • #39
The proof of the pudding will come when astronauts are asked to risk their lives in that vehicle.
 
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  • #40
Successful docking.

Here it is at the ISS

The approach path is designed to always miss the station if the capsule stops firing at any point in time, excluding the last meters when the approach is so slow that a collision should do larger damage (~5 cm/s for the last 7 meters, they dock with the ISS at that speed). Leaving the ISS is easier.

They'll have to find out what happened with the thrusters but that's likely something that can be done on the ground before the next crewed flight. The primary goal - reaching the ISS - has been achieved. After the flight Boeing will have to convince NASA that the risk of a loss of mission and the risk of a loss of crew are below their thresholds (1 in 270 for a loss of crew. Spaceflight is still dangerous).
 
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  • #41
mfb said:
They'll have to find out what happened with the thrusters but that's likely something that can be done on the ground before the next crewed flight.
Are the bad thrusters on the capsule or the service module? There are some on each, right?
 
  • #42
hutchphd said:
Are the bad thrusters on the capsule or the service module? There are some on each, right?
The OMAC thrusters, responsible for orbit raising (where we saw two failures), are on the service module.
The RCS thrusters, responsible for docking (where we also saw two failures), seem to be partially on the capsule (12) and partially on the service module (28). Source for the numbers. I don't know where the two failed RCS thrusters are. That system has a massive redundancy so losing two isn't a big deal here.

A sublimator in the cooling system started later than planned
An issue with the NASA Docking System delayed docking by an hour.

It's still on track to have a successful mission, but it's more things Boeing and NASA will have to work on.
 
  • #43
The service module does not survive re-entry. How will they troubleshoot this I wonder? You don't want to be doing functional tests while attached to ISS (the Crew Dragon Super Draco firing event comes to mind). Seems to me this analysis could be a nontrivial problem.
 
  • #45
Upside, much improved.
Downside, no Boeing executives seem willing to hitch a ride...
 
  • #46
anorlunda said:
I had to search for the word sublimator. I was surprised to find it in a description of the Apollo Lunar Module.
Also used to cool the space EVA suits They are really clever devices. As I understand them they are essentially self regulating because ice accumulation slows the cooling (subliming) rate as the feedwater gets colder and vice-versa.
 
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  • #47
hutchphd said:
The service module does not survive re-entry. How will they troubleshoot this I wonder? You don't want to be doing functional tests while attached to ISS (the Crew Dragon Super Draco firing event comes to mind). Seems to me this analysis could be a nontrivial problem.
Maybe some tests after undocking. Now they had a few days to study it.

Undocking is planned 25 May 2022, 18:36 UTC, reentry is planned 25 May 2022, 22:49 UTC.
It is currently 24 May, 06:20 UTC, so undocking is in 1 day 12 hours.
 
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  • #48
Speculation:
They may already know what's wrong. There is a dispute between Boeing and Aerojet-Rocketdyne (the RCS system supplier) that is on the verge of becoming a lawsuit. I found NASA's willingness to continue with the docking (After several apparently unexplained thruster failures) to be extremely un-NASA-like. If they semi-expected these problems (and understood the cause), that decision would make a lot more sense.
 
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  • #49
Dullard said:
If they semi-expected these problems (and understood the cause), that decision would make a lot more sense.
Did they know this before launch? Then it makes no technical sense at all to me that the flight proceeded. These are the re-entry thrusters, right? Fiasco.
 
  • #50
As I said, I'm just speculating. It is a fact that Boeing and AJRD are about to go to the mattresses. Boeing has stated that the RCS system has design flaws (and blames AJRD). AJRD has a different story.

It seems possible that they took whatever steps that they could to 'mitigate' the known issues and decided to fly it - There almost certainly wasn't time to fix it (they just 'discovered' it during the last launch attempt). It's important to remember that egg on Boeing's face is also egg on NASA's face - Everyone needed a win.
 
  • #51
So is this a win? Do you now do a change and then stuff pink bodies in the next flight? I am mystified.
 
  • #52
There will be victory laps. They did accomplish most of their test objectives, but multiple failed thrusters seems like a pretty big asterisk in a test which was supposed to demonstrate readiness for human spaceflight. Particularly so, if the design remediation is significant.
 
  • #53
Shuttle Colombia also accomplished most mission objectives.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled."
 
  • #54
hutchphd said:
Do you now do a change and then stuff pink bodies in the next flight?
You could include Astronaut Propulsion Units along with their spacesuits to serve as a backup... :wink:

1653398926790.png

https://en.wikipedia.org/wiki/Astronaut_propulsion_unit
 
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  • #55
Burning up on reentry is very different from using redundant thrusters.

Starliner's hatch has been closed in preparation for undocking. Planned re-entry path, visibility in the US will be limited to southern New Mexico and small corners of Arizona and Texas.
18:50 ET, that should be in 9:20. Undocking will happen about four hours earlier.
 
  • #56
It returned to Earth safely.
Now Boeing and NASA will go over every aspect of the flight, fix the thruster issues, and then likely set a launch date for the crewed test flight.
 
  • #57
Having to use redundant thrusters isn't great but I feel it has been overblown due to previous issues. On Dragon mission CSR-2 three out of four Draco thruster pods failed due to insufficient pressurization which put the spacecraft in Passive Abort Mode. Space X had to wait until they could establish a link with a ground station in Australia before they could issue a manual override. That sounds to me like a bigger deal but I have never seen anyone criticize Space X over that issue.
 
  • #58
glappkaeft said:
but I have never seen anyone criticize Space X over that issue.
The event in question took place in 2013 on the cargo dragon, not on the penultimate uncrewed test flight for a man-rated vehicle. It also did not occur during active firing. The reason it was not treated with grave concern is that it did not warrant such concern.
SpaceX was not criticized because their engineering response was appropriate and successful. Perhaps Boeing will perform well but recent performance casts some doubt on that prospect.

.
 
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  • #59
hutchphd said:
The event in question took place in 2013 on the cargo dragon, not on the penultimate uncrewed test flight for a man-rated vehicle. It also did not occur during active firing.
And it was resolved in flight, it only delayed docking with the ISS.
 
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