Boeing's Starliner (CST-100) - Discussion Thread 6

[sdsds]

With today's Vulcan Cert-2 launch, it's interesting to note that Starliner launches on Atlas are planned to use AJ-60A rather than GEM-63 solids. Here's a situation where being ultra-conservative might have played in Boeing's favor.

[DanClemmensen]

With today's Vulcan Cert-2 launch, it's interesting to note that Starliner launches on Atlas are planned to use AJ-60A rather than GEM-63 solids. Here's a situation where being ultra-conservative might have played in Boeing's favor.

Atlas V has launched about 20 times since 2020, with most launches using multiple GEM 63, for a total of about 43 GEM 63. There have been no failures, anomalies, or "observations".

Vulcan Centaur has launched twice, with two GEM 63XLs on each launch, for a total of four GEM 63XL, with an anomaly on one of the four.

At this point, we have no reason to believe that the anomaly on the GEM 63XL is relevant to the GEM 63. I have no insight into all of the differences between the '63 and the '63XL, but one difference is a substantial increase in thrust.

[catdlr]

With today's Vulcan Cert-2 launch, it's interesting to note that Starliner launches on Atlas are planned to use AJ-60A rather than GEM-63 solids. Here's a situation where being ultra-conservative might have played in Boeing's favor.

Atlas V has launched about 20 times since 2020, with most launches using multiple GEM 63, for a total of about 43 GEM 63. There have been no failures, anomalies, or "observations".

Vulcan Centaur has launched twice, with two GEM 63XLs on each launch, for a total of four GEM 63XL, with an anomaly on one of the four.

At this point, we have no reason to believe that the anomaly on the GEM 63XL is relevant to the GEM 63. I have no insight into all of the differences between the '63 and the '63XL, but one difference is a substantial increase in thrust.

It's not meant to answer your question on thrust, but just historical family history and the difference between the GEM 63 and 63XL.

GEM 63:
The GEM 63 is a 63-inch-diameter strap-on solid rocket booster that powers ULA’s Atlas V launch vehicle.
Here are the key specifications for the GEM 63:

Nozzle Exit Cone Diameter: Approximately 58 inches.
Propellant Mass: About 97,195 pounds (44,200 kilograms).
Burn Time: Approximately 97.6 seconds.
Maximum Thrust: Around 370,835 pounds-force.
Total Length: More than 72 feet (791 inches).
Motor Diameter: 63 inches.
Exit Plane Diameter: 54 inches.

GEM 63XL:
The GEM 63XL is an extended version of the GEM 63, designed to provide additional performance for ULA’s upcoming Vulcan Centaur launch vehicle.
Notably, the GEM 63XL holds the distinction of being the longest monolithic, single-cast solid rocket motor ever produced.

Here are the specifications for the GEM 63XL:
Nozzle Exit Cone Diameter: 60 inches.
Propellant Mass: Approximately 105,497 pounds (48,000 kilograms).
Burn Time: Approximately 87.3 seconds.
Maximum Thrust: Around 463,249 pounds-force.
Total Length: Impressive 864 inches (more than 72 feet).
Motor Diameter: Still 63 inches.
Exit Plane Diameter: Slightly larger at 56 inches.

Why the XL?:
The GEM 63XL’s extended length allows it to provide more thrust and performance, making it ideal for supporting heavier payloads and ambitious missions.
Manufacturing the GEM 63XL as a single piece (monolithic) enhances reliability by reducing joints and hardware.
In summary, the GEM 63XL has a slightly larger nozzle exit cone diameter and propellant mass compared to the GEM 63. Both boosters are part of the Graphite Epoxy Motor family, ensuring reliable access to space for various payloads.

[tbellman]

GEM 63:
Total Length: More than 72 feet (791 inches).

GEM 63XL:
Total Length: Impressive 864 inches (more than 72 feet).

791 inches is significantly less than 72 feet (slightly less than 66 feet).  And the 864 inches of the GEM 63XL is exactly 72 feet, not more than.

I hope their actual engineering is better than the above PR blurbs...

(Also, how the heck do they get six significant digits on the thrust?  [Neither figure looks like false precision from converting an approximate number in kilonewtons to pound-force.])

[clongton]

Please move further discussion about the Vulcan LV anomaly to the Vulcan Discussion thread, and leave this thread to be specifically about Starliner.

[deltaV]

https://spacenews.com/boeing-plans-more-commercial-crew-charges/

Boeing expects to take up to several hundred million dollars in additional charges against earnings for its CST-100 Starliner commercial crew program in the third quarter.

[WmThomas]

NASA seems to be unsure whether to certify Starliner after CFT-1.

Of course, they didn't feel comfortable with Starliner's problems going to station on CFT-1, and so they sent it back without crew.

But in overview, the Starliner made it to the ISS with crew aboard, and then came back to Earth fine without crew. If the crew had stayed aboard, they would have landed fine.

So I'm not sure why Starliner shouldn't be certified.

Now, I'm no Starliner fan, but hasn't Starliner performed the tasks it was supposed to perform in the CFT-1 test?

[mn]

NASA seems to be unsure whether to certify Starliner after CFT-1.

Of course, they didn't feel comfortable with Starliner's problems going to station on CFT-1, and so they sent it back without crew.

But in overview, the Starliner made it to the ISS with crew aboard, and then came back to Earth fine without crew. If the crew had stayed aboard, they would have landed fine.

So I'm not sure why Starliner shouldn't be certified.

Now, I'm no Starliner fan, but hasn't Starliner performed the tasks it was supposed to perform in the CFT-1 test?

Would you be comfortable to fly on a plane that had many fault codes and warning bells in the cockpit during the flight but then landed safely?

[Twark_Main]

NASA seems to be unsure whether to certify Starliner after CFT-1.

Of course, they didn't feel comfortable with Starliner's problems going to station on CFT-1, and so they sent it back without crew.

But in overview, the Starliner made it to the ISS with crew aboard, and then came back to Earth fine without crew. If the crew had stayed aboard, they would have landed fine.

So I'm not sure why Starliner shouldn't be certified.

Now, I'm no Starliner fan, but hasn't Starliner performed the tasks it was supposed to perform in the CFT-1 test?

Cf.

"The Shuttle landed fine! Why worry about some partial O-ring burn-through?"

      -or-

"The Shuttle landed fine! Why concern yourself with a little foam shedding?"

[Lee Jay]

NASA seems to be unsure whether to certify Starliner after CFT-1.

Of course, they didn't feel comfortable with Starliner's problems going to station on CFT-1, and so they sent it back without crew.

But in overview, the Starliner made it to the ISS with crew aboard, and then came back to Earth fine without crew. If the crew had stayed aboard, they would have landed fine.

So I'm not sure why Starliner shouldn't be certified.

Now, I'm no Starliner fan, but hasn't Starliner performed the tasks it was supposed to perform in the CFT-1 test?

Would you be comfortable to fly on a plane that had many fault codes and warning bells in the cockpit during the flight but then landed safely?

Actually, yes, I would.  I would not, however, be fine with flying on a plane that just landed with an engine out before the engine failure was fully understood, and the engine repaired or replaced.

[craiglv2]

I would not expect certification until Boeing proves to NASA that they understand and have resolved what's causing the thruster failures.  A safe unmanned return doesn't mean much if they don't know what's causing the failures.

[abaddon]

NASA seems to be unsure whether to certify Starliner after CFT-1.

Of course, they didn't feel comfortable with Starliner's problems going to station on CFT-1, and so they sent it back without crew.

But in overview, the Starliner made it to the ISS with crew aboard, and then came back to Earth fine without crew. If the crew had stayed aboard, they would have landed fine.

So I'm not sure why Starliner shouldn't be certified.

Now, I'm no Starliner fan, but hasn't Starliner performed the tasks it was supposed to perform in the CFT-1 test?

Would you be comfortable to fly on a plane that had many fault codes and warning bells in the cockpit during the flight but then landed safely?

Actually, yes, I would.  I would not, however, be fine with flying on a plane that just landed with an engine out before the engine failure was fully understood, and the engine repaired or replaced.

Since Starliner has "thrusters" and not "engines", it sounds like you are saying all of Starliner's faulty thrusters that failed need to be fully understood before certification?  "Repaired or replaced" doesn't make sense in this context, since most of them were expended on the service module...

[Lee Jay]

NASA seems to be unsure whether to certify Starliner after CFT-1.

Of course, they didn't feel comfortable with Starliner's problems going to station on CFT-1, and so they sent it back without crew.

But in overview, the Starliner made it to the ISS with crew aboard, and then came back to Earth fine without crew. If the crew had stayed aboard, they would have landed fine.

So I'm not sure why Starliner shouldn't be certified.

Now, I'm no Starliner fan, but hasn't Starliner performed the tasks it was supposed to perform in the CFT-1 test?

Would you be comfortable to fly on a plane that had many fault codes and warning bells in the cockpit during the flight but then landed safely?

Actually, yes, I would.  I would not, however, be fine with flying on a plane that just landed with an engine out before the engine failure was fully understood, and the engine repaired or replaced.

Since Starliner has "thrusters" and not "engines", it sounds like you are saying all of Starliner's faulty thrusters that failed need to be fully understood before certification?  "Repaired or replaced" doesn't make sense in this context, since most of them were expended on the service module...

Understood and replaced with a new design and build that will fix the root cause.

[DanClemmensen]

Since Starliner has "thrusters" and not "engines", it sounds like you are saying all of Starliner's faulty thrusters that failed need to be fully understood before certification?  "Repaired or replaced" doesn't make sense in this context, since most of them were expended on the service module...

Understood and replaced with a new design and build that will fix the root cause.

There were at least three separate independent serious failures. Two of them were on the SM, which by design cannot be recovered for analysis. This means that the root cause analysis, however exhaustive, can never be completely validated based on that CFT. For me, this means it's very difficult to know that a new design will actually solve the problem. I feel that another uncrewed flight is needed.

[Lee Jay]

Since Starliner has "thrusters" and not "engines", it sounds like you are saying all of Starliner's faulty thrusters that failed need to be fully understood before certification?  "Repaired or replaced" doesn't make sense in this context, since most of them were expended on the service module...

Understood and replaced with a new design and build that will fix the root cause.

There were at least three separate independent serious failures. Two of them were on the SM, which by design cannot be recovered for analysis. This means that the root cause analysis, however exhaustive, can never be completely validated based on that CFT. For me, this means it's very difficult to know that a new design will actually solve the problem. I feel that another uncrewed flight is needed.

Yup.

[sstli2]

Since Starliner has "thrusters" and not "engines", it sounds like you are saying all of Starliner's faulty thrusters that failed need to be fully understood before certification?  "Repaired or replaced" doesn't make sense in this context, since most of them were expended on the service module...

Understood and replaced with a new design and build that will fix the root cause.

There were at least three separate independent serious failures. Two of them were on the SM, which by design cannot be recovered for analysis. This means that the root cause analysis, however exhaustive, can never be completely validated based on that CFT. For me, this means it's very difficult to know that a new design will actually solve the problem. I feel that another uncrewed flight is needed.

Perhaps this question should be re-framed as, is a Starliner that is certified without a complete flight test better than no Starliner at all. Which is the outcome that it would seem another uncrewed flight would entail, absent NASA injecting more money.

[DanClemmensen]

Since Starliner has "thrusters" and not "engines", it sounds like you are saying all of Starliner's faulty thrusters that failed need to be fully understood before certification?  "Repaired or replaced" doesn't make sense in this context, since most of them were expended on the service module...

Understood and replaced with a new design and build that will fix the root cause.

There were at least three separate independent serious failures. Two of them were on the SM, which by design cannot be recovered for analysis. This means that the root cause analysis, however exhaustive, can never be completely validated based on that CFT. For me, this means it's very difficult to know that a new design will actually solve the problem. I feel that another uncrewed flight is needed.

Perhaps this question should be re-framed as, is a Starliner that is certified without a complete flight test better than no Starliner at all. Which is the outcome that it would seem another uncrewed flight would entail, absent NASA injecting more money.

That must be evaluated as objectively a possible. In my opinion, NASA and the taxpayers would be better off without Starliner. The sooner this hard decision is made, the quicker we benefit.

[AmigaClone]

Since Starliner has "thrusters" and not "engines", it sounds like you are saying all of Starliner's faulty thrusters that failed need to be fully understood before certification?  "Repaired or replaced" doesn't make sense in this context, since most of them were expended on the service module...

Understood and replaced with a new design and build that will fix the root cause.

There were at least three separate independent serious failures. Two of them were on the SM, which by design cannot be recovered for analysis. This means that the root cause analysis, however exhaustive, can never be completely validated based on that CFT. For me, this means it's very difficult to know that a new design will actually solve the problem. I feel that another uncrewed flight is needed.

Perhaps this question should be re-framed as, is a Starliner that is certified without a complete flight test better than no Starliner at all. Which is the outcome that it would seem another uncrewed flight would entail, absent NASA injecting more money.

That must be evaluated as objectively a possible. In my opinion, NASA and the taxpayers would be better off without Starliner. The sooner this hard decision is made, the quicker we benefit.

I would be in favor of using one or two of the Starliner 'operational' missions as additional test missions, potentially with one of them uncrewed. By that I mean that as far as the budget would be concerned those missions would be included in the six operational Starliner missions while in reality they would be a lot more limited in scope,

[Jim]

That must be evaluated as objectively a possible. In my opinion, NASA and the taxpayers would be better off without Starliner. The sooner this hard decision is made, the quicker we benefit.

That makes no sense.

[sdsds]

[...] it sounds like you are saying all of Starliner's faulty thrusters that failed need to be fully understood before certification? [...]

Understood and replaced with a new design and build that will fix the root cause.

This gets to the heart of it. A 'root cause' never ends up being a manufacturing flaw or a design flaw. The root cause is always a cultural flaw that allows the more proximate flaws to slip into the produced system. Imagine if a  redesign of the thrusters or doghouse or control software fixes the thruster issue. If the cultural practices aren't changed, how can NASA be certain a different flaw — as yet unobserved — isn't still lurking in the Starliner system?

One answer to that is to get more experience flying the vehicle. I don't know what's legally possible for NASA to offer, but flying a cargo resupply mission on a Starliner in place of the first crew rotation mission seems really attractive.