Can Starliner bring its astronauts home? Boeing, NASA test-fire spacecraft's engines at ISS

[Admin]

Boeing's Starliner spacecraft completed a hot fire July 27 at the ISS as part of certification for reentry. Its 1st historic test flight with astronauts is more than 50 days into a planned 10-day mission, following technical issues.

Can Starliner bring its astronauts home? Boeing, NASA test-fire spacecraft's engines at ISS : Read more

 

[brunodoggy]

How can you report: "Ground testing on a thruster this month uncovered why CFT's RCS had issues" and in the same paragraph say: "NASA and Boeing also said this issue could not have been uncovered on the ground"?

 

[Classical Motion]

I can dig it. Space was required to indicate and determine. Ground was required for confirmation of what space indicated.

 

[JPL_ACE]

How can you report: "Ground testing on a thruster this month uncovered why CFT's RCS had issues" and in the same paragraph say: "NASA and Boeing also said this issue could not have been uncovered on the ground"?

I can imagine a situation where the ground tests do not directly explain a problem but it is immediate in space. you can not test a rocket in a vacuum on the ground. Before it is even lit, it is no longer a vacuum. Other problems are the sun and dark every 45 min, an insulated dog house, and chem reactions of fuel are different in space than the ground.

 

[Unclear Engineer]

I tend to agree with brunodoggy. It seems like firing the thrusters on the ground in a pattern that simulates the firing sequence for approach and docking would have uncovered a heating problem in the doghouses, and created the same teflon seal problem if that is really due to overheating.

Yes, there are differences in the space environment, but nothing specific was said about why this could not have been identified with proper testing on the ground. So, I am not really "buying" this press release.

 

[josefnspace]

"Ground testing on a thruster this month uncovered why CFT's RCS had issues: If fired repeatedly, especially in conjunction with the orbital maneuvering and control system (OMAC) thrusters, the "doghouses" or insulated bays sheltering groups of RCS thrusters tend to heat up, leading to thrusters shedding Teflon insulation from their seals. NASA and Boeing also said this issue could not have been uncovered on the ground, ahead of flying CFT."

Why weren't the RCS and OMAC systems included in the pre-flight ground tests?
The "conditions are different in space" explanation is similar to "the dog ate my homework" excuse.

Boeing & NASA have spent billions of dollars with years of delays on a half completed flight.
Meanwhile SpaceX has successfully transported 50 astronauts to the ISS with four more on Crew-9.

 

[Hal_S]

Wait, I thought there were protocols that prohibited / strictly limited the amount of thruster firing when NEAR the ISS, let alone when attached to it?

 

[billslugg]

They boost ISS to a higher orbit frequently. Lots of thruster firing in that process. Maybe there are protocols about not firing a thruster directly at ISS.

 

[buzzallnight]

Astronauts Butch Wilmore and Suni Williams need to be working on realistic dummies they can put in that space craft to save their own lives!!!

 

[DanaBspaced]

I can imagine a situation where the ground tests do not directly explain a problem but it is immediate in space. you can not test a rocket in a vacuum on the ground. Before it is even lit, it is no longer a vacuum. Other problems are the sun and dark every 45 min, an insulated dog house, and chem reactions of fuel are different in space than the ground.

Explain how the chemical reactions are different in space. It is a simple hyperbolic system. Used for decades.

And explain so I can understand "before is even lit, it is no longer a vacuum."

 

[DanaBspaced]

How can you report: "Ground testing on a thruster this month uncovered why CFT's RCS had issues" and in the same paragraph say: "NASA and Boeing also said this issue could not have been uncovered on the ground"?

You should be there for their next news conference.

 

[ZZTOP]

Boeing's Starliner spacecraft completed a hot fire July 27 at the ISS as part of certification for reentry. Its 1st historic test flight with astronauts is more than 50 days into a planned 10-day mission, following technical issues.

Can Starliner bring its astronauts home? Boeing, NASA test-fire spacecraft's engines at ISS : Read more

What people miss is that NASA is not even mentioning a parts mission which means that artemis has already been abandoned

 

[ChrisA]

Explain how the chemical reactions are different in space. It is a simple hyperbolic system. Used for decades.

Cooling is different. In space, the valve is surrounded by very insulation, a vacuum. But on Earth, there is air surrounding the valve which would cool it by convection or conduction. In space, we only have radiative cooling which is much less effective.

Lubrication is also different in space and on the ground. The boiling point of the components in the grease depends on the air pressure. Boiling points are always reduced in a vacuum. That said, "everyone" knows to use "vacuum grease" so I'm sure they did, but I forget how this grease works at Sealevel and if it would affect testing. But heating is always VERY different in space.

But we don't know the exact design of this valve so the above as only general observations that apply to all valves (and many other parts.)