Not sure if there is anoyone left in the group, but just in case.
Consideirng SLS has been in development for over 10 years, considering
they already had quick disconnect experience for H2 refueling on
Shuttle, I am curous on what constraints would have prevented them from developping a reliable H2 fill line quick disconnect for SLS ?
I take it that they can't test it at VAB because they don't have LH2
lines there. (and leaking H2 indoors, not a great idea).
But when this quick disconnect was designed, wouldn't it have had some
real testing with LH2 to ensure it works well and that any limitations
and maintenance requiremenmts (eg: change rubber seals every X refills)
would be well known.
And considering the number of tests they did of this rocket, how come
this quick disconnect problem didn't get noticed before ?
On Sep/10/2022 at 12:21, JF Mezei wrote :
Not sure if there is anoyone left in the group, but just in case.
Consideirng SLS has been in development for over 10 years, considering
they already had quick disconnect experience for H2 refueling on
Shuttle, I am curous on what constraints would have prevented them from
developping a reliable H2 fill line quick disconnect for SLS ?
I take it that they can't test it at VAB because they don't have LH2
lines there. (and leaking H2 indoors, not a great idea).
But when this quick disconnect was designed, wouldn't it have had some
real testing with LH2 to ensure it works well and that any limitations
and maintenance requiremenmts (eg: change rubber seals every X refills)
would be well known.
And considering the number of tests they did of this rocket, how come
this quick disconnect problem didn't get noticed before ?
It's normal on a new system to have some bugs.
The real question, in my opinion, is why didn't they disconnect the whole programme years ago. Why not buy rides from SpaceX and Blue Origin to go to the moon. It would be much cheaper than the SLS boondoggle.
On Saturday, Alain Fournier exclaimed wildly:
The real question, in my opinion, is why didn't they disconnect the
whole programme years ago. Why not buy rides from SpaceX and Blue
Origin to go to the moon. It would be much cheaper than the SLS
boondoggle.
Well, of course you know the answer is political, and that SLS is a
giant jobs program.
Not sure if there is anoyone left in the group, but just in case.
Consideirng SLS has been in development for over 10 years, considering
they already had quick disconnect experience for H2 refueling on
Shuttle, I am curous on what constraints would have prevented them from developping a reliable H2 fill line quick disconnect for SLS ?
I take it that they can't test it at VAB because they don't have LH2
lines there. (and leaking H2 indoors, not a great idea).
But when this quick disconnect was designed, wouldn't it have had some
real testing with LH2 to ensure it works well and that any limitations
and maintenance requiremenmts (eg: change rubber seals every X refills)
would be well known.
And considering the number of tests they did of this rocket, how come
this quick disconnect problem didn't get noticed before ?
Il giorno sabato 10 settembre 2022 alle 18:21:39 UTC+2 JF Mezei ha scritto:
Not sure if there is anoyone left in the group, but just in case.
Consideirng SLS has been in development for over 10 years, considering
they already had quick disconnect experience for H2 refueling on
Shuttle, I am curous on what constraints would have prevented them from developping a reliable H2 fill line quick disconnect for SLS ?
I take it that they can't test it at VAB because they don't have LH2
lines there. (and leaking H2 indoors, not a great idea).
But when this quick disconnect was designed, wouldn't it have had some
real testing with LH2 to ensure it works well and that any limitations
and maintenance requiremenmts (eg: change rubber seals every X refills) would be well known.
And considering the number of tests they did of this rocket, how comeNothing will never colonized by roketry
this quick disconnect problem didn't get noticed before ?
It is a physical law,
Continue till to the disaster
On Monday, September 12, 2022 at 4:18:17 AM UTC-4, pnn calmagorod wrote:
Il giorno sabato 10 settembre 2022 alle 18:21:39 UTC+2 JF Mezei ha scritto: >> > Not sure if there is anoyone left in the group, but just in case.
Nothing will never colonized by roketry
Consideirng SLS has been in development for over 10 years, considering
they already had quick disconnect experience for H2 refueling on
Shuttle, I am curous on what constraints would have prevented them from
developping a reliable H2 fill line quick disconnect for SLS ?
I take it that they can't test it at VAB because they don't have LH2
lines there. (and leaking H2 indoors, not a great idea).
But when this quick disconnect was designed, wouldn't it have had some
real testing with LH2 to ensure it works well and that any limitations
and maintenance requiremenmts (eg: change rubber seals every X refills)
would be well known.
And considering the number of tests they did of this rocket, how come
this quick disconnect problem didn't get noticed before ?
It is a physical law,
Continue till to the disaster
I am pretty sure those are American flags on the moon, not Italian.
Il giorno sabato 10 settembre 2022 alle 18:21:39 UTC+2 JF Mezei ha scritto:
Not sure if there is anoyone left in the group, but just in case.
Consideirng SLS has been in development for over 10 years, considering
they already had quick disconnect experience for H2 refueling on
Shuttle, I am curous on what constraints would have prevented them from
developping a reliable H2 fill line quick disconnect for SLS ?
I take it that they can't test it at VAB because they don't have LH2
lines there. (and leaking H2 indoors, not a great idea).
But when this quick disconnect was designed, wouldn't it have had some
real testing with LH2 to ensure it works well and that any limitations
and maintenance requiremenmts (eg: change rubber seals every X refills)
would be well known.
And considering the number of tests they did of this rocket, how come
this quick disconnect problem didn't get noticed before ?
Nothing will never colonized by roketry
It is a physical law,
Continue till to the disaster
AIUI, the GSE (which is a whole separate set of contractors) wasn't
done much sooner than the Green Run, which used different GSE.
But a nice little test tank would have been handy, wouldn't it?
Something like the 7.1 test tank, except validating the GSE in stead of
tank welds.
On Sep/12/2022 at 04:18, pnn calmagorod wrote :
Il giorno sabato 10 settembre 2022 alle 18:21:39 UTC+2 JF Mezei ha scritto: >>> Not sure if there is anoyone left in the group, but just in case.
Consideirng SLS has been in development for over 10 years, considering
they already had quick disconnect experience for H2 refueling on
Shuttle, I am curous on what constraints would have prevented them from
developping a reliable H2 fill line quick disconnect for SLS ?
I take it that they can't test it at VAB because they don't have LH2
lines there. (and leaking H2 indoors, not a great idea).
But when this quick disconnect was designed, wouldn't it have had some
real testing with LH2 to ensure it works well and that any limitations
and maintenance requiremenmts (eg: change rubber seals every X refills)
would be well known.
And considering the number of tests they did of this rocket, how come
this quick disconnect problem didn't get noticed before ?
Nothing will never colonized by roketry
It is a physical law,
Continue till to the disaster
There is no physical law that prohibits space colonisation by rocketry.
On the other hand there is a physical law that prohibits space
colonisation using PNN. If you don't know what physical law that is let
me give you a hint. PNN stands for propulsione non newtoniana.
Alain Fournier
This is just but one example of why it's more difficult to do this when
a government agency is trying to accomplish something via contractors vs doing it yourself.
On 2022-09-26 1:54 AM, JF Mezei wrote:
On 2022-09-23 09:58, David Spain wrote:
This is just but one example of why it's more difficult to do this when
a government agency is trying to accomplish something via contractors vs >>> doing it yourself.
NASA had over 25 years experience with Shuttle/hydrogen and quick
disconnects.
On 2022-09-23 09:58, David Spain wrote:
This is just but one example of why it's more difficult to do this when
a government agency is trying to accomplish something via contractors vs
doing it yourself.
NASA had over 25 years experience with Shuttle/hydrogen and quick disconnects.
The whole SLS project was specced by NASA via political pressure to
maintain jobs at the contractors that did Shuttle. I would have hoped
that experience from shuttle would have been transferef especially sicne
NASA had experience with those contractors.
But there are other worrysome things like limited battery lifetime once
out of VAB for so many systems instead of powering the rocket while at
pad to not deplete batteries. Just curious why this wasn't implemented. Weather delays and scrubs for technical issues are not something that
are unknown.
Due to IAN, the rocket is being rolled back to VAB, so I assume they
will get to change batteries at that point.
One can criticise NASA's design of the system (SRBs etc), but in the
past, NASA was very pedantic on testing and validating designs, so it is
very strange to see components arriving on pad with less than stellar reliability especially when NASA is fully aware of difficulties of
working with LH2.
As Rand Simberg points out on his blog a whole set of clocks start
ticking once the SLS rocket rolls out of the VAB.
continue on the Shuttle even after it had been rolled out to the pad.
SLS does not have this, because why would you need to service an
*expendable* rocket?
On 2022-09-26 08:34, David Spain wrote:
As Rand Simberg points out on his blog a whole set of clocks start
ticking once the SLS rocket rolls out of the VAB.
I can understand SRBs which have a "best before" date because
built-already fueled. I can understand limits on how many times you
can fill/empty the tanks since going from tropical to cryo temperature
cycles impacts the metals.
But to design the Orion Capsule such that it either doesn't get power
from pad or didn't bother with provisions to power experiments while at
pad is very strange for NASA. Same with the flight termination system
whose batteries should be able to be recharged while at pad.
The odds of delays at pad are the same whether rocket is reusable or
not. And the cost of providing pad power to these systems wouldn't be
that great compared to overall cost.
It is just strange that pedantic NASA wouldn't have required the rocket
to be able to stand at pad without using batteries.
continue on the Shuttle even after it had been rolled out to the pad.
SLS does not have this, because why would you need to service an
*expendable* rocket?
It was decided to complete preparation at the pad, and load payloads at
the pad, hence the RSS for shuttle. But the shuttle itself was getting
pad power and the crew compartment was fully powered and experiments,
fridges etc powered by pad until a minute or two before launch.
The fact that SLS can't be maintained at pad is all the more reason to
allow it to be powered by the pad since changing AA or CR2032 batteries >spread throughout the stack requires roll back to the VAB.
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