Catching up on "For all Mankind" (season 2, I am very late).
They depict the shuttle as going to/from the moon. Forgetting
landing/taking off on moon (and reality):
If the payload pay had been filled with hydrazine tanks, could the OMSs
have gotten the shuttle to a moon orbit and back?
Easy with plenty of space left in payload bay?
Close but no cigar?
Not even close?
Any issue with the OMS engines running long enought for TLI delta-V (and leaving moon orbit?) Or can all hydrazene engines run for short or long period?
Would fuel needed to go from LEO to moon and back have exceeded the
roughlty 15 tonnes payload max for takeoff?
From a re-entry point of view at much higher speed, could tweating the insulation (tiles, RCC) make this possible (thicker tiles and
carbon-carbon surfaces), or is this a "not even close" situation?
And generic question: say payload bay has plenty of fuel: coming back to Earth, would retrograde firing of OMS to put Shuttle into speed its
tiles could support end up costing roughly the same amount of fuel as
the TLI to get to moon? much less? more ?
If this is within realm of "possible", would it have costed less than
SLS to go around the moon? (and perhaps of there is space in payload
bay, drop off a LEM and bring it back).
On 13/11/2022 5:36 pm, JF Mezei wrote:
Catching up on "For all Mankind" (season 2, I am very late).
They depict the shuttle as going to/from the moon. Forgetting
landing/taking off on moon (and reality):
If the payload pay had been filled with hydrazine tanks, could the OMSs
have gotten the shuttle to a moon orbit and back?
Easy with plenty of space left in payload bay?
Close but no cigar?
Not even close?
Any issue with the OMS engines running long enought for TLI delta-V (and
leaving moon orbit?) Or can all hydrazene engines run for short or long
period?
Would fuel needed to go from LEO to moon and back have exceeded the
roughlty 15 tonnes payload max for takeoff?
From a re-entry point of view at much higher speed, could tweating the
insulation (tiles, RCC) make this possible (thicker tiles and
carbon-carbon surfaces), or is this a "not even close" situation?
And generic question: say payload bay has plenty of fuel: coming back to
Earth, would retrograde firing of OMS to put Shuttle into speed its
tiles could support end up costing roughly the same amount of fuel as
the TLI to get to moon? much less? more ?
If this is within realm of "possible", would it have costed less than
SLS to go around the moon? (and perhaps of there is space in payload
bay, drop off a LEM and bring it back).
I'm pretty sure the shuttle orbiter could not survive a direct entry
into the atmosphere from the moon. Not only would the thermal
environment be too severe, but the mechanical stresses would likely
exceed the limits of the structure. The Apollo missions pulled some
serious gs on reentry, and the shuttle was never designed for that.
The Wikipedia article for the Apollo missions indicate that the
translunar injection required a delta-v of somewhat over 3km/s. If we
assume that the shuttle were put onto a free return trajectory, and that
on the return it needed to shed the same 3km/s of delta-v, then it would
need 6km/s of delta-v.
The Wikipedia article for the Shuttle's OMS system indicates that it
used about 10 tonnes of propellant to achieve a 300m/s delta-v, for a 29 tonne payload. We're talking about 20 times the delta-v, which even
ignoring the propellant required to accelerate the propellant, is 200
tonnes, or way above anything plausible. And note that this just takes
you around the moon and back - you don't even get into lunar orbit.
So, unless some gravity assist method can be found to get to the moon,
the shuttle is not going there, and it's definitely not coming back intact.
Sylvia.
On Nov/13/2022 at 02:41, Sylvia Else wrote :
On 13/11/2022 5:36 pm, JF Mezei wrote:
Catching up on "For all Mankind" (season 2, I am very late).
They depict the shuttle as going to/from the moon. Forgetting
landing/taking off on moon (and reality):
If the payload pay had been filled with hydrazine tanks, could the OMSs
have gotten the shuttle to a moon orbit and back?
Easy with plenty of space left in payload bay?
Close but no cigar?
Not even close?
Any issue with the OMS engines running long enought for TLI delta-V (and >>> leaving moon orbit?) Or can all hydrazene engines run for short or long
period?
Would fuel needed to go from LEO to moon and back have exceeded the
roughlty 15 tonnes payload max for takeoff?
From a re-entry point of view at much higher speed, could tweating the >>> insulation (tiles, RCC) make this possible (thicker tiles and
carbon-carbon surfaces), or is this a "not even close" situation?
And generic question: say payload bay has plenty of fuel: coming back to >>> Earth, would retrograde firing of OMS to put Shuttle into speed its
tiles could support end up costing roughly the same amount of fuel as
the TLI to get to moon? much less? more ?
If this is within realm of "possible", would it have costed less than
SLS to go around the moon? (and perhaps of there is space in payload
bay, drop off a LEM and bring it back).
I'm pretty sure the shuttle orbiter could not survive a direct entry
into the atmosphere from the moon. Not only would the thermal
environment be too severe, but the mechanical stresses would likely
exceed the limits of the structure. The Apollo missions pulled some
serious gs on reentry, and the shuttle was never designed for that.
The Wikipedia article for the Apollo missions indicate that the
translunar injection required a delta-v of somewhat over 3km/s. If we
assume that the shuttle were put onto a free return trajectory, and
that on the return it needed to shed the same 3km/s of delta-v, then
it would need 6km/s of delta-v.
The Wikipedia article for the Shuttle's OMS system indicates that it
used about 10 tonnes of propellant to achieve a 300m/s delta-v, for a
29 tonne payload. We're talking about 20 times the delta-v, which even
ignoring the propellant required to accelerate the propellant, is 200
tonnes, or way above anything plausible. And note that this just takes
you around the moon and back - you don't even get into lunar orbit.
So, unless some gravity assist method can be found to get to the moon,
the shuttle is not going there, and it's definitely not coming back
intact.
Sylvia.
You wouldn't need to shed the 3 km/s of delta-v on the way back. You use aero-breaking, making multiple passes. So instead of having zero
probability to make it to the Moon and back as Sylvia was saying your probability of doing it is double that ;-)
Alain Fournier
On 14/11/2022 12:09 am, Alain Fournier wrote:
You wouldn't need to shed the 3 km/s of delta-v on the way back. You
use aero-breaking, making multiple passes. So instead of having zero
probability to make it to the Moon and back as Sylvia was saying your
probability of doing it is double that ;-)
Alain Fournier
I think the problem with aerobraking is that there's a limit on how much energy it can shed on the first pass. So the question then, is where
will it go? I suppose it won't leave the Earth-Moon system - probably.
But it could then be in a highly elliptical orbit taking days for each
pass. Perhaps with no limits on time in space it would be doable, but
the shuttle did have such limits.
So we're still on zero ;)
Sylvia.
So, unless some gravity assist method can be found to get to the moon,
the shuttle is not going there, and it's definitely not coming back intact.
I'm pretty sure the shuttle orbiter could not survive a direct entry
into the atmosphere from the moon.
The Wikipedia article for the Shuttle's OMS system indicates that it
used about 10 tonnes of propellant to achieve a 300m/s delta-v, for a 29 tonne payload.
They had a working vehicle with known eprformance and known components/engines, it sees to me it should have been faster and cheaper
to upgrade it compared to building that SLS boondgle to nowhere. And as shuttles got upgraded (or new one built,) they could have been tested to
ISS to continue to service it).
I think what they'd realised about the shuttle was that it was hideously dangerous, and an absolute money pit.
And generic question: say payload bay has plenty of fuel: coming back to Earth, would retrograde firing of OMS to put Shuttle into speed its
tiles could support end up costing roughly the same amount of fuel as
the TLI to get to moon? much less? more ?
instead, and see how that works out.-- Katy Jennison
Catching up on "For all Mankind" (season 2, I am very late).
They depict the shuttle as going to/from the moon. Forgetting
landing/taking off on moon (and reality):
If this is within realm of "possible", would it have costed less than
SLS to go around the moon? (and perhaps of there is space in payload
bay, drop off a LEM and bring it back).
Returning from the moon (free return, frex) converts that potential to kinetic energy; to return to orbital speed, you need the same delta-v
as the TLI.
The changes you describe would require about as much redesign work as
SLS; you'd essentially have a whole new shuttle except for the RS25s
and the fragile tiles, and the shuttle would still be exposed to ice
debris.
I'd love to see them shoehorn in the flight software for a pointless
trip to the moon. Pointless because, 1) It ain't landing on the moon,
and 2) it probably ain't carrying much cargo in lieu of fuel.
Shuttle was purpose built for LEO operation only.
Waving the re-usability flag means little when the cost to refurbish per flight isn't better than or worse than an ELV.
SpaceX got us off that
curve thank goodness.
On 2022-11-15 05:25, Snidely wrote:
The changes you describe would require about as much redesign work as
SLS; you'd essentially have a whole new shuttle except for the RS25s
and the fragile tiles, and the shuttle would still be exposed to ice
debris.
both Boeing and Airbus make iterative improvements to their aircraft
(called derivatives). (the MAX fiasco was due to regulatory issues that pushed Boeing to keep the new 737 cockpit behaving as the original 1967
one to keep commonality and hence not add new warnings, buttons etc).
NASA aklready had the plans to go with electric APU instead of hydrazine APUs. Had already converted cockpit to glass cockpit. And early on made
major modifications to heat shield system by using blakets for top
portion. The Shuttle wasn't as static as it seemed.
So a modified Shuttle woudln't need a total redesign as happened with
SLS for 12st stage, 2nd stage and service module and Orion.
On 2022-11-15 05:25, Snidely wrote:
The changes you describe would require about as much redesign work as
SLS; you'd essentially have a whole new shuttle except for the RS25s
and the fragile tiles, and the shuttle would still be exposed to ice
debris.
both Boeing and Airbus make iterative improvements to their aircraft
(called derivatives). (the MAX fiasco was due to regulatory issues that pushed Boeing to keep the new 737 cockpit behaving as the original 1967
one to keep commonality and hence not add new warnings, buttons etc).
On 2022-11-14 08:55, David Spain wrote:
I'd love to see them shoehorn in the flight software for a pointless
trip to the moon. Pointless because, 1) It ain't landing on the moon,
and 2) it probably ain't carrying much cargo in lieu of fuel.
SLS is also pointless saince they will need to launch a big heavy
Starship to land on moon.
Shuttle was purpose built for LEO operation only.
Ny curiosity pertains to converting the Shuttle to act as a shuttle
between earth and moon orbit. And only after seeing the massive costs/boondoggle of Constellation/SLS.
SLS/Orion *is* primarily that conversion. Not happy with that?
Waving the re-usability flag means little when the cost to refurbish per
flight isn't better than or worse than an ELV.
But one isn't comparing against private enterprise, one is comparing
against SLS where costs are far greater per flight. And the disposable SSMEs/RS25 won't be cheap.
SpaceX got us off that
curve thank goodness.
SpaceX was not a player at the time decisions for SLS were made. And it
still isn't. As I post this, all Musk has achieved is 1 successful hop
of something in the shape of starship. (and earlier, succesful hop of something unlike Starship).
Considering the way he is managing Twitter, I have concerns that the
whole starship project may be a Spruce Goose. once FAA told Musk that
he can't keep exploding rockets over Texas willy-nilly, that whole
iterative testing thing went out. Once Musk realised the cost of
building the launch tower, he realised that he can't afford to blow up rockets at the pad anymore. And it remains to be seen if the
revolutioanry approach to landing will work again, consider the cost of
the tower should a landing fail.
While it looked lie Starship would fly well before SLS, tonight, that
didn't happen and it remains to be seen when it will fly. I know people
say first starship orbital flight is imminent. But it has been imminent
for how many years now?
For a lunar lander sharship to work, it will need to be refueled in
lunar orbit. That means a Starship shuttle that bring in fuel and
returns to Earth, so Musk has to deal/develop a proper heat shield for re-entry from moon.
Has Musk given details of habitable volume on the lunar lander version
of Starship? ECLSS that works in 0G as well as lunar gravity? toilets
that work in 0-g as well as lunar gravity?
As for the SLS, it might fly, but then so might pigs. I'm not holding my breath.
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