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#20
by
Dante80
on 31 May, 2017 19:42
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Is there anything wrong with Avcoat when used in tiles? Why wound NASA want to change to PICA anyway?
Cost. Primarily because it is very labor intensive to hand-inject every cell in the honeycomb.
Wouldn't changing to PICA after EFT-1 showed cracks introduce a lot more development cost (and schedule overrun)? Recurring cost differences are almost completely irrelevant for a flagship spacecraft like Orion (and the number of missions that is projected to have).
Also, what would changing the material do to the weight of the system (shield + structure)? (any guesses, I have no idea)
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#21
by
Raj2014
on 06 Jun, 2017 23:24
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Is there anything wrong with Avcoat when used in tiles? Why wound NASA want to change to PICA anyway?
Cost. Primarily because it is very labor intensive to hand-inject every cell in the honeycomb.
Wouldn't changing to PICA after EFT-1 showed cracks introduce a lot more development cost (and schedule overrun)? Recurring cost differences are almost completely irrelevant for a flagship spacecraft like Orion (and the number of missions that is projected to have).
Also, what would changing the material do to the weight of the system (shield + structure)? (any guesses, I have no idea)
It is best to have the heat shield strong but not adding mass that will negatively effect the Orion spacecraft.
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#22
by
Raj2014
on 13 Aug, 2017 20:23
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What is the height of the crew module of the Orion Spacecraft? I have looked at some websites but can not get an accurate measurement. Sources say it is 3.3 metres tall. Is the Orion C.M taller than the Apollo C.M?
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#23
by
Jim
on 13 Aug, 2017 22:10
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What is the height of the crew module of the Orion Spacecraft? I have looked at some websites but can not get an accurate measurement. Sources say it is 3.3 metres tall. Is the Orion C.M taller than the Apollo C.M?
Yes, because it is has the same form factor as Apollo CM and it is wider.
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#24
by
Raj2014
on 17 Aug, 2017 21:07
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How tall is the Apollo C.M? On the research I have done, some of the websites shows 3.23 metres tall. Is this correct?
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#25
by
whitelancer64
on 17 Aug, 2017 21:33
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How tall is the Apollo C.M? On the research I have done, some of the websites shows 3.23 metres tall. Is this correct?
The Apollo CM, from the base of its heat shield to the tip of its docking probe, was 10 ft. 7 in, or 3.23 meters in height.
The Orion CM, from the base of its heat shield to the top of its forward bay cover, is 10ft. 10 in, or 3.3 meters in height. This height does NOT include its docking system.
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#26
by
Raj2014
on 27 Sep, 2017 20:43
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Thank you whitelancer64 for the information. I have a idea here. Can they combine the H.I.A.D (Hypersonic Inflatable Aerodynamic Decelerator) to the Orion Spacecraft so you can also have the service module returned and re-used, would this not bring down costs and save time? Has N.A.S.A looked into this?
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#27
by
whitelancer64
on 27 Sep, 2017 20:50
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Thank you whitelancer64 for the information. I have a idea here. Can they combine the H.I.A.D (Hypersonic Inflatable Aerodynamic Decelerator) to the Orion Spacecraft so you can also have the service module returned and re-used, would this not bring down costs and save time? Has N.A.S.A looked into this?
It probably could be done, but it would require a major redesign - and that may cost much more time than it is worth. Also it is the ESA that is building the service module.
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#28
by
Raj2014
on 27 Sep, 2017 21:12
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Thank you whitelancer64 for the information. I have a idea here. Can they combine the H.I.A.D (Hypersonic Inflatable Aerodynamic Decelerator) to the Orion Spacecraft so you can also have the service module returned and re-used, would this not bring down costs and save time? Has N.A.S.A looked into this?
It probably could be done, but it would require a major redesign - and that may cost much more time than it is worth. Also it is the ESA that is building the service module.
True E.S.A is building the S.M but really a major redesign? What I find surprised is that the inflatable heat shield technology has been researched for some time and that they have not thought about it or at list made design plans for a future upgrade for the Orion spacecraft. Is the Orion going to, or not, get upgraded over the years with newer technologies and efficiency?
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#29
by
Jim
on 28 Sep, 2017 00:12
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Thank you whitelancer64 for the information. I have a idea here. Can they combine the H.I.A.D (Hypersonic Inflatable Aerodynamic Decelerator) to the Orion Spacecraft so you can also have the service module returned and re-used, would this not bring down costs and save time? Has N.A.S.A looked into this?
It probably could be done, but it would require a major redesign - and that may cost much more time than it is worth. Also it is the ESA that is building the service module.
True E.S.A is building the S.M but really a major redesign? What I find surprised is that the inflatable heat shield technology has been researched for some time and that they have not thought about it or at list made design plans for a future upgrade for the Orion spacecraft. Is the Orion going to, or not, get upgraded over the years with newer technologies and efficiency?
Yes, it is a major design. inflatable heat shield technology still needs work. It is not useable for the SM, still need a solid heat shield, the inflatable part is just an extension. Plus the SM would need parachutes and the ability to land on water. The SM is not designed for reuse.
The Orion hasn't even flown once as a fully operational vehicle, it is not going be upgraded for some time, if at all.
why do you keep asking about upgrades? The basic vehicle hasn't been built yet
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#30
by
Nibb31
on 28 Sep, 2017 10:40
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HIAD is a decelerator, not a heat shield.
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#31
by
envy887
on 28 Sep, 2017 13:32
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HIAD is a decelerator, not a heat shield.
If it decelerates using hypersonic atmospheric compression, it had better also be a heat shield or it won't work well.
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#32
by
theinternetftw
on 26 Dec, 2017 22:06
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Can anyone speak to the history of Orion's delta-v number? Why did they decide to initially rely on Altair for LOI? And why have low delta-v numbers persisted after Altair's cancellation and, later, a complete change in who's doing the SM? What's driving this lack of capability? (and is "lack of capability" an accurate perception of Orion's delta-v budget?)
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#33
by
Jim
on 28 Dec, 2017 16:30
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Can anyone speak to the history of Orion's delta-v number? Why did they decide to initially rely on Altair for LOI? And why have low delta-v numbers persisted after Altair's cancellation and, later, a complete change in who's doing the SM? What's driving this lack of capability? (and is "lack of capability" an accurate perception of Orion's delta-v budget?)
High delta-V is unneeded. There is no lack of capability
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#34
by
Proponent
on 28 Dec, 2017 17:22
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Can anyone speak to the history of Orion's delta-v number? Why did they decide to initially rely on Altair for LOI?
My guess is that the low delta-V was needed to allow launch on Ares I, which in turn was needed for political reasons. Just my guess.
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#35
by
envy887
on 28 Dec, 2017 17:48
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Can anyone speak to the history of Orion's delta-v number? Why did they decide to initially rely on Altair for LOI?
My guess is that the low delta-V was needed to allow launch on Ares I, which in turn was needed for political reasons. Just my guess.
Ares 1 was canceled 8 years ago. The SM could have been enhanced, but there was no initiative by the powers of the time to go anywhere beyond it's current capabilities. If going to the lunar surface is now once again an objective, Orion is underfueled and that capability will have to be made up by a larger lander or on-orbit fueling.
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#36
by
Jim
on 29 Dec, 2017 00:08
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If going to the lunar surface is now once again an objective, Orion is underfueled and that capability will have to be made up by a larger lander or on-orbit fueling.
Not true. It has plenty of propellant to get into lunar orbit and back. If a lander is involved, then the lander should provide its own delta V. Apollo conop is not the only nor correct one.
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#37
by
brickmack
on 29 Dec, 2017 00:14
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SLS seems little better than Ares 1 for SM sizing though. Orion is near the limit of Block 1 performance to TLI, and Block 1B allows only ~10 tons margin to that trajectory for comanifested payload, which a larger SM will directly reduce. The new Orion Main Engine from EM-3 onwards could improve this without much increase in mass (depending on what engine is selected), but probably not substantially.
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#38
by
envy887
on 29 Dec, 2017 01:37
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SLS seems little better than Ares 1 for SM sizing though. Orion is near the limit of Block 1 performance to TLI, and Block 1B allows only ~10 tons margin to that trajectory for comanifested payload, which a larger SM will directly reduce. The new Orion Main Engine from EM-3 onwards could improve this without much increase in mass (depending on what engine is selected), but probably not substantially.
A larger SM could increase co-manifested payload to TLI, since it can drop the 15 tonnes of EUS and act as another stage.
If going to the lunar surface is now once again an objective, Orion is underfueled and that capability will have to be made up by a larger lander or on-orbit fueling.
Not true. It has plenty of propellant to get into lunar orbit and back. If a lander is involved, then the lander should provide its own delta V. Apollo conop is not the only nor correct one.
The lander will already have to provide over 5,000 m/s of delta-v, while Orion can only provide about 1,300. Adding that dry mass to a stage that has to go to the lunar surface and back is inefficient. Could it be done? Sure. Will it make the lander bigger, more complex, and more expensive? Most likely.
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#39
by
Patchouli
on 29 Dec, 2017 03:49
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Can anyone speak to the history of Orion's delta-v number? Why did they decide to initially rely on Altair for LOI?
My guess is that the low delta-V was needed to allow launch on Ares I, which in turn was needed for political reasons. Just my guess.
Another reason Altair was intended to also be a cargo lander capable of landing large payloads for a lunar base on the moon which meant it had to be able to do LOI without Orion to maximize payload.