Author Topic: Orion Spacecraft Q & A  (Read 11327 times)

Offline Dante80

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Re: Orion Spacecraft Q & A
« Reply #20 on: 05/31/2017 07:42 PM »
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)
« Last Edit: 05/31/2017 07:43 PM by Dante80 »

Offline Raj2014

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Re: Orion Spacecraft Q & A
« Reply #21 on: 06/06/2017 11:24 PM »
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.
« Last Edit: 08/13/2017 08:17 PM by Raj2014 »

Offline Raj2014

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Re: Orion Spacecraft Q & A
« Reply #22 on: 08/13/2017 08:23 PM »
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?

Offline Jim

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Re: Orion Spacecraft Q & A
« Reply #23 on: 08/13/2017 10:10 PM »
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.

Offline Raj2014

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Re: Orion Spacecraft Q & A
« Reply #24 on: 08/17/2017 09:07 PM »
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?

Offline whitelancer64

Re: Orion Spacecraft Q & A
« Reply #25 on: 08/17/2017 09:33 PM »
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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Offline Raj2014

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Re: Orion Spacecraft Q & A
« Reply #26 on: 09/27/2017 08:43 PM »
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?

Offline whitelancer64

Re: Orion Spacecraft Q & A
« Reply #27 on: 09/27/2017 08:50 PM »
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.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline Raj2014

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Re: Orion Spacecraft Q & A
« Reply #28 on: 09/27/2017 09:12 PM »
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? 

Offline Jim

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Re: Orion Spacecraft Q & A
« Reply #29 on: 09/28/2017 12:12 AM »
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


Offline Nibb31

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Re: Orion Spacecraft Q & A
« Reply #30 on: 09/28/2017 10:40 AM »
HIAD is a decelerator, not a heat shield.

Offline envy887

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Re: Orion Spacecraft Q & A
« Reply #31 on: 09/28/2017 01:32 PM »
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.

Offline theinternetftw

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Re: Orion Spacecraft Q & A
« Reply #32 on: 12/26/2017 10:06 PM »
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?)

Offline Jim

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Re: Orion Spacecraft Q & A
« Reply #33 on: 12/28/2017 04:30 PM »
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

Offline Proponent

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Re: Orion Spacecraft Q & A
« Reply #34 on: 12/28/2017 05:22 PM »
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.

Offline envy887

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Re: Orion Spacecraft Q & A
« Reply #35 on: 12/28/2017 05:48 PM »
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.

Offline Jim

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Re: Orion Spacecraft Q & A
« Reply #36 on: 12/29/2017 12:08 AM »

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.

Offline brickmack

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Re: Orion Spacecraft Q & A
« Reply #37 on: 12/29/2017 12:14 AM »
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.

Offline envy887

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Re: Orion Spacecraft Q & A
« Reply #38 on: 12/29/2017 01:37 AM »
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.

Offline Patchouli

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Re: Orion Spacecraft Q & A
« Reply #39 on: 12/29/2017 03:49 AM »
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.
« Last Edit: 12/29/2017 03:51 AM by Patchouli »

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