Quote from: Dante80 on 05/31/2017 06:49 pmIs 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.
Is there anything wrong with Avcoat when used in tiles? Why wound NASA want to change to PICA anyway?
Quote from: Lars-J on 05/31/2017 07:15 pmQuote from: Dante80 on 05/31/2017 06:49 pmIs 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)
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?
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?
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?
Quote from: Raj2014 on 09/27/2017 08:43 pmThank 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.
Quote from: whitelancer64 on 09/27/2017 08:50 pmQuote from: Raj2014 on 09/27/2017 08:43 pmThank 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?
HIAD is a decelerator, not a heat shield.
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?)
Can anyone speak to the history of Orion's delta-v number? Why did they decide to initially rely on Altair for LOI?
Quote from: theinternetftw on 12/26/2017 10:06 pmCan 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.
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.
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.
Quote from: envy887 on 12/28/2017 05:48 pmIf 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.