Wikipedia lists Dragon 2 pressurized volume at 10 cubic meters while the Apollo CSM is listed at 10.4 cubic meters pressurized.
The propulsion system of Dragon v2 wouldn't be very good at efficient insertion into NRHO because the efficient trajectories include powered lunar flybys. The draco thruster has 2 orders of magnitude less thrust than then the OMS engine on Orion and the super-draco thrusters have poor vacuum isp and off axial thrust. All of this can be fixed by beefing up the trunk into a service module for dragon v2. But it is no where near ready to go as it was designed for LEO crew transportation.
Quote from: ThereIWas3 on 07/27/2017 07:55 pmQuote from: GWH on 07/27/2017 07:31 pmHow anyone GETS to the lander though is anyone's guess.Some Dragon or CST-100 type vehicle?Yeah one would probably be better off discussing that in more detail here: https://forum.nasaspaceflight.com/index.php?topic=35787.100Probably wouldn't be quick and easy. Starliner is limited to 60 hour free flight, Dragon at least lacks the dV, and is a tight ride. ....
Quote from: GWH on 07/27/2017 07:31 pmHow anyone GETS to the lander though is anyone's guess.Some Dragon or CST-100 type vehicle?
How anyone GETS to the lander though is anyone's guess.
Sorry for the tangent I've sent this thread on Chris!Back to a more Orion specific focus: https://twitter.com/SciGuySpace/status/890972613706690560Quote from: Eric BergerSummary: Crew on EM-1 would have accelerated NASA exploration. Unfortunately, they weren't sure the heat shield would work. Also, money.This is the first I've heard on the heat shield, I know they wanted to redesign for lowered cost. Anyone that can summarize why the heat shield wouldn't be up to the task?
Summary: Crew on EM-1 would have accelerated NASA exploration. Unfortunately, they weren't sure the heat shield would work. Also, money.
Coastal is right about capsules(/reentry vehicles) not being ideal for BLEO travel. A OTV with attached habitat module would be better and far more flexible. But require fuel depots and in orbit refuelling, as BLEO -LEO DV is same as LEO-BLEO.
Big picture though, if we are only thinking about having four people in space at a time, then sure, Orion can be a capable vehicle for cislunar operations. Not the most comfortable ride, but those going would put up with such discomforts for the chance to do what few have done in space.But I would hope we are setting our sights at having more than four people in space at any one time, which is one of my touchstones for critiques of any HSF hardware. Does it allow & promote the expansion of humanity out into space? With expansion in this case not meaning distance, but the number of people.
QuoteBig picture though, if we are only thinking about having four people in space at a time, then sure, Orion can be a capable vehicle for cislunar operations. Not the most comfortable ride, but those going would put up with such discomforts for the chance to do what few have done in space.But I would hope we are setting our sights at having more than four people in space at any one time, which is one of my touchstones for critiques of any HSF hardware. Does it allow & promote the expansion of humanity out into space? With expansion in this case not meaning distance, but the number of people.I don't understand this pure fantasy.
We have not in anyway proven how to live and survive in deep space without the aid of earth.
Until that is well known and proven, you can't start building spacecraft for 100s of people, its just too risky.
You are acting like we're on the verge of Star Trek technology or something.
Quote from: TrevorMonty on 07/28/2017 05:16 pmCoastal is right about capsules(/reentry vehicles) not being ideal for BLEO travel. A OTV with attached habitat module would be better and far more flexible. But require fuel depots and in orbit refuelling, as BLEO -LEO DV is same as LEO-BLEO.
Orion (or any other capsule) is fine.
Disagree. It only takes 3 days to reach lunar orbit or back. That compares to a couple days to launch or return from ISS, and up to 2 weeks for Shuttle missions. Cislunar transport doesn't need extra space than is needed for typical LEO capsule missions.
A separate cislunar transport craft (in addition to a capsule and a lander) doesn't make sense to me. Just another development project to amortize and another docking event.
Looking at the risk chart, NASA gives the same orange or high risk for both shields, so there is no increase in safety. Apollo had a greater risk of cracks, but the consequence was much less. Blocks have a much lower risk of cracks, but the consequence is catastrophic.
Heritage? Space X Dragon
Since the heritage they are copying is Dragon, why not use PicaX? Avcoat is known to crack...
Quote from: AncientU on 01/25/2018 01:25 pmSince the heritage they are copying is Dragon, why not use PicaX? Avcoat is known to crack... Well, for one, though I can't speak to PicaX, Pica tends not to like getting hit by MMOD. Avcoat does much better.
MMOD resistance was not the main driver for selecting Avcoat over Pica.
Quote from: woods170 on 01/25/2018 06:37 pmMMOD resistance was not the main driver for selecting Avcoat over Pica.Your link notwithstanding (note that it says nothing about MMOD other than that testing was performed), this statement is not really all that accurate. It was a driver in the downselect. I have some direct knowledge in this field.
What letter in the word "main" did you not parse?When I state that something was "not a main driver" it means that it was a driver, just not one of the main (as in: biggest) drivers.The link I provided does a nice job of summing-up what down-select evaluation metrics were used. And guess what: MMOD resistance is not even in that list.
MMOD resistance is not even in that list.
About to start 2 days of Net Habitable Volume testing for Orion. Basically, do we have enough room to do stuff with our current cabin config & stowage arrangements.
This afternoon, I'm leading a half-day review of the @NASA_Orion fire response concept of operations to determine if the planned design sufficiently supports Orion crew fighting & recovering from a fire.
While our engineering teams have designed everything to preclude the possibility of a fire through materials selection, atmosphere composition, power system safing, etc., we could never reduce the chance of a fire to 0.0%.
Much of the fire-fighting or protection equipment is going through design reviews now. The goal today is to see how all the individual component designs mesh together into an integrated con ops or to find gaps in the design and assess the associated risk.
Very important for us to understand where we are with these potentially life-saving capabilities as we try to finalize(-ish) the Orion design in the fall.