Quote from: Robotbeat on 10/05/2014 03:04 pmI will say one thing: since both designs chosen were capsules, they are both relevant for any future BLEO missions and should be considered for inclusion by mission planners.None of these vehicles will be evolved for BLEO - they are too small. Be glad to talk on another thread about it if you want...
I will say one thing: since both designs chosen were capsules, they are both relevant for any future BLEO missions and should be considered for inclusion by mission planners.
Yes. But there is limited use in taking them with you past some kind of L1/2 gateway station.
Aerobraking takes too much time with a crew aboard.
It believe it's passing through the radiation belts too many times that TomH may have been thinking about.
My point was that Dragon and CST-100 and Orion and Apollo command module, etc, all would need an extra module, so all are big enough with a module and none are big enough without a module, assuming beyond short trips to and from an EML gateway or something. And they are big enough for a few days.I mean Gemini was cartoonish lot small for 2 guys (WAY smaller than CST-100, Dragon, etc), and they spent 2 weeks in it. Dragon or CST-100 are like mansions compared to Gemini.
If the habitat is launched/built separately and put in a permanent cycling orbit, then the capsule could rendevous with it during Earth approach, go along with it on the mission, then separate and return to Earth on the return leg.
...and you have astronauts watching the Earth go by over and over while they cannot land, likely enduring psychological stress from being so near physically, while still so far away temporally.
Orion is perfectly suited for.....absolutely no mission
But having BEO rated avionics, heat transfer through heat plates, high distance comm system, long term ECLSS, BEO astrogation capabilities, limited radiation protection for crew, etc. those thing are the hard part.
Quote from: TomH on 10/06/2014 03:54 amOrion is perfectly suited for.....absolutely no missionTo the contrary I think Orion is the right size to taxi a crew of four between Earth and a space station in the lunar vicinity, e.g EML1, EML2, or DRO. The current design is too heavy for this (due to the parachute issue), and no one who knows why seems willing to say. I've expressed my guess that it's the result of structural mass left over from CxP mission requirements that is not required in this taxi role. That mass could be taken out by redesigning the structure. Alternately, EFT-1 may show a way to reduce mass, if it indicates the heat shield is over-built.
In my opinion (for what it's worth) Orion should have been largely composite in structure, much like the ATK Liberty proposal which I also think might have been a 'mere' 4.5 meters in diameter and doubtlessly thousands of kilos lighter than Orion's large aluminium/lithium etc structures.