Hello francisdrake, nice to see you back
I have also been (still am) in a kind of 'away mode' although continue to incrementally improve my addons (but not really being able to pack all up and release). Moving on: based on such past virtual 'simcosmos' development experiments, I have a little of feedback that may be useful for the topic in hand (Delta IV Heavy – Orion integration).
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I. DIVH - Orion: EFT-1
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This was a great test flight but we all need to be aware that such kind of DIVH mission performance (Orion entry from an high elliptical orbit to, among other things, do a good test on Orion's TPS) was only possible because Orion's EFT-1 configuration was not a full one.
In particular, the service module was mostly a shell of the operational one... For example, no 8t up to 9t or so propellant load there... neither main / auxiliary engine nor RCS... other systems also not present, etc. The capsule, although had mass simulators, was not a full spec version.
The EFT-1 is something I'm very interested in virtually replicating but that will still require a good bit of study. This was valid before the flight (with the press kit info) and it is now even more valid because we do have some data to crunch over, from the actual flight!
For the moment, this is something I would perhaps use as a departure point if wishing to try to simulate EFT-1 (approximated values):
7300 kg : LAS (approximated mass properties, inert main motor)
9300 kg : CM (Orion Landing mass was ~8.6t, need to check the budget for FBC + parachutes)
2065 kg : SM (EFT-1, test version as described above)
1200 kg : SM covers
1000 kg : SM adapter + stage adapter
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20865 kg
Such total was based on:
http://www.nasa.gov/sites/default/files/files/JSC_OrionEFT-1_PressKit_accessible.pdf
(as previously mentioned by DaveS)
II. Full Orion and Delta IV Heavy... But wait, what are the specs of an operational Orion MPCV?
The biggest question, from quite some time now, is: what might be the specs of a complete Orion spacecraft? (including here the LAS, SM panels, Spacecraft Adapter and, of course, the CM + SM)
Back in 2009 (ho my, the time flies!!!) I wrote (nasaspaceflight forums) a number of posts about the topics of Orion CM + SM specs and DIVH integration. The simulation files in which I based such posts would need to be properly reviewed and updated, mostly because there seems to exist a trend of mass growth in Orion's development (and this independently of specific issues caused by past Orion-AresI integration challenges)...
There are however some 'recent' news telling that Orion (both the CM and SM) might be on track (vs such mass issues):
- EFT-1's data may help on saving heat shield mass
- it seems that the next Orion CM is already being made with a slightly different methodology that allows to save on its structural mass
- the SM mass (by ESA) also had some issues but may be back on track (?)...
But... I'm not really sure of any of that... If people have patience, please read...
http://forum.nasaspaceflight.com/index.php?topic=26133.msg950931#msg950931
http://forum.nasaspaceflight.com/index.php?topic=26133.msg951146#msg951146
http://forum.nasaspaceflight.com/index.php?topic=26133.msg1254114#msg1254114
(MPCV's Service Module Requirements)
… where I tried to provide a quick overview (and links).
Of particular interest, for virtual number crunching, is the most 'recent' (which may already be outdated) quick-facts, which I comment on the third post above (1254114)
http://www.nasa.gov/sites/default/files/fs-2014-08-004-jsc-orion_quickfacts-web.pdf
As a side note, I'm currently assuming (on AresI / V brainstorms related with CxP lunar mission updated simulations): ~7.64t LAS, 25.5t Orion (CM + SM + Adapter), 1.38t SM panels, for a total liftoff mass of ~34.5t or so. I'm then using a slightly lower SM mass than the one stated on that 2014-08-004 fact sheet...
III. Back to integration with Delta IV Heavy / Conclusion
As mentioned, I would need to go back and redo some input numbers (the 3D models were also just placeholders) and then re-do the performance assessment but, on past experiments, IF assuming RL-10-B2, I had to offload Delta IV Heavy's upper stage in order to be able to inject a complete Orion into 29 degrees (and for ISS, like were the plans for AresI, I used an Orion with half the prop. load).
http://www.flickr.com/photos/simcosmos/4013284353
Again, for orbinauts with patience, please grab a cup of hot tea / coffee and biscuits and feel free to read the related NSF forum thread where brainstormed a little about the topic:
http://forum.nasaspaceflight.com/index.php?topic=11826.0 (Probability of D-IVH Replacing Ares I)
My posts start at
page 40 and go up to page 42, with juicy info about basic configuration assumptions, ascent ground rules, abort options, etc.
The conclusion:
Although probably not strictly required, if wishing to implement easier ascent to orbits of a full Orion on top of a Delta IV Heavy and IF not wishing to do a more specific and careful brainstorm about trajectory optimization work vs ascent events (which is something I do enjoy but which also takes a bit of time), the easiest way, for addon developers, would be to cheat a little and replace the RL-10-B2 with an RL-60 (or a cluster of 3 RL-10 without the B2 long nozzles...).
The above would greatly help with gravity losses, on the upper stage portion of the ascent, for an heavy Orion MPCV. The alternative would be to improve the quality of the ascent guidance, but in the end it all depends of looking at the 'problem' from a really integrated perspective ('crew-rated' Delta IV Heavy mods + Orion full capability mass + trajectory). Bonus for thinking on margins and procedures related with non-nominal ascent scenarios ;-)
Sincerely hope that this somehow helps current brainstorms.
Cheers,
António Maia
(back to lurker mode)