120 ton mission?!?!? using two 21 metric ton Orions?!? Where is the other 80 tons coming from? Remember, they only need 2800 m/s^2 of Delta V to get to the NEO, 1100 m/s^2 to stop at the asteroid, and 1400 m/s^2 to get back. The Orions themselves can produce over 1500 m/s^2 by themselves. To push the 42 metric tons to the Asteroid you would only need a DCSS to get it to 2500 m/s^2, and the Orion itself can supply the remainder 300 m/s^2, while still holding the remaining delta-v for arrival.
I have been trying to run the numbers my self and I can't get it to work with out a large EDS. I could be that I am missing something. I just read an overview of the Plymouth Rock proposal again and it says that the mission requires 46mt through C3 +1 to +4 km/s or the equivalent of 50-65 mt through TLI. That would be more then 2.5km/s and outside of what a DCSS could do. Seems like an EDS would be needed either launched on an HLV or filled up by a depot. Am I missing something here?
Did you take into account the DCSS on the Orions as well? The unmanned one would launch without a LAS, so it would have more fuel left over in it's DCSS.
Once Europeans developed the capability to construct ocean crossing ships, arguments about what part of the New World to explore became pointless.
Eh? Spain became the richest country in Europe by exploiting the precious metals in Mexico. What did the English and French get from their colonies to the north? Maybe some tobacco and cotton? Whoopee. Choosing the right destination -- and the right infrastructure to get there -- is hardly pointless!
EML-1 vs. EML-2? Not really worth argument, since the same capabilities are needed for either. And those capabilities enable deployment of further missions, i.e. the flexible path. A tiny rock in heliocentric orbit, though? Other than public relations, and science better done with robotics, what would a mission there gain us? NASA can't afford to develop too many useless capabilities!
Agree with you on the fact that the science on NEO's is better done with sample returning robots. The only thing I can see that a manned NEO mission gets you is DEEP space experience beyond cislunar space, and probably of necessity a deep space hab module (which could be a very handy thing to have if it were designed to be adaptable to different missions and not a one-trick pony).
Later! OL JR
Did you take into account the DCSS on the Orions as well? The unmanned one would launch without a LAS, so it would have more fuel left over in it's DCSS.
I must admit I am not understanding your proposed architecture very well. I think that your figure of 2800 m/s DV to get to an NEO may be incorrect. C3 is 3220 m/s from LEO and an NEO would require additional impulse.
I did a crude calculation and it looks like a fully fueled DCSS would only give 2080m/s DV to two Orions, another DCSS would give that stack an additional 1366m/s. But the total mass of two DCSS's would be 61.1 mt which is a large EDS. I don't think that a Delta IV H can get a fully fueled DCSS into LEO. So that would mean depots and or HLV.
Did you take into account the DCSS on the Orions as well? The unmanned one would launch without a LAS, so it would have more fuel left over in it's DCSS.
I must admit I am not understanding your proposed architecture very well. I think that your figure of 2800 m/s DV to get to an NEO may be incorrect. C3 is 3220 m/s from LEO and an NEO would require additional impulse.
I did a crude calculation and it looks like a fully fueled DCSS would only give 2080m/s DV to two Orions, another DCSS would give that stack an additional 1366m/s. But the total mass of two DCSS's would be 61.1 mt which is a large EDS. I don't think that a Delta IV H can get a fully fueled DCSS into LEO. So that would mean depots and or HLV.
Plymouth Rock assumed an Ares V US for pushing the payload towards the NEO.
I think a Bigelow module probably would be a better option then a second Orion.
As for propulsion go with a Delta-K on the Bigelow module and use a J-2X upper stage for departure.
The only thing I can see that a manned NEO mission gets you is DEEP space experience beyond cislunar space, and probably of necessity a deep space hab module (which could be a very handy thing to have if it were designed to be adaptable to different missions and not a one-trick pony).
Totally agree on the hab module -- something that Orion can dock with and supports the crew for extended duration missions outside the Van Allen belts. I wonder where a good place for a first mission would be? Best if it were someplace with easy anytime return. Oh I know, <grin> what about a Lagrange point?
Leaving the hab module there would also conveniently start the core of a new space station.
Did you take into account the DCSS on the Orions as well? The unmanned one would launch without a LAS, so it would have more fuel left over in it's DCSS.
I must admit I am not understanding your proposed architecture very well. I think that your figure of 2800 m/s DV to get to an NEO may be incorrect. C3 is 3220 m/s from LEO and an NEO would require additional impulse.
I did a crude calculation and it looks like a fully fueled DCSS would only give 2080m/s DV to two Orions, another DCSS would give that stack an additional 1366m/s. But the total mass of two DCSS's would be 61.1 mt which is a large EDS. I don't think that a Delta IV H can get a fully fueled DCSS into LEO. So that would mean depots and or HLV.
Plymouth Rock assumed an Ares V US for pushing the payload towards the NEO.
It did, however it was written when there was considerable debate about what a future HLV might be so it discussed different configurations. It looked at two launches of a smaller HLV like SLS or Direct.
Leaving the hab module there would also conveniently start the core of a new space station.
I'd still want to take the hab module back in case something goes wrong with the Orion.
Plus most NEOs are in orbits that don't allow regular access.
It also fixes issues with return time.
Orion by itself you need to get back in 14 to 21 days but if you have lets say a BA-330 to live in you can take three months.
Actually a fully stocked BA-330 probably could support a crew of three or four for a year but I'd want to keep the total mission time to that of an ISS stay at first.
Leaving the hab module there would also conveniently start the core of a new space station.
I'd still want to take the hab module back in case something goes wrong with the Orion.
Plus most NEOs are in orbits that don't allow regular access.
I think this was intended to suggest leaving the hab module behind after a mission to a Lagrange point. The return times from those are relatively short (3 to 5 days, depending on trajectory, etc.) so the crew could crowd into the Orion and likely not suffer too much.
Did you take into account the DCSS on the Orions as well? The unmanned one would launch without a LAS, so it would have more fuel left over in it's DCSS.
I must admit I am not understanding your proposed architecture very well. I think that your figure of 2800 m/s DV to get to an NEO may be incorrect. C3 is 3220 m/s from LEO and an NEO would require additional impulse.
I did a crude calculation and it looks like a fully fueled DCSS would only give 2080m/s DV to two Orions, another DCSS would give that stack an additional 1366m/s. But the total mass of two DCSS's would be 61.1 mt which is a large EDS. I don't think that a Delta IV H can get a fully fueled DCSS into LEO. So that would mean depots and or HLV.
Plymouth Rock assumed an Ares V US for pushing the payload towards the NEO.
It did, however it was written when there was considerable debate about what a future HLV might be so it discussed different configurations. It looked at two launches of a smaller HLV like SLS or Direct.
Yes. And all of the options assumed a fairly substantial initial mass in LEO. Ares 1 + Ares V is somewhere north of 150 tonnes in LEO. 2 times J-130 is about that.
Leaving the hab module there would also conveniently start the core of a new space station.
I'd still want to take the hab module back in case something goes wrong with the Orion.
Plus most NEOs are in orbits that don't allow regular access.
I think this was intended to suggest leaving the hab module behind after a mission to a Lagrange point. The return times from those are relatively short (3 to 5 days, depending on trajectory, etc.) so the crew could crowd into the Orion and likely not suffer too much.
Now that would make a lot of sense and then the hab could be reused maybe as a lunar stop over etc.
If a BA-330 or Russian DOS station is used the module should still have lots of life after an asteroid mission.
Maybe make restocking and refueling it a project for commercial entities.
The only extras Orion should need then would be some Shuttle/later Apollo type meals and a Soyuz style toilet.
Would not be hard at all to fit in esp if the EVA suits get left on the hab.
Probably could omit the oven the Shuttle has and go with just hot and cold water dispensers like Apollo.
Did you take into account the DCSS on the Orions as well? The unmanned one would launch without a LAS, so it would have more fuel left over in it's DCSS.
I must admit I am not understanding your proposed architecture very well. I think that your figure of 2800 m/s DV to get to an NEO may be incorrect. C3 is 3220 m/s from LEO and an NEO would require additional impulse.
I did a crude calculation and it looks like a fully fueled DCSS would only give 2080m/s DV to two Orions, another DCSS would give that stack an additional 1366m/s. But the total mass of two DCSS's would be 61.1 mt which is a large EDS. I don't think that a Delta IV H can get a fully fueled DCSS into LEO. So that would mean depots and or HLV.
Plymouth Rock assumed an Ares V US for pushing the payload towards the NEO.
It did, however it was written when there was considerable debate about what a future HLV might be so it discussed different configurations. It looked at two launches of a smaller HLV like SLS or Direct.
Yes. And all of the options assumed a fairly substantial initial mass in LEO. Ares 1 + Ares V is somewhere north of 150 tonnes in LEO. 2 times J-130 is about that.
Yep. There is no way to do an NEO mission without about that much mass in LEO or more. Most of that mass is the propellant needed to escape from Earth.
Now that would make a lot of sense and then the hab could be reused maybe as a lunar stop over etc.
In theory a SEP propelled Hab could take itself back to l1/l2 on autopilot and Orion could depart some time before hand.
I think you would need EVA suits(or suits capable of EVA) in Orion, but you could leave the MMU behind or be more like Skylab suits(with the umbilical cord rather than shuttle suits(with the back pack). Just in case you need to make a spacewalk from Orion or during the trip to or from.
I would agree that an oven is overkill (although Orion currently was planned to have a Galley).
In theory the hab could be reused for another mission if you had a new propulsion module(for safety reasons). I also think it could excite the public for a bit (i.e. the Nautilus departs again for such and such place.).
It also could be upgradeable (depending on the radiation issues). I.e. Add storage and possibly bigger propulsion unit/kick stage) for next mission and slowly work our way to Mars.
I also wonder would it be possible to design the SEP in such a way that the engine is the only thing that gets replaced (i.e. keep solar panels/refuel tanks).
I think it needs to be much smaller than the Nautilus presentation and much less grand but if done I think it will fire the imagination like the shuttle did.
In theory the hab could be reused for another mission if you had a new propulsion module(for safety reasons). I also think it could excite the public for a bit (i.e. the Nautilus departs again for such and such place.).
It also could be upgradeable (depending on the radiation issues). I.e. Add storage and possibly bigger propulsion unit/kick stage) for next mission and slowly work our way to Mars.
I also wonder would it be possible to design the SEP in such a way that the engine is the only thing that gets replaced (i.e. keep solar panels/refuel tanks).
I think it needs to be much smaller than the Nautilus presentation and much less grand but if done I think it will fire the imagination like the shuttle did.
"low price" variant Nautilus?
"L ship":
http://www.irs.uni-stuttgart.de/SSDW/history/results2008.en.php
http://www.irs.uni-stuttgart.de/SSDW/history/estec2008/results_red/SSDW08_PosterRED.jpg
