So, please America and NASA, I would suggest you do NOT waste time, effort and huge funds on building an asteroid manned mission
One of the 'ideas' being touted is for NASA to send a manned Orion on a BEO mission to a 'nearby' close-approach asteroid .Well, today is day 1 of the unmanned DAWN spacecraft in orbit about the asteroid Vesta.Was it featured on your Tv station ? Or mentioned on your radio ? In the daily newspaper ? Unlikely , and if it did I doubt if it was a "top item" or front or even early inside pages ?
Quote from: Apollo-phill on 07/16/2011 08:47 pmSo, please America and NASA, I would suggest you do NOT waste time, effort and huge funds on building an asteroid manned missionI think it's entirely reasonable for us to at least ask, "How did the idea for this mission become the plan?" Was there an independent cost estimate? Was it developed through some open public discussion or blue-ribbon commission? Is it simply something that is politically expedient to talk about right now, regardless of its practicality or intrinsic value?I believe the first time President Obama mentioned it was the April 15, 2010 speech at KSC. (This was the speech where he tacitly admitted that his FY11 budget proposal from February 2010 was a non-starter.) Am I inventing that history? Was there an earlier mention of this from Obama? (Obviously others -- certainly including Garver -- would have talked about it as a theoretical option. But when did it become the President's plan?)http://www.whitehouse.gov/the-press-office/remarks-president-space-exploration-21st-century(EDIT: fix dates; add link.)
Quote from: sdsds on 07/16/2011 09:56 pmWas it developed through some open public discussion or blue-ribbon commission? [...] I believe the first time President Obama mentioned it was the April 15, 2010 speech at KSC.The Augustine Commission promoted it as their preferred BEO option, 'Flexible Path'
Was it developed through some open public discussion or blue-ribbon commission? [...] I believe the first time President Obama mentioned it was the April 15, 2010 speech at KSC.
Once Europeans developed the capability to construct ocean crossing ships, arguments about what part of the New World to explore became pointless.
Lockheed describes doing it with two Orion capsules, that works for me. Buy 2 Orions from Lockheed (fixed cost), buy launches commercially, dock them together in space. Send humans and fueled Earth Departure Stage up on separate commercial launches. You couldn't send up a fueled EDS that could launch two loaded Orions to a NEO on a separate commercial launch. You would need something like 3-4 Falcon/EELV Heavies and then docking between all 5-6 elements and then cryo propellant transfer. This would not be a simple quick cheap mission without a HLV. Forget anything meaningful to Mars or its moons using this method.
However, if we had to move an asteroid, given that we had the ability to send humans, would we use a robotic craft or a crewed one?I am unsure of the answer.
I do know, however, that unlike a mission to Mars, crewed missions to asteroids have benefits to national security.
Quote from: marsavian on 07/18/2011 06:43 pmLockheed describes doing it with two Orion capsules, that works for me. Buy 2 Orions from Lockheed (fixed cost), buy launches commercially, dock them together in space. Send humans and fueled Earth Departure Stage up on separate commercial launches. You couldn't send up a fueled EDS that could launch two loaded Orions to a NEO on a separate commercial launch. You would need something like 3-4 Falcon/EELV Heavies and then docking between all 5-6 elements and then cryo propellant transfer. This would not be a simple quick cheap mission without a HLV. Forget anything meaningful to Mars or its moons using this method.Pardon me, what? Orion would only need a DCSS to serve as EDS, the rest of the thrust would be provided by the two Service Module.
Quote from: Downix on 07/18/2011 07:25 pmQuote from: marsavian on 07/18/2011 06:43 pmLockheed describes doing it with two Orion capsules, that works for me. Buy 2 Orions from Lockheed (fixed cost), buy launches commercially, dock them together in space. Send humans and fueled Earth Departure Stage up on separate commercial launches. You couldn't send up a fueled EDS that could launch two loaded Orions to a NEO on a separate commercial launch. You would need something like 3-4 Falcon/EELV Heavies and then docking between all 5-6 elements and then cryo propellant transfer. This would not be a simple quick cheap mission without a HLV. Forget anything meaningful to Mars or its moons using this method.Pardon me, what? Orion would only need a DCSS to serve as EDS, the rest of the thrust would be provided by the two Service Module. No either both Orions have an EDS or a single EDS would have to be refueled. This is a 110-120 ton mission at least. Maybe you could just get away with using two crossfed Falcon Heavies if they really did do 53mT LEO (no margin ?).http://forum.nasaspaceflight.com/index.php?topic=25975.msg776844#msg776844
They put the combined weight of the Orions at 43-47mT and give an EDS DeltaV of 3.32-3.35 Km/s.
At what orbit could the Falcon Heavy push the Orion? If it can do 19tn to a 185 km x 35,786 km x 28.5deg GTO, then it should be able to put the Orions on some high energy orbit. The question is if Orion (and it's crew) can do the multiple Van Allen passes.
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.