http://www.nasaspaceflight.com/2015/04/asteroid-redirect-mission-path-mars/Didn't want to get too wordy, so there's a State Of Play, some key points (such as SEP and the suits) and I've attached the NASA presentation for those who want to dig deeper into what this article was based on.
Quote from: Chris Bergin on 04/22/2015 02:00 amhttp://www.nasaspaceflight.com/2015/04/asteroid-redirect-mission-path-mars/Didn't want to get too wordy, so there's a State Of Play, some key points (such as SEP and the suits) and I've attached the NASA presentation for those who want to dig deeper into what this article was based on.Thanks for the shout-out to Altius! That said, AIUI, the NASA baseline for Option-B is using robot arms derived from the FREND Arms that MDA has developed for DARPA and for Goddard's satellite servicing group (with JPL microspine grippers), though we'd love to find a way to stay involved.~Jon
Is there more info on the SEP modules available? Mass, propellant fraction, thrust, isp?
Quote from: Kaputnik on 04/22/2015 09:46 amIs there more info on the SEP modules available? Mass, propellant fraction, thrust, isp?Agreed, that would be vital information. I'd like to see calculations for using the ARV to do a Deimos/Phobos visit instead. If SEP can't do orbit insertion/departure at Mars it becomes redundant at best and useless at worst, at least for anything beyond shuttling cargo to the edge of Earth's gravity well. I'm far from convinced SEP is needed for a Mars mission at all.
Quote from: jongoff on 04/22/2015 03:57 amQuote from: Chris Bergin on 04/22/2015 02:00 amhttp://www.nasaspaceflight.com/2015/04/asteroid-redirect-mission-path-mars/Didn't want to get too wordy, so there's a State Of Play, some key points (such as SEP and the suits) and I've attached the NASA presentation for those who want to dig deeper into what this article was based on.Thanks for the shout-out to Altius! That said, AIUI, the NASA baseline for Option-B is using robot arms derived from the FREND Arms that MDA has developed for DARPA and for Goddard's satellite servicing group (with JPL microspine grippers), though we'd love to find a way to stay involved.~JonIt was always going to be a reference to Altius, not just because "it's you" (we've got MDA friends here too) but because Altius' twitter feed is one of the few I follow, as it's very proactive at showing the development work. In a swamp of nonsense on Twitter, that's a great one to follow.
Quote from: redliox on 04/22/2015 11:00 amI'd like to see calculations for using the ARV to do a Deimos/Phobos visit instead. If SEP can't do orbit insertion/departure at Mars it becomes redundant at best and useless at worst, at least for anything beyond shuttling cargo to the edge of Earth's gravity well. I'm far from convinced SEP is needed for a Mars mission at all.SEP can do orbital insertion/departure at Mars, of course. And if you bothered to read the ARM proposal, you would know the information on mass fraction, Isp, and power (thrust is not the most useful metric when calculating missions for SEP, though of course it's trivial to derive the thrust given Isp, power, and efficiency).
I'd like to see calculations for using the ARV to do a Deimos/Phobos visit instead. If SEP can't do orbit insertion/departure at Mars it becomes redundant at best and useless at worst, at least for anything beyond shuttling cargo to the edge of Earth's gravity well. I'm far from convinced SEP is needed for a Mars mission at all.
Quote from: Robotbeat on 04/22/2015 01:51 pmQuote from: redliox on 04/22/2015 11:00 amI'd like to see calculations for using the ARV to do a Deimos/Phobos visit instead. If SEP can't do orbit insertion/departure at Mars it becomes redundant at best and useless at worst, at least for anything beyond shuttling cargo to the edge of Earth's gravity well. I'm far from convinced SEP is needed for a Mars mission at all.SEP can do orbital insertion/departure at Mars, of course. And if you bothered to read the ARM proposal, you would know the information on mass fraction, Isp, and power (thrust is not the most useful metric when calculating missions for SEP, though of course it's trivial to derive the thrust given Isp, power, and efficiency).The funny thing advocates of electric propulsion leave out is how weak the thrust is while going on about ISP. Where is the data that says how long the setup requires to do the ~1.5 km/sec just to brake into High Mars Orbit? I wouldn't advocate a setup that needs a solid 2 months or more to do a burn like that. Dawn had to fire it's engines for years for a gentle rendezvous with its targets; a crew vulnerable to radiation can't afford that much time.I agree SEP would be perfect for moving cargo, but a crew can fly to Mars more efficiently with methalox. Disprove me by showing how long SEP needs to do MOI.
Quote from: redliox on 04/23/2015 01:15 pmQuote from: Robotbeat on 04/22/2015 01:51 pmQuote from: redliox on 04/22/2015 11:00 amI'd like to see calculations for using the ARV to do a Deimos/Phobos visit instead. If SEP can't do orbit insertion/departure at Mars it becomes redundant at best and useless at worst, at least for anything beyond shuttling cargo to the edge of Earth's gravity well. I'm far from convinced SEP is needed for a Mars mission at all.SEP can do orbital insertion/departure at Mars, of course. And if you bothered to read the ARM proposal, you would know the information on mass fraction, Isp, and power (thrust is not the most useful metric when calculating missions for SEP, though of course it's trivial to derive the thrust given Isp, power, and efficiency).The funny thing advocates of electric propulsion leave out is how weak the thrust is while going on about ISP. Where is the data that says how long the setup requires to do the ~1.5 km/sec just to brake into High Mars Orbit? I wouldn't advocate a setup that needs a solid 2 months or more to do a burn like that. Dawn had to fire it's engines for years for a gentle rendezvous with its targets; a crew vulnerable to radiation can't afford that much time.I agree SEP would be perfect for moving cargo, but a crew can fly to Mars more efficiently with methalox. Disprove me by showing how long SEP needs to do MOI.Look at the Boeing "six not so easy pieces" architecture.260 days to mars, 200 days return (450 days on surface).For comparison DRM 5.0 was 174 days out, 201 days back (539 days on surface). So the Boeing SEP proposal has about 25% longer transit (overall mission actually shorter).
Still, is 5 tons of a Martian moon worth more than 70 tons of an asteroid? If you want to send people to Mars, arguably it is.
The article states that the Phobos mission would still collect a boulder. It just has to be smaller than one collected from an asteroid.QuoteStill, is 5 tons of a Martian moon worth more than 70 tons of an asteroid? If you want to send people to Mars, arguably it is.I agree.