Quote from: RonM on 04/24/2015 08:46 pmThe 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.NAC says they should go to Mars whether they can get a sample or not.
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.
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.
Quote from: arachnitect on 04/24/2015 09:04 pmQuote from: RonM on 04/24/2015 08:46 pmThe 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.NAC says they should go to Mars whether they can get a sample or not.Even if they don't do the ARM grab a boulder routine, there should be some sort of sample return. If not, why bother to fly to Phobos?We already know SEP works from previous long duration missions. If all they want to do is test the engines on a large SEP tug then just fly it to the Moon and back.If they are going to have a SEP tug go to Phobos, it should bring something back. Otherwise, it is just as uninspiring and pointless as sending a manned Orion to DRO so the crew can twiddle their thumbs.
WOW! Christmas came early this year - real early. Look what the NASA Advisory Council just suggested NASA do.http://blog.chron.com/sciguy/2015/04/advisors-to-nasa-dump-the-asteroid-mission-and-go-to-phobos-instead/Upthread I think I pretty much said the exact same thing. (Dances around the Christmas tree)
WOW! Christmas came early this year - real early. Look what the NASA Advisory Council just suggested NASA do.http://blog.chron.com/sciguy/2015/04/advisors-to-nasa-dump-the-asteroid-mission-and-go-to-phobos-instead/Upthread I think I pretty much said the exact same thing.
SLS will need to launch something that will actually garner some genuine public interest.
The enhanced gravity tractor demo should /not/ be underestimated. By using this method, humanity will demonstrate the precise maneuvering of an asteroid larger than Apophis. That alone would be worth the $1.25 billion price tag. And a larger boulder would allow real scale demonstration of ISRU, allowing us to fill up 90% of our propellant in orbit without having to launch it from Earth. That would also be a game changer and well worth the mission cost (although this part would likely be demonstrated by commercial companies).Phobos (or Deimos) would be a good second mission, though. But following NAC's poor advice would dramatically reduce the value of ARM.
Quote from: Robotbeat on 04/25/2015 12:32 amThe enhanced gravity tractor demo should /not/ be underestimated. By using this method, humanity will demonstrate the precise maneuvering of an asteroid larger than Apophis. That alone would be worth the $1.25 billion price tag. And a larger boulder would allow real scale demonstration of ISRU, allowing us to fill up 90% of our propellant in orbit without having to launch it from Earth. That would also be a game changer and well worth the mission cost (although this part would likely be demonstrated by commercial companies).Phobos (or Deimos) would be a good second mission, though. But following NAC's poor advice would dramatically reduce the value of ARM.I like everything you've written here. ARM supporters have been shouting this into the wind. It's the most practical mission I can imagine for a rocket that's eminently unpractical. It seems to me that NASA should never have attempted to cast ARM as a stepping stone to Mars, except perhaps as a secondary consideration. ARM should be sold as NEO mitigation first, asteroid mining second, and stepping stone third. If the general public saw ARM as asteroid mitigation, they'd be cheering for it, and Congress can't very well call Bolden on the carpet for trying to save humanity.Perhaps the manned aspect was sufficiently weak that they didn't feel it could be sold that way to Congress. But Congress doesn't want to cancel SLS; it's their rocket, after all. They just want something for SLS to do that the public will find inspiring.
I find the Phobos re-direct idea rather silly, it comes off as an attempt to just 'Mars up' an idea to try to portray it as being more 'on the road to Mars' for people who don't understand anything about the actual technical challenges. SEP vehicles have already been well past Mars, the DISTANCE is trivial and not an improvement over current capabilities.
Quote from: Impaler on 05/03/2015 03:28 amI find the Phobos re-direct idea rather silly,Hehe.. I find that terminology slightly worrying. Imagine towing Phobos into high lunar orbit. "Look what I found, mum!"However my understanding is that the original NAC proposal did not mention sample return at all, which begs an obvious question...
I find the Phobos re-direct idea rather silly,
ARM option B would test out a gravity tractor. As neat as that is what is the chance of devastating impact happening in the next few decades? I am not sure of the wisdom in developing a technology which might not be needed for millennia. Let me posit this though, if the threat of an asteroid impact causes real concern why not use the money to fund something like the B612 Foundation's Sentinel telescope so we could find all the potentially dangerous asteroids? If there is a rock heading at us the most pressing thing is to find it as soon as possible. Funding will materialize for all sorts of deflection strategies in short order.
Using ARM to test a gravity tractor is begging the question of the danger of asteroid impacts, it assumes that in the near future there will be one. ...
Quote from: notsorandom on 05/05/2015 04:41 pmUsing ARM to test a gravity tractor is begging the question of the danger of asteroid impacts, it assumes that in the near future there will be one. ...No it doesn't. It only presumes there's a risk of an asteroid impact sometime within, say, the next century. By developing the tech sooner, this gives us a much better chance of deflecting an asteroid once it is determined to be a hazard.You don't ignore the risk just because it's not guaranteed to kill you.
Quote from: Robotbeat on 05/05/2015 05:18 pmQuote from: notsorandom on 05/05/2015 04:41 pmUsing ARM to test a gravity tractor is begging the question of the danger of asteroid impacts, it assumes that in the near future there will be one. ...No it doesn't. It only presumes there's a risk of an asteroid impact sometime within, say, the next century. By developing the tech sooner, this gives us a much better chance of deflecting an asteroid once it is determined to be a hazard.You don't ignore the risk just because it's not guaranteed to kill you.There will always be a risk until the entire population is known. At some point that risk becomes low enough that the available finite funding is best spent on more pressing things. The the analysis based on what we know now is that over the next 100 years there is a 99% chance that a gravity tractor demo will be useless. ...