Quote from: JohnFornaro on 04/26/2013 02:56 pmIf all we get to choose from is an unknown rock...For the umpteenth time:ArkydsIn Fornaro's world we would drag back a rock we know absolutely nothing about. But PR's plan is to drag back a rock after extensive reconnaissance and prospecting. And NASA has expressed a desire to work with PR and DSI.
If all we get to choose from is an unknown rock...
If the Chelyabinsk meteor had entered at a different angle it would have detonated with its ~50X Nagasaki power at ground level, not 35km up. Even the expense of this mission is justified to be able to prevent the destruction of a city in the future.
Quote from: rcoppola on 04/26/2013 02:15 pmQuote from: go4mars on 04/26/2013 01:20 pmWhy not just test the propulsion system on an unmanned, relatively inexpensive program instead (if it's a "must have" for Mars)?Exactly. There is no need to invent another "Mission" just to test SEP.The SEP will be on the unmanned portion of the mission- the robotic asteroid fetching leg. Having the proven capability to find, travel too, grab, and re-direct something of this size (the Chelyabinsk meteor class is only a bit larger) is a great start to planetary protection, and a worthy goal in and of itself, and an excellent use of a 40 kW SEP module, and a good reason to do the test exactly this way. If the Chelyabinsk meteor had entered at a different angle it would have detonated with its ~50X Nagasaki power at ground level, not 35km up. Even the expense of this mission is justified to be able to prevent the destruction of a city in the future.Addendum: Development of the kind of advanced space infrastructure required to make everyone/anyone in the human spaceflight fan camp happy requires money. The biggest historical driver of spending on space was to counter perceived geopolitical threats. The cold war space race was great for space, and the specter of asteroid threats can fill a similar role. Embrace this mission.
Quote from: go4mars on 04/26/2013 01:20 pmWhy not just test the propulsion system on an unmanned, relatively inexpensive program instead (if it's a "must have" for Mars)?Exactly. There is no need to invent another "Mission" just to test SEP.
Why not just test the propulsion system on an unmanned, relatively inexpensive program instead (if it's a "must have" for Mars)?
Otherwise, we've already embraced a mission. It's called Mars. And we don't need to capture rocks to test out the tech with which to get there. It's a nice to have, not a need to have. And with our current funding levels, we should only be looking at need to have.
Quote from: LegendCJS on 04/26/2013 06:46 pmIf the Chelyabinsk meteor had entered at a different angle it would have detonated with its ~50X Nagasaki power at ground level, not 35km up. Even the expense of this mission is justified to be able to prevent the destruction of a city in the future.Cite on either of those claims?
IIRC Orion's capability of supporting EVA was placed on back burner some time ago - am I wrong ?
Quote from: JohnFornaro on 04/26/2013 07:29 pmQuote from: LegendCJS on 04/26/2013 06:46 pmIf the Chelyabinsk meteor had entered at a different angle it would have detonated with its ~50X Nagasaki power at ground level, not 35km up. Even the expense of this mission is justified to be able to prevent the destruction of a city in the future.Cite on either of those claims?1) Ok. You got me. I made up numbers to support my argument without actually looking them up. ...2) Steeper entry angle = deeper detonation: go to a library and find a geophysics textbook3) Velocity vector projection of blast effects: the statements of Peter Brown of the University of Western Ontario, as summarized in the April 15th article on thespacereview by Jeff Foust titled "Piecing together the Chelyabinsk event"4) The only matter of opinion in my post is if the capability to prevent this in the future is worth the expense. For that claim I can't provide a citation beyond saying that many cities have a yearly contribution to the GDP of their countries much larger than the total sum of money needed to execute this asteroid capture mission.
"We’re greatly exaggerating the danger," said David Morrison of NASA and the SETI Institute, noting that many people were killed in shootings or automobile accidents just during the time of the session, while Chelyabinsk killed no one. "It would greatly distort our true interest in surveying for near Earth objects in the 100, 200, 300 meter range that are the real danger if we try to divert our interest to worrying about a once-in-a century event that didn’t kill anyone."
Addendum: Development of the kind of advanced space infrastructure required to make everyone/anyone in the human spaceflight fan camp happy requires money. The biggest historical driver of spending on space was to counter perceived geopolitical threats. The cold war space race was great for space, and the specter of asteroid threats can fill a similar role. Embrace this mission.
http://www.spacedaily.com/reports/Astronomer_Asteroid_could_make_close_flyby_in_2026_999.htmlSays close approach of a Chelyabinsk at 5300 miles (8500 km)http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2013%20GM3;orb=0;cov=0;log=0;cad=1#cadPuts it (as of today) between 46000 km near and 274000 km nominal.
Quote from: Hernalt on 04/27/2013 10:09 amhttp://www.spacedaily.com/reports/Astronomer_Asteroid_could_make_close_flyby_in_2026_999.htmlSays close approach of a Chelyabinsk at 5300 miles (8500 km)http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2013%20GM3;orb=0;cov=0;log=0;cad=1#cadPuts it (as of today) between 46000 km near and 274000 km nominal.Is that unusual - 0.008 AU flyby of Venus (1977), and 0.002 AU flyby of Earth (2026)?
>>> Mr. Gerstenmaier mentioned NASA teams “were looking at potentially using the launch and entry suits with modified EMG (electromyographic sensors) to provide an EVA capability. <<<Or maybe modified TMG, thermal meteoroid garment ?=========Thanks for the article, good stuff !
I suppose you could revert to Hop_David's strategy, personally denigrating this messenger,
When folks around here ask for a cite, this isn't exactly what they accept.
Chelyabinsk lucked out, though, since the track of the meteor was relatively shallow: about 16 degrees. Had the Chelyabinsk meteor come in at a steeper angle—say, 16 degrees to the vertical—the shock wave effects would have been an order of magnitude stronger, Boslough estimated. “The damage on the ground at ground zero would have been much more serious,” he said. “The people in Chelyabinsk and surrounding villages were lucky that this came in at such a shallow angle.”
"We’re greatly exaggerating the danger," said David Morrison of NASA and the SETI Institute...
NASA has a policy against re-use. This is why Jim keeps pointing out that the USG has no need to re-use space hardware.
Somehow, he has lost the ability to use the PageDn key, and claims that he has been "forced" to read opinions that are not his own.
Quote"We’re greatly exaggerating the danger," said David Morrison of NASA and the SETI Institute...
It would greatly distort our true interest in surveying for near Earth objects in the 100, 200, 300 meter range that are the real danger if we try to divert our interest to worrying about a once-in-a century event that didn’t kill anyone.
I hope they don't fit this architecture model for science. Let the science float. Let the science quality of the target be the dead last concern. Photo ops can be re-captioned to enhance or make crucial the science achievements. Prioritize making the rockets go, on time, as soon as the least acceptable target allows, and getting boots beyond LEO. Behind the scenes, behind the photo ops, robots can cover the actual science and sample return from many places no boots will live.