Quote from: a_langwich on 04/10/2013 04:51 amYou can frame just about any initiative to look ridiculous.A standard debate point, used by people who do not care to discuss TRL levels of technology, poor cost estimating, and other details of sketchy analysis.
You can frame just about any initiative to look ridiculous.
OK some questions that I have that are probably a bit funny:1. So once NASA's spacecraft caught the asteroid, does it mean that a certain United States authority would have the ownership of the asteroid. Suppose that before/after EM-2, someone else (China/private organization etc.) want to visit the asteroid too - can the US denies the right to do so (even when, of course, there's no way to do that physically!)?
2. Since the asteroid is put in a high lunar orbit, it will eventually spiral down and collide with the Moon some many years later. Who should be responsible from preventing (or leading, depending on the reason) this happening, and when?
Quote from: Chris Bergin on 04/11/2013 01:38 amQuote from: ARD on 04/11/2013 01:35 amQuote from: Chris Bergin on 04/11/2013 01:18 amUnless I've missed it, have they mentioned what LV will be used for the retrieval craft? Dare I say this could be the mystery SLS Cargo mission in 2019, or is this in the realm of a medium launcher?The Keck study said Atlas V, and a spacecraft mass of 18,000 kilos. If the retrieval craft ends up weighing in at less than 20 tonnes, I don't think this can justify an SLS cargo mission. Of course, if this would be an SLS cargo launch, then why not scale up the design? Three times the IMLEO, three times the asteroid mass, square-cube law makes that almost half-again as wide. Excellent, thanks!Robotbeat posted this earlier, but look at pg 14 mentions an Atlas 551 as baseline http://www.kiss.caltech.edu/study/asteroid/asteroid_final_report.pdf
Quote from: ARD on 04/11/2013 01:35 amQuote from: Chris Bergin on 04/11/2013 01:18 amUnless I've missed it, have they mentioned what LV will be used for the retrieval craft? Dare I say this could be the mystery SLS Cargo mission in 2019, or is this in the realm of a medium launcher?The Keck study said Atlas V, and a spacecraft mass of 18,000 kilos. If the retrieval craft ends up weighing in at less than 20 tonnes, I don't think this can justify an SLS cargo mission. Of course, if this would be an SLS cargo launch, then why not scale up the design? Three times the IMLEO, three times the asteroid mass, square-cube law makes that almost half-again as wide. Excellent, thanks!
Quote from: Chris Bergin on 04/11/2013 01:18 amUnless I've missed it, have they mentioned what LV will be used for the retrieval craft? Dare I say this could be the mystery SLS Cargo mission in 2019, or is this in the realm of a medium launcher?The Keck study said Atlas V, and a spacecraft mass of 18,000 kilos. If the retrieval craft ends up weighing in at less than 20 tonnes, I don't think this can justify an SLS cargo mission. Of course, if this would be an SLS cargo launch, then why not scale up the design? Three times the IMLEO, three times the asteroid mass, square-cube law makes that almost half-again as wide.
Unless I've missed it, have they mentioned what LV will be used for the retrieval craft? Dare I say this could be the mystery SLS Cargo mission in 2019, or is this in the realm of a medium launcher?
Quote from: Galactic Penguin SST on 04/10/2013 06:10 pmOK some questions that I have that are probably a bit funny:1. So once NASA's spacecraft caught the asteroid, does it mean that a certain United States authority would have the ownership of the asteroid. Suppose that before/after EM-2, someone else (China/private organization etc.) want to visit the asteroid too - can the US denies the right to do so (even when, of course, there's no way to do that physically!)?This is why beneficent Providence has created lawyers and diplomats. I suspect that the proper approach would be for the US to encourage creation of a cooperative regime to exploit the asteroid. The fact that the rock, per today's excellent video, would remain attached to and indeed enveloped by US property would probably give the US some legal leverage.Quote2. Since the asteroid is put in a high lunar orbit, it will eventually spiral down and collide with the Moon some many years later. Who should be responsible from preventing (or leading, depending on the reason) this happening, and when?Interesting point. Again per the video, the SEP unit would remain attached and so potentially provide some options for future maneuvering of the asteroid. Or a new propulsion unit could be provided when the time came.
I'm curious if the capture mechanism could also be used to remove spent upper stages from earth orbit to help mitigate orbital debris. Any comments on if that would be a good dual use of the technology developed if this goes forward?
I hate it when people don't read the entire thread before posting!
Who else thought of that scene in You Only Live Twice where the supervillain captures a Gemini capsule in orbit?
The early work done to find a candidate will pay off in much-needed knowledge, no matter what.
Animation Of Proposed Asteroid Retrieval Mission | VideoPublished on Apr 10, 2013NASA's 2014 budget proposes a mission to robotic-ally capture a small near-Earth asteroid and bring it into a stable lunar orbit where astronauts can visit and explore it, a 'stepping stone' to future missions to farther asteroids.
attached … enveloped … future maneuvering
Lord of the Rings theme (Howard Shore)
Quote from: aero on 04/09/2013 04:04 pmCan anyone provide a "for example asteroid" and guess what the delta-V needed to bring it into orbit (HEO, HMO, LM1/2). Then we can guess some of the mission parameters such as thrust and power needed vs. duration of the mission.The paper gives an example on page 16, NEA 2008HU4, which has close approaches in 2016 and 2026. On page 28, they list the delta-V required to place it in high lunar orbit as 160 m/s. Since the weight of this asteroid is not known, they give example trajectories for weights ranging from 250t to 1300t in Table 5 on page 30, with arrival C3s between 1.6-1.8 km^2/s^2. If, instead of high lunar orbit, you drop it exactly at L2, the total mass moved drops to 200t even using an 8-year travel time.
Can anyone provide a "for example asteroid" and guess what the delta-V needed to bring it into orbit (HEO, HMO, LM1/2). Then we can guess some of the mission parameters such as thrust and power needed vs. duration of the mission.
No response from PR or DSI?
Quote from: JohnFornaro on 04/10/2013 01:44 pmQuote from: a_langwich on 04/10/2013 04:51 amYou can frame just about any initiative to look ridiculous.A standard debate point, used by people who do not care to discuss TRL levels of technology, poor cost estimating, and other details of sketchy analysis.John, you are living up to your signature.
The TRL levels of the hardware mentioned in the paper are said to be at TRL 6 or better. Which specific parts are you concerned about?
It will probably come as a surprise to some that the asteroid capture mechanism itself is "assumed" to be at TRL6. As is DSH, ECLSS, 40 kW class SEP, and more. More? "reliable robotic anchoring capability"; "Structural characterization, especially of the surface layers"; "dust levitation and settling behavior [mitigation thereof]"; "gravity tractor (GT) concept"; "Proximity operations"; "extraction and purification of water"; "autoreduction of the major mineral magnetite"; "using the released CO as a reagent for the extraction, separation, purification, and fabrication of iron and nickel products". All of these assumed to be at TRL6. No exceptions given.
If you mention anything relating to SLS, I am going to mock you mercilessly. The riskiest portion of the ACR mission, IMO, is the capture. As the paper points out, it's not "capture" so much as attachment to a ~500 tonne spinning object. But as far as I can tell, you are swinging your rhetorical sword at random other phantoms, some of which have no basis in reality.You obvious have a big burr in your shorts about SLS. ...
We are talking the 2021-2025 time frame...how many events in 2021 have you planned out in detail?
Edit: the one criticism you've made with which I might agree is that there's a good chance the timing for the robotic capture mission will not line up well with the timing for EM-2, or whichever mission they planned to use. ... However, these don't seem like showstoppers to me. ...
Quote from: JohnFornaro on 04/09/2013 12:56 pmQuote from: arachnitect on 04/09/2013 06:03 amJust to be clear: $2.6B is the cost to move the asteroid to an L point only, and doesn't include the cost of a subsequent manned mission or sample return, correct? Yes, that is correct, to answer the question simply and in a straightforward fashion. See Figure 17.To this cost must be added the several billion dollars per year just to keep the SLS job force employed, with no launches; several more billion for the DSH; several more billion for the actual launch itself to the rock; a few more billion for the capture mechanism; and finally, ignoring the development costs and test flights to evolve SLS to the predetermined size, because these costs have already been characterized as sunk costs.all costs from the $2.6B Keck estimate also assume everything is TRL6..."Assumes all technologies are at TRL Level 6 – the estimate does not include any cost for technology development up to TRL 6"This, IMHO, is also suspect:"Represents the most likely estimate based on cost-risk simulation results"It's fine to present the ML, but in general cost risk estimates include the actual s-curve...why? Because almost anyone can interpret the relative risk posture of the estimate via the slope and range...Why bother telling me you did a cost risk estimate and not even include the most basic visual output of the analysis (e.g. cost s-curve)? Also, why not include even a simple statement on what was actually varied in the risk analysis and by how much (assuming this was inputs-based)From the format, it looks like a NAFCOM estimate - which is all fine and good but makes it even more questionable why the s-curve wasn't included...that's a standard output from NAFCOM...and it would have been really easy to throw a sentence in there about how mass was varied and by how much...And lastly, if you actually did a 'cost risk simulation' adding 30% reserves to the ML at the end is a real head scratcher. The whole point of a risk analysis (cost, schedule, joint, whatever) is to provide a probabilistic range of values so we don't have to go off and apply some 30% rule of thumb to a point estimate. Show the s-curve, highlight a point (like the ML) for budgetary purposes (or the actual budget if it's already set) and provide the confidence levels. I mean come on guys... Sigh. Sorry, had to vent. I know studies like this don't often allow a lot (if any) time for the estimator too so perhaps I am jumping the gun here with my nits. Apologies in advance to the poor guy or gal reading this who may be thinking to themselves, "man i only got like 2 days to generate estimate". Been there.
Quote from: arachnitect on 04/09/2013 06:03 amJust to be clear: $2.6B is the cost to move the asteroid to an L point only, and doesn't include the cost of a subsequent manned mission or sample return, correct? Yes, that is correct, to answer the question simply and in a straightforward fashion. See Figure 17.To this cost must be added the several billion dollars per year just to keep the SLS job force employed, with no launches; several more billion for the DSH; several more billion for the actual launch itself to the rock; a few more billion for the capture mechanism; and finally, ignoring the development costs and test flights to evolve SLS to the predetermined size, because these costs have already been characterized as sunk costs.
Just to be clear: $2.6B is the cost to move the asteroid to an L point only, and doesn't include the cost of a subsequent manned mission or sample return, correct?