So, from NASA’s overview on the planned “Journey to Mars”, sometime in the next decade, they plan to redirect an asteroid into lunar orbit in order to stage and test new tech and manned missions before we make the big leap to the Red Planet in the '30s.
[QUOTE=NASA]
Our next step is deep space, where NASA will send a robotic mission to capture and redirect an asteroid to orbit the moon. Astronauts aboard the Orion spacecraft will explore the asteroid in the 2020s, returning to Earth with samples. This experience in human spaceflight beyond low-Earth orbit will help NASA test new systems and capabilities, such as Solar Electric Propulsion, which we’ll need to send cargo as part of human missions to Mars. Beginning in FY 2018, NASA’s powerful Space Launch System rocket will enable these “proving ground” missions to test new capabilities. Human missions to Mars will rely on Orion and an evolved version of SLS that will be the most powerful launch vehicle ever flown.
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What are some of the prescient details to this sort of mission? Which asteroid? How big is it (or need to be)? Do we already have the tech to do something like this? Will it stay in orbit indefinitely, or eventually crash it into the Moon? Etc.
This would certainly be a first: Artificially inserting a natural satellite around another natural satellite.
Nope! I’m sifting through some of NASA’s info on their ARM (Asteroid Redirect Mission) page, but I’d be interested in a more Dope-esque summary and discussion.
Okay, so after watching the video on that linked page, it appears they’re just picking off a several-ton boulder from an asteroid and not the whole shebang?
Granted that in itself is a huge effort, but it’s sort of misleading with their initial verbiage.
There are a number of candidate objects that have been identified for study but which one is selected would depend on a number of factors including composition, orbital energy at the time of interception, capability of the yet-to-be-designed propulsion system, et cetera. We don’t currently have the technology to do this, and in fact, that is the point; to take on a challenging technical effort that drives development of technologies and processes to extend the capability of accessing and processing space reources. There would be no reason to direct it to impact the Moon; anything in a high orbit will remain there indefinitely, subject to perturbation by the Sun’s gravitational influence and that of other passing objects, but we could expect the orbit to be stable for at least tens or hundreds of thousands of years without maintenance.
The general concept is a good idea from the standpoint of developing the technologies that are a precursor to a sustainable space-based infrastructure, e.g. being able to make propellants, extract mineral resources, produce consumables, et cetera from space rather than to lift them up out of a gravity well. It also gives us a flavor for how to deal with potentially hazardous objects, though anything we would do on this scale would be multiplied by several orders of magnitude in energy and effort for something truly threatening. This object would be only a few tens of meters in diameter at most and probably selected to be mostly water ice rather than a mineral bolide; not large enough to endanger anyone on Earth even in the astronomically unlikely event it ends up in an Earth intercept technology.
However, the astronaut corps don’t like this because it isn’t really going somewhere like a planet, and will have very limited opportunties for crewed missions (probably just one or two at most). The exploration crowd don’t like this because it is more of a technology development than exploration mission. The planetary science people don’t care for it because while it will give some information on the development of the solar system it isn’t really exploration of planetary phenomenon and will detract from budget robotic planetary science missions because of the expense of the crewed flights. And the aerospace industry is fairly indifferent because as currently outlined it offers little opportunity for future systems development and sustainment compared to Apollo/Saturn and Space Transportation System (“Shuttle”). The budget estimates I’ve seen for this effort are pretty outrageous, again largely driven by the crewed component, and nobody seems exactly clear on what a crew will do that couldn’t be better done remotely, especially as a space manufacturing infrastructure would have to be largely automated to be fiscally viable. So, I’ll be a little suprised if this actually has legs and doesn’t get cut come the next presidential administration.
Thanks so much, Stranger, for weighing in. I was hoping, thought not explicitly, that’d you’d share your expertise and opinion. You’re, IMHO, one of the top posters on the board.
I’m not all that optimistic it’ll survive the next presidential campaign, but who knows. If it does, I think from a civilian level, it’ll be a really interesting mission to follow for the next decade (despite the various professional opinions that may taint it, as you’ve described).
It’d be the first time humans would travel into deeper space since the Apollo missions, and that alone excites me. Whether or not we get a boulder into lunar orbit, let alone get a crew to land on Mars in the '30s, remains to be seen. But, finger’s crossed. I can’t imagine you’d be opposed to such a mission by far?
The point I haven’t seen anyone officially raise about this mission is that the same technologies we’d develop for this mission would also be the technologies we’d need to divert an object which would otherwise hit the Earth. Which is going to happen sooner or later, if we don’t prevent it, with catastrophic results. Being ready for when the Big One comes sounds to me like an excellent justification for the cost of this mission.
I’m in favor of the mission in concept; however, I’ve seen some of the objectives and costs that make me question the specific plan, such as it exists currenlty. The crewed objectives seem to exist more for the purpose of using the SLS and invoking crew than for a practical need, and I suspect there will be a lot of safety issues with astronauts in the presence of an object. I’d actually like to see a crewed program addressing some of the human space physiology issues such as function in fractional acceleration in simulated (centrifugal) gravity and protection against interplanetary radiation at one of the libration points which can’t be addressed by current ISS missions. The asteroid capture and extraction objectives can probably best and most cheaply addressed by using robotic systems, avoiding problems of contamination and the hazard of freely moving debris. Another major objective should be testing and improving propulsion systems which would permit faster transit which would be essentially required for actual crewed interplanetary missions.
I touched on this a bit above, but while this mission would certainly offer the opportunity to develop things like approach systems and methods to rendezvous with asteroids, the scale of energy and impulse to redirect a potentially hazardous object (PHO) on the scale of 100 m diameter or larger (solid bolide) would be several orders of magnitude higher. The biggest advantage would be getting more insight into the composition and integrity of Near Earth Objects as part of a survey to investigate target objects by which an effective redirection method could be assessed. Once of the most important systems needed, however, is a space-based telescope array to identify and track PHOs so we have a good idea of what the threats are an a higher confidence estimate of when such an event may occur. Given the enormous cost of even a single impact event–potentially on the order of trillions of dollars and tens of millions of lives even for an object in the 150 m diameter range–there is a favorable cost-benefit analysis even for a very extensive effort.
How hard would it be to blast such an object into smithereens? I’ve read that that’s not necessarily a good idea; it could potentially compound the problem. But is it doable?
Well, according to your cite it looks like they plan to keep the thing pretty small:
So, I assume they will keep it under 80 meters (probably a lot less…maybe 10 meters or less, of which over such objects hit the earths atmosphere about every 10 years, so shouldn’t be even noticeable in the unlikely event it goes out of control) so that, at most, it would be an air burst. Seems pretty controllable, and presumably they will also want one that is fairly light. I don’t see an issue, though not sure how much we’d get out of a manned mission to do this, though I suppose it would be fairly cool to do if they could pull it off.
Fragmenting an asteroid “into smithereens” probably isn’t difficult, given that most objects that we’ve found are actually aggregated from smaller, boulder-sized pieces. And therein lies the problem; blowing it apart absorbed energy without diverting the mass, leaving it to pose essentially the same hazard except spread out over a wider span of space and time. A single 20 m diameter piece doesn’t pose a that much of a hazard, but thousands of them impacting the atmosphere in approximately the same location, to be spread over a wide geographic area does. (Someone will doubtless point out that a 20 m bolide will mostly burn up in the atmosphere and not impact the surface, which ignores the fact that the atmosphere is a part of our planet and has a limited capacity to absorb the heating from a disintegrating meteor; a large enough cloud would be similar to a gigantic thermonuclear bomb equivalent to many times the nuclear arsenals of the US and Russia combined.) So just breaking up a PHO doesn’t, by itself, help, and may also create a more distributed hazard both on Earth’s surface and to objects in orbit, which itself could compound into cascading debris creation, i.e. Kessler Syndrome.
I’ve discussed [THREAD=573725]in this thread[/THREAD] an elsewhere a proposal that would use a puck of doped polystyrene heated to plasma by a nuclear detonation to push an entire mass of PHO out of an intercept trajectory without blasting it apart. Other concepts such as wrapping it with netting before applying thrust or using a gravity tug have been proposed, but they rely on the object having minimal rotation or essentially unlimited propulsive capabity, whereas the the Gaoithe Móire concept pushes the entire mass (whether it remains aggregated or not) to the side. A modest number of impulses should be able to deflect anything up to the size of a 1 km diameter solid bolide, or push/vaporize a 2 km diameter water ice PHO well out of an intercept trajectory from as little as a few months out using conventional propulsion technology and leveraging off of experience from Project ORION. The estimated development cost is surprisingly modest; around US$10B in 2010 dollars. The rub is using what are basically nuclear weapons in space, which is prohibited by treaty. But I think a consensus would agree under actual threat of impactt hat adhering to a well-intentioned treaty of limited scope to prevent weapon proliferation is less crucial than preventing regional or continental devastation.
Coincidentally, a couple weeks ago I was reading about 2006 RH120, a small asteroid that every now and then enters into Earth orbit.
Next time it’s supposed to come back will be in 2028, passing by earth at a sluggish 136 m/s. I would think very slow speed and it’s slow mass would make the job of nudging it into a more stable orbit relatively easy.
On the other hand it’s believed to be a piece of the Moon, so that would make it a less interesting target than a proper asteroid.
Seeing as how NASA currently has to beg rides into space from Russia, I’m saying that plans to redirect an asteroid in the next decade are, to put it very mildly, quite optimistic.
Well, given that this is dependent on the qualification for crewed flight of the Space Launch System and Orion capsule both of which are behind schedule, the skepticism is justified. However, the most challenging portion of the actual redirect is the capture; everything else, including the ion drive system planned for use, is fairly mature. I think the current estimate is US$2.6B and the system could potentially fly on a Delta IV Heavy (or the Falcon Heavy, provided it can be certified to NASA LSP acceptance) so that portion at least is possible.
Reliance on using the Soyuz system to reach the ISS is largely the result of poor planning and oversight of Shuttle replacement efforts. The assumption that commercial crew spaceflight providers will step in and provide the service has not been validated, and even the most ambitious commercial crew providers are basically focused on LEO and specifically transport to the ISS, which may not even be in service by the time commercial crew capability is a reality. There is just a general lack of consensus on what the NASA crewed program should do, much less an actual plan to do it and concerted development of infrastructure and capability. The SLS is really a pig of a vehicle that will never be cost effective nor does it advance propulsion and spaceflight technology in any appreciable way. So…yeah, optimism is not warranted. It’s very frustrating for those who have proposed potential architectures and technologies that, while not as sexy or appealing to legislators looking to get jobs in their districts, are much more practical to implement in a reasonable period of time.