NASA's next small step: to an asteroid

By Phil Plait | September 10, 2010 7:16 am

Some time ago, I caught wind of an idea I really liked: instead of our next space destination being the Moon (again) or Mars, we should go to a near-Earth asteroid.

I loved this idea. It has a lot of merit: a lot of these rocks pass us at relatively low speeds, making them easier to get to in terms of time and fuel. We know very little about them, and a manned mission will teach us a lot about them (as well as how to do long-term missions like this). And given that these objects can be a real threat, the more we know, the better.

I was interviewed about this briefly for an article in the Houston Chronicle where I give this opinion. The article has some interesting info about a potential asteroid mission, and I really do think this is a good idea… except for one thing. I want to see us planning for and executing a mission to an asteroid at the same time as we do the same thing to return to the Moon, and keeping our eyes on an eventual mission to Mars.

All these worlds really are ours. We just need the will to go and explore them.

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Comments (44)

Links to this Post

  1. The Value of NASA | | May 17, 2011
  1. Rob

    Well, all these worlds are ours except for Europa.

  2. dcwarrior

    Shouldn’t a goal be to catch an asteroid or comet and put it into orbit so its water and minerals can be used for space industry?

  3. R2K

    Correction: most of these worlds are ours, just not Europa. Attempt no landings there.

  4. Pft. Like we’re afraid of some ancient god-like aliens.

    I say bring it on.

  5. Chris

    spend three months flying more than 7 million miles to an asteroid that’s about 33 feet across.
    It seems to me it might be easier to just bring an asteroid that small to us.

  6. Daniel

    “We need the will to go and explore them.” Really, we need the will to go and exploit them. As much as good science and exploration should be an end to themselves, the reality is that the opportunity to make a buck is what will change things in space.

  7. I am not a big fan of manned extra planetary missions at the moment. The mars rover programs have proven that we can get a lot out of robotic missions for far less than the cost of a manned mission. Imagine how much it would have cost to have 2 astronauts up on Mars for over a YEAR, not to mention the cost of bringing them home.

    I think NASA’s mission statement of “smaller, cheaper, faster” is one that should be stuck with.

  8. Messier Tidy Upper

    Going to an asteroid sounds good to me – Cruithne – a “quasi-moon” asteroid noted in Stephen Baxter’s ‘Time’ Manifold series novel would be my first choice.

    Arthur C. Clarke’s suggestion of Icarus which has an eccentric orbit that takes it from beyond Mars to inside Mercury’s orbit. Although having a surface glowing red hot at perihelion may make things somewhat tricky! 😉

    There was also a good suggestion noted in a New Scientist magazine (last year sometime?) of travelling to the asteroid-like Martian moons, Phobos & Deimos as a first stepping stone to a human mission to Mars.

    Of course the big problem is in order for us to anywhere we need to have a manned spaceflight program & Obama is keen on killing that off. :-(

    NASA under Obama’s plan won’t be able to go anywhere because it won’t have any spacecraft available. Cancelling Ares-Constellation = worst spaceflight decision ever.

  9. Messier Tidy Upper

    @1. Rob & 3. R2K :

    Correction: most of these worlds are ours, just not Europa. Attempt no landings there.

    Attempting to *land* on Venus, Jupiter, Saturn, Ouranos and Neptune while not forbidden would be pretty foolish and almost certainly doomed to failure too. 😉

    Floating balloons in the Jovians atmosphere’s maybe but actually landing? Uh uh. 😉

    I’m guessing asteroids then Mars, maybe Mercury maybe some of the moons of Jupiter and Saturn (radiation sheilding permitting) will be the order we progress first landings~wise.

    A human landing on Mars has always seemed to be twenty years away since 1970 until Obama came into power and, now, well I just don’t know when or even *if* we’ll ever advance anywhere anymore. :-(

  10. Greg in Austin

    Can we send Ben Affleck and Bruce Willis there on a suicide mission?


  11. MarcusBailius

    Not a new idea… See John Lewis’s book “Mining the Sky” for much more. And indeed his earlier one, “Rain of Iron and Ice”.

    I like the books, although I am sure he slightly over-eggs the pudding here and there.

    Easy to get to an asteroid, energetically speaking; there isn’t a gravity well to worry about at the other end, you don’t need a lander, you haven’t got to worry about those pesky atmosphere things… Mind you, you still need to keep your astronauts fit in the absence of that gravity thing (but sending two or three spacecraft and then tying them together and spinning a bit might help – and this might mean the crews can rotate (sorry) from ship to ship, thus avoiding any nastinesses should crew member A take strongly against crew member B), and you might need some decent shielding to keep the astronauts and the electronics reasonably safe against an unfortunate solar flare…

  12. Theron

    It’s time to start hyping the Apophis threat. I realize that it’s now believed the chances of being struck are nil for 2029 and vanishingly small for 2036. So what? Absurd fears of Russians under every bed got us to the moon, so there’s already a proud tradition of grand space projects for loopy reasons. We need a better term than “keyhole” to describe the spot Apophis has to hit to turn into a real threat. “Sweet spot” is innocuous and open to a wide range of interpretations. (I’m looking at you, Discovery channel programmers!)

    Seriously though, no need to be deceptive, but it is useful to give a “face” to the danger if you are trying to wrangle funding out of your average congresscritter.

  13. Messier Tidy Upper

    For more info on Cruithne “earth’s second moon” (of sorts) see :

    For Baxter’s Time see :

    & for Icarus see :

    Hmm … 3 posts for the price of one here – my comments, my reply to others & now one for the links. Is this a good thing? Do people enjoy having these links? Feedback anyone?

  14. jrpowell

    I propose a radical departure from boots and flags exploration. I think all crewed trips to the Moon and Mars should be one-way colonization efforts. Send the scientists and engineers that want to study a new world and create new homes for humanity.

  15. owlbear1

    I guess instead of, “to the Moon, Alice” we’re going to have to start saying, ‘To CERES, CEDRIC!’


    to Amos, Andy!!

  16. Theron

    @ jrpowell:

    When I first heard the notion of a one way trip (in the Mars context) I thought it odd, but then quickly realized that there would no doubt be no shortage of highly qualified volunteers for such a mission. I wonder if the tax-paying public could accept such a mission? It would certainly solve a lot of problems if you didn’t have to worry about the “bring them back alive” problem.

  17. We need a better term than “keyhole” to describe the spot Apophis has to hit to turn into a real threat.


  18. Chris A.

    @Messier Tidy Upper (#13):

    “Hmm … 3 posts for the price of one here – my comments, my reply to others & now one for the links. Is this a good thing? Do people enjoy having these links? Feedback anyone?”

    If you were actually willing to modify your behavior in response to feedback, you’d have stopped posting your anti-Obama screed long ago, as you have received ample indications from this forum that it has become redundant and tiresome.

  19. R2K

    @ Messier Tidy Upper

    Arg Rob beat me to the joke! :(

    Landing on Mercury would be pretty brutal also. The radiation in that area alone would make the trip very hard. The only good targets for manned missions are, in order of difficulty; manned flyby missions to Venus or Mars, rendezvous with an asteroid (not really “a landing for most of them, just a docking), or landing on Mars. I hold out hope that we will find some really interesting things on Ceres and send people there. Mars is, always has been, and always will be our key target. Nothing else makes sense between now and Mars unless it is some form of practice for a Mars landing. And yes, asteroids would be great practice for Mars missions – the Moon would not. (Note I left the Moon out above – while it is an interesting target, it should only be visited if all of the above missions are already satisfied and funded.)

    “A human landing on Mars has always seemed to be twenty years away since 1970 until Obama came into power and, now, well I just don’t know when or even *if* we’ll ever advance anywhere anymore. :-(”

    As Zubrin says, this is the problem. If you want to land on Mars in 30 years, you can’t do it. Not in 20 years either. Only by chosing 10 years or fewer will you get it done. That is why the Apollo challenge was so smart; you plan a mission that will finish within the political environment that spawned it.


  20. KiltBear

    Things being “ours” is one of the reasons we need to make sure we eventually can colonize other planets to survive as a species (nod to Carl Sagan).

    I prefer the “we belong to the planet” way of thinking of things, myself.

  21. TedY

    I recently came across a YouTube vid of a presentation by Jim Garvin (NASA Chief Scientist) to a group of interns. What makes it interesting is that it gives great insights into the direction NASA is heading and why.

  22. Don

    A small NEO might be interesting as an Earth Mars transfer ferry. Stabilize it. Excavate living quarters, and shape into something we can put an ion engine on, and it solves what I think is a major problem with an Earth Mars mission which is radiation. Several feet of rock should take care of that.

  23. I love the idea of going to an asteroid as well. That would be awesome!

  24. Tribeca Mike

    Theoretically and romantically, I’m all for going back to la luna and sending humans to Mars. But pragmatically, I don’t see where the money will come from. We live in a land where many citizens don’t want to pay for obvious things like public education or a more equitable and affordable health care system (or even repairing sidewalks). Due to the well-publicized dangers from asteroids, it should be an easier sell to convince the public to spend the money needed to research and avoid/avert them.

    Your interview in the Houston Chronicle is most interesting, but it’s ironic that it appeared in the major newspaper of a city which has benefitted very well financially over the years from the space program. Just my two cents.

  25. Gary Ansorge

    9. Messier Tidy Upper

    “A human landing on Mars”

    You seem to consistently confuse “human exploration” with Americans. Last time I looked, we only accounted for about 6 % of the current human species. That other pesky 94% are just as capable as Americans of accomplishing space exploitation.

    21. Don

    It would require approximately 3 meters of rock to provide adequate radiation protection.

    Interesting note from the ’60s lunar endeavor: we discovered that passing thru the van Allen belts with heavy metals (like iron) in the space craft walls had very undesirable side effects, in that energetic electrons impacting those metals released x-rays within the craft. Same way we make x ray machines(but in those we generally use a tungsten target).

    All particle impacts, alpha, beta, free neutrons and energetic protons produce x rays when impacting a heavy nucleon(like iron) but they tend to pass right through lighter materials w/o producing those pesky ionizing E.M. photons. A high carbon material tends to absorb particulate radiation w/o producing x rays. Which is why Bigelow uses thick polypropylene walls in his space habs(at least I THINK it’s polypropylene. He wouldn’t actually say. The specific material is confidential).

    Gary 7

  26. XPT

    The idea is very interesting and it would be a great PR campaign for NASA, less costly than going to Mars.
    I’m always thinking nobody walked on another celestial body in the last 30 years.
    We had a huge deal of science and technology results, but we really need another “earth as seen from the moon” type of photo to let this generation dream about space. (Of course we need HD/3D videos and constant tweets, not a mere photo!)

  27. R2K

    “it solves what I think is a major problem with an Earth Mars mission which is radiation. ”

    I think those who say this should re-read the studies on Mars missions. The radiation is not a show stopper at all, and does not call for anything more than either light shielding or careful spacecraft design where food, water, fuel, and other essentials are placed around the crew cabin. In the former case, the storm shelter would be surrounded by those supplies, while the cabin is surrounded by modest (few cm) shielding. Most would gladly accept a 1-3% greater chance of cancer, or slightly higher risk of cataracts, to get to go to Mars.

    The only show stopper is funding, everything else is doable and no more of a challenge today than landing on the moon was in 1963.

    “It would require approximately 3 meters of rock to provide adequate radiation protection.”

    Nonsense, you seem to be referring to complete radiation protection. We can substantially relax our exposure limits for astronauts. They are not living in deep space, only spending a year or two.

    Further, the exposure levels (say 150 – 200 rem in 2 years) are exceptional by Earth standards, but not biologically threatening. Certainly other hazards are much greater for this type of exploration in deep space. I will restate this that 150 rem, over long periods of time, is only going to add a 1 or 2 percent increase of cancer risk and not cause any serious health effects such as immune system or digestive system problems.

    It is funny, someone once compared the risk posed by smoking and by Mars mission radiation. It turns out that, assuming a 2 or 3 year Mars mission (and discounting solar storms which can be removed with a storm shelter), one has about the same risk as the mission if they stay on Earth and smoke a pack a day during the same time frame. Yes that is not ideal, but to go to Mars, most would agree it is worth the risk.


  28. Tribeca Mike

    To add to my previous comment, I just remembered that the Spanish group Organización Nacional de Ciegos Españoles has been running a daily lottery, the proceeds of which benefit programs for the blind, for many decades. Perhaps there could be a national lottery for space exploration? Being a big fan of the great Italian Renaissance mathematician and all-around rascal Gerolamo Cardano, I avoid lotteries and most “house rules” games of chance, but I could get into that, especially if you did the commercials.

  29. Jim O

    I like the thought of having an asteroid missions along with going back to the moon. The current Obama plan of just going to an asteroid by 2025 seems to me to be an ‘all your eggs in one basket’ plan. Everything is planned on just this one asteroid mission and that’s 15 years off.

    As of the current Obama plan there isn’t even a spacecraft planned to make this asteroid mission. He wants to resurrect Orion as a lifeboat for the spacestation when I think that we should just continue working on the Orion craft as planned. Then we would have a craft to make this mission. The development is pretty far along and it just doesn’t make sense to start over with something else. I also think that we should stick with the Ares V for the heavy lift. The solid rockets for it are already developed and the full 5 segment version has been successfully tested twice.

    I do think that we should be pushing the commercial vehicles for docking with the space station.


  30. Tribeca Mike

    R2K — “I’d walk 300 million kilometers for a Camel”? 😉

  31. Buzz Mega

    As a test of steering them away from an earth collision, we might drop one into the moon.

  32. Pete Jackson

    I think that a potentially very useful place for extended manned space flight is to the L1 or L2 points. There, astronauts could perform maintenance on the sophisticated observatories that are going to be placed there.

    The very expensive James Webb Space Telescope is going to be sent to the L2 point, and it hasn’t been designed for astronaut maintenance in case something goes wrong. Presumably, it has been considered cheaper to just build and launch another one if something does go wrong. However, with the huge cost overruns for JWST, I wonder if this should be rethought.

    We have all observed the spectacular synergy between the Space Shuttle and Hubble programs whereby the shuttle has repaired and enhanced the Hubble five times. Now, a bean counter could say that it would have been cheaper to launch five Hubbles rather than use the Space Shuttle, but, in practice, there would never have been the popular support to do this.

    Likewise, I think that there could be much more support for large observatories near L1 and L2 if they were developed in conjunction with a manned space program that could repair and maintain them if necessary.

    Now, there might be objections that the astronauts and all their support systems would temporarily or permanently pollute the L1 and L2 regions, and interfere with other ongoing missions there. Those objections could be mitigated by assuming that observatories undergoing maintenance would temporarily de-station themselves to some reasonable distance away from L1 or L2.

  33. I say all these worlds are ours, ESPECIALLY Europa. Attempt lots of landings there.

  34. R2K

    The JWST will have a grapple point so it can be visited, but there are no plans to do so.

  35. Sounds like it’ll be perfect timing for an Armageddon remake. This time, no green screens. Everything will be shot on site….Actually, with the rate that hollywood movie budgets are growing compared to NASA’s funding, it might be the only way.

  36. Ghost

    There’s no point having a manned mission. Send a robot. It will do a better job, for 100x less money.

  37. amphiox

    A small NEO might be interesting as an Earth Mars transfer ferry. Stabilize it. Excavate living quarters, and shape into something we can put an ion engine on, and it solves what I think is a major problem with an Earth Mars mission which is radiation.

    Might not even need the ion engine. We could gravity tractor one into a an orbit with close passes to Mars, land on it when it’s closer to earth, and then just ride it. (Maybe we’ll even get lucky and just find one with a usable orbit)

    All the Lagrange points are interesting targets. Particularly if there are “trojans” at the L4/5’s.

  38. amphiox

    Actually, combine 1. gravity tractor with 2. manned asteroid docking with 3. long term life support using asteroid raw materials and we have a system that could take us anywhere we want in the solar system. The only real stumbling block is the time required for some of these steps. (If there isn’t already an asteroid with an orbit we can use, it’s going to take a long time to gravity tractor it into one we want.)

  39. Brian Too

    @29. Jim O,

    You know, I’m not normally one for cynical theories, but you made me think.

    Hypothetically consider a plan that is 15 years out, and any politically feasible space project must be done within 10 years (more or less 1 president’s sitting term, assuming 2 successful elections and term limits prohibiting more).

    Could this be a way of avoiding the issue? Place a plan near enough in time to seem feasible, convincing people that ‘something’ is being done. Yet at the same time, it’s far enough away to lull everyone into complacency. “Don’t get panicky, we’ve got lots of time…”. In 5 years when it’s clear little or no progress is being made, you simply say, oh, circumstances changed, the problem was harder than expected, we’re resetting the clock to 15 years from now.

    Any sitting President might attempt to use such a strategy. If they don’t want to expend the required resources, or they think it’s too risky, or maybe they think that in 50-100 years technology will make the problem drastically easier/cheaper to solve. Especially if they are convinced that the initial budget estimates will be completely blown and the project will end up requiring 3-10X initial estimates?

    What do you think? Too Machiavellian?

  40. Grand Lunar

    Interesting idea for a 2019 mission; two Orions together to go to the asteroid. I imagine one is for supplies.
    A two-person crew, though? I would’ve thought four.
    Well, a Gemini-size crew can still get a lot done.

    I like your suggestion Phil, with a modification. Let the return to the moon be an international effort, not just NASA’s effort.
    Each nation would be a contribute an element to the lunar base.
    And get commercial companies involved too.

  41. Gary Ansorge

    27. R2K

    “It would require approximately 3 meters of rock to provide adequate radiation protection.”

    This was from Gerard K. O’Neilles book on space colonization, referencing the shielding on a space colony to provide complete protection from solar flares, coronal mass ejections and cosmic rays.

    I expect one day we’ll be able to generate mag. fields with super conductors powerful enough to shield us from any charged particle radiation. Then most of this radiation discussion will be moot. We may have such tech already. It’s just confined to fusion experiments like the Tokamak.

    Gary 7

  42. réalta fuar

    @MarcusBailius Thanks for referencing John Lewis’s classics on asteroids and solar system resources. Anyone who reads them will know that asteroids AND the moon is completely unrealistic. Pick the right ONE and open up the solar system for human use, pick the wrong one and end any expectations of doing the same. Your choice, folks.

  43. MarcusBailius

    Actually, I quite liked his plan for mining the atmosphere of Uranus for helium-3… Much more there than on the Moon.

    D – 3He fusion is good, the ejected 14 MeV particle is a proton, energy stays in the plasma and helps keep the fusion going. D – T fusion produces 14 MeV neutrons, which whip out into the surrounding material, (a) without contributing to the plasma temperature and (b) creating a shedload of highly active waste…

    You’re right though. The Moon is a nice visible target but it’s not the most practical one from the engineering viewpoint, or indeed looking forward to a time when we might begin to exploit the resources up there. (…Don’t hold your breath…)


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