Random Thoughts: A Change of Heart in NEO Size of Interest?

I’ve been following the various twists and turns in NASA and private interest in NEOs for a few years, ever since the Flexible Path concept was suggested by the Augustine Committee. While I’ve always been of the opinion that the Moon makes the most sense of all the potential off-earth bodies to settle and develop, I at least could see the appeal of the original Flexible Path concept. Basically you stagger the development of systems in a way to keep the peak “cashflow” needs for NASA as low as possible, and try and do some useful missions as soon as enough mission elements come online to support those missions. At least at the time, that seemed to imply that going to NEOs before the Moon looked feasible.

But somewhere along the process, that idea seemed to go off the rails. Instead of NEOs being a quick “target of opportunity” that could be visited cheaply along the way to the Moon and eventually Phobos, Deimos, and Mars, you started seeing concept architectures coming out of NASA for these massive NEO mission stacks complete with four or five new pieces of expensive in-space hardware that needed to be developed (a Hab module, an MMSEV, a CPS, a big solar electric tug or two, etc, etc) just to visit a NEO. At first I was somewhat baffled at why NASA thought you needed a significant portion of a Mars mission stack to visit a NEO. After all, Josh Hopkins of Lockheed Martin had suggested a much more modest approach (Plymouth Rock) using just two “kissing Orions” that seemed to close just fine.

After doing a little digging, and talking with Josh and others involved in looking at NEO missions from outside of NASA, the best answer I could get was that NASA had set some rather arbitrary minimum requirements that were driving their mission analyses. One of the most important of these was the minimum size of interest for NEOs. Simply put, they didn’t want to go to too small of a NEO, for fear it either wouldn’t be scientifically interesting (yeah right), or because they were somehow afraid that people wouldn’t be impressed to see an Orion visit a rock not much bigger than itself (more likely reason IMO). I can’t remember what the minimum size they set was, but I think it was somewhere in the 60-100m diameter range. The problem is that for NEOs, that narrows things down a lot, which makes mission opportunities much less frequent, and also eliminates many of the easiest to visit NEOs. Hence the big mission stacks. Not only that, but the larger the NEO targets you look at, the fewer “undiscovered” NEOs there are out there to potentially increase your number of potential targets–we know where most of the biggest stuff is, it’s the sub 100m ones that we only know a small fraction of.

Anyhow, we’re three longwinded paragraphs into this blog post, and some of you are probably wondering “what’s Jon’s point?” The point of this blog post is merely to point out the amusing fact that while before NASA wouldn’t even consider sending a mission to a 20m diameter NEO, the new plan would have them visiting a 5-7m diameter rock instead. While I’m not at all opposed to the new “fetch an asteroid” mission (other than the fact that once you’ve brought it back to L2, justifying using Orion/SLS to visit it seems wasteful), I just find it amusing that all of the sudden 7m is exciting, edgy, and NASA-hard, while before it was well below the threshold of interest. Not even yawn-worthy, really.

I guess I’m just curious what NASA could’ve done if they hadn’t originally restricted smaller NEOs from consideration when doing NEO visit architectures. I’m glad they’re finally reconsidering that arbitrary assumption though.

That’s all.

The following two tabs change content below.
Jonathan Goff

Jonathan Goff

President/CEO at Altius Space Machines
Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and is the founder and CEO of Altius Space Machines, a space robotics startup in Broomfield, CO. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
This entry was posted in NASA, NEOs. Bookmark the permalink.

9 Responses to Random Thoughts: A Change of Heart in NEO Size of Interest?

  1. What changed? It became politically fashionable to talk about Planetary Protection again and now even small rocks are considered threatening enough. Thanks Russia!

    Personally, I don’t care where they get the raw materials from, I find it encouraging that they’re talking about “resources in orbit”. It suggests that we might actually see another Mars architecture where not everything is launched from the Earth. (The last one being Paul Spudis et al.) This time it might gain some traction.

  2. reader says:

    Setting hard to trace arbitrary requirements for government projects is the oldest trick in the book for bureaucrats, to make sure the contract goes to the right supplier. As demonstrated here, applies at every scale

  3. DougSpace says:

    My take is that Congress has committed NASA and the Administration to a rocket bigger than what’s needed in the near-term. So, in order to justify it being built and operated for years thereafter, any possible near-term use of it is being embraced. As we can see, the point of such missions isn’t really science nor planetary protection. That can be done at far less cost and risk robotically.

    Whereas I recognize that it is difficult to make a valid argument for any useful-and-exciting near-term need of the SLS, it is the rocket sized for missions to Mars which is a legitimate non-commercial goal. And yes, we need intermediate steps to that path. Likewise, I can understand that sending humans to empty space halfway to Mars would be a useful intermediate step, but doing so would not be as exciting as going to an asteroid halfway to Mars. Fine. Why not.

    However, I just want to make sure that, in the process of heading to Mars, the commercial track is adequately funded and extended to include lunar resources. The resulting in-space propellant would be easily justifiable, enhance the capabilities of a topped-off SLS, and give NASA ample planetary surface experience needed for the eventual Mars mission. A rather significant side-effect would be a permanent commercial lunar base which I think all should value greatly.

  4. Doug,
    Whereas I recognize that it is difficult to make a valid argument for any useful-and-exciting near-term need of the SLS, it is the rocket sized for missions to Mars which is a legitimate non-commercial goal.

    Not really. What’s needed for Mars missions isn’t a large first stage, it’s a large and mass-efficient upper stage combined with propellant transfer capabilities. SLS isn’t really funding a true upper stage for some time yet, and the current concepts have all had such awful mass efficiency that they’re pretty suboptimal for actual exploration.

    ~Jon

  5. ken anthony says:

    The big news is Bechtel joining Planetary Resources.

    After choosing a target, we need a robot tug to retrieve it. That tug determines the size of the rock.

    After returning it to lunar orbit, the next step is crushing it (in a bag so nothing is lost.) Then you take samples and figure out how to get the purified stuff out of it.

  6. Robert Clark says:

    Jon,
    Not really. What’s needed for Mars missions isn’t a large first stage, it’s a large and mass-efficient upper stage combined with propellant transfer capabilities. SLS isn’t really funding a true upper stage for some time yet, and the current concepts have all had such awful mass efficiency that they’re pretty suboptimal for actual exploration.

    Good point. ULA has shown that propellant mass fraction far and away has the strongest influence on increasing performance compared to other specs:

    http://selenianboondocks.com/2012/08/newspace-2012-space-architectures-panel/

    A graphic in the video linked on that page taken at the NewSpace 2012 conference shows mass fraction dominates the other variables.
    Getting upper stages of high mass fraction would only require techniques already known for decades in the industry. And compared to the cost of the SLS would be relatively low cost.
    To put in perspective the import of this, as discussed by ULA a lightweighted Centaur-style 40 mT upper stage could get a 20 to 1 mass ratio. This means it could transport a Dragon-sized capsule from LEO to the lunar surface and back again as a single stage.
    This could be lofted to LEO by one launch of the Falcon Heavy in 2014 or one launch of the SLS in 2017.

    Bob Clark

  7. Robert Clark says:

    Doug,
    Whereas I recognize that it is difficult to make a valid argument for any useful-and-exciting near-term need of the SLS, it is the rocket sized for missions to Mars which is a legitimate non-commercial goal. And yes, we need intermediate steps to that path. Likewise, I can understand that sending humans to empty space halfway to Mars would be a useful intermediate step, but doing so would not be as exciting as going to an asteroid halfway to Mars. Fine. Why not.

    There is a destination for the SLS in the near term, the Moon. The current administration decided against the Moon by the argument “been there, done that”. But they didn’t consider the clear fact there would overwhelming support for a manned return to the Moon if it could be done in the near term among the public, the industry, and even within NASA’s own ranks, whereas the support for an asteroid mission is virtually non-existent.
    The reason why the administration remains opposed to lunar missions is because of the assumption it has to be high cost. But we’ve had plans on how to achieve this at low cost since the early 90’s, such as “Early Lunar Access” proposal:

    Encyclopedia Astronautica.
    Early Lunar Access.
    http://www.astronautix.com/craft/earccess.htm

    Following such an approach of going small, we could mount a manned lunar landing mission, not just a lunar flyby, by the first launch of the “70 mT” SLS in 2017. In fact, it could even be done by the 53 mT Falcon Heavy, scheduled for first launch in 2014.

    Bob Clark

  8. Chris (Robotbeat) says:

    NASA is getting a flat budget or worse; that much is certain (unless MAYBE China gives a real shot at the Moon). And Congress, so far, is guaranteeing SLS and Orion stay alive. ISS won’t be abandoned until late 2020s at earliest. Can’t rob other parts of NASA, they have their own political power as well.

    That leaves two options /given those constraints/: 1) Stunts. 2) Capture a tiny asteroid (could possibly visit one of those tiny temporary moons) and visit that. SLS/Orion take up essentially all the budget such that there’s really not enough for even a lunar lander.

    This is by far better than a stunt to empty space, IMHO, unless you’re going to just try to make NASA HSF so pathetic that SLS/Orion gets canceled*, but that counts as letting the better be the enemy of the good (or even just “not horrible”) in my opinion.

    It serves a real scientific purpose (samples, which usually costs ~$1billion per asteroid for a very small sample), it could enable ISRU, it definitely extends the state of the art in characterizing NEAs and deflecting them, and it would be further out than any human has been before, and useful as a stepping stone for Mars orbit missions. Also, it would encourage commercial space exploitation by nailing down stuff that is currently just conceptual and helping silence the laughing factor (forgot the buzzword for that) in asteroid mining.

    *But there are much better ways to get SLS/Orion canceled. I think people are genuinely still skeptical of SpaceX and commercial crew… if commercial crew actually gets people to orbit and Falcon Heavy flies successfully (and SpaceX demonstrates a sustainable business) then there may be room for persuasion, like morphing SLS and Orion into some payload efforts, like an in-space upper stage or a lander or something.

  9. Paul451 says:

    Robert Clark,
    “The reason why the administration remains opposed to lunar missions is because of the assumption it has to be high cost.”

    I disagree. The reason that the current administration opposes lunar missions is because it doesn’t trust the “moon faction” at NASA not to go off the rails, as demonstrated by the Constellation mission proposal.

    It’s slightly unfair, since it’s not just the lunar faction which is broken at NASA. As Jon showed with the asteroid mission profiles, any flagship program tends to follow the same pattern. They take political support to mean “big budgets are coming!” and everyone throws every idea they’ve had for the last 30 years into the plan. Then budget reality hits and the profile gets stripped back piece by piece, until there’s nothing left except the most politically supported hardware in the smallest mission possible to achieve the absolute minimum necessary to achieve the “goal” (“return to the moon” or “manned asteroid mission”) while completely ignoring the purpose of that original challenge (using the moon to develop resources for a Mars mission (ie, lunar ice as fuel), using asteroid missions to incrementally develop and test multi-purpose hardware for a Mars flight.)

    “Following such an approach of going small, we could mount a manned lunar landing mission, not just a lunar flyby, by the first launch of the “70 mT” SLS in 2017. In fact, it could even be done by the 53 mT Falcon Heavy, scheduled for first launch in 2014.”

    Aim for 2019. Fiftieth anniversary of Apollo 11. That would give SLS time for a test flight (or two years of slip), or give Falcon Heavy five years to work out any kinks. Plus gives NASA time to build the lander. (Altair was stupid, but Masten and LM are playing with a dual thrust-axis lander based on a Centaur; a la Space1999’s Eagle.)

Leave a Reply

Your email address will not be published. Required fields are marked *