How to land on an asteroid
Asteroid landers in this computer simulation resemble Weebles, familiar toys for anyone who grew up in the 1970s.
February 14th, 2013
07:30 AM ET

How to land on an asteroid

By Paul Gabrielsen, Special to CNN

Editor's note: Paul Gabrielsen is a science writer based in Santa Cruz, California. He is a science communication graduate student at the University of California, Santa Cruz, and has written for ScienceNOW, the San Jose Mercury News, Geospace and

In the future, scientists want to be able to send spacecraft to study asteroids such as the one that will approach the Earth on Friday. A concept for these landers may look familiar to anyone who grew up in the 1970s.

Egg-shaped and weighted at the bottom, the landers - prototype designs for a possible future NASA mission - look like roly-poly Weebles, which wobble, as the old jingle goes, but don’t fall down.

The craft are still only computer simulations, a decade away from being ready to launch, but their simple design overcomes some of the biggest challenges in exploring asteroids’ alien landscapes.

Planetary scientists Naor Movshovitz and Erik Asphaug designed the landers, which they call “pods.” NASA’s Near Earth Object Program funded their work, which grew out of Movshovitz’s doctoral research on deflecting asteroids from Earth’s orbit. Movshovitz is a doctoral student at the University of California, Santa Cruz; Asphaug, his advisor, recently moved to Arizona State University.

Photos: Asteroids

Whether attempting to deflect an asteroid or trying to land an astronaut on its surface, scientists need to know the basics of what its surface is like. Small, low-cost surface landers (less than $1 million, with no moving parts) can travel to an asteroid and provide the needed information, if they can land successfully.

Asteroids are tricky places to land a spacecraft right-side up. Spinning through space, an asteroid’s small, uneven terrain and extremely weak gravity make even the idea of “up” and “down” fluid concepts. The techniques that have safely landed the recent Mars rovers (bouncy airbags for Spirit and Opportunity, a complicated “sky crane” for Curiosity) simply don’t work on an asteroid.

“Asteroids being weird and wacky places, we have to be prepared for any situation,” Asphaug said.

Saving Earth from asteroids

Their first design was boxy, like a deck of playing cards with one side coated in bouncy-ball rubber. The idea was for these landers to bounce around the asteroid before coming to rest, nonbouncy side down.

Since asteroids are in short supply in Santa Cruz, California, the scientists tested their designs in a computer model, using a video game physics simulator. Video game physics are just as good as scientific physics models, Asphaug said, and modern graphics cards can run the simulations 100 times faster.

Movshovitz tossed the square landers onto a computer-simulated asteroid. The rubbery side bounced, as designed. But too many landers came to rest wrong-side down.

They developed a new design - an egg-shaped lander weighted on the bottom, just like the Weebles that Asphaug played with as a kid.

“I was fascinated by Weebles,” Asphaug said. The toys, first produced in 1971, could be knocked in any direction but would still come to rest right-side up. Asphaug bet Movshovitz that the wobbly pods would work better than the previous “sandwich” lander, even in microgravity.

Movshovitz made the lower half of the pod nine times heavier than the upper half. In his simulation, the lower half was colored red, the upper half green. The landers, descending to the simulated surface, look like tomatoes falling from heaven.

Every roly-poly lander popped right up, even one that had landed on its head. Asphaug won the bet.

Movshovitz also is using video game physics to study how asteroids break apart in a planet’s orbit. The physics will be key, he said, to understanding the balance between the friction that holds the asteroid together and the strong planetary gravity that could tear it apart.

Asphaug said he hopes to continue to take advantage of the computing power developed by the video game industry to advance science. Video gaming, after all, is a $65 billion industry obsessed with making graphics faster, smoother and closer to reality than ever before. NASA’s entire budget, by comparison, is less than $18 billion.

Movshovitz uses a high-performance gaming computer sporting a graphics card with around 500 processors. His black metallic keyboard features sharp, angular lines and an amber backlit glow. With such a machine, is there ever a temptation to play games?

“After hours,” Movshovitz said with a smile.

Researchers presented these ideas at the 2012 American Geophysical Union Fall Meeting in San Francisco in December.

Asphaug’s Arizona State University team is now working on real-life pod prototypes, about the size of two softballs end to end, to prepare for NASA’s next asteroid mission, launching in 2022.

“Time flies,” Asphaug said. “We’ll be ready.”

soundoff (54 Responses)
  1. crawler crane

    Very interesting information!Perfect just what I was searching for! "Fear not that thy life shall come to an end, but rather fear that it shall never have a beginning." by John Henry Cardinal Newman. crawler crane

    March 11, 2013 at 5:22 pm |
  2. How To Make Money

    Usually I don't read post on blogs, however I would like to say that this write-up very forced me to try and do it! Your writing taste has been surprised me. Thank you, quite great article.

    February 19, 2013 at 1:53 pm |
  3. frosty

    The next space project should be to build a large conductive ring and place it in a spin, over a pole. Just like the "levitron" toy..There it would levitate above the earth either side of the induction "d" layer.. and act as a platform for both asteroid deflection and asteriod collection when the minerals suit.. Which is probably much more important to those in the path of such an unexpected event as an earth smashing out of control meteorite or asteroid impact.

    February 18, 2013 at 7:45 am |
    • c smythe

      you wanna suck what? seriously, you make no sense, how big does this thing have to be? the size I am thinking of is so big it would likely tear it's self apart. pure fantasy . . .

      February 21, 2013 at 1:03 am |
  4. plumbline

    Droughts, famines, earthquakes, and asteroids.......
    ...............Mark 13:8
    For nation will rise against nation, and kingdom against kingdom. And there will be earthquakes in various places, and there will be famines and troubles. These are the beginnings of sorrows.....
    Believe on the Lord Jesus Christ, and you will be saved.......
    Luke 21:25-26........
    ........The Coming of the Son of Man..................
    ........25 "And there will be signs in the sun, in the moon, and in the stars; and on the earth distress of nations, with perplexity, the sea and the waves roaring; 26 men’s hearts failing them from fear and the expectation of those things which are coming on the earth, for the powers of the heavens will be shaken......

    February 17, 2013 at 2:52 pm |
    • frosty

      I think a few asterois just went past Ur,anus, may the Clingons save you!

      February 18, 2013 at 7:31 am |
  5. Will

    There is no way I would try to land on an asteroid. Imagine if you have problems leaving for some reason. You'd be on your way on a long trip through space at 30,000 mph or whatever they move at. Not much hope for rescue then.

    February 17, 2013 at 12:18 pm |
  6. Lewis

    I say we send Bruce Willis up there for the fun of it.

    February 15, 2013 at 12:58 am |
    • Online_Comments

      Mork from Ork came in an Egg!

      February 15, 2013 at 6:06 pm |
  7. rikki liman

    If you think Gladys`s story is neat..., three weeks-ago my friend's cousin got paid $8027 workin at home and they're friend's step-mother`s neighbour has done this for four months and earnt more than $8027 part-time on there pc. the tips here......... BIT40.ℂOℳ

    February 14, 2013 at 7:30 pm |
    • c smythe

      spamm- a- rooney

      February 21, 2013 at 1:05 am |
  8. crow petty

    i think the real reason for the "pod" is to be able to travel farther, faster...makes sense to me.

    February 14, 2013 at 5:30 pm |
  9. Daniel

    It would be amazing if they could put a camera on an asteroid. I would love to watch as it travels through space.

    February 14, 2013 at 1:44 pm |
  10. Harry Stamper

    Two words...Harry Stamper

    February 14, 2013 at 1:17 pm |
  11. tony

    Any vehicle that is shaped like a piece of toast and coated in warm butter on one side, will land butter side down.

    February 14, 2013 at 12:43 pm |
  12. Bruce Willis

    I was never even consulted on this article. This entire piece is a sham.

    February 14, 2013 at 12:41 pm |
    • Canada Dry

      Bruce, take control of the situation!

      February 14, 2013 at 1:00 pm |
  13. Canada Dry

    Ok, .....huehue is right! Free food is never an incentive for anyone who's hungry.... learning about a frozen chunk of crap in a vacuum gives not only incentive to the homeless, but hope as well!
    Go huehue go!!

    February 14, 2013 at 12:16 pm |
  14. Canada Dry

    Lets spend a bazillion dollars trying to land a spider legged doodad on a spinning chunk of frozen crap hurtling through a vacuum....... Or we can feed everyone who lives under a bridge for 1400 years!

    February 14, 2013 at 11:53 am |
    • huehuehue

      Or we can spend the money to land the spider on the frozen object in a vacuum and learn something and have a significant greater chance at increasing employment in the vacuum for 1400 years.. Cause just giving away free food is not motivation enough for people living under a bridge to better themselves and contribute.

      February 14, 2013 at 12:02 pm |
    • bob aussie

      A couple of astroids will hit earth too soon to last 1400 years.

      February 14, 2013 at 12:11 pm |
  15. Organic1

    Unless these asteroids are the size of the moon, it will not matter how the craft is shaped. No gravity is still no gravity, spongy side up or down makes no difference. Besides spinning they are not just floating thru the space of dark matter, they are doing serious speed and if they just step those craft in front of them it will leave a mark, or maybe a smudge.

    February 14, 2013 at 11:43 am |
    • Keith T. Maxwell

      Everything has gravity. We have alread orbited asteroids smaller than the moon. (Vesta, for one)

      If you are staying home sick from school today, you shouldn't be playing on your mom's computer.

      February 14, 2013 at 11:51 am |
    • Canada

      The is gravity in space, it is called micro gravity.

      February 14, 2013 at 3:12 pm |
  16. danny

    the ethnics of againts to the god or asteroid will gone but the asteroid is not,,, this people againts in asteroid is the enemy of humanity by using of lying the people that the asteroid is a killer of dinosaur,,this are all invented,,,why the mammooth are still alive until now the mammoth is much older than dinosaur because dna of dinosaur are came from elephant and turthle,,,all prediction of that scientist are only invented and only to create a job or money,,, to lie the people ang govt to support her bad buissnes

    February 14, 2013 at 11:39 am |
    • toby

      How do we know you're real and not just some figment of are collective imagination?

      February 14, 2013 at 11:45 am |
      • Grammer Naxi

        Our. It's Our immagination.

        February 15, 2013 at 11:22 am |
    • Just me

      Are you aware that the dribble in your comment makes absolutely no sense at all. Are you on drugs or what?

      February 14, 2013 at 11:54 am |
    • Brian

      I just think it's awesome that you're using a computer and the Internet. Don't ever let anyone place limits on what you're capable of. You're absolutely special and can do anything you set your mind to.

      February 14, 2013 at 11:56 am |
  17. The Master

    It's more like a big ball of wibbly wobbly... time-y wimey... stuff. 😀

    February 14, 2013 at 11:26 am |
  18. Oscar Pitchfork

    Considering there are about 1 ONE asteroid for every million cubic miles of space around us, there's not going to be any kind of goldrush of asteroid-related cottage-industries springing up anytime soon. SORRY, ARMCHAIR ASTROPHYSICISTS !

    February 14, 2013 at 11:23 am |
  19. Ben Dover

    Space flight is a far more dangerous proliferation technology than either biological or nuclear weapons.
    Perturbing asteroid orbits is a phenomenally dangerous activity on long timelines.
    Asteroids do not live in geo-centric orbits, they live in mechanical-balance in a much larger and more complex system.
    The solar system is a web of orbital relationships, semi-stabilized over a period of millions/billions of years.
    It is computationally impossible for us to create/analyze hi-fidelity models to predict the wider-system effects of even 'successful' expeditions.
    A screw up would not be obvious at time it happened, it would be revealed decades/centuries later.
    We are one unregulated hillbilly away from an extinction level event.

    February 14, 2013 at 11:17 am |
    • toby

      I also have to wonder about the ROI. The current issue of Nat Geo gives examples and comparisons of how much of certain metals are obtained from 100 tons of earth and asteroid. It compares the values, but not the cost of the operations.

      February 14, 2013 at 11:43 am |
    • stanley

      Tell me, what's your astrophysics background? Did you know that astronomers can track Mars' center of mass to within 1 meter? Or measure the distance to the Moon to within a few centimeters? Orbit prediction is not guesswork; it's often precise to more than 10 decimal points. It's true that planetary orbits exhibit chaos, but only on timescales of millions of years, which is more than enough time to nudge any troublesome asteroid out of the way.

      February 14, 2013 at 12:20 pm |
  20. Horse Pucky

    Hey Buck, we went to the moon.
    We havent been back because we had a bad welcome on the dark side.
    By the way, the moon is "hollow".

    February 14, 2013 at 11:17 am |
    • toby

      ...and made of cheese.

      February 14, 2013 at 11:35 am |
  21. constantine16621990

    Well we can land on asteroids the same way the Master Chief dose, you can use a jet pack and jump from asteroid to another until we find another planet outside our solar system.

    February 14, 2013 at 11:10 am |
  22. RalphS

    This sounds all well and good but we should be so much further ahead in space flight, manned and unmanned. Certainly not a decade away for landing a pod on an asteroid. Sad that funding has dried up, but that's the reality. My fear is that our desire to explore has dried up as well. Its amazing to me how got a man on the moon in 1969, but have basically accomplished little else in that arena. Space station is great for experiments and testing human duration in weightlessness, but the Apollo missions were trail blazing.

    February 14, 2013 at 11:03 am |
    • toby

      The missions to Mars with the rovers is trail blazing. blazing trails for humans to go there one day soon.

      February 14, 2013 at 11:33 am |
      • Canada

        That Idea will get scrapped. and the rovers.... iunno, they just dont get me going.... it's a rc car. Lets set up a real station there!

        February 14, 2013 at 3:21 pm |
  23. Steve

    How to land on an Asteroid:

    First, you get an asteroid....

    February 14, 2013 at 10:58 am |
    • Craig in KC

      Steve Martin reference, I love it!

      February 14, 2013 at 11:17 am |
  24. Buck Rogers

    Ah, the comical claims of spaceflight fakery continues....

    February 14, 2013 at 9:02 am |
    • dATRUTH

      You need to get help, Buck. Try reading a book that isn't full of faerys, monsters, and floating cloud creatures. Your IQ may increase into the double digits. Space flight is real, science is real. We have been to the moon, we will soon go to Mars and, eventually, beyond. You are a detriment to the gene pool of your species. Do not reproduce

      February 14, 2013 at 10:56 am |
      • stanley

        I read Buck's comment as saying "people who claim spaceflight is fake, are comical". Or maybe I have too much faith in humanity.

        February 14, 2013 at 12:25 pm |
    • constantine16621990

      Buck your an idiot:/

      February 14, 2013 at 11:06 am |
      • CueBallSTL

        If you're going to call someone an idiot it's best not to say, "your an idiot".

        February 14, 2013 at 11:23 am |
    • Just me

      NEWS FLASH !!!!! Buck Rogers doesn't believe in Santa Claus or Big Foot.

      February 14, 2013 at 12:01 pm |


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