#2225: Furrowflight

I’m ploughing my way through Walter Lewin’s 8.01 Physics course online. He recently covered orbital mechanics, on which today’s invention is based.

It’s a way to sample the surface of an asteroid without having to create and deploy a costly lander.


A body in space with no atmosphere, such as an asteroid, would allow a small spacecraft (yellow) to enter into orbit around it (1->2->3->4->5).

From this would be ejected backwards a tiny (red) satellite (eg a cubesat).

This could be given an intial speed just great enough to allow it to return to the mothership, without significant additional fuel cost or active control, following the kind of orbit shown.

As the cubesat passed close to the asteroid’s surface, it would drop a small mass which would create a plume of dust through which the craft could fly on a second orbit before returning to the main satellite.

I’m tempted to suggest that repeated applications of this technique could be used to erode and thus deflect a dangerous, earthbound rock.


  1. I’m sorry that the smaller satellite appears less obviously red here than it should. I’ve also indicated that the dust plume arises only some time after the red satellite has passed. The dust is shown as being pushed along its trajectory a little, although I’m not sure that this would be very visible.

  2. Why not send two (yellow) satellites in pairs, and the first one would shoot the small mass to the asteroid and the second satellite which passes a few minutes later does the analysis. No need for the small cubesat, no need to go into orbit (which costs energy too).

    • Yes, I see. So it would be just a very low flypast by two vehicles, one after the other. That’s a much better idea than mine. Doh.

      It would only be able to sample one spot, but I guess that’s all that you might need.

  3. Wow, these people look like they are seriously getting ready.

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