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The Art of Aerobraking

Posted by michael on from the flat-rock-on-a-still-pond dept.

gizmo_mathboy writes: "Yahoo! Dailynews has the following Space.com article about the risk of using aerobraking for orbital insertion of spacecraft versus the certainty of using conventional propulsion systems. This is all explained in terms of the Mars Global Surveyor craft that is expected to do its orbital insertion on October 23. Skip the wimpy aerobraking and as a prophead trapped in a code monkey's job I say, "In Thrust We Trust.""

1 of 86 comments (clear)

  1. Re:Aerobraking and probe intelligence... by Johnny+Vector · · Score: 5, Interesting
    for christ sakes, I can get a Lego Mindstorms to run around my livingroom by itself; one would hope that we might be able to build a semi-autonomous space probe.

    You mean like Deep Space 1? Or Clementine? Yep, it's being done.

    (3 minutes later, and atmosphere unexpectedly thickens) SP: oh no! Quick, recalculate! rocket, give me a 2 second burn then turn 43 degress for a 1 second burn!

    Oop, doesn't work that way. Orbital mechanics is funny until you wrap your head around it. To change the perigee, you have to burn at the apogee. Once you're in the atmosphere, there's bugger all you can do about it until the next time around. (Well, unless you're carrying gobs of fuel, and if you can do that, the screw this aerobraking stuff.)

    Of course, you can make the probe autonomously adjust the next pass based on the results of the current one. But I wouldn't want to even try until we have at least one more probe's worth of data on exactly how to model all this.

    And in response to the AC who thinks that rad-hard processors aren't up to this, all I have to say is HAW! Go look up what processing power the guidance computer on Apollo 11 had, and marvel at how much you can do when you're not spending cycles drawing aqua-colored drop shadows. I could make a useful aerobraking auto-adjust system with an RTX-2010 and half a meg of RAM. (That's an 8 MHz Forth processor, folks.) If that's not enough for you, Lockheed-Martin is selling rad-hard 250 MHz PowerPC 750 boards for only two arms and a leg.