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Space Science

Simulations May Explain Loss of Beagle 2 Mars Probe 98

Posted by timothy
from the gremlins-are-everywhere dept.
chrb writes "Researchers at Queensland University have used computer simulations to calculate that the loss of the US$80 million British Beagle 2 Mars probe was due to a bad choice of spin rate during atmospheric entry, resulting in the craft burning up within seconds. The chosen spin rate was calculated by using a bridging function to estimate the transitional forces between the upper and lower atmosphere, while the new research relies on simulation models. Beagle 2 team leader Professor Colin Pillinger has responded saying that the figures are far from conclusive, while another chief Beagle engineer has said 'We still think we got it right.'"
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Simulations May Explain Loss of Beagle 2 Mars Probe

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  • this could have been cool to watch. poof, nothing.

  • Everyone always blames the bridging function...
  • by master811 (874700) on Friday December 19, 2008 @04:54AM (#26170741)

    .... that The Transformers got it.

  • by Scoldog (875927) on Friday December 19, 2008 @05:01AM (#26170763)
    In fact, it broadcast 13 seconds of footage. It can be viewed here. http://au.youtube.com/watch?v=wFvUdt9BQhU [youtube.com]
  • Crazy talk (Score:3, Insightful)

    by Hobadee (787558) on Friday December 19, 2008 @05:07AM (#26170787) Homepage Journal
    Now, this may be crazy talk, but shouldn't you do the computer simulations BEFORE sending the $80m craft on it's way?
    • Re: (Score:3, Funny)

      by Hognoxious (631665)

      but shouldn't you do the computer simulations BEFORE sending the $80m craft on it's way?

      LOL, that's so BDUF [wikipedia.org], are you still in the 1980s?

      The landing wasn't a failure, just the first iteration using an agile methodology. They'll get there in the next scrimmage. Or something.

  • Ummmmm..... (Score:3, Funny)

    by IHC Navistar (967161) on Friday December 19, 2008 @05:19AM (#26170831)

    "Beagle 2 team leader Professor Colin Pillinger has responded saying that the figures are far from conclusive, while another chief Beagle engineer has said 'We still think we got it right.'"

    -So they really *did* intend to burn the craft up on re-entry? If they did, what's all the hubbub about?

  • This has to be the coolest name for a scientist I have ever encountered!:
    Dr. Madhat Abdel-Jawad...Madhat FTW!!!

    Or, maybe I have watched too many 1950's-1960's grade B (or some/most less than 'B') 'mad scientist' movies for my own good.
    It could also be Lewis Carroll's fault for "Alice in Wonderland" having the 'MadHatter'....I just don't know anymore...

    Oh yeah, have pink flamingo, will travel...BTW, WHO are you, again? [imdb.com]. (Don Ameche's character as the senile father)
    Worth watching, a very funny but family safe

  • Explanation? (Score:4, Insightful)

    by Schiphol (1168667) on Friday December 19, 2008 @05:27AM (#26170857)
    There is something wrong but interesting about the idea that a computer simulation can explain what happened in a real-life incident. In the normal usage of "explain", only causally-related events can explain other events.

    There is undoubtedly something to the contention that a computer simulation does some explanatory work, but it must be in a roundabout way. Maybe this: the computer simulation provides evidence to the effect that some prior event was able to cause the known outcome; but then it is the prior event (the bad choice of spin rate in this case) that explains the loss of the Beagle 2, not the computer simulation.
    • by mabinogi (74033)

      I think your idea of normal usage of "explain" may be slightly at odds with the entire rest of the English speaking world.

      You seem to be thinking of the "That explains it!" context (being the explanation), rather than the "Bob explains it to Alice" (Providing the explanation) context.
      I don't think you could say that one is more normal usage than the other, and I don't think anyone else had much trouble picking the correct context from the headline, even though headlines are often fairly impenetrable.

      • by Eaque (1435177)
        +1 !
      • by Schiphol (1168667)
        I think you are right, and I made my point in a careless way. I stand corrected.

        It is nevertheless still the case that scientists tend to think these days that computer simulations do explanatory work of the other kind. It is still an interesting question: do computer simulations provide evidence at all that some events in the real world have turned out one way or another?
    • Re: (Score:3, Informative)

      by DerekLyons (302214)

      There is something wrong but interesting about the idea that a computer simulation can explain what happened in a real-life incident. In the normal usage of "explain", only causally-related events can explain other events.

      Huh? The dictionary definition of explain [merriam-webster.com] pretty much matches how I've used it and seen it used all my life - and bears no relation to your "definition".

  • So what is a "bridging function"? Definitely not something about Ethernet bridging... but what is it?

    • Re: (Score:2, Funny)

      by zbharucha (1331473)
      It's one of these: http://www.sciencecartoonsplus.com/images/miracle3.gif [sciencecartoonsplus.com]
    • Re: (Score:2, Informative)

      by Anonymous Coward

      So what is a "bridging function"? Definitely not something about Ethernet bridging... but what is it?

      From the context, I would imagine that it is a function that interpolates between the behavior of and forces on the craft in orbit (well studied by previous orbiters) and the behavior expected in the lower atmosphere (well studied by previous probes). The intervening region is probably not that well covered by available data, so some sort of function must be guessed to fill-in the gap between the two datasets. There may be features in the upper Martian atmosphere that were not present in the bridging functi

      • Re: (Score:2, Funny)

        by Tablizer (95088)

        [What is a bridging function?] The intervening region [of atmosphere] is probably not that well covered by available data, so some sort of function must be guessed to fill-in the gap


            b = guess(a)

         

  • by Anonymous Coward
    There has been a very detailed assessment of this failure by the European Space Agency at the time, and the guys were quite competent being the ones that built the (successful) Huygens probe to Titan embarked on Cassini.
    ESA found many issues, mostly due to way too severe cost constraints (a "british-only" program...).

    Among them IIRC, the main parachute that was changed in extremis (when the unpaid earlier maker announced they wouldn't go up to offer the flight model too) resulted in a drag coefficient t
  • Some Background (Score:5, Informative)

    by Catmeat (20653) <mtm@@@sys...uea...ac...uk> on Friday December 19, 2008 @06:15AM (#26171075)
    Beagle 2 always was an underfunded project with zero margin for error. For background, see this 2005, 2-part article by respected space historian and author, Dwayne Day.

    http://www.thespacereview.com/article/330/1 [thespacereview.com]

    http://www.thespacereview.com/article/347/1 [thespacereview.com]

    As for Colin Pillinger, note that the (initially secret) ESA report on the Beagle failure put much of the blame on project management failings and he's not been put in charge of any large project since.

    • Re: (Score:3, Informative)

      by zrq (794138)

      As for Colin Pillinger .... he's not been put in charge of any large project since.

      According to Wikipedia [wikipedia.org], he was diagnosed with progressive multiple sclerosis in 2005. So he might not feel up to spending the next few years fighting the inevitable political and administrative battles a project like this would involve.

  • Calculate This (Score:5, Insightful)

    by DynaSoar (714234) on Friday December 19, 2008 @07:24AM (#26171391) Journal

    How many different independent forces could have influenced Beagle? Represent each with a variable. Calculate how many emergent properties could have influenced the craft (those arising from interactions between main variables). Assign these a variable. Estimate the range of values for each variable. Calculate the dynamics of each variable (ie. linear, logarithmic, hyperbolic, etc., including estimation of those whose behavior does not fit a simple function, instead requiring complex functions). For each variable, estimate a reasonable granularity (they may be analog, but the resulting computation would include infinities, so digitizing is necessary). Calculate the matrix necessary to represent all the possible results. Determine whether the calculations could be completed in polynomial time. Almost certainly not, so estimate how many variables (and their dynamics) must be retained and drop the rest. Calculate the solutions matrix for this reduced set. Check for polynomial time solution. If no, reduce yet again. With each reduction estimate the error range introduced, and whether any of them are unacceptable and the prior value retained.

    Estimate the amount of computational power/time necessary to complete the solutions matrix, including the cost of buying/building/renting/etc. and your available resources. Calculate how many orders of magnitude there are between what's necessary to solve the problem and what you have to work with. From that estimate how much you have to reduce the solutions matrix in order to be able to arrive at some solutions, as well as how inaccurate any results will be.

    Once you have the calculation of the solution set down to polynomial time and within your budget, look at how inaccurate your results will be. If the accuracy is found to be acceptable, and the calculation therefore worth doing, chances are you've made a mistake in your estimations. Almost certainly the inaccuracy will become too great before your reductions result in a solvable problem. Also note that the minimal matrix dimension will probably not be an integer. Choosing the best number of variables would be trivial, as you simply choose the next highest integer. However just because the solution here is between N and N+1 does not mean that there is only one variable with a fractional influence; estimate how many and which variables are best characterized as non-integers and select the best set of variables to use in the model. Calculate how far back into non-polynomial time your solution estimate has drifted, or at best how far over your resource budget the calculations will require.

    Take a dose of analgesic of your choice sufficient to eliminate your headache. Begin building a model using the minimum number of (integer) variables necessary to arrive at a variable/value set that produces a result matching the behavior of the phenomenon you wish to model. Ignore the probability calculations that would indicate how likely it is you're wrong, and how many such wrong solutions you'll arrive at before you happen on a possibly right solution. Instead of using probability estimates to calculate statistical significance of any calculated solution, use the fact that a solution can be found that results in the same behavior as the one to be modeled, and wrongly call that accidental similarity 'practical significance'. Publish a factually unsupportable assertion that your model describes what happened based only on the fact that your model achieves the same result and count on the fact that nobody else on your research team, or anyone for that matter, is capable of accomplishing the necessary calculations described here to conclusively state you're wrong, or at best that you can't say you're right.

    Estimate the positive influence the number of publications, regardless of validity, has on the probability of receiving future funding and amount thereof. Conclude that minimal-guess "modeling" provides you with the ability to say something that sounds reasonable whereas attempting to achieve real validity would take too

  • by BB128 (1435253)
    This is clearly a matter of an unfortunate choice of names. Naming it "beagle" was clearly asking it to wander off and get lost. Any beagle owner will be able to attest to this.
    • Re: (Score:1, Informative)

      by crowne (1375197)
      I thought that it was named after the HMS Beagle upon which Darwin made his first observations that led to his theory of natural selection / evolution.
  • I thought it was swallowed up by the Sycorax on Christmas two years ago.

    (Yes, I know that The Christmas Invasion aired three years ago, but there was that one year time loss early in the first season of Doctor Who, between Rose and Aliens of London that hasn't really been accounted for since. Should actually put Torchwood ahead a year, too.)

"Out of register space (ugh)" -- vi

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