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Mercury Probe Delayed by Ten Weeks, and Two Years

Posted by michael on from the testing-1-2-3 dept.

Gogo Dodo writes "Spaceflight Now reports that NASA's MESSENGER probe launch has been delayed by 10 weeks. Unfortunately, this means MESSENGER will not arrive at Mercury until 2011, a two year delay."

5 of 35 comments (clear)

  1. An Understandable Shame by Embedded+Geek · · Score: 5, Insightful
    I think it's a shame they'll miss the better window, but giving more time to check out the on board diagnostics seems like a dang fine reason. I'd hate to see the thing get all the way to Mercury and then go dead. If the program mangers want this breathing space (and you can be sure they'd only consider this if they were getting a lot of warnings from within the ranks), they'd be fools not to take it. Still, the extra Venus flyby would have been nice (2 vs. 3).

    I'm kinda concerned about the budget hit, though. Maintaining an engineering infrastructure on the ground for an additional two years, even one in "standby," is going to be costly. Sure, they can loan out personell to other projects during the interim, but you're going to see two more years of attrition and then retraining costs to catch up. A boom or bust in the tech cycle will simply agravate the situation (boom=more people leaving, bust=fewer new engineers to fill vacated slots).

    The delay is probably acceptable, but let's hope the added budget doesn't hurt another probe.

    --

    "Prepare for the worst - hope for the best."

  2. Re:Why 2 years? by Neil+Blender · · Score: 5, Informative

    Mercury goes around the sun in 87 days. Assuming that the orbits are circles (they're pretty close) it should never be more than 86 days for the planet to be in an optimal position to launch a probe. So, why would it be off by two years? What am I missing here?

    Uh, maybe an in depth knowledge of how the gravity of all the planets affects trajectories?

  3. Re:Why 2 years? by eingram · · Score: 5, Informative

    This may answer your question. Either that or just confuse you more. ;P

  4. Re:Why 2 years? by Anonymous Coward · · Score: 5, Funny

    What am I missing here?


    a degree in astrophysics.


  5. Re:Why 2 years? by CheshireCatCO · · Score: 5, Informative

    The links already posted answer the question, but the short, simple answer is "angular momentum". Specifically, the need to dump a lot of it (and, equivelently, a lot of energy). The energy changed needed to get to Mercury is actually greater than that needed to reach Pluto. This means that it's better to use the inner planets (Earth, Venus, and/or Mercury) in gravitational slingshots (but backwards of how we usually use them) to save fuel. In theory, if you jacked up NASA's budget, you could go straight there once a synodic (not sideral: it doesn't matter how often Mercury orbits, but how long it takes to get back to the same relative arrange with Earth) period. But NASA, alas, has a finite budget for this sort of thing, so slow and cheap is the way to go.