Planet Hunters Talk

Just a little spacecraft rant

  • ajamyajax by ajamyajax

    After seeing a headline like this, "Philae Falls Silent as Batteries Run Out," plus our Kepler reaction wheel failures -- I can't help but wonder why our engineers aren’t including more redundancy in their system designs. Sure cost can always be cited as a factor, but it seems to me that survivability for these long duration missions needs a higher priority. Look at the time and money it takes just to get there. My suggestion is simply this: if a few more delays and costs are necessary to include another backup power supply or another set of reaction wheels, maybe it’s worth doing that next time.

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  • DZM by DZM admin

    Here's the article @ajamyajax is referring to, incidentally:

    http://www.scientificamerican.com/article/philae-comet-lander-falls-silent-as-batteries-run-out/

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  • mschwamb by mschwamb scientist in response to ajamyajax's comment.

    I agree, Philae could have done with a bigger batter, but the mission is a success, and they got almost everything they wanted out of a primary mission. Same thing with Kepler, it completed 4 years of the prime mission which is what is was designed to last for.

    If only everyone was as passionate about solar system and space exploration as you. The problem is with delays and cost overruns (and Kepler was frought with them) impact the science budget which includes money to fund scientists to work on the data coming from these missions and other missions in the pipeline. There's a balance to be made, where exactly that is I can't say. I know t it can be gut-wrenchingly frustrating when something breaks on a mission. Especially when you're invested. I know I felt that way about Kepler, and I can only imagine how their science team and engineers felt.

    In terms of Philae, we should look at the mission as a successful, it's sad the lander didn't survive longer (and there is the slim chance it could wake up in a few or more months time as the comet gets closer to the Sun). If you live in the UK or have ways of watching things on the BBC iplayer streamer, I highly recommend you check out the Sky at Night Rosetta special. I watched it last night, and I think it accurately took viewers (me included) through the highs and lows and triumphs of the landing.

    Cheers,

    ~Meg

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  • DZM by DZM admin

    Personally, I'm still wondering if it's possible to harpoon a comet. That's one question that we didn't get answered!

    (The harpoons did not deploy properly.)

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  • mschwamb by mschwamb scientist in response to DZM's comment.

    Well the hammer didn't scratch the surface. The MUPUS probe's hammer didn't go into the surface even when they cranked it up to 'desperate' mode (their words not mine - level 4 where it would start breaking some of the electronics at that strength), it didn't make it through the crust. Latest preliminary results released suggest 10-20 cm of dust covering a strong ice or ice and dust mixture. More on the Rosetta blog.

    Cheers,

    ~Meg

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  • Artman40 by Artman40

    It seems that spacecraft with penetrators and harpoons have high failure rate.

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  • DZM by DZM admin in response to mschwamb's comment.

    In other words, the surface of the comet (at least where they landed) was much harder than they expected?

    So if their calculations about the hammer were off, perhaps their calculations about how strong the harpoon would need to be would be as well.

    Would be interesting to know if it was just that they landed on a hard patch, or if this comet as a whole had a much harder surface than they thought it would.

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  • mschwamb by mschwamb scientist in response to DZM's comment.

    In other words, the surface of the comet (at least where they landed) was much harder than they expected?

    Likely - all preliminary results - going to take months to a year or more to analyze the data that came from Philae

    So if their calculations about the hammer were off, perhaps their calculations about how strong the harpoon would need to be > would be as well.

    Harpoons didn't fire so unclear and I don't know how much force difference is between the hammer and the harpoons.

    Would be interesting to know if it was just that they landed on a hard patch, or if this comet as a whole had a much harder surface than they thought it would.

    Welcome to planetary science especially mission science- Those kinds of questions is why I love solar system science. and one of the reasons I got into it. My expertise are Kuiper belt objects not specifically comets. We'd all like to know. only got one lander but likely once they nail down exactly where Philae is, you can use the orbiter data to extrapolate if the conditions are likely similar. Though it's still one one measurement from the surface, but it's the best we have. I'm looking forward to hearing more results in the coming months and next year at conferences.

    Cheers,

    ~Meg

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