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Space Science

One Last mission For Deep Space 1 102

Posted by timothy from the do-it-for-the-gipper dept.
Vertigo01 writes: "Looks like NASA has found a fitting end for Deep Space 1, they're going to fly her THROUGH the coma of a comet to try and take some pictures of the comet's core ... the kicker is that they're doing it with barely any fuel left, and a kludged-together science-camera to replace the toasted navigation system ... kind of a fitting end for her IMO."
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One Last mission For Deep Space 1 More

One Last mission For Deep Space 1

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  • Scientific value? (Score:1, Interesting)

    by shd99004 ( 317968 )
    I wonder how much scientific value will come out of this, compared to the cost of $12 million. I mean, they say they have to almost make a guess on where to point the camera and to set the exposure. They could have used those bucks on other space crafts or missions, perhaps. But then again, $12 million is not a lot in this business.

    • Re:Scientific value? (Score:2, Funny)

      by Anonymous Coward
      If for $12 million they can show that the special effects in the $140 million movie "Armageddon" were crap, I say it's a great value.
    • perhaps it's not a lot "in this business", but face it, it is a helluva sum of money. I fail to grasp how NASA can manage to spend $12 million on a "duck-tape" mission. it's not as if they could have refueled the probe or anything, so all that money has went to radio contact, mission planning and reprogramming. Now, assuming that's the cost of the mission since October 1999, when the main mission ended, it's half a million dollars for every month of the continued existence of the probe. Where has it gone? $1000 floppy disks? 50 person full-time ground crew?

      Not that I actually need to care since it wasn't me paying for it.

      • Re:$12 million (Score:5, Insightful)

        by FTL ( 112112 ) <slashdot@neil.frase[ ]ame ['r.n' in gap]> on Tuesday September 11, 2001 @06:00AM (#2276824) Homepage
        > Where has it gone? $1000 floppy disks? 50 person full-time ground crew?

        In order to communicate the probe you need to rent time on the Deep Space Network [nasa.gov]. This network is currently running at capacity, so getting time on it is rather expensive.

        But an even bigger expense is the mission software. Modifications to the programming of the probe need to be codded. Then the code has to be proved to be mathematically perfect. You cannot afford to compile it, upload it, and get a message back saying "stack overflow, press any key to continue". The software must be proven to be 100% bug free before it goes up.

        It takes a lot of people to manage a space mission correctly. Cut corners, and your mission fails because of something stupid (e.g. metric vs imperial).

        • Re:$12 million (Score:3, Funny)

          by csbruce ( 39509 )
          Then the code has to be proved to be mathematically perfect.

          Does the proof itself need to be prooved to be correct, or is that taken on faith?
          • It's taken on faith--you have to assume some axioms.
            • It's taken on faith--you have to assume some axioms.

              Axioms aren't in question; it's whether all of the steps of the proof are correct. It seems to me that it's just as easy to make a mistake in a proof as it is in a program.
              • If you make a mistake in a proof, then you will go over both the proof and the program, which means that you will discover that the proof is faulty, and correct the proof. If you have no proof at all, then you can't say with 100% certainty whether or not the program works (unless it's "Hello world"). It all boils down to redundancy, similar to N-version programming, where you implement N (N>=3) version of a program (implementation techniques should differ as much as possible). Then run these N version in parallell, and when they do not agree with each other, they take a vote. Hopefully only a minority of these versions are wrong.
                • If you make a mistake in a proof, then you will go over both the proof and the program, which means that you will discover that the proof is faulty, and correct the proof. If you have no proof at all, then you can't say with 100% certainty whether or not the program works (unless it's "Hello world").

                  Formal proofs of programs increase the probability of noticing a mistake since you're essentially implementing the program twice, but they don't guarantee 100% certainty of correctness, since there is always the possibility of an error in the proof. Computer-system theory is littered with published papers containing incorrect proofs.

                  It all boils down to redundancy, similar to N-version programming, where you implement N (N>=3) version of a program (implementation techniques should differ as much as possible).

                  Triple-modular redundancy also has difficulty when applied to software systems because systems have some parts are easy and some that are hard, and the implementors of all three systems are most likely to make most of their mistakes in the harder parts.

                  If only software systems were as trivial to build as bridges and airplanes!

                  {now if you'll pardon me, I have a flight to catch...}

        • Metric vs Imperial (Score:2, Informative)

          by Cadre ( 11051 )

          The problem NASA had with the Metric vs Imerial calculations was due to rounding errors in the conversion equations (ie: only going out x amount of decimals points; where x wasn't large enough). The error introduced by the lack of precision wasn't due to a single conversion but due to multiple back and forth conversions (probably in the order more than a hundred). It was not a single incident of "oops, I meant five meters, not five feet."

          This doesn't justify it, but I don't think a lot of people actually know what the real problem was. It was a precision error, not a Metric vs Imperial error.

          • But why were there any Imperial units used on-board at all? Slugs and foot/lbs in space?

            Conversions using floating point numbers always give me the willies. Case in point: Microsoft DATE class for holding time/date values. It uses a floating point number to hold the value, with the fractional part holding the time. If you add/subtract to convert local time to GMT and back, the number has shifted out about the 8-9th decimal place. As a result, a time comparision with an unshifted number will fail. *shudder*

            There's a reason financial calculations should never use floating point.
        • >But an even bigger expense is the mission software. Modifications to the programming of
          >the probe need to be codded.

          And do you have any idea how much it costs to send that much fish into space? Why, the dill sauce alone runs into the millions.

          (sorry, couldn't resist)
        • There's also probably some magic bean counter stuff going on as well. The project likely gets assigned its "share" of a lot of things like the cost of the building, electricity, phones, the coffee machine and the salaries of people who would be doing the same job regardless: janitors, security, support staff, etc.

          Weird, but it's a common accounting practice.
        • The software must be proven to be 100% bug free before it goes up.

          So, I guess they contract out to M$ then, huh?

          skribe

      • Re:$12 million (Score:1, Informative)

        by Anonymous Coward
        In the space industry, $12M gets eaten up pretty quickly. First, you have the proposals given by each company bidding on the contract. In general, you get paid for your proposal. This cost could vary greatly. People will lay claim that the cost of the software development is the major cost in a project such as this. That simply is not true. Your programmers are getting paid a salary, and its probably a pretty small team. Sure, you have the QA people, support, etc, but that is also probably pretty small.

        The vast majority of the cost is in specialized hardware. I don't know for certain, but there is probably a pretty good chance that the processor board used on this is a RAD6000. Lockhead produces these, you can buy a not flight qualified board for about $75k, and the flight qualified run over $300k. For the most part, there is no such thing as commodity space parts. Everything is specially designed. Everything from wire harnesses to nuts to fasteners to you name it are called 'tools' and specially designed and modeled to the job. Realestate is extremely important and you would be amazed how much time it takes to simply get all the wires and cables to fit.

        While the price tag seems excessive, keep in mind this. Take your cheapest car on the markey, I dont know, say an $11k hyandi. Now, only produce one of them and put a price tag on it. I suspect you'll find that it is much more than $12M. Yes it's expensive, but space is an expensive business.

    • Re:Scientific value? (Score:1, Interesting)

      by Anonymous Coward
      Money and ethics are irrelevant when the physics is this tempting. This applied to the scientists working on the a-bomb and still applies today.
    • I'm sure there are plenty of ways to justify the $12m bill - the ground operation will already be fairly immense, and keeping it running costs money (admin staff, office space, hefty electricity bills etc). Mainly, I expect it goes to consultants and contractors, and on purchasing hardware from "military approved" vendors (i.e. the expensive ones).

      In this country (UK), a post-doctoral space scientist at a top academic institution probably earns around 20,000 pounds PA if they're lucky (that's about $30,000, I think). If you consider that they'll be employed for maybe three years doing the data analysis and planning the next comet missions, a team of 20 scientists would account for $1.8m.

      So I can see (almost) where they get the figure from. And it's probably quite easy to convince the funding bodies (is that the US public? I don't know how NASA do things) that comets are already lining up to take aim at the Earth, and we must learn more about them so we can work out a defence mechanism... sounds insane, but that's how a lot of science gets funded nowadays.

      Me? I'd rather they built some hospitals in Africa.

    • Re:Scientific value? (Score:4, Insightful)

      by GTRacer ( 234395 ) <gtracer308&yahoo,com> on Tuesday September 11, 2001 @10:51AM (#2277531) Homepage Journal
      Ugh...

      The point of the Deep Space series of missions, of which the Mars Polar Lander was #2 and went AWOL, was to test new tech for next to nothing (in NASA terms).

      Do any of you realise that DS1, apart from being 8 revs away from the greatest Trek ever, was powered by an ion engine? You know, like Star Wars?

      Plus, when the nav system went tits up, they were able to retask other optical instruments to allow for autonomous piloting.

      DS1 wasn't even supposed to make it this far. IIRC, it was expected to have a 3-month primary mission to test the equipment. Then, if there was enough gas in the tank and the thing still worked, they were going to find something else for it.

      An asteroid flyby and now a comet encounter...not bad for $12 mil!

      P.S. I'm a bit biased on this one - I watched the launch and have read every one of the oddball logs posted by Dr. Raymond.

      C'mon, NASA, where's DS3?

      GTRacer
      - Wants to be first at something

      • I always thought that the Deep Space series was for labeling probes testing experimental technology. The Deep Space 2 probes on Mars Polar Lander were part of that because they were designed to survive impact after being just DROPPED from MPL during descent, penetrate the surface, take samples, and beam back data. MPL itself was not really part of the Deep Space series.

        The whole concept that MPL and the other Mars probes (and maybe... probably... the deep space probes) fall under has generally been refered to (at least in the press) as "better, cheaper, faster". Prevailing wisdom seems to suggest the first two parts of that are mutually exclusive given the Mars failures. But there are some big successes there too, and perhaps even a 50% casualty rate is better than quadrupling the cost. Hopefully they'll build in more redundancy ;).

        Regardless, I'm just parsing semantics...

        - StaticLimit

  • The JPL: Geeks in Spaaaaaaaace! (Score:5, Funny)

    by odaiwai ( 31983 ) on Tuesday September 11, 2001 @04:21AM (#2276720) Homepage
    This is just the sort of thing we used to expect from the JPL: "We've got fifteen bytes spare and a few milli-amps left in the batteries. We can probably take out the Death Star with that."

    What was that old story? With a small amount of memory remaining after all the main programs had been entered, someone at JPL wrote a program to look for and identify previously unknown moons of Jupiter and send pictures back.

    dave "wist"

  • Kudos to NASA (Score:3, Interesting)

    by BrickM ( 178032 ) on Tuesday September 11, 2001 @04:26AM (#2276724)
    I mean, you've got to give them credit for refusing to throw in the towel. Ideally, things like Deep 1 wouldn't malfunction in the first place, but at least NASA is trying to make the most of things.

    • Useful testcase (Score:3, Interesting)

      by coreman ( 8656 )
      One of the important things to remember is that just like Apollo 13, these guys are where they are for coming up with innovative fixes to tough problems. This is just another great rehearsal for a situation that could just as easily come up with human life at stake. This is why these guys are kept on the project long after the system gets put into cruise mode. It's just another case of "I've done so much with so little for so long that now I'm attempting the impossible with nothing." You have to push the boundries to find where they are in practice. Also, real problems are far more challenging than anything they might have considered in simulation.

    • Re:Kudos to NASA (Score:3, Insightful)

      by cdipierr ( 4045 )
      It's unfair to call DS1 a failure just because of early engine and navigation problems. It successfully completed its mission (and then went beyond the call of duty with the landing) and now is just being put to the test again. DS1 was an extremely successful mission, not a "malfunction".

  • Official NASA pages (Score:5, Interesting)

    by Zarhan ( 415465 ) on Tuesday September 11, 2001 @04:27AM (#2276725)
    http://nmp.jpl.nasa.gov/ds1/ [nasa.gov]

    Check out the monthly reports. They are quite fun to read, because they are written in a "layman" fashion. Especially the parts where they are putting together the "using science camera for navigation"-kludge. And rebooting a system half a solar system away and hoping it comes up again after an OS upgrade.

    It's kinda sad that all the public focus is on the Mars missions, when there's stuff like DS1, Galileo, and NEAR that just keep on going..
  • I'm curious as to how the 12million is arrived at. Seems a lot for just pointing a nearly dead device in another direction. How many ground based resources are involved?
    • Well, consider this. The programs for things like navigation have to work without fail. If the thing turns the wrong way, we could lose the ability to feed it directions. Just making 100 percent sure that doesn't fail can take a ton of money. I'm sure that is only a small part of it but it would be expensive cause you have to run it through all kinds of testing to make sure it doesn't fail on the working environment. Then you have the rocket scientists that determine what can be done, the trajectories. Then you have to pay for the computers (mainframes, mission crit network, etc). You have to pay janitors, security, cafeteria staff. You have to pay people to monitor the craft and others to monitor their computers (to make sure they don't surf on the job :). It can build up to a few million. I imagine most of the cost is just various kinds of support staff.
      • Well, consider this. The programs for things like navigation have to work without fail.


        Oh yeah, we've really been programming things lately that don't fail. OK, maybe I'm a little harsh -- I'm certain I couldn't do any better. But I am curious as to how much of the $12MM would have to be allocated to other projects if we chose not to include this last flyby. What I mean is, those people that are getting paid would probably still have jobs, but the costs would be allocated to other projects. So how much of this cost is truly related to this final song?

    • The costs stated are the continuing costs of tracking the satellite versus turning a deaf ear and ignoring it. Deep Space Net time isn't free, they have to allocate it and maintain the dishes used.

  • duct tape (Score:4, Funny)

    by astafas ( 232064 ) on Tuesday September 11, 2001 @04:45AM (#2276742)
    I didn't know McGyver worked at NASA.

    • McGyver bashing (Score:2, Insightful)

      by Anonymous Coward
      Why are you people bashing McGyver?

      It was a good, clean and funny TV show that has made me want to become an engineer.

      • Agreed, it was actually pretty entertaining. It did go downhill at the end though, especially with the made for TV movie which introduced mysticism.
      • It's not really bashing. It's having a sense of homour about it. McGyver was fun, but you got the impression that if you locked him in an airtight chamber with a stick of chewing gum and a pair of sneakers and buried it in concrete, McGuyver would invent a teleporter before the air ran out.

        Although much more plausible, McGuyver's character was a bit like "The Professor" on Gilligan's Island. The show also has a Sherlock Holmes flavour, because both characters did amazing things because the authors had set things up so that they could do those things. Doyle left clues, while McGuyver's writers gave him access to substances and objects he needed to succeed.
    • Don't you mean Red Green? [redgreen.com]
  • did they manage to spend an extra $12 million? This is on a spacecraft that is already in space, the only changes are in software and in the control equipment (which should still work...).

    The software needs to be reprogrammed to redirect the spacecraft and aim the cameras, and of course all the fun trajectory math and so on, but $12 million is over 60 person-years!!

  • Already been done (Score:1, Interesting)

    by morbid ( 4258 )
    Back in about 1986 the ESA sent a probe called Giotto through the coma of Halley's Comet which sent back live video.
    • But the scientists (dimwits that they can be, at times) neglected to allow for the possibility of hot-spots on the surface, so their cameras only got some REALLY good pictures of some deep-space water fountains.


      Mind you, Patrick Moore was on fine form, that night, and was able to turn some fuzzy low-res photots of two vents into something dramatic & well-worth the watch.

    • They should have put this info in the article. Maybe even should have mentioned it twice, perhaps in the intro and then a few paragraphs down. You should write a letter to the editor about that glaring omision.
      What ever happened to the good old days of people reading and THEN posting?

      mfkap
  • "That's nothing compared to the cost of building a new spacecraft," said Paul Hertz, the Deep Space 1 program executive at NASA headquarters.

    Landing it on earth is much more likely to succeed

  • Why fly downstream from the comet? (Score:4, Interesting)

    by Mxyzptlk ( 138505 ) on Tuesday September 11, 2001 @06:27AM (#2276848) Homepage
    I was just wondering - why fly downstream from the comet and subjecting DS1 to the shower of particles, when you could approach it from upstream (put DS1 between the comet and the sun). The primary purpose is to get pictures of the nucleus, not the coma, right? So - let DS1 slowly drift towards the nucleus, and steer it by looking at the whole of the coma and centering on it (we know the nucleus is in the middle, because we've placed DS1 approximately in the middle between the sun and the coma). This allows as much time and small adjustments (saving fuel) as possible, getting DS1 as close to the nucleus as possible.

    When this is done, continue past the nucleus into the comp and try to get a closeup picture or two of the coma before being blown to smithereens by the particles.

    • A comet gives off gas which is fairly tenious and gets blown away more or less directly away from the sun. Its the dust and grit that is the risk, and that gets left behind in the vicinity of the orbital path, in the same region of space where DS1 will be. (same stuff also causes meteor showers when earth orbits accross the dirt trail)
      The important thing from DS1's point of view is to keep the relative motion between the coment and the probe as small as possible, both to maximise encounter time and to make it easier to 'aim' the probe and its cameras at the comet. (this also saves fuel, which is a heavy, scarce and precious resourse in outer space)
      In effect, the two objects are on almost on a parallel path, at slightly different speeds, not a perpendicular intersection as one would think.
      Its like two veichicles on a slowly curving highway, one slowly overtaking the other. If the comet is an open dumpster truck in the slow lane, you will be showered with garbage for miles before you eventually pass it out! (even though you are only 'alongside' it for a few seconds)
  • I don't really know how much they expect DS1 to retrieve getting in such proximity to the commet. I remember when 4 or so minutes into the start of the mission a single spec of space dust prevented the ion drive from working. Now they expect it to pass through a commets coma which is filled with all kinds of particles? I expect it will be yet another failure to rack up on the DS1 as soon as it gets within range of the commet. I wouldn't hold my breath, after all look at what happened when they tried to get the picture of asteroid Braille (just a bunch of black pics). I would also like to ask why the heck they couldn't have put more than one camera and in addition a light source to enhance the pictures?

  • 60 people and $12 million (Score:1, Informative)

    by Anonymous Coward
    Yep, it's about time you guys learned:

    High quality software ain't cheap. Sometimes, for some programming jobs, slapping togther a 100 line Perl script ain't good enough.

    If you were smart, you'd tell your boss too.

  • This mission is somewhat similar to that of the Giotto probe in 1986. Here is the link [esa.int] to the ESA site with more information about Giotto. But where Giotto was a dedicated mission, designed to take pictures and collect data of a comet core, the DS1 comet mission is "just" a great bonus mission.

  • go read the log entries. ( http://nmp.jpl.nasa.gov/ds1/archives.html )The software they wrote seems pretty sophisticated. It attempts to find the comet by analyzing the pictures the camera takes and steering accordingly. Probably not easy to do...
    • Sounds like a (difficult) version of "Robots" :-) Do you remember that game (Crobots and Jrobots are two variants)? You're supposed to write the software for a robot that runs around and A) scans for other robots, and when they find them B) shoot them, until your robot is the only one still standing.

      Yes, probably not easy at all to do. It's probably good that they have the help of CASPER [nasa.gov].

  • "There's a very real chance that none of this is going to work"

    Yeah...there's a chance that something nasa does (think polar lander) isn't gonna work...what is he, some kind of rocket scientist? =)
  • 'cause they forgot the bubble gum and baling wire to go along with the duct tape!

    "Deep Space 1 is flying on duct tape and good wishes," he [Marc Rayman] said.

  • This has been one of my favorite recent NASA projects. It tested all of the technologies that I read about in SciFi when I was a kid.

    The failures have been highly publicized, but most of them came well after the primary mission was completed. Overall, this little probe has been a great experiment.

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