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Space Science

More on the Pluto-Kuiper Express 89

Posted by michael from the stopping-at-chambers-and-14th-st dept.
addie writes "Scientific American has a great, extensive article about Pluto and the possibilities of exploring it in the near future. Neat descriptions of Kuiper Belt and what we can learn about solar system birth and growth from the tiny planet."
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More on the Pluto-Kuiper Express More

More on the Pluto-Kuiper Express

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  • Thank goodness (Score:1, Insightful)

    by RoguePsion ( 558561 )
    I don't know about the rest of you, but I personaly was really disapointed when I found out that Bush yanked the funding for this. It's good to see that it might still happen.
    • Why look for Pluto? Everyone [whitehouse.gov] knows he is safe at Disney protected with his friends Micky and Donald by the copyright extension act.
    • I certainly hope he gains interest in science. He wants the US to play World Cop. Well, if we are gonna be a world leader, why should our science lag? Technology was one field that helped us get where we're at today. Being at the forefront of the tech industry places us in a very good position. I think that this mission could easily be done, and for even less than a cool $500M.

      How, you say?

      NASA wants relatively few scientific measurements taken. There's a whole basket full of stuff they aren't doing. This project could easily be subsidized by foreign countries. Don't you think there are a few European countries that would pay $50 or even $100 million to get onboard with one or two of their own scientific devices onboard? That's a *really* good deal for them, considering where it's going and how cheap that is.

      I really hate to see productive science budgets dwindle.
      • That's a *really* good deal for them, considering where it's going and how cheap that is.
        the whole $500,000,000 shebang is somewhere in the region of about 15 cents a mile, about the same as I pay for petrol in the UK.

  • Don't go there (Score:1, Interesting)

    by _damnit_ ( 1143 )
    This sounds interesting, but I think there are closer subjects of interest that could be explored. Too many things could go wrong with a trip that long. I'd like to see more emphasis put on getting to Mars, developing a cheap replacement for the shuttle and whatever happened to that space elevator? I know, it was just a book. But it sounded so cool.

    • Re:Don't go there (Score:2, Insightful)

      by Tim Colgate ( 519024 )
      From the article:

      Now--or Never?

      ... the potential for discovery will be lost if the mission is not launched in 2006. Because of the changing alignment of the planets, after 2006 the spacecraft will no longer be able to accelerate toward Pluto by swinging past Jupiter. If this window is missed, NASA would have to wait until 2018...

      By that time ... much of the planet's southern hemisphere--will by then be covered in a dark polar shadow, thereby preventing it from being observed. Also, it is likely that virtually all the planet's atmosphere will have condensed by then, closing off any opportunity to study it until the 23rd century ...

      So, yes there are closer objects to study, but not ones where now is the last chance for two centuries.

    • and whatever happened to that space elevator?

      We're waiting for diamondoid remember?

      One day someone in a lab will figure out how to grow [slashdot.org] the stuff, and the very "next day" we'll be building more efficient rockets to launch/find-and-tow carbon to geosync orbit where it can be strewn in both directions (since you can't build it like a beanstalk)...
      --

    • Re:Don't go there (Score:3, Insightful)

      by stevelinton ( 4044 )
      Compare budgets. Manned Mars missions are currently being placed in the 20-50 billion $ range, relatively unambitious shuttle replacements at 10 bn, and space elevators are still at the "let's do some possibly related basic science and see if anything interesting drops out" stage. PKE is budgetted at US$500m. It's not making any real dent in the budgets for the kind of programs you like.

    • Why exploring Pluto is worth something (Score:4, Interesting)

      by jesterzog ( 189797 ) on Monday May 06, 2002 @07:10AM (#3468768) Journal

      There are several good reasons to study Pluto ASAP, not the least of which is the changing of the seasons. It's not really a Pluto mission as much as it's a Kuiper Belt mission. Among other things:

      • The Kuiper Belt is believed to be very representative of where comets come from, so studying Kuiper objects will give a much better insight into comets and what they are. This could also help with plans for any opssible doomsday-avoiding strategy. (I'll leave it up to you whether you consider that important or not.)
      • Pluto isn't just a Kuiper Belt object, it's also the one that we know most about having tracked and studied it from Earth since it was discovered in 1930. Any information returned can be correlated with existing information.
      • The plan isn't just to study Pluto. It also includes flying past several other Kuiper Belt objects.
      • JPL's had some high profile failures lately, and maybe that's why you think there's a lot that can go wrong. But New Horizons [jhuapl.edu] is a flyby mission, and by JPL standards it's easy, and it's been done heaps of times before 100% successfully. There's probably a much better chance today of this thing working than there is in the next Mars rovers [nasa.gov] working.

      And anyway, how much would scuttling this mission help to explore Mars, which compared to this tiny mission already has a massive armada of effort and funding going into it? Maybe we'd get there a couple of months faster.. except we wouldn't anyway because the optimal launch window would stay where it was.

  • Pluto has been fairly bitter about our attitude toward it in times past. The Brunching Shuttlecocks [brunching.com] have interviewed Pluto on two previous occasions [ first interview [brunching.com], second interview [brunching.com] ], on the second of which it complained about the lack of attention we've been giving it, and also claimed to support life. I wonder whether these latest developments will change its tune at all.

  • Too late (Score:4, Interesting)

    by Faux_Pseudo ( 141152 ) <Faux.Pseudo@gmail.cFREEBSDom minus bsd> on Monday May 06, 2002 @05:39AM (#3468679)
    It's all find and nice of them to have ideas about exploring Pluto now but its too late for the fun stuff. If they had launched a craft 5 years ago we would have gotten there in time to witness the changing of the seasons.
    Now its going to be another 250 years before we get to see both the summer and winter time on the planet. And what a seasonal change it is. In the summer it has a liquid nitrogen atmosphere and in the winter it freezes and falls to the ground.
    If only they had gotten off their but sooner.
    • On the same note I saw a [fired] NASA scientist guy on TV once speaking about their Mars program.

      He lost his job because of budget cuts, but claimed that those same cuts are what kept us off of Mars.

      He says the technology was always there, but needed to be tweaked and said we could have had a man there in 1985.

      I guess eating is almost as cool, but damn I would have liked to see men (no women allowed, Venus trip only) on Mars by now.

      Men are from Mars, Women are Scientologists
      • Right, and right. It's sad that space exploration has become such an unpopular topic (at least in the US). For being the "Last Frontier", it sure isn't getting the attention it deserves. The recent push in space tourism could be exactly what everyone needs right now, creating a media stunt just strong enough to get the ball rolling. If only people were exposed to this more often we might not be bitching today about NASA budget cuts and cancelled missions.

        If only... *mumbles"

    • Now its going to be another 250 years before we get to see...

      In another 250 years we'll have probably already disassembled Pluto for its matter along with the rest of the non-gasgiant planets. And I'm sure by that point we'd be able to simulate those "fascinating seasonal changes" in minute detail... :)

      --

      • Hmmmm....

        If we're mining for resources, and we change primary fuel sources to Hydrogen, I have a feeling we'll be doing much of our 'mining' on gas giants. Nothing beats floating balls of liquid and gaseous H2.

      • ...we'll have probably already disassembled Pluto for its matter...

        Nah. Environmental activists will the process tied up in courts for at least three centuries.

    • In the summer it has a liquid nitrogen atmosphere...
      I think the technical term for a liquid atmosphere is "ocean".
    • The atmosphere won't have snowed out by 2014. Remember, Pluto orbits very slowly.

      In actuality, it is looking rather UNLIKELY that the atmosphere will snow out at all. Larry Esposito, who was competing with Alan Stern for this mission, found out in his research that the models that predicted this appear out of date and that newer models do not indicate that the atmosphere will solidify. Unfortunately, it's a cool idea and people have a hard time letting go of it.

  • tech details from the article... (Score:5, Interesting)

    by bedessen ( 411686 ) on Monday May 06, 2002 @06:19AM (#3468711) Journal
    Like most of these it was light on hardware details, but this was hidden in one of the captions:


    The spacecraft has a design mass of 416 kilograms (917 pounds) and is about the size of a small lifeboat.

    On the journey to Pluto, the probe will reach a top speed of about 70,000 kilometers per hour.

    The craft's computers will be able to store 48 gigabits of data and transmit the information to Earth at up to 770 bits per second from Pluto (16,000 bits per second from Jupiter).


    48 gigabits of radiation-hardened memory must cost a fortune...I seem to remember that Flash ram is not suited to this kind of thing since its especially susceptible to energetic particles (alpha, gamma rays) dislogding the charge trapped in the gate dielectric (which holds the information.) Anyone know how data storage is usually carried out on these things? I can't imagine using anything with moving parts, and since the craft is supposed to be powered down for most of the time while it drifts, I'd think you'd want something non-volatile. I would hate to think what would happen if there was a brief power shortage or something and all the readings from the entire mission that were queued up to be sent were lost.

    As to the 770 bits/s, I'm amazed it's even that fast. Consider that the RF power decreases as 1/r^2, where r is about 7.5 billion km. They are using a directional 2.5m antenna, lets say that's 100 dBi gain. Still, even if they managed to transmit 10W at the satellite (which is a lot for radio), we'd receive about a picowatt (1e-12) of it here on earth. I've heard that number thrown around before as a typical power level that we receive from deep space, and it boggles the mind that we can detech such faint signals... guess that's why it takes arrays of gigantic dishes with supercooled LNAs to do it. And it's great example of how power and bandwidth are related in communications. The more power your signal has at the receiver, the more information you can convey (bandwidth.)
    • 770b/s?

      That's faster than my last dialup connection!
    • An all spacecraft that were operated in the harsh environment of jupiters radiation belt and/or beyond jupiter they have used tape recorders.

      • Re:tech details from the article... (Score:4, Informative)

        by PD ( 9577 ) <slashdotlinux@pdrap.org> on Monday May 06, 2002 @08:16AM (#3468843) Homepage Journal
        That's true, but solid state tape recorders are starting to be used in missions closer to home.

        Hubble Tape deck replaced with solid state recorder in 1997, stores 12 gigabits. Old tape deck stored 1.2 gigabits:
        http://www.shuttlepresskit.com/STS-103/ payload52.h tm

        The ESA is also tinkering with them:
        http://esapub.esrin.esa.it/pff/pffv5n2/maeu sli.htm

        NEAR - Near Earth Asteroid Rendesvous - carried a 1.7 gigabit solid state recorder
        http://near.jhuapl.edu/spacecraft/

        On the other hand, Galileo used a regular tape deck, and had some mechanical problems with it.
        http://www.jpl.nasa.gov/galileo/mess38/TAPE.h tm

        So, it's true that all missions past Mars have used a tape deck, it's also true that mechanical systems can break down pretty easily. I predict that the success of solid state recorders on several missions is going to lead to these devices being universally used everywhere in the solar system.
        • Geez, I totally forgot to check out what Cassini uses. Sure enough, Cassini is carrying a solid state recorder all the way to Saturn! It's a 2 gigabit recorder, and it has enough spare memory cells and redundancy to guarantee 1.8 megabits after long exposure to radiation in space.

          http://www.jpl.nasa.gov/cassini/english/spacecra ft / ommand.html

    • Hmm... 48 gigabits and 770 bits/s? That'd mean two years to send the whole lot... or is most of that likely to be used for processing?

      Hmm, I suppose if you compress the signals, you could get the whole lot in a matter of months...

    • Re:tech details from the article... (Score:5, Interesting)

      by stevelinton ( 4044 ) <sal@dcs.st-and.ac.uk> on Monday May 06, 2002 @08:31AM (#3468880) Homepage
      Actually the received power levels are much LOWER than that.

      10W at the antenna, say it's at 1cm wavelength (not sure about this, but it should be within a factor of 10). Thats a 250 wavelenth tranmitting dish, so the signal is spread over a 4 milli-radian diameter cone. At 7.5e12 m that is
      9e20 m2 spot, so a 250m dish on Earth receives
      125^2*pi / 9 e20 of the signal, which is about
      5 e-16 W.about half a femtoWatt, ignoring any imperfections in either dish, noise, absorbtion, etc.

      By radio astronomy standards this is actually quite a powerful signal. I think they work down to 10^2? W for fairly small values of ?. On the other hand, they need a 770Hx bandwidth here, which is relatively wide.

      Someone else commented on the time it would take to dump 48Gb of data over this link. This fits the mision profile beautifully. They fly past Pluto/Charon in a few hours, recording frantically on all instruments, then the slowly download the results, which coasting out into interstellar space. This mission is a fly-past, not an orbiter.

      • Re:tech details from the article... (Score:1, Interesting)

        by Anonymous Coward
        Note: I'm a radioastronomer involved in instrumentation.

        Half a femtowatt is still quite a lot of power in a 1kHz bandwidth (you want to have some redundancy in the 770 bits, so let us round it up to 1kHz).

        Let us start from the noise power of a resistor at room temperature in 1kHz bandwidth, it is about -144dBm or 4e-17 W, or 40 attowatts. Now building narrowband amplifiers whose effective noise temperature is much lower than 300K is a no brainer (for people who know how to build amplifiers around discrete pseudomorphic high electron mobility transistors). I've not checked recently what the room temperature performance of the most recent transistors is but I'd believe that a noise figure of 0.5 dB (equivalent to the noise of a resistor at 40 Kelvin) is routinely guaranteed at 12 GHz on commercial transistors, like Fujitsu's FHX13. As I said better models might be available now. In a 1KHz bandwidth the equivalent input noise power of an amplfier like his ould be around 5 attowatts.

        Now if you push me, I'd tell you that by carefully selecting the transistors and operating them at cryogenic temperature, the amplifier noise will be even lower, perhaps by a factor 5 or so (over 3 guaranteed).

        At this point the most difficult problem even with a high quality antenna is probably to get rid of human interference and noise is probably dominated by the scattering of the antenna beam. Note that I do millimeter radioastronomy so I don't know well the detailed technical problems of centimeter guys, but while we don't (yet) have problems of interference with other human activities, it is a severe problem at longer wavelengths.

        In any case, you have a reasonable signal to noise ratio, even if the antennas are smaller than what you think (DSN antennas are 60 or 64 meters, I can't remember the exact value).

        Ok, that's all, but remember that we radioastronomers use the Jansky as flux measurement unit. A Jansky is 1E-26 W/Hz/m, so it would be about 0.01 attowatt on a DSN antenna in 1 KHz BW. And 1 Jy is a strong source, even in the millimeter range, we are rather chasing the milliJansky (on wide bandwidth however).

        • (I don't mind copying this, because I feel it needs to be moderated up (from 0) and, given that an AC posted it, I'm don't risk stealing karma from anybody)
          Anonymous Coward wrote:

          Note: I'm a radioastronomer involved in instrumentation.

          Half a femtowatt is still quite a lot of power in a 1kHz bandwidth (you want to have some redundancy in the 770 bits, so let us round it up to 1kHz).

          Let us start from the noise power of a resistor at room temperature in 1kHz bandwidth, it is about -144dBm or 4e-17 W, or 40 attowatts. Now building narrowband amplifiers whose effective noise temperature is much lower than 300K is a no brainer (for people who know how to build amplifiers around discrete pseudomorphic high electron mobility transistors). I've not checked recently what the room temperature performance of the most recent transistors is but I'd believe that a noise figure of 0.5 dB (equivalent to the noise of a resistor at 40 Kelvin) is routinely guaranteed at 12 GHz on commercial transistors, like Fujitsu's FHX13. As I said better models might be available now. In a 1KHz bandwidth the equivalent input noise power of an amplfier like his ould be around 5 attowatts.

          Now if you push me, I'd tell you that by carefully selecting the transistors and operating them at cryogenic temperature, the amplifier noise will be even lower, perhaps by a factor 5 or so (over 3 guaranteed).

          At this point the most difficult problem even with a high quality antenna is probably to get rid of human interference and noise is probably dominated by the scattering of the antenna beam. Note that I do millimeter radioastronomy so I don't know well the detailed technical problems of centimeter guys, but while we don't (yet) have problems of interference with other human activities, it is a severe problem at longer wavelengths.

          In any case, you have a reasonable signal to noise ratio, even if the antennas are smaller than what you think (DSN antennas are 60 or 64 meters, I can't remember the exact value).

          Ok, that's all, but remember that we radioastronomers use the Jansky as flux measurement unit. A Jansky is 1E-26 W/Hz/m, so it would be about 0.01 attowatt on a DSN antenna in 1 KHz BW. And 1 Jy is a strong source, even in the millimeter range, we are rather chasing the milliJansky (on wide bandwidth however).

  • they told him they were going to see Pluto the disney character. His eyes lit up and he jumped up and down saying "oh boy oh boy".
    • They should get Disney to fund Pluto exploration.

      Of course with our luck, it'll turn into a DMCA case and Disney will have Pluto nuked for copyright infringement.
    • they told him they were going to see Pluto the disney character. His eyes lit up and he jumped up and down saying "oh boy oh boy"

      However, when he found out in February that what they were talking about was actually a cold rock in space, he "removed the $122 million needed for the mission from NASA's budget for the 2003 fiscal year". Sigh.

  • Western scientific ideals vs terrorism (Score:4, Interesting)

    by Anonymous Bullard ( 62082 ) on Monday May 06, 2002 @08:03AM (#3468827) Homepage
    And given the romance and adventure of exploring uncharted worlds, it is not surprising that so many citizens and grade school children have also become excited about this mission to new frontiers.

    To me this quote represents some of the best ideals of the so-called western civilization. There's a deep-rooted sense of purpose in pushing the barriers of scientific knowledge and understanding. Despite the fact that military is also interested in any advances stemming from such exploration the ultimate aim is to have this knowledge advance the whole of humanity.

    So how does terrorism - as demonstrated by the relatively recent islamic jihad against the western world - fit into this picture? Well, for a long time while "The Old World" was suffering under the Dark Ages (imposed by religion, the Church) the islamic empire had a thriving scientific culture. That fine and rather benevolent islamic culture was eventually suffocated by increasing religious dogmatism so it is highly ironic that those same forces are now attempting to destroy the West where the evolution of the State and Religion followed the opposite route.

    I don't think I'm much off the mark by saying that the driving force, or motive, behind the actions of the "ultra-islamic" terrorists is simple envy and the desire to pull the West down to the same level of stagnation and religious revival that they themselves are under. If the western governments, and especially the US, decrease their scientific commitments in favour of military spending the religious terrorists have gained a victory of sorts.

    PS. Would it not be ironic if scientific missions such as this one to study the Kuiper Belt would help us (the humanity) to better understand dangerous asteroids and help us learn how to repel them. Suppose just one, say 10 miles across, was on a collision course with Earth and was calculated to strike the Middle East in the 2030's. Would the Mid-East populations still support the destruction of the West? Of course, if the object was calculated to hit North America or even Europe there would probably be much rejoicing in God punishing the infidels...
    • Well, you can't calculate what side of the Earth an object is going to hit if it's going to happen in the 2030s, since objects that small can have their orbits continually perturbed by other objects.
      But even if you could, an asteroid 10 miles in diameter would destroy all very nearly all life on the surface of the planet, regardless of which continent it struck.

  • The Galactic Construction Co. (Score:4, Interesting)

    by Alien54 ( 180860 ) on Monday May 06, 2002 @08:17AM (#3468844) Journal
    I remember a short SF story where some people are exploring Pluto, and they come across what is essentially a construction shack left over from the construction of the Solar System, complete with leftover diagrams.

    They don't get it at first, but they figure it out because in some part, the maps they find obviously display the solar system, but some things are very different, and they come to the conclusion that the original contractor screwed up the original job.

    Who knows what we'll find.

    • And here is the story info:

      'Construction Shack'
      by Clifford Simak (Short story, 1973)

      A manned expedition discovers that Pluto is an artificial world, built by alien engineers billions of years ago. But if the 'construction shack' was the size of a world, how big was the entire project?

      And I came across this bit which is also interesting, although slightly off topic.

      One Thousand years in Space Travel [totse.com]

      some of the author's notes are interesting:

      FUNDAMENTAL ASSUMPTIONS:

      (A) The human race is not wiped out or set back to the stone age by nuclear war, giant meteor strike, global warming or new ice age (Footnote 3) in the course of the next two hundred years or so. After that, these events could no longer stop us. If we are then spared a nearby (10 LY) supernova for another 300 or 400 years, we (Footnote 4) should be virtually immortal.

      (B) There are no unexpected scientific discoveries that change the rules. Faster that light travel is the classic example. If any such assumptions were included, this whole work would then be nothing but science fiction (Footnote 5).

      {...}

      ABOUT THE INDICATORS:

      It may not be apparent, but when you study the timetable below, especially for later periods, the figures for economy, energy generation and non-Earth population are all based on remarkably modest growth rates. In each case they are similar to that experienced over the last 300 years here on Earth.(Footnote 10)

      All in all a longer read, but interesting in it's own right

  • Christine Lavin [christinelavin.com] wrote the definitive song on the subject. [christinelavin.com] Whenever I hear about the possibility of exploration to Pluto, I hear Christine singing its praises, and intoning the URL "http colon slash slash dosxx dot colorado dot edu slash plutohome dot html".

  • Does Uranus have two small moons around it?
  • If you want to help save the Pluto and Europa missions, sign the petition the Planetary Society is currently heading.

    Here's the URL: https://planetary.org/petition2/index.php

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