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Space

NASA Set To Launch Probe To Mercury 216

Posted by CmdrTaco from the careful-he's-a-quick-one dept.
antispam_ben writes "CNN is reporting the upcoming Messenger mission to Mercury is set to launch August 2. The spacecraft uses a combination of technologies (insulation, Peltier devices, careful design and orbit, always keeping the shield side toward the Sun) to keep its electronics at room temperature."
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NASA Set To Launch Probe To Mercury More

NASA Set To Launch Probe To Mercury

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  • Cool... (Score:5, Funny)

    by JosKarith ( 757063 ) on Tuesday July 27, 2004 @10:16AM (#9810975)
    ...well, compared to the melting point of Tin anyway...

    • Re:Cool... (Score:5, Funny)

      by haystor ( 102186 ) on Tuesday July 27, 2004 @10:23AM (#9811073)
      Because it's so hot near the sun, NASA plans to go to Mercury at night.
      • You say it as funny, but I bet that the flight plans include hiding the other side of planets/moons for as long as possible to take advantage of all that lovely shade.
        Hell - if fuel wasn't a consideration I bet they'd love to run straight up Mercury's shadow and just park in it.
        • Quoth the poster: [slashdot.org]

          I bet that the flight plans include hiding the other side of planets/moons for as long as possible to take advantage of all that lovely shade.

          Space is mighty big. Shadows are few and far between. When you have a spacecraft that has to take 11 suns beating on its face for months at a time during cruise, why would a mission designer compromise his science by trying to pass behind bodies just for the shade? (For gravity-assist maneuvers, yes. Shade, no.)

          ... if fuel wasn't a consideration

  • Messenger huh? (Score:4, Funny)

    by Deflagro ( 187160 ) on Tuesday July 27, 2004 @10:17AM (#9810998)
    Better hope Microsoft isn't watching, they may sue for copyright violation.

    Nasa: But it isn't MS Messenger!!
    Gates: I don't care, gimme mo' money beeyatch!@#

  • hmm (Score:5, Funny)

    by Docrates ( 148350 ) on Tuesday July 27, 2004 @10:17AM (#9810999) Homepage
    Nasa's Messenger? I wonder if Trillian will cover it...

  • room temp? (Score:3, Interesting)

    by Anonymous Coward on Tuesday July 27, 2004 @10:18AM (#9811000)
    Is room temperature an actual degree? I always thought it was just the temp of the envirnment that the time. If that's the case, room temp for the spacecraft is pretty hot no?
  • as long as its room temperature in there, why not toss a few people/monkeys/whatever in with it?

    • Re:hey (Score:2)

      by Rei ( 128717 )
      Sure, if you can get them into suspended animation, want to double the weight of the craft, want to have them die of exposure to solar radiation and GCR while in suspended animation, and never want their bodies back again.

    • Re:hey (Score:2, Informative)

      by Bill Hayden ( 649193 )

      as long as its room temperature in there, why not toss a few people/monkeys/whatever in with it?

      That would be because it's going to take several years to arrive.

    • Room temperature and room pressure are two different things.
  • Whoa, Peltzer devices? Awesome. I'm not sure how it's going to help us in space, but who am I to say that putting a smokeless ashtray, a juicer and a weird swiss army thing with a toothbrush that shoots out toothpaste onto a space probe is wrong?

    • Re:peltzer device?! (Score:4, Informative)

      by carnivore302 ( 708545 ) on Tuesday July 27, 2004 @10:56AM (#9811492) Journal
      Actually, it's a Peltier device. Peltier devices, also known as thermoelectric (TE) modules, are small solid-state devices that function as heat pumps. A "typical" unit is a few millimeters thick by a few millimeters to a few centimeters square. It is a sandwich formed by two ceramic plates with an array of small Bismuth Telluride cubes ("couples") in between. When a DC current is applied heat is moved from one side of the device to the other - where it must be removed with a heatsink. The "cold" side is commonly used to cool an electronic device such as a microprocessor or a photodetector. If the current is reversed the device makes an excellent heater.


      Click on the Mystery Futures Link [tradesims.com]!
      • Yea thanks for the explanation.. but you missed the point... it was a reference to the movie Gremlins...

        oh nevermind.. :-p only one person got it.. thanks, person who got it, for replying... hah..
  • Does "always keeping the shield side toward the Sun" count as technology?

    Sorry if I'm skeptical about this stuff... not in the moon hoax sense, but in the building a base on the moon and sending people to Mars sense.

  • Careful design (Score:4, Insightful)

    by Malc ( 1751 ) on Tuesday July 27, 2004 @10:21AM (#9811042)
    Is this a novelty or something? Why does it even need to be mentioned?
    • Well they were just normal-careful before with the Mars probes. But after losing about 60% of them they decided to be double-secret careful with the Mercury probe.

      -

  • Actually NASA is borrowing cooling technology... (Score:5, Funny)

    by Anonymous Coward on Tuesday July 27, 2004 @10:21AM (#9811043)
    ...developed by nVidia for the NV30 launch, but scaled back because they only need to protect Messenger from a class G star as opposed to a modern graphics card.

  • Go Messenger! (Score:5, Informative)

    by hpulley ( 587866 ) <hpulley4&yahoo,com> on Tuesday July 27, 2004 @10:21AM (#9811056) Homepage

    While most other planets have been well studied, Mercury has not even had half its surface mapped [nasa.gov]! Messenger has non-visual light detectors including a laser altimiter [jhuapl.edu] which will let it map the whole planet, counteracting its slow rate of rotation [uiowa.edu]. I hope the launch goes well and look forward to the data return. Kudos to NASA for doing some good science on what is considered a less sexy target than some others which seem to hog all the research money.

  • Yeah, but what about the other side? (Score:4, Funny)

    by FortKnox ( 169099 ) on Tuesday July 27, 2004 @10:21AM (#9811057) Homepage Journal
    ...to keep its electronics at room temperature.

    But what about the other side? Lets ask Roosevelt E Roosevelt:

    Well, thank you, Roosevelt. What's the weather like out there?
    "It's hot. Damn hot! Real hot! Hottest things is my shorts. I could cook things in it. A little crotch pot cooking."
    Well, can you tell me what it feels like?
    "Fool, it's hot! I told you again! Were you born on the sun? It's damn hot! I saw... It's so damn hot, I saw little guys, their orange robes burst into flames. It's that hot! Do you know what I'm talking about?"
    What do you think it's going to be like tonight?
    "It's gonna be hot and wet! That's nice if you're with a lady, but it ain't no good if you're in the jungle."

    Ahh, what a great movie.

  • Another mission to Mercury to be in 2012 (Score:5, Informative)

    by zzabur ( 611866 ) on Tuesday July 27, 2004 @10:23AM (#9811071)
    For more information, see ESA BepiColombo [esa.int] page.

  • Reply from Messenger (Score:3, Funny)

    by Anonymous Coward on Tuesday July 27, 2004 @10:25AM (#9811102)
    M'Ger: It's getting hot in here, so take off all your clothes.

    P.S. Please send more info on carbon-based units infesting Earth.

  • Proof of a Male-dominated design? (Score:5, Funny)

    by grunt107 ( 739510 ) on Tuesday July 27, 2004 @10:25AM (#9811108)
    "...the spacecraft must swing once past Earth, twice past Venus and thrice past Mercury before slowing down enough to slip into orbit around Mercury"

    Her>That's the 2nd time I've seen Mercury! Stop and ask!
    Him>I will not ask for directions! I know where we are now
    Her>I have to pee! And you promised we'd get some Venutian shopping done!

    *NOTE* - It is rather interesting that the craft must maneuver like this to get a stable orbit and not get crushed.

  • Very interesting. (Score:5, Interesting)

    by robslimo ( 587196 ) on Tuesday July 27, 2004 @10:26AM (#9811117) Homepage Journal
    I know thermal issues have always been central to spacecraft design, but this sounds like a nicely engineered approach to temperature control.

    I'm reminded of the faulty heater on one of the Mars Rovers. Could such problems be avoided or at least mitigated by use of more passive thermal management (insulation, heat pipes, heat sinking/sourcing)?

    I'm also reminded of the Russian probes to Venus which had uderstandably short lives due to both heat and pressure (possibly corrosive gases as well).

    I'm firmly in the camp that promotes more unmanned probes, maximizing the power of money spent on advancing spacecraft technology and knowledge from expanded exploration rather than blowing it all on the dubious value of letting a person stand on Mars.

    • Re:Very interesting. (Score:4, Informative)

      by confused one ( 671304 ) on Tuesday July 27, 2004 @10:53AM (#9811446)
      The Mars rover heater is a faulty switch, causing the heater to be always on. It's so damn cold on Mars you need heaters on all the joints to keep the lubrication from freezing solid. passive thermal management wouldn't work because it assumes you've got a heat source to draw from. The most passive approach you could apply to the Mars rover would be (would have been) to use radio-thermal heaters at each of the joints.

      Wouldn't work well on Venus either. You need a sink into which to pump the heat. Given the 800F surface temperature, you'd have to do an awful lot of work to pump to an acceptable temperature in the electronics bays. I'm not saying it's impossible, just hard.

      the Mercury mission will work because they're putting a big insulative blanket between the electronics and the sun, to provide shade; and, they're pumping the heat from the electronics bays to the cold side (facing away from the Sun) of the craft where it's -200F

    • I'm also reminded of the Russian probes to Venus which had uderstandably short lives due to both heat and pressure (possibly corrosive gases as well).

      Wasnt the main longevity problem due to the batteries and no way to recharge them on the planet?
      • No. It was the atmospheric pressure that crushed these probes like beer cans. The sulphuric acid clouds didn't help either. The electronics was supposedly fairly standard (Soviet) stuff.
      • (Note, previous response is wrong.)

        The Venera landers were able to make it down to the surface, and IIRC one or two of them actually sent back pictures for a while. Their lifespans were very strictly limited by their insulation; as heat soaked in there was no way to pump it out again, and it did not take long before the electronics were too hot to function.

        • Of those that actually reached the surface, almost all worked until their batteries ran out or the Spacecraft bus which was used as a relay left radio range, whichever happened first. If I'm not mistaken, the early ones were cracked by pressure and not cooked - the immense pressure on the surface wasn't known until Venera 7. There's a very interesting website on the russian missions to Venus. And at least Venera 9, 10 13 and 14 returned pictures from the surface, that's 4.
    • Besides being very hot on venus, it literally rains sulfuric acid.

    • Most spacecraft thermal designs are to some extent passive, including MESSENGER. They are using some heat pipes - where it makes sense to use them to minimize heater power. Some of the heaters use software control, but most use series-redundant thermostats - they won't come on inadvertantly unless 2 thermostats fail - a very unlikely occurrence for space-qualified thermostats. If a heater fails, it has a backup.

  • Explanation (Score:4, Interesting)

    by Timesprout ( 579035 ) on Tuesday July 27, 2004 @10:29AM (#9811150)
    Even though Mercury is 50 million miles from Earth at closest approach, Messenger will travel 5 billion miles to get there. It's technologically infeasible to fly straight to Mercury, a trip of a few months, and so the spacecraft must swing once past Earth, twice past Venus and thrice past Mercury before slowing down enough to slip into orbit around Mercury.

    Can someone explain why such a convoluted and time consuming route is required?

    • Re:Explanation (Score:5, Informative)

      by HarveyBirdman ( 627248 ) on Tuesday July 27, 2004 @10:37AM (#9811252) Journal
      You can launch a giant ship with a giant fuel tank that cost 800 billion dollars, or you can launch a small, reasonably priced craft and use the gravitation of the planets to do your work for you.

      NASA can explain it better: http://messenger.jhuapl.edu/the_mission/mission_de sign.html [jhuapl.edu]

      • It's a shame that the idea of having a set of magnetic accelerator rings in orbit to provide the initial shove is still in the realms of sci-fi.

        • Re:Explanation (Score:4, Informative)

          by HarveyBirdman ( 627248 ) on Tuesday July 27, 2004 @10:51AM (#9811411) Journal
          It's not the shove. It's the slowing down part. The gravity assists decelerate the probe until the onboard propellant has a hope of establishing a stable orbit around Mercury. It's a way of tapping the vast potential energy represented by a planetary sized mass.

          Remember, the probe is moving further into the Solar System, so it needs to *decelerate* from Earth-normal angular momentum.

      • Does this work if I run around fat people?

    • Re:Explanation (Score:5, Funny)

      by edremy ( 36408 ) on Tuesday July 27, 2004 @10:50AM (#9811388) Journal
      You can't carry enough fuel on the probe to match the orbital velocity and still launch on a small rocket. Mercury's orbital speed is about 47.9 km/sec, Earth's is 29.8 km/sec- you've got to get about 20km/sec (~40,000 mph) from somewhere, and chemical rockets aren't feasible.

      However, you can steal energy from planets using gravity assists. [howstuffworks.com] JPL is amazingly good at doing these.

      <tinfoilhat> We do need to worry that JPL is slowly robbing orbital energy from the planets they use. I've been worried about our profligate use of this irreplaceable resource for a long time. Worse, JPL seems to be totally blase about using Earth as one of their prime engines- enough gravity assists and the earth will fall into the sun!

      Join the League to Conserve the Angular Momemtum of Planets today!

      • Earth's is 29.8 km/sec

        You mean that we're flying through this "space" stuff at Mach 87.5? That's crazy-talk, man! If you're so smart, where's the sonic boom? And what about the poor turtles?

        You kids and your "physics". Bah. When I was your age, we'd glide through the ether, and we liked it that way!

      • Mercury's orbital speed is about 47.9 km/sec, Earth's is 29.8 km/sec- you've got to get about 20km/sec (~40,000 mph) from somewhere, and chemical rockets aren't feasible.

        Oops--you have to watch for gravitational potential energy. Since you're dropping much closer to the sun, you convert a whole bunch of potential energy into kinetic energy. Back of the envelope says about 1.3 GJ per kilogram, but I could have goofed.

        If I didn't mess up the numbers, then a probe that departs earth travelling 30 km/s p

    • Re:Explanation (Score:5, Informative)

      by merlin_jim ( 302773 ) <{James.McCracken} {at} {stratapult.com}> on Tuesday July 27, 2004 @10:57AM (#9811513)
      Can someone explain why such a convoluted and time consuming route is required?

      It's all about delta-v... how much can you change your velocity?

      Earth orbits the sun at a specific velocity.

      Mercury orbits the sun at a much smaller velocity.

      But in order to fly straight there, you have to counteract all of the orbital velocity you have at earth, then either free fall or thrust to the new location, and then build up the orbital velocity of Mercury to make orbit. That's a lot of delta v, and a lot of working fluid to put into your thrusters. In fact, even if we felt like paying that fuel bill, we don't really have the technology to build a probe large enough to carry all that fuel, or to get that fuel out of Earth's gravity well in the first place.

      So instead what we do is figure out a low-delta v way to launch it, bringing it into the inner solar system and slowing it down on the way. The key to this is slingshot maneuvers - using the gravity wells peppered throughout the solar system to change the direction of velocity without having to spend delta-v on it.

      That and the craft makes use of a little-known feature of relativity; the more energy in your fuel, the heavier it is; if you burn the fuel you have deep in a gravity well, it is quite a bit more effective than it would be in space. This is related to the law that predicts you cannot travel at the speed of light; as you go faster, your intertial mass rises, in such a way that it would take an infinite amount of thrust to reach the speed of light.

      Sure your craft has more inertial mass, too, but you'll be slowing down as you exit the gravity well, leaving your fuel behind you, and that's where the mathematical magic happens.
    • "Repeat after me, we are all individuals."

      Individuals, some of which do not read much in the way of science.

  • They totally modded out that bird... (Score:3, Funny)

    by JBMcB ( 73720 ) on Tuesday July 27, 2004 @10:30AM (#9811163)
    Entec case fans, Swiftech water cooling with dual radiators, Thermaltake fanless PSU, PC Power bay coolers, the works! Lian-Li designed the case to the BTX standard, and the radiation-hardened 486 is overclocked to 100MHz! All they need now is the NASA case badge...

  • Proudly sponsored by MSN!
  • All that technology - what a waste. The cost too!

    If they had sent it at night...

  • I like their cooling solution much better; high temperature superconductors and peltiers to move the heat to a central location, where the kinetic energy is used to power a communications laser.

    Too bad our current superconducting technology is scaling more slowly the higher temperature it gets. What we're currently calling "high temperature" means room temp. We'll make it there eventually. But without a whole new technology (nanotech anyone?) we'll never make superconductors that remain super conducting at temperatures much higher than that.

    But what about a laser powered by heat? Can it happen without having to reach the ionization temperature of the lasing medium? Anyone have any insight?
    • But what about a laser powered by heat? Can it happen without having to reach the ionization temperature of the lasing medium? Anyone have any insight?

      Now I am not a laser scientist (IANALS) but I am an electrical engineer. Almost all lasers are powered by heat, in a roundabout way. Power generators usually use a heat differential to produce a circular motion which is turned into electricity. Electricity goes to your laser and makes it go. So yes, a laser can be powered by heat. I don't think it can
      • They could use a Sterling, but I guess moving parts in space are not such a good idea...
      • There are two ways that an object can stay cool - either by bleeding heat into surrounding medium (none or very very little in space) or radiate it away

        That's what the heat powered laser is for. If you have some high efficiency way to turn that heat energy into light, you can then transmit it away at high speed.

        I briefly considered the steam plant idea (actually I was thinking about the solid state version of same)... but there are too many inefficiencies in that process, you would be putting out only a
        • If you have some high efficiency way to turn that heat energy into light, you can then transmit it away at high speed.Which is exactly what I was suggesting with the high tech answer of "paint one side black and the other white"

          When you do that the white side absorbs only a little of incoming heat, and then it is transferred by contact to the black side, which transmits the heat away pretty well. Yes, you don't have any "lasers" and you can't send any information or zap aliens this way, but all it requir
          • When you do that the white side absorbs only a little of incoming heat, and then it is transferred by contact to the black side, which transmits the heat away pretty well.

            Hmmm... maybe phase-change solid-state heatpipes would help this even more; integrate them directly with the material of the ship...

            As a matter of fact that may be a good technique for any space ship, to guarantee that no part of the ship gets too hot or too cold.
            • I am not sure heatpipes would work because they use different densities of the heat transfer medium (like water or air) to cycle it. While the mediums will still have different densities, they won't move at all because there would be no gravity. I guess you could spin the spacecraft, and that would produce a similar effect. However I think that the movement of the medium would eventually screw up the spin of the spacecraft until it became an uncontrolled tumble - bad. You could counteract this with gyro

  • NASA Website for Messenger (Score:4, Informative)

    by tpdei ( 103125 ) on Tuesday July 27, 2004 @11:06AM (#9811657)
    For those that care, here's the link for the NASA site on Messenger. http://www.nasa.gov/mission_pages/messenger/main/i ndex.html [nasa.gov]
  • I know the future of exploration is in the private sector, but must NASA pander so obviously to its industrial sponsors? At least the craft's design is pretty cool... http://new-cars.com/concept/2003/mercury-messenger -concept-photos.html [new-cars.com]

  • The really amazing thing... (Score:4, Interesting)

    by Anonymous Coward on Tuesday July 27, 2004 @11:28AM (#9811983)
    ...isn't the 5 gigamile trip. It's the launch window. They have a 12 second launch window to either launch it or wait for the next 12 second window-- the next day, at the earliest. Because of the multiple fly-bys, the math gets a little complicated, and error tends to cascade towards failure.

    Talk about performance anxiety!

    Wife: OK Honey, I'm ready. You've got 12 seconds.

    Enough for a high school boy, I imagine, but not us mighty slash dotters, right? ;-)
  • ...so this mission doesn't have to worry about providing power like the missions to the outer planets. There should be more solar power than they could possibly want. That's probably why the solar panels are 1/3 solar cells and 2/3 mirrors.

    Of course, they have other problems that don't occur on outer planet missions like making sure your space craft doesn't melt.

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