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Space United States Science

NASA to Map Solar System Boundary 68

Posted by michael from the mapquest dept.
StyroCupMan writes "NASA has announced that it will launch a satellite to map our solar system's boundary. It will also study the particles and radiation that pose a health and safety hazard to humans. Time to invest in that shiny new spacesuit."
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NASA to Map Solar System Boundary More

NASA to Map Solar System Boundary

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  • What about the galactic boundary? (Score:3, Interesting)

    by daeley ( 126313 ) * on Thursday January 27, 2005 @01:02PM (#11493537) Homepage
    Reminds me of that Star Trek TOS episode -- the first after the pilot if I recall correctly -- where they "break through" the "galactic boundary," thus triggering god-like powers (and accompanying morality tale) in a couple of crew members.

    You also get to see the phaser rifle for one of the few times ever in that episode. :)

  • The birth of interstellar exploration (Score:3, Interesting)

    by It doesn't come easy ( 695416 ) * on Thursday January 27, 2005 @01:03PM (#11493545) Journal
    Pretty cool. We are about to transition into the age of interstellar exploration, at least technically speaking, once the Voyager 1 probe "officially" cross into interstellar space. The actual boundary shifts in relation to the activity of the sun and so this new satellite should help determine (among other things) when Voyager has crossed over.

    Interesting note: The Pioneer/Voyager probes illustrate the space exploration concept that the later you leave, the sooner you get there...

    • I remember a short story (no idea where or who; probably an old Analog or Asimov's Sci-Fi Magazine) in which a "life-boat" had left Earth, and about halfway to Alpha Centauri they were awoken by a klaxon and saw a flash.

      Then they went back to sleep.

      When they finally got there (only 4 light years away), they came upon a civilization of humans thousands of years advanced beyond ours, and the worst part was that the travelers stank like pigs (apparently the olfactory sense and sweat glands had evolved in t

  • Historically speaking... (Score:4, Insightful)

    by anactofgod ( 68756 ) on Thursday January 27, 2005 @01:18PM (#11493719)
    This "surveying" of boundaries by my government has traditionally been the first step in the staking of claims and the erection of fences and walls. When does the landgrab start? I want to plan my flag on a choice piece of real-estate. *g*

    So, I have a question. Why is it that when scientists talk about exploring the edges of the solar system, they insist in sending probes "out past Pluto"? On the one hand, I understand why we do so - our solar system does lie (primarily) in a plane, so it's natural to think that way.

    But I argue it'd be easier to explore phenomina at the edges of our solar system by going in the third dimension - orthogonal to the plane of the solar system. After all, the Sun isn't just radiating in a 2-d plane. Or am I wrong in my assumption about how solar winds radiate?

    Any scientifically sound reason why this is a bad idea?

    Or are we doomed to continue think as Khan did/does/will? *grynn*

    • Re:Historically speaking... (Score:4, Interesting)

      by iainl ( 136759 ) on Thursday January 27, 2005 @01:25PM (#11493826)
      The problem, if memory serves, is that it's a lot easier to sling a probe out along the plane than it is to send it "up or down" with any speed - simply because it's being launched from Earth any probe will already have a substantial amount of momentum in the plane.
      • It'd take a few years to get up to speed but I'm sure we could send it any direction we really wanted. Inline with the solar poles (e.g. straight up or down) would be interesting. Is the solar plane related to out direction of movement round the galaxy and if so how? Many questions... oh yess!
    • That is a very good question. There a couple reasons I can think of as to why exploration is primarily in the same plane as the planets.

      First, you can get there faster by using the gravity of intervening planets.

      Second, you can do some interesting science (take pictures, etc) on the planets and other objects you pass by.

    • Re:Historically speaking... (Score:5, Informative)

      by CrimsonAvenger ( 580665 ) on Thursday January 27, 2005 @01:30PM (#11493882)
      Any scientifically sound reason why this is a bad idea?

      DeltaV required to head out perpendicular to the plane of the ecliptic is quite a bit higher than to go out along the ecliptic.

      Achieving Solar escape speed from LEO in the plane of the ecliptic is ~9Km/s.

      Perpendicular to the ecliptic, deltaV required is ~26Km/s.

      And it's tough to use planetary slingshots when you're going out perpendicular to the ecliptic.

      • i never understood this. why do you have to go 9km/s to escape the Earth's gravity?

        if you can move upwards at an inch a day, eventually you would leave gravitational pull, woudln't you? why is the 9km/s significant?

        • i never understood this. why do you have to go 9km/s to escape the Earth's gravity?

          if you can move upwards at an inch a day, eventually you would leave gravitational pull, woudln't you? why is the 9km/s significant?

          The 9km/s is significant if you only have the launch velocity to work with (like throwing a rock).

          The inch per day example only works if you're constantly accellerating (say, via a rocket).
        • 9 km/s is the static speed you must be moving if you stop applying thrust. In other words, when you stop applying thrust, you'd better be going 9 km/s or faster or the Earth will eventually pull you back.

          Your example of moving up 1 inch per day (do you work for NASA, mixing measurement systems like that, now really!) implies that you continue to accellerate enough to maintain your position (i.e. you do not allow yourself to fall back that one inch) until you move up further.

        • Re:Historically speaking... (Score:5, Informative)

          by mopomi ( 696055 ) on Thursday January 27, 2005 @02:11PM (#11494385)
          Basically, an object needs a specific amount of energy to escape the gravitational well of some other object. Remember that kinetic energy is
          KE = 1/2 mv^2,

          where m is mass and v is velocity.

          Gravitational binding energy is the energy required to escape a gravity well (basically):

          GE = GmM/R,

          where G is the gravitational constant, m is the mass of the escaping object, M is the mass of the planet, and R is the planet's radius.

          Setting KE=GE and solving for velocity gives you the escape velocity (the very minimum INITIAL velocity required to escape with NO ADDITIONAL ACCELERATION). Notice that the object's mass cancels, so you're left with a constant value for the planet's escape velocity (of course, you need more energy to accelerate a more massive object to the same velocity). Earth's escape velocity is actually 11.1 km/s. Not sure where that 9 km/s comes from.

          • Re:Historically speaking... (Score:5, Insightful)

            by CrimsonAvenger ( 580665 ) on Thursday January 27, 2005 @02:48PM (#11494869)
            Earth's escape velocity is actually 11.1 km/s. Not sure where that 9 km/s comes from.

            Read carefully. That was deltaV required to go from LEO (Low Earth Orbit) to Solar escape speed.

            It assumes a starting speed of ~8Km/s (Actually, the orbit I assumed had ~7650m/s orbital speed), and a single burn in the direction of both the orbit around the Earth and the Earth's orbit around the Sun. It further assumed Solar escape speed was 42.1Km/s, which is true for a couple points along Earth's orbit, but I'm not sure exactly where, so I won't tell you the dates required for the burn.

            If you add 9Km/s to your speed under those conditions, then you will find yourself moving along smartly in the plane of the ecliptic at just over 5250m/s relative to the Sun at some point in the indefinite future, when you are some arbitrarily large distance from the Sun (on the order of two light-months out, give or take a couple light-weeks)

        • if you can move upwards at an inch a day, eventually you would leave gravitational pull, woudln't you?

          Well, yes. Eventually you'd be far enough away that "escape speed" would be less than one inch per day. Let's, see, that would be about 10E27 years from now.

          When departing a major body, there are advantages to a fast initial burn to put you over escape speed - it gets you some "free" speed. Given a fusion rocket or such that allows effectively unlimited deltaV for insystem work (it's not really unlimit

        • You don't exactly, but it's the only sensible way (Score:4, Insightful)

          by Julian Morrison ( 5575 ) on Thursday January 27, 2005 @03:11PM (#11495122)
          Escape velocity is for a ballistic trajectory. Ballistic, meaning unpowered after the launch. That is, if you chuck a rock at sea level upwards at that speed, it will slow and slow but never quite stop.

          What you're talking about is escaping by just continually going upward, like climbing a ladder. Which you could, if there were a big enough ladder - but of course there isn't. So rather than standing on a solid, you have to continuously accelerate against gravity to even stay put. Possible - it's what a Harrier jump jet does when hovering at take-off - but expensive in fuel, meaning you can't do it long enough to get anywhere useful before the fuel runs out. It makes more sense to burn all your fuel as early as possible, accelerate as fast as possible, and coast most of the way ballistically. That way you get rid of the fuel fast (it's heavy and expensive to lug) and you don't waste effort just staying put.
          • "What you're talking about is escaping by just continually going upward, like climbing a ladder. Which you could, if there were a big enough ladder - but of course there isn't."

            There isn't yet.

            However there are plans for a space elevator, going from a spot on the equator to, and beyond geosynchonous orbit.
            • ...there won't be one to earth escape velocity.

              Now, if someone really did invent unobtanium, the next nifty space ladder idea, would be one in solar orbit. Park the center of mass in earth's orbit a little way off to the side, and grow ladders down to Venus and up to Mars...
        • I never understood this. why do you have to go 9km/s to escape the Earth's gravity?

          You don't. However, if you want to throw something and have it escape, that is how fast you have to throw it. If you are prepared to keep pushing you can go as slowly as you like.

          The escape velocity is a reflection of how much energy you need to put in. If you do it all in one bang, the energy is equivalent to a fixed velocity because the mass of the object cancels out of the equation (more massive objects need more ener

        • BTW, the slow and steady method was most famously used by the Grand Dutchie of Fenwick for their moon shot.
      • And it's tough to use planetary slingshots when you're going out perpendicular to the ecliptic.

        I suppose you could plan your final planetary slingshot to go either north or south of the planet, rather than near its orbital plane, thereby ending up with a trajectory aimed quite far from the ecliptic. I think at least one of the Pioneer/Voyager probes did something like that.

        • Arthur C. Clarke mentioned going over the poles to leave the ecliptic in "The Conquest of Space," a science book that came out around 1969.
          • Arhtur C CLarke was a great man, he really was.

            But he was wrong here. If you're in a polar orbit to start with, you'll need a bit more deltaV than I described, since I assumed the ideal departure orbit (one where the burn was entirely in the direction of travel).

            The big difficulty with going into a Solar polar orbit is that you have to cancel Earth's orbital speed as part of the orbital insertion burn. And Earth's orbital speed is ~30Km/s, more in northern-hemisphere winter, less in northern-hemisphere

    • The boundary is three dimensional, that's true. It is expected that the interstellar wind pretty much dominates in the plane of the galaxy, meaning the actual shape of the solar boundary should be quite oblong. Also, the plane of the solar system is not lined up with the galactic plane and the solar plane "wobbles" in a circle every 31 million years or so, so the interaction of the solar wind and the galactic wind, i.e. the definition of the solar boundary, changes constantly.

      The reason humankind explore

      • I understand all the points being made about "slingshotting" off other planets to gain speed, etc. That's all good and fine. But what I meant to argue is that in for *this* particular mission, where the stated goal is to determine how the solar winds interact with "materials between the stars" (as quoted from the article), I wanted to know why it's important to go to a point where the "solar winds flow out past Pluto"?

        I'm arguing that we could achieve that boundary quicker by going orthogonal to the plan
        • I don't think you really understand the need for gravitational assists. Without such assists a probe using current launch technology would not be able to make it anywhere close to the edge of the solar system. We can't just fire these things off in a roughly straight line. They're launched in what are essentially variations of a Hohmann [nasa.gov] transfer orbit [wolfram.com]. Instead of moving from one circular orbit to another though, you're transfering from a circular orbit to a hyperbolic one. The same concept applies, energy n

    • Yes there is on reason this is a bad idea: most probes slingshot off other planets to gain speed. We often will send a probe destined for the outer solar system to Venus first, where it will gather speed from gravity before moving to deeper space. (of course this requires careful calculation to make sure you go in the direction you want, particularly if your goal is a planet and not just leaving)

      One other disadvantage: there is much less interesting things when you get off the plane of the ecliptic.

    • Re:Historically speaking... (Score:3, Interesting)

      by jnik ( 1733 )
      Why is it that when scientists talk about exploring the edges of the solar system, they insist in sending probes "out past Pluto"?

      Your question has been answered by others here, but I should point out that this particular mission is exploring the edges of the Solar system from Earth orbit. Hardly out past Pluto :) (article doesn't specifically say that, but implied from the budget, the program it's under, and the fact that it's observing ENA's...remote sensing using ENA's is one of the Cool Things right n

    • Re:Historically speaking... (Score:2, Informative)

      by Anonymous Coward
      Two reasons why these probes have been sent out along the orbital plane (at least initially):

      1) Much of the speed is generated by the slingshot effect from a planet. The Voyagers used this effect at each planet to gain the necessary speed to reach the next- they did not attain enough speed to escape the solar system until after the third or fourth planet.

      2) These probes are EXPENSIVE. If we want to launch one out of the solar system, why not along the direction where we can make planetary observations a
    • Gravitational assist. It's impossible to escape the solar system without slingshots using today's rockets. (It would require about 4 times the exhaust velocity, and Tsiolkovsky tells us that even an ideal rocket would need to be over 98% propellant. We can do 90% but not 98%.)
    • Why would it be easier? The edges of the solar system aren't any closer in the +/-Z direction than along the plane. And moving in the plane gives you benefits as mentioned in other posts.
      Interference from planets? Not likely, as long as you don't aim the probe to graze Pluto just before the Big Moment.

  • Understanding our environment (Score:3, Insightful)

    by helioquake ( 841463 ) on Thursday January 27, 2005 @01:19PM (#11493731) Journal
    A fascinating mission.

    Every scientific study indicates that the Big Bang had generated light atomic elements (Hydrogen and Helium, etc). But other heavier elements -- the founding block of life and everything we live in -- have been synthesized by stars. We have a pretty good model in nucleosynthesis, really. But little we know HOW these heavier elements are re-distributed throughout interstellar space. This mission will touch upon that topic by exploring the condition where the Sun's wind interacts with the primodial (?) material that surrounds the Solar system.

    Cool, indeed. And the principle institute is located in San Antonio, TX. Even if they go over budget, it's gonna be easy to impress the congress or the White House to allocate more money...well, I'm quasi-kidding about that!

  • Why? (Score:3, Interesting)

    by MikeyToo ( 527303 ) on Thursday January 27, 2005 @01:25PM (#11493823)
    Why do we need this? Someone please explain it to me. None of the Pioneer or Voyager probes have yet to reach the heliopause and they were launched in the 1970s. So we should expect to see results in sixty years? How about doing some USEFUL exploring like investigating Pluto/Charon and KBOs?

    • Re:Why? (Score:2, Informative)

      by Anonymous Coward
      If you read the article this is part of the Small Explorer Mission so this probe has a very limited set of instruments and a narrow focus of inquiry, so it is relatively inexpensive. Note the estimated price, $124 million, a few orders of magnitude cheaper than the Gaileo probe, and you would want a probe with that range of capabilities to go to Pluto.

      I do agree that a mission to Pluto would be great, especially before it progresses to the part of its orbit where its atmosphere freezes. However, this is

    • Re:Why? (Score:2, Insightful)

      by Anonymous Coward
      How in the world is this useless? Everytime there are plans on exploration in space, or someone announce a new discovery in the lab, someone says "so what? what's the point?" I suppose it's futile to explain the point of science, to someone who refuses to see a point at all.

  • The article merely says that IBEX is to be placed in a highly elliptical orbit around the Sun, but offers no quantitative details. How far out is it meant to go? If beyond Pluto at 40 AU, its average distance to the Sun will be at least 20 AU, resulting in an orbital period of around 90 years (much like comet Halley with 76 years). I think that's a long-term science commitment. The Pioneer and Voyager probes were able to get out there faster because they are on non-return trajectories (hyperbolic, I suppose

    • Re:Long-term science (Score:5, Informative)

      by jnik ( 1733 ) on Thursday January 27, 2005 @02:02PM (#11494277)
      Nobody said the probe is actually crossing the termination shock. It's observing ENA's generated at the termination shock.

      Uber-brief introduction to energetic neutral atoms: Ions (charged particles) are susceptible to magnetic and electric forces. As a result, they can be boosted to very high energies in certain situations, but also usually can't travel very far before being modified in some way by electromagnetic forces. If, however, an ion interacts with a neutral (charge exchange), it can "steal" one or more electrons from the neutral without substantially changing the energies of either, leaving a nonenergetic ion and an energetic neutral, which then leaves the vicinity as it is no longer subject to EM forces. We can observe these ENA's and infer properties of the acceleration region.

    • Re:Long-term science (Score:1, Informative)

      by Anonymous Coward
      It doesn't say anything about an elliptical orbit around the SUN. The exact wording is "IBEX will make these observations from a highly elliptical orbit that takes it beyond the interference of the Earth's magnetosphere." I'd take that to mean an orbit around the Earth in such a away as to avoid the Earth's magnetosphere. It will image the termination shock, not go there. You can also infer this from the statement "The Small Explorer program (SMEX) consists of rapid, small, and focused science explorati

      • It doesn't say anything about an elliptical orbit around the SUN.

        Ah. The thought of actually checking with the article momentarily struck my mind, but as every other poster was busy discussing gravity assists and how this project compared to the Pioneer and Voyager missions, the notion that you could place such a probe in Earth orbit seemed just too bizarre... Thanks for the clarification. I see adeyadey has arrived at the same conclusion below.

        Now I wonder, will that satellite cross Moon orbit, maybe e

    • Actually, it's in a highly elliptical /EARTH/ orbit.

  • How much will this cost? (Score:4, Insightful)

    by VoxVeritas ( 851496 ) on Thursday January 27, 2005 @01:38PM (#11493979)
    I think this is a good idea. I just wish that they would save Hubble. They way they are dealing with Hubble is like junking your car just because it needs a new battery.

    Hmmm... my girlfriend tried that logic too...
    • I agree the Hubble needs to be saved...but it isn't quite THAT simple.

      It is like junking a car because it needs a 1K transmission.

      Getting the parts to the huubble and fixing it WITHOUT destroying the thing is not a trivial or cheap problem to solve.

      Personally I think it is worth it, but the price tag is big enough to give some people pause.
    • The problem was that it was beginning to look like big money ($0.5-1 billion+) to do this Hubble repair. For that sort of money, we could built another cheap scope..

  • Better maps of the solar system needed (Score:2, Interesting)

    by Anonymous Coward
    I'd much rather see them put some resources into mapping out the solar system. They should start producing some mini-probes with just enough power onboard to run a RADAR dish and a small telecommunications router for a couple of decades. Launch a couple of these every year and let them start to discover many of the smaller bodies scattered throught the solar system. They could also begin service as an interplanetary communications network. If the RADAR dish consumes too much power, then just give them v
    • A radar isn't a low-power device, especially at the range you'll need (calculating the volume you'll have to scan is left as an excercise to the reader). Simple navigation/weather radars (range: 200 km) require hundreds of W.
      An omnidirectional antenna doesn't give you information on the direction of the signals (which you need), and relying on 'reflected transmissions'? How would you differentiate between reflections and sources?

  • Why? (Score:2, Interesting)

    by dolphin558 ( 533226 )
    There are so many other interesting ideas out there. Why spend tens(hundreds) of millions on a mapping of the so-called interstellar boundary. Besides, it's not like they're going to the Oort Cloud. Why not revisit Venus, send a probe to Io, plug that money into Pluto Express. I can't see how anyone can be too enthusiastic about this mission. lilmac558@gmail.com

  • Wait a minite guys.. (Score:3, Informative)

    by adeyadey ( 678765 ) on Friday January 28, 2005 @08:47AM (#11502224) Journal
    IBEX will make these observations from a highly elliptical orbit that takes it beyond the interference of the Earth's magnetosphere.

    Guys, I know the article says very little, but from what I can see this probe orbits the EARTH, not the sun, in an elliptical orbit, with sensors to examine (amongst other things) particles from the heliopause. Makes sense - $134 million would not be nearly enough money for a deep-space mission - the Plutonium nuclear batteries (RTG) alone would cost most of that. Deep space needs expensive support from Deep Space Network, and advanced/expensive comms. To get to Earth-escape you need an expensive big rocket too, unless you use ion. This probe will probably run off solar.

    To get an idea of what even a "cheap" mission to Pluto & Heliopause is going to cost see the New Horzons page
    http://pluto.jhuapl.edu/ [jhuapl.edu] - this will be around $600 million. Apparantly they are in a real race against time to make the Jan 2006 launch window - there was a hitch at Los Alamos where they make the RTGs - Plutonium 238 is currently very hard to get hold of & they might not have enough by launch date. Shame they are not funding a "cheap" copycat 2007-8 NH-2 mission which could swing by Jupiter,Uranus & a few more KBOs including a nice double system..

    By the way I do think it could be done cheaper still - when are we going to have a true deep space ion craft? (solar+RTG)
  • This is actually a joint venture between NASA and Mossad. Once the boundary has been mapped, they will build a large concrete fence on it. This will keep Earth safe from aliens and cosmic rays.

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