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Mars Space Science

Mars Express Captures Phobos and Deimos 84

Posted by Soulskill
from the holding-for-ransom dept.
westtxfun writes "The Mars Express Orbiter captured a very cool movie of Phobos and Deimos on Nov 5. Besides the 'wow factor,' the images will be used to refine models of the moons' orbits. The orbiter has also captured high resolution images of Phobos back in July. 'The images were acquired with the Super Resolution Channel (SRC) of the High Resolution Stereo Camera (HRSC). The camera took 130 images of the moons on 5 November at 9:14 CET in a span of 1.5 minutes at intervals of 1s, speeding up to 0.5-s intervals toward the end. The image resolution is 110 m/pixel for Phobos and 240 m/pixel for Deimos — Deimos was more than twice as far from the camera. '"
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Mars Express Captures Phobos and Deimos

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  • Wow. (Score:5, Funny)

    by FlyingSquidStudios (1031284) on Saturday December 12, 2009 @03:17AM (#30411804) Homepage
    It's so weird when reality looks like bad Photoshop.
    • Re: (Score:3, Informative)

      by Tablizer (95088)

      It looks kind of fake because it was taken through a telescopic lens, and thus you don't see the perspective of movement. When photographers and artists want to exaggerate perspective, they do the opposite: use a wide-angle lens.

    • Re:Wow. (Score:5, Informative)

      by DNS-and-BIND (461968) on Saturday December 12, 2009 @05:39AM (#30412234) Homepage
      Most "space images" are very heavily processed. If they took a normal picture it wouldn't look nearly as good. NASA learned a long time ago that its only reason for getting funded (besides being a jobs program) was making pretty pictures.
    • by snaz555 (903274)

      It's so weird when reality looks like bad Photoshop.

      They can't afford tabletop models anymore, so in this project they used paper cutouts on a black canvas.

    • Not really. They look more like poorly tweened objects in Flash. Which is actually worse.
  • Anyone noticed ... (Score:3, Interesting)

    by PIBM (588930) <pbnadeau@g m a i l.com> on Saturday December 12, 2009 @03:26AM (#30411846) Homepage

    That the jpg weight in at 666kb ?!!!?

  • Ask slashdot (Score:3, Interesting)

    by papabob (1211684) on Saturday December 12, 2009 @03:29AM (#30411854)
    Please, forgive my ignorance (physics is not my field): What orbit model is going to be refined? I've always thought that planetary movements were resolved centuries ago, and that modern cosmology studies the 'very big' things, portions of universe so massive that introduce glitches in relativistic theories, instead of moons' orbits.
    • Re:Ask slashdot (Score:5, Informative)

      by Tablizer (95088) on Saturday December 12, 2009 @03:42AM (#30411902) Homepage Journal

      Please, forgive my ignorance (physics is not my field): What orbit model is going to be refined? I've always thought that planetary movements were resolved centuries ago

      Solar radiation and the solar "wind" has an effect on smaller bodies, such as those moons. The effects vary depending on the color, composition, and texture of the moons' surfaces. We need better models to know their impact on orbits. Relativity may also have a very minor impact on orbital changes.
           

    • by Linzer (753270)

      Please, forgive my ignorance (physics is not my field): What orbit model is going to be refined? I've always thought that planetary movements were resolved centuries ago

      Sure, the physics behind planetary movements is well-known, but the zillion parameters that are at play (including the mass distribution of the objects involved) are only measured to finite precision. They are talking about refining the model by refining its parameters.

    • Re: (Score:3, Interesting)

      by sznupi (719324)

      Planetary models from centuries were basically an example of:
      a) idealized scenario (frictionless vacuum kind of stuff)
      b) based on Newtonian physics; which is not quite accurate...

      With the number of bodies and their interactions, Solar System is pretty much chaotic:

      http://en.wikipedia.org/wiki/N-body_problem [wikipedia.org]
      http://en.wikipedia.org/wiki/Stability_of_the_Solar_System [wikipedia.org]

    • Re: (Score:3, Informative)

      by Brett Buck (811747)

      The theory behind orbits in general is a solved problem, for some limited specific condtions (i.e. gravity as a point source, two bodies, and stuff like that). But that doesn't mean you know the actual parameters of the orbit (inclination, semi-major axis (period), etc) of any particular body. Any orbit "fit" is alwasy being refined.

      The other issue is that gravity actually isn't a point source with a simple inverse-square law nor are there only two bodies involved. The gravity o

    • Re:Ask slashdot (Score:4, Informative)

      by mbone (558574) on Saturday December 12, 2009 @10:05AM (#30413560)

      The orbit of Phobos, particularly, has an oddity that has attracted a lot of interest, and more data is always welcomed.

      The orbit of Phobos is decaying, presumably due to tidal friction [cornell.edu] - the work required for Phobos to raise a small tidal bugle in the part of Mars below it. There is nothing surprising in that, per se (Moons inside a geostationary orbit will decay inwards due to tidal friction, Moons outside a geostationary orbit will "decay" outwards), but what is surprising is the "Q" required to match the observations. (The Q is total energy in the bulge divided by the rate of energy lost per orbit.) The Q inferred from observations of Phobos's orbital decay, and the rigidity of the Martian surface found from observations of the Martian Solar tide [berkeley.edu], is about 90. The corresponding Q for the Earth is about 12, but that is mostly due to ocean tides, and the Q inferred for the Earth's mantle is about 280.

      So, the Mars-Phobos system has a higher solid-body dissipation [usra.edu] than the Earth-Moon system, which is surprising. In nailing this down, all sorts of data have been acquired for Phobos (including eclipse data from the Mars Rovers), but there is always room for more. What the current data should do is provide a tie for the relative longitudes of Phobos and Deimos which (especially if this can be repeated) will help make sure that there are no drifts between the orbits of the two Moons.

      By the way, with the current orbital decay, the expected lifetime of the orbits is somewhere in the 20 to 40 million year range [arxiv.org] - it seems unlikely that we just happen to catch Phobos at its end-of-life, which has raised speculation about its decay being time variable.

      • By the way, with the current orbital decay, the expected lifetime of the orbits is somewhere in the 20 to 40 million year range [arxiv.org] - it seems unlikely that we just happen to catch Phobos at its end-of-life, which has raised speculation about its decay being time variable

        Why is it unlikely? That longer time period represents almost 1% of the lifetime of the entire solar system, (so far). Sure, 40 million years is considered short on a cosmic scale, but don't forget the fact that it is still a LO

        • Re: (Score:3, Interesting)

          by mbone (558574)

          Well, if you pick times at random, we would say that a 1% chance of encountering something is fairly low. But, of course, 1% events happen all of the time, even in Astronomy.

          Here is a better way to look at probability in astrophysics and planetary physics - if you conclude that you just happened to observe something or catch some event at an unlikely point of its life-cycle, that may be a clue that you are calculating your probabilities wrong, i.e., that your theory is wrong or incomplete. So, improbable ev

  • action films (Score:5, Insightful)

    by f3r (1653221) on Saturday December 12, 2009 @03:53AM (#30411946)
    It's sad that we are so used to action and sci-fi films with amazing simulations of astonishing things, that when it comes to the real one (a piece of rock which really exists up there, and IS cool) we think we are seeing the intro for a 1985 asteroid game, and think for ourselves 'where are the explosions? I myself had to do an effort to rationally avoid that thinking and covince myself of the real coolness of the thing.
  • by jtownatpunk.net (245670) on Saturday December 12, 2009 @03:55AM (#30411948)

    I don't see any Leather Goddesses. Maybe I need to set the naughtiness level to "lewd".

  • Nice mission overall (Score:2, Interesting)

    by dragisha (788)

    Movie is only one of mission returns, and it surely looks like a video game to many who don't think further than WoW when thinking about exploring unknown :).

    Mission itself is what is important here - being technologically advanced far more than Voyagers and giving us previews of what will come in future.... Better cameras and other instruments, better communications, faster spacecraft.... We are only beggining to see around solar system (Voyager is only 32 yrs old) and Mars Express is BIG THING.

    What is als

    • by tftp (111690) on Saturday December 12, 2009 @05:31AM (#30412210) Homepage

      What I can't understand is why they're still inventing whole lander thing when technology for safe landing (and going back up) of people is tried FORTY years ago?!!

      We know how to land in dense atmosphere (Earth, Venus) and in vacuum (the Moon). But there are no good solutions for landing in thin atmosphere (Mars). You can't use a parachute because there isn't enough atmosphere for it, and you can't use a rocket engine because incoming flow of atmospheric gases interferes with the engine (extinguishes flame and creates oscillations like in a whistle.) That's why robots are just dropped on Mars in a big airbag. But the deceleration is too high for a human.

      • by Teun (17872)

        You can't use a parachute because there isn't enough atmosphere for it,

        And yet it has been done.

        and you can't use a rocket engine because incoming flow of atmospheric gases interferes with the engine

        And yet it has been done.

        Any other wisdom you want to share?

        • Re: (Score:3, Informative)

          by sznupi (719324)

          Yes, it has been done, but only for objects with small mass; decelerating them fairly easy in comparison to what would be required from several-tonne lander capable of carrying humans.

        • by david.given (6740)

          And yet it has been done.

          Given that of the 16 landers that have been dispatched to Mars, only 6 of them actually ended up on the surface in working order, I think it's more accurate to say that it hasn't been done.

          • Given that of the 16 landers that have been dispatched to Mars, only 6 of them actually ended up on the surface in working order, I think it's more accurate to say that it hasn't been done.

            If it's been done once, it's been done. It hasn't been done reliably but that's something different.

      • Re: (Score:3, Interesting)

        by Brett Buck (811747)

        We know how to land in dense atmosphere (Earth, Venus) and in vacuum (the Moon). But there are no good solutions for landing in thin atmosphere (Mars). You can't use a parachute because there isn't enough atmosphere for it, and you can't use a rocket engine because incoming flow of atmospheric gases interferes with the engine (extinguishes flame and creates oscillations like in a whistle.) That's why robots are just dropped on Mars in a big airbag. But the deceleration is too high for a human.

        • by mbone (558574)

          Landing large payloads on Mars is tough [universetoday.com], if by landing you mean, at a reasonable G force.

          "An airbag landing subjects the payload to forces between 10-20 G's." For a human, that's not a landing, that's a crash.

          Parachutes are inefficient, especially for the last few hundred meters / second. The best solution for human sized crafts is probably parachutes plus rockets a la Viking.

          I don't have a good solution, except that we should always land in Hellas (the deepest basin on Mars, with about 50% higher surface a

        • I think one problem with using rockets to slow your descent, at least near the ground, is that you risk serious damage to the very ground you want the robot to study.
        • by dragisha (788)

          "So much fuel" being one of crown problems with whole landing thing. Until we don't have very energy/fuel_mass efficient fuels and very sophisticated drives landing (and esp. returning it back to orbit) will present problems ranging from very hard to impossible.

      • We know how to land in vacuum with little gravity. Mars has too strong gravity to use rockets all the way. Both parachutes and breaking rockets are still useful for landing on Mars, but it is very different from both Earth and the Moon.

  • most awesome ...'awesome' is so over-used, but it's truly appropriate here

    • by Brad1138 (590148)

      most awesome ...'awesome' is so over-used, but it's truly appropriate here

      Your comment is awesome dude....

  • Encapsulating planets takes a BIG satellite.

    It must stretch itself out really thin for only weighing 1123 kg.
  • If you want the "HI-RES TIFF" versions of the images, you'll need to add another "f" onto the ends of the URLs.

  • What is really creepy about these movies and pictures is, that somehow you always expect stars in the background (like on a ship at night). Instead you get two rocks hanging in a black void. Just one vast emptiness. Scary.
    • by sznupi (719324)

      Just shows that also this move was done in Arizona desert.

    • by Gerafix (1028986)
      Anybody with experience using a camera will not expect such a thing at all, in fact the opposite. Well, with current technology anyway. Plus big dynamic range isn't really that useful in space...
  • that whole "we've sent things to Mars" myth that the Conspiracy is trying to force on you. I think the whole thing was shot on a soundstage in Southern California ... I'm pretty sure I can see the support wires.

    • by Gerafix (1028986)
      Pff, seems like they got to you too. You see, Mars is just a conspiracy made by the Illuminati to take over the world with their panspermia.
  • Or you might end knee-deep in the dead.

  • Anybody know the absolute magnification? These objects are really close, but small. Whatever, I suppose. It would surely still be weird to see them track across the sky live.

  • The RSS feed headline said "Mars Express Captures Phobos and Deimos" and I thought to myself, if we can do that then any future comet or asteroid impact should be easy to avoid, we just capture it and park it at Lagrange Point 4. Then we can maybe use the materials as resources for other missions....

    Then I read the story and see we have a stop frame animation that looks like a cut from Robot Chicken.

    It just doesn't pay to get excited about science.
  • Notice that both moons move in a perfect horizontal line? So the camera was perfectly aligned at the time? Or ???
    Did anyone else expect tumbling or rotation, however slowly?
    • by Gerafix (1028986)
      Post-processing is your best friend when dealing with the trials and tribulations of astrophotography. Or maybe it's because Mars Express has a pointing accuracy of 0.04 degrees with regard to its inertial reference frame and 0.08 for Mars orbital reference frame. Either way I guess.
  • by macraig (621737) <mark DOT a DOT craig AT gmail DOT com> on Saturday December 12, 2009 @01:38PM (#30415290)

    What's the deal with the curious striations running longitudinally across the whole surface? Notice, in particular, that they even continue down into and through craters! What could cause that?

    My first thought was that Phobos must have a fast spin in addition to its fast orbit, and that it was acquiring those gouges as it spins through clouds of debris. Then I read the notes and learned that the "N" marked the north pole of its axis, meaning that the striations are running perpendicular to its rotation!?

    Back to the drawing board....

    • Well, I thought that they were a system of cracks spreading out from the largest crater on Phobos, Stickney (not visible on the still image in the story, but visible edge-on in the lower right in the movie, or here [wikipedia.org]. It was thought that the impact that created Stickney nearly tore Phobos apart, leaving prominent scars all over the surface, but apparently the system of grooves is far more complex, as was actually determined by the Mars Express mission. One of the sources for the wikipedia page on Stickney i
      • Re: (Score:3, Informative)

        by macraig (621737)

        After I commented, I found and read quite a few commentaries about them, none of which had an adequate explanation. The most curious aspect is how they continue THROUGH craters, even deep ones. It's almost as if something drove, or was dragged, across those areas. I'm having a hard time visualizing how any impactor could "slide" across the surface like that, even down into and then back out of craters and continuing. At first, second, and third glance they certainly appear to be unnatural.

    • by dvs01 (1192659)

      I believe they were caused by Barons of Hell.

  • Phobos and Deimos have a significant amount of water.
    How about a manned deep space mission to sample them...probably cheaper
    than a return to the moon, and demonstrably more interesting.

  • I'm looking at those craters and am trying to figure out where the Phobos bases are. Perhaps it's at the wrong angle. Did the UAC cover it up?

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