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Mars NASA Space Science Technology

Getting the Latest Rover To Mars 191

Posted by timothy from the ftd-take-note dept.
derGoldstein writes "New Scientist has a great video up detailing every step of how the latest Mars rover will reach its target and get deployed. It's drastically different than the bouncing air-bag delivery system previously used (YouTube video)."
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Getting the Latest Rover To Mars More

Getting the Latest Rover To Mars

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  • Won't all that extra propellant for the various deceleration stages add up to a lot more than the bouncing airbag thingie in the end?

    • It's too large for airbags.

      • Which is why they need to split it into several smaller rovers which can self-assemble into one larger one, Voltron style. Tell me that wouldn't be a cool lander!

    • When I saw the last stage I almost fell out of my chair!. What the hell happened to keeping it simple!

      • Re:Stop me if I'm wrong but... (Score:5, Informative)

        by Animats ( 122034 ) on Monday July 25, 2011 @02:55AM (#36868150) Homepage

        When I saw the last stage I almost fell out of my chair!. What the hell happened to keeping it simple!

        It's no worse than the various lunar landers. The real question is whether they can get the budget to send that much mass to Mars.

        Landing anything big on Mars turns out to be quite hard. [universetoday.com] There's not enough atmosphere for a soft parachute landing. But there's enough atmosphere to require a heat shield while plowing through it. Then there's not enough atmosphere to brake from Mach 5 to Mach 1 before running out of altitude. There's too much gravity for a full rocket-powered descent. A rocket facing into the atmosphere won't work until the craft has slowed below supersonic speeds.

        That's what leads to what looks like an overly complex system.

        • "Running out of altitude" is the most awesome synonym for hitting the ground I've yet heard.

        • It's no worse than the various lunar landers.

          ...There's not enough atmosphere for a soft parachute landing.

          The lunar landings were easier because there was no atmosphere. The problem here is that there *is* an atmosphere, but, as you mention, it's too thin for just parachutes. So you have to deal with re-entry heat, wind, particles flying around (all the "bad" stuff that comes with landing on a planet with an atmosphere), but you don't get to just pop a triple-parachute the way they return objects for a soft landing on earth.

          I'm sure they know what they're doing, they've had some experience at this after all.

        • When I saw the last stage I almost fell out of my chair!. What the hell happened to keeping it simple!

          It's no worse than the various lunar landers.
          The real question is whether they can get the budget to send that much mass to Mars.

          Landing anything big on Mars turns out to be quite hard. [universetoday.com] There's not enough atmosphere for a soft parachute landing. But there's enough atmosphere to require a heat shield while plowing through it. Then there's not enough atmosphere to brake from Mach 5 to Mach 1 before running out of altitude. There's too much gravity for a full rocket-powered descent. A rocket facing into the atmosphere won't work until the craft has slowed below supersonic speeds.

          That's what leads to what looks like an overly complex system.

          There's not too much gravity for a full rocket-powered descent; fully-propulsive Mars entry is a perfectly valid option, it just requires a lot more mass. Supersonic retropropulsion, even without much thought put into how you do it, is certainly no worse than retropropulsion in a full vacuum, it's just that it tend to decrease the drag... but it does still slow you down! "A rocket facing into the atmosphere" most certainly DOES work, just not as well as we would like (for the simplest case).

          And besides, the

    • The difference is size (Score:5, Informative)

      by SmallFurryCreature ( 593017 ) on Monday July 25, 2011 @02:35AM (#36868068) Journal

      This rover is FAR larger the current ones, those tires? Not cute cart wheels, they are roughly the same size as a car tire. The entire vehicle is easily the size of a large SUV although far more open. (Hey nasa, if you want to make things understandable how about instead of adding sounds in space, maybe project a human next to thing so we get a sense of scale)

      A bouncing ball for this vehicle wouldn't need to be far to large. It is the old story of how spider won't even notice a 4 meter fall, a human would shatter bones and an elephant would go splat.

      There are a lot of risks with this method, so many parts that can fail, but if you want something big to land safely...

      Not that this is new. There are airdrop uses on this planet that involve just wrapping what you want to drop in something bouncy and throwing it out of an aircraft, works for small supplies in remote areas where a parachute might drift to far and the russians have used rocket decelerated chute systems for dropping tanks out of aircraft. Because finding enough bubble wrap for a tank is a hard.

      Did I complain yet about the sound in space? Yes? Well, it is a pretty big fucking issue. Everything you need to know about the US can be summarized as a NASA science video having sound in space... why not go the whole way and include cute green aliens on mars to show the life you might have found if Mars wasn't the hell hole it is?

      • It's not the size, it's how you use it. ;-)

      • Re:The difference is size (Score:5, Informative)

        by naff ( 150984 ) on Monday July 25, 2011 @02:53AM (#36868140) Journal

        Not showing the scale of the rover is inexcusable! Thank you for mentioning it.

        Here are some people next to it: http://en.wikipedia.org/wiki/File:Mars_Science_Laboratory_wheels.jpg [wikipedia.org]

        • That's a pretty small SUV.

          C'mon, NASA! Put a Humvee on Mars!

        • Re: (Score:2)

          by node 3 ( 115640 )

          That photo really should be at the beginning of the animation. It would provide some context that makes an already rather impressive landing even more so.

        • And then compare it to the previous rovers: here [wikipedia.org] and here [wikipedia.org].
          The Curiosity Rover weighs almost a ton(!). Not that the Phoenix is any lightweight.
      • A more engineering centric view [engineerin...lenges.org] of your general point.

        And yes, the sounds were stupid.

      • Re: (Score:2, Interesting)

        by mosb1000 ( 710161 )

        Space is not entirely soundless. If you were to put a microphone nearby a rocket nozzle, or thrusters firing, you would record sound. Likewise, if the microphone were attached to the vehicle while it was undergoing stage separation you would record sound. I'm not gonna say the video was perfectly technically accurate, but you can't just say "no sound in space" either.

        • I'm gonna be overly literal and note that "no sound in space" is exactly the statement you can make. What you're describing is monitoring the vibrations going through solid objects, and/or placing a microphone in the path of the expanding gas exiting the thrusters. If you placed a microphone literally "in space" a few feet away from the vehicle, you'd hear nothing.

          • Vibrations going through solid objects are called sounds. And in A/V streams, you'd often have the sound and the video being taken from different viewpoints. If you're watching someone doing a spacewalk, would you be bothered that you can hear what they are saying (through the microphone in the suit), even though the camera is almost floating in deep space and not hearing anything?

        • If you read the ALSJ [nasa.gov] there are plenty of examples of sound transmission on the moon. Sitting on the lunar rover, the crew could hear the electric motors through the seats they were sitting on. Striking a rock or tool with a hammer, astronauts could hear the sound of impact through their suits, and this sound was transmitted to the other astronaut via radio.

      • Re: (Score:2)

        by FleaPlus ( 6935 )

        Did I complain yet about the sound in space? Yes? Well, it is a pretty big fucking issue. Everything you need to know about the US can be summarized as a NASA science video having sound in space...

        Sound doesn't get transmitted through space, but a microphone mounted on the rover would have easily picked up all the sounds in the video.

        • We're used to listening to sound moving through air. If you placed a microphone on the body of the vehicle, you'd get vibration readings, but they wouldn't "sound" like that, you'd hear a lot of spikes and creaking. But we're kind of nit-picking -- they wanted the video to be interesting, and adding sound to what we'd expect to *produce* sound makes it seem more natural.

          • ... they wanted the video to be interesting, and adding sound to what we'd expect to *produce* sound makes it seem more natural.

            It also makes it wrong, which I could - albeit grudgingly - live with
            in a SciFi movie, but this is supposed to be about science.

      • Re: (Score:2)

        by sjames ( 1099 )

        We all know martians either look much like Ray Walston with antennae or were ovoid creatures whose feet doubled as hands. They sure liked Tang a lot.

  • I see that it has a laser. I hope that laser is beefy enough to let it make like a land shark and defend itself if the Martians stumbleupon it.

  • How is this powered? Not the landing stages, the rover itself? The video doesn't show any solar cells on the rover. Are they omitted from the simulation for simplicity, or is it using some sort of radiosotope battery. The video mentioned it had a planned life of two years. If that's the case, and given the size of the thing, then it almost has to be. That makes perfect sense of course, it's the ideal use of the technology. But don't they always run into political obstacles when they launch anything with "nu

    • Re:Power? (Score:5, Informative)

      by Anonymous Coward on Monday July 25, 2011 @03:03AM (#36868172)

      http://en.wikipedia.org/wiki/Mars_Science_Laboratory#Power_source [wikipedia.org]

      The Curiosity rover will be powered by radioisotope thermoelectric generators (RTGs), as used by the successful Mars landers Viking 1 and Viking 2 in 1976.[29][30] Radioisotope power systems are generators that produce electricity from the natural decay of plutonium-238, which is a non-fissile isotope of plutonium used in power systems for NASA spacecraft. Heat given off by the natural decay of this isotope is converted into electricity, providing constant power during all seasons and through the day and night, and waste heat can be used via pipes to warm systems, freeing electrical power for the operation of the vehicle and instruments.[29][30]

      The Curiosity power source will use the latest RTG generation built by Boeing, called the "Multi-Mission Radioisotope Thermoelectric Generator" or MMRTG.[31] Based on classical RTG technology, it represents a more flexible and compact development step,[31] and is designed to produce 125 watts of electrical power at the start of the mission and 100 watts after its minimum lifetime of 14 years.[32][33] The MSL will generate 2.5 kilowatt hours per day compared to the Mars Exploration Rovers which can generate about 0.6 kilowatt hours per day.[13]

    • Power source
      The Curiosity rover will be powered by radioisotope thermoelectric generators (RTGs), as used by the successful Mars landers Viking 1 and Viking 2 in 1976. Radioisotope power systems are generators that produce electricity from the natural decay of plutonium-238, which is a non-fissile isotope of plutonium used in power systems for NASA spacecraft. Heat given off by the natural decay of this isotope is converted into electricity, providing constant power during all seasons and through the day and night, and waste heat can be used via pipes to warm systems, freeing electrical power for the operation of the vehicle and instruments.
      The Curiosity power source will use the latest RTG generation built by Boeing, called the "Multi-Mission Radioisotope Thermoelectric Generator" or MMRTG. Based on classical RTG technology, it represents a more flexible and compact development step, and is designed to produce 125 watts of electrical power at the start of the mission and 100 watts after its minimum lifetime of 14 years. The MSL will generate 2.5 kilowatt hours per day compared to the Mars Exploration Rovers which can generate about 0.6 kilowatt hours per day.

      http://en.wikipedia.org/wiki/Mars_Science_Laboratory#Power_source

  • Almost as complex as Apollo 11 supposedly was. Maybe someday we'll make it to the moon.

  • Awe (Score:4, Insightful)

    by Spigot the Bear ( 2318678 ) on Monday July 25, 2011 @03:33AM (#36868282)
    I am in absolute awe after watching the video about the new rover. As people bicker over whether NASA's miniscule budget is worth it, because "space isn't important", it's nice that NASA can still bring out that child-like wonder in me. How can you not be amazed that we can send a robot like this to another planet, land it safely with precision, and study the composition of the planet from millions of miles away? Isn't that awe worth a few billion dollars a year, even if "it doesn't benefit me"?

    (Also, it has a laser tricorder. I mean, come on.)
    • But we're the 'type' of people who would get excited over this. To someone who isn't technical in any way whatsoever, all this seems like is "well, they put another 6-wheeler on mars... How many times am I supposed to get excited about that?". There are a lot of people who think that any space research is a waste, and this time you can't even show them a human doing the exploring, just "those RC cars".

      I really wish it weren't the case. The first time I saw the scale of the Curiosity rover my jaw dropped,

    • As these systems are designed by some of our most talented scientists and engineers it isn't so much about whether or not to pay them but what we should be paying them to do. Is this what these people should be spending their efforts on, just because they want to. Wouldn't society be better off if these resources (people as well as money) were spent on other activities.

  • The landing procedure look entirely too complex to me. It is one thing to let something crash in a controlled way, but quite another to land it in the way they desscribe. There is a host of things that could go wrong, like failing thrusters, frozen fuel lines, malfunctioning controllers, etc etc... And all that after months in space, having survived a launch and re-entry and then completely automated, with only seconds to react if something fails... I will be really,really impressed if they pull this off...

    • Re: (Score:2)

      by Zeussy ( 868062 )
      Its the same or even less complexity as an Apollo mission: Apollo Mission Steps: Launch from Earth, Do a burn for an orbital insertion Do a brake burn to get into lunar orbit Land the Lunar Module Take off from the moon, dock with the command module Do another burn to come back to earth Enter the atmosphere at the correct angle deploy parachutes Hit an ocean Curiosity Mars Mission: Launch from earth Do a burn to Mars Enter mars atmosphere Deploy parachutes Land using a lunar module esk lander. It has quit

    • Re: (Score:2)

      by mbrod ( 19122 )
      I agree, if they want to land in that way they should send at least four rovers. Possibly have one survive.

  • I would love to see the landing parts.

    • Here's the only physical test I found: http://www.youtube.com/watch?v=YasCQRAWRwU [youtube.com]

      Earth's atmosphere is entirely different. If you tried using the same scale, the same thrusters, and the same weight, the entire thing would crash. I'm sure there were separate tests of the individual steps, using dummy loads, but I can't find any videos of them.

  • Whooshing sound? (Score:3)

    by Spy Handler ( 822350 ) on Monday July 25, 2011 @04:42AM (#36868508) Homepage Journal
    I thought there was no sound in the vacuum of space.

    But then maybe all that manmade global warming New Scientist likes to report is causing air molecules in our atmosphere to heat up and expand into the other reaches of space, causing all that whooshing noise as the mars lander speeds by the camera.

    Or maybe they consulted with George Lucas before making the video...
    • People always confuse the distortion of the magnetic field caused by a spacecraft travelling at high speed through the tenuous plasma and cosmic rays of space and the currents associated with that distortion which are induced into the audio pickup circuitry of the camera as "sound in the vacuum of space"?

  • Doomed to become a statistic (Score:4, Interesting)

    by petes_PoV ( 912422 ) on Monday July 25, 2011 @07:22AM (#36869046)

    I counted 8 systems where any problem at all would kill the mission:

    Heatshield that has to protect, then deploy (or fall off in non-techno speak)
    Guidance rockets that have to work just right
    A parachute that mustn't rip or tangle
    A hovering system that must balance,irrespective of any storms it may encounter
    A winch that must not jam (after 40+ weeks in cold and vacuum)
    ... and pay out slowly enough
    ... and detach when the lander is down safely
    and finally the hovering platform that must not run out of fuel and drop onto the lander, or think it's detached and fly off with the lander in tow (If they got that on video, I'd laugh for a week)

    In short there are far too many ways it can fail, and far too many things that have to work perfectly. I think there's a bad case of hubris from having 2 landers out of 2 that not only survived the trip, but exceeded expectations. Sadly, I think this thing will even up the score.

    • I counted 8 systems where any problem at all would kill the mission:

      Only 8? Damm, NASA is doing pretty good if they've gotten the mission killers down to 'only 8'. (In case you didn't get it, that was sarcasm.) There's dozens of things that must work without a problem (counting the booster, which is really hundreds of things, as only one) for the mission to succeed. You've only identified the flashiest and most obvious - congratulations!

      In short there are far too many ways it can fail, and far t

  • The National Academy of Engineering had an article a long while ago about the Challenges of Landing on Mars [engineerin...lenges.org], detailing the various merits of the systems used for Viking, Pathfinder/Spirit/Opportunity, and the upcoming Curiosity. It's a little dry, but it explains with good reasoning why the chosen landing solution is appropriate for Curiosity.
  • I wish that they would put this on the edge of the crater, rather than in it. If Mars has water, where would it be? Not high. It would be in the ice and at the bottom of craters. At the least, I would rather that we put it there around winter.

  • Oh you simply must watch the video. It really is something out of a Bruce Willis movie. Nothing even close to simple. I can't imagine it'll make it through to the final plan. And if it does, I can't imagine it actually working. And if it does, I hope someone goes and films it happening -- that might be the easier part. Seriously, video games aren't this cool.

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