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Simulation of the Mars Science Laboratory Sky Crane

Posted by kdawson on from the rocket-science dept.

An anonymous reader points us to Gizmodo for a fascinating video of NASA's Sky Crane. "When I read that the UFO-looking Mars Science Laboratory's aeroshell would use a floating crane — called Sky Crane by NASA — to softly land the rover on Mars, I couldn't believe it. Now, watching this hyper-realistic NASA simulation, I still can't believe how the whole thing works. I don't know about you, but the whole operation mesmerizes me to no end."

145 of 195 comments (clear)

  1. Cool Movie - but bad idea! by jackb_guppy · · Score: 4, Interesting

    That is so complicated. The "beach ball" idea from the two current rovers was much better.

    Maybe if the Sky Crane was a ballon system so it can float around Mars would make this better. But still way too complicated.

    1. Re:Cool Movie - but bad idea! by fishinatree · · Score: 1

      Obsfucated physics is a great way to get people to fund your project. If they don't know the plausibility but it looks like it works, then you have a good idea.

    2. Re:Cool Movie - but bad idea! by Nyeerrmm · · Score: 5, Informative

      I think the idea is that as you get more massive that doesn't work as well anymore. The weight of the airbags becomes untenable... I haven't looked at the math in few years, so unfortunately I can't be more specific.

      Mars is one of the hardest places to land because its atmosphere is so wispy; on Earth some simple parachutes and a well-shaped capsule do the trick. On Venus the atmosphere is so thick anything you drop in will happily land softly as long as it doesn't melt. The moon and other such places you really only have the landing rocket option, which can be heavy but not particularly complicated.

      On Mars though, the atmosphere is too thin to allow the capsule to slow it down to subsonic speeds on its own, meaning supersonic chutes are necessary if you want to use the atmosphere to slow you down. If you want to land with a rocket, you run into issues of trying to light an engine with supersonic flow going into the nozzle; trying to light it and flip around I imagine introduces some pretty wretched dynamic and structural problems. That tends to mean a series of parachutes including custom Mach 2 or Mach 3 chutes that would never be needed on Earth, or in this case using an aeroshell as well. Even then, you're still going too fast, so you need to slow down more. As suggested before, the airbags have worked in the past but don't scale well with higher mass vehicles. Thus you really need some kind of rocket (that ignite at subsonic speed); I'm not sure why a sky crane works better than some other system with rockets, I'd imagine its the easiest method of separation and also allows you to use less fuel since the crane itself doesn't have to slow down to a safe speed (i.e. release it down and reel it back up to reduce landing speed.)

      Also, they had this option out there three years ago when I worked on a Mars mission for a class, so it's been out there a while and is probably as well developed as a non-tested system can be.

    3. Re:Cool Movie - but bad idea! by Anonymous Coward · · Score: 3, Informative

      Airbags don't work on something as big as the MSL rover. It's that simple.

    4. Re:Cool Movie - but bad idea! by Anonymous Coward · · Score: 5, Interesting

      I'm on the project, and I understand all the reasons why we're doing it this way, but for what it's worth, I think it's as bat-shit insane as the rest of you. One thing no one can argue, though: it's incredibly cool.

    5. Re:Cool Movie - but bad idea! by LurkerXXX · · Score: 4, Interesting

      Or you need to send down a bunch of pieces which assemble themselves into a larger vehicle.

      "Mars Mission. The Beginning of Megatron"

      (queue theme music and intro credits...)

    6. Re:Cool Movie - but bad idea! by bozojoe · · Score: 1

      Its all about the weight.

      I almost took a job with the UCLA NASA branch for the doomed lander (yes it crashed 1 month later (yeah the metric/english thing)) and asked the PM why didnt you use the tried and proven beach ball design. The response, weight. Apparently it cost triple the price in strap on rockets for the delta to get the beach ball into orbit, vs the traditional retro rocket platform.

      go figure

      --
      lick the cancle button (at least thats what our Chinese QA says)
    7. Re:Cool Movie - but bad idea! by Anarchitect_in_oz · · Score: 2, Interesting

      My first thought on why the space crane works is the rocket don't need to change speed. They can keep blasting out the same pressure slowing the craft with the right acceleration the crane has near zero vertical speed at the right height. From then it starts to accelerate upwards. I figure the crane cables are to give enough of a time window between slowly falling and slowly rising to cut the cables. Should massively reduce the control systems needed in the crane.

      --
      "Call us when the New age is old enough to drink" Beck
    8. Re:Cool Movie - but bad idea! by gnick · · Score: 1

      Awesome post. I'm fairly ignorant on the whole space topic - I researched briefly what we have to gain from actual visits to other planets in our system and compared it to the cost of actually sending craft to visit right before deciding that it made the most sense to develop all the necessary exploratory technology but not implement it for a number of years.

      But that will in no way stop me from reiterating the basics of your post the next time I'm discussing extraterrestrial exploration in an effort to sound informed.

      Hopefully there will be no follow-ups. Thanks!

      --
      He's getting rather old, but he's a good mouse.
    9. Re:Cool Movie - but bad idea! by khallow · · Score: 3, Interesting

      My concern is that the crane is another failure mode. And it's not clear to me what value the crane adds to justify that risk. If the crane fails to deploy or it doesn't retract fast enough, then the vehicle is at the least immobilized, either with a heavy weight of the crane on top of it and/or damaged suspension system from hitting too hard.

    10. Re:Cool Movie - but bad idea! by Mr2cents · · Score: 1

      To quote Monty Ptython: are you a man or a mouse?

      Really, the Viking Landers used retro rockets. Phoenix used retro rockets. So I guess we can assume retro rockets are a proven technology. The only thing added is a few cables, and cables also are a proven technology. And given todays sensors and processing power, I don't see any problem in making a platform hover a while and fly away.

      And before you all start jabbing, yes, I do believe MSL will be a great engineering feat, a fantastic machine and a great achievement for humanity, but there is no hocus-pocus involved. It's doable and there just aren't many safe ways to go from thousands of kilometers per hour to zero in a few minutes and land safely on the ground. It's a new idea but it makes sense.

      --
      "It's too bad that stupidity isn't painful." - Anton LaVey
    11. Re:Cool Movie - but bad idea! by Joce640k · · Score: 1

      I thing the point of this is to keep the rocket engines completely separate from the rover.

      The rover doesn't need the weight of any engines when it's rolling around a planet. Maybe you could separate the engines from the rover once it's landed but that's probably more complex/risky than a winch and cable mechanism.

      --
      No sig today...
    12. Re:Cool Movie - but bad idea! by wjsteele · · Score: 1

      That is so complicated. The "beach ball" idea from the two current rovers was much better.

      That system worked great for the first 3 small rovers, but the larger rovers would simply splat through the ballons because of the size of them. The Mars Polar Lander and it's "sister" Phoenix used soft landing techniques that had the rockets slow their desenct all the way down. (BTW - You only mentioned two rovers, but in 1997, Sojorner pioneered the ballon assisted landing process.)

      The problem with the rocket assisted desent is the fact that the rocket exhaust will contaminate the ground surrounding the landing site. They Skycrane idea get's around that and has the chemials and residues fly away several hundred feet to avoid that.

      Bill

      --
      It's my Sig and you can't have it. Mine! All Mine!
    13. Re:Cool Movie - but bad idea! by Mr2cents · · Score: 1

      I don't think so. Cable cutters are very, very reliable. That's the least of my worries.

      --
      "It's too bad that stupidity isn't painful." - Anton LaVey
    14. Re:Cool Movie - but bad idea! by Shivetya · · Score: 1

      Well if they get wormsign they can always come back and pick up the harvester

      --
      * Winners compare their achievements to their goals, losers compare theirs to that of others.
    15. Re:Cool Movie - but bad idea! by dotancohen · · Score: 1

      My concern is that the crane is another failure mode. And it's not clear to me what value the crane adds to justify that risk.

      What most posters here are forgetting is that the retro rockets, as used on the Phoenix mission, served _two_ purposes:
      1) to slow the craft
      2) to level the craft

      To level the craft they took reading from differing points on the craft relative to the ground, and 'steered' toward the higher point, leveling the craft. This had the unfortunate side effect of also steering the craft towards obstacles such as boulders. One could only assume that with the crane there is no need to level the craft, gravity takes care of that.

      Additionally, with the rockets, tanks, and related mechanisms off the buggy, the landing weight on the suspension is greatly reduced. Thus, less risk of suspension damage on landing.

      --
      It is dangerous to be right when the government is wrong.
    16. Re:Cool Movie - but bad idea! by mykdavies · · Score: 1

      You might enjoy reading this paper on the EDL system.

      --
      The world has changed and we all have become metal men.
    17. Re:Cool Movie - but bad idea! by daniel_newby · · Score: 1

      "Maybe you could separate the engines from the rover once it's landed but that's probably more complex/risky than a winch and cable mechanism."

      That would actually be simpler and easier, except that the descent rockets produce about 6000 newtons (1500 pounds) of thrust. That kicks up an almighty cloud of debris, which the rover would have to be protected from. That means a dust-proof box, a very reliable door opener for the box that works even if it is dented from a hard landing, and a ramp for the rover to reach the surface with (if it rides atop the lander). The final leg of the landing would also be blind, into a total brown-out (well, red out on Mars).

      Winch and cable sounds daft, but sucks less than the alternatives once you work out the details.

    18. Re:Cool Movie - but bad idea! by TheDarkMaster · · Score: 1

      I agree, is too complicated. Have too much "phases" and too much parts (more parts = more chances of failure), maybe a vicking-style landing is a better idea for a vehicle of this size

      --
      Religion: The greatest weapon of mass destruction of all time
    19. Re:Cool Movie - but bad idea! by HangingChad · · Score: 1

      I thing the point of this is to keep the rocket engines completely separate from the rover.

      Too bad the sky crane couldn't drop the rover, then land somewhere to become a stationary observation station. Turn it over to a university to operate for whatever data they can get from it. Seems a waste just crash it somewhere. There wouldn't be a lot of room in there but it seems like you'd want to put instruments on just about anything you're going to send all the way to Mars.

      --
      That's our life, the big wheel of shit. - The Fat Man, Blue Tango Salvage
    20. Re:Cool Movie - but bad idea! by Goaway · · Score: 1

      Gee, too bad nobody thought of that before they built it!

    21. Re:Cool Movie - but bad idea! by Goaway · · Score: 1

      Too bad you weren't on the team so they could hear from a real expert about how to land on Mars!

    22. Re:Cool Movie - but bad idea! by khallow · · Score: 1

      Really, the Viking Landers used retro rockets. Phoenix used retro rockets. So I guess we can assume retro rockets are a proven technology. The only thing added is a few cables, and cables also are a proven technology. And given todays sensors and processing power, I don't see any problem in making a platform hover a while and fly away.

      Fine. I get retro rockets. My question is what do cables add aside from another way to fail the mission? I might add until someone does this on Earth or Mars, it is an unproven technology.

    23. Re:Cool Movie - but bad idea! by n-baxley · · Score: 1

      Well, as others have pointed out, this is much heavier than the earlier rovers. But just as important, is that this helps determine a good way to land humans on later missions. There's no way you could land humans in the beach ball. Even if this method doesn't work flawlessly, hopefully much will be learned about how to land large "delicate" cargo on mars...US!

      --

      THIS SPACE FOR RENT
    24. Re:Cool Movie - but bad idea! by The+Fun+Guy · · Score: 2, Informative

      The cables allow for some leeway in how hard you can hit the ground and still have a functioning rover. If you come in too fast with a single piece of equipment, the whole thing goes crunch. The rockets and ground acquisition sensors are good, but not perfect.

      With the rover on the end of the bridle, this decouples the weight of the scientific payload from the weight of the support equipment needed to ensure a soft landing of the payload. Once the thing is on the ground, you don't need any of the support equipment anymore. You can make the rover tough enough to handle a harder-than-expected landing, even tough enough to bounce a bit. Accelerometers on the rover will send the signal back up the umbilical to give the crane the green light to cut loose and go away. I suppose that you could even have tilt sensors on the rover to tell the crane, "This is a bad place to leave me, pick me up and put me someplace else."

      A lot of the weight of the (rover + sky-crane) is up in the crane. This set up will let you have a thinner engineering margin in the crane part, saving weight that can be used for more fuel. As long as the crane can fly, it can take pictures and serve as a supplementary probe.

      --
      The man who does not read good books has no advantage over the man who cannot read them. - Mark Twain
    25. Re:Cool Movie - but bad idea! by korean.ian · · Score: 1

      Well, they're on the way. ckBot is an awesome beginning to this type of robot. Have a quick gander at this youtube clip.

      ckBot broken apart and comes back together

    26. Re:Cool Movie - but bad idea! by stranger_to_himself · · Score: 1

      I thing the point of this is to keep the rocket engines completely separate from the rover.

      Too bad the sky crane couldn't drop the rover, then land somewhere to become a stationary observation station. Turn it over to a university to operate for whatever data they can get from it. Seems a waste just crash it somewhere. There wouldn't be a lot of room in there but it seems like you'd want to put instruments on just about anything you're going to send all the way to Mars.

      Crash it fast enough and you might get an interesting fresh impact crater to explore. Don't know if that's possible though.

    27. Re:Cool Movie - but bad idea! by khallow · · Score: 1

      Ok, the weight savings makes sense. Plus your remark about overbuilding the rover indicates that this scheme has some hidden advantages. Namely because some mass on the vehicle serves also to assist in landing, you can afford a heavier vehicle than with a design that doesn't expose the vehicle to landing impact.

    28. Re:Cool Movie - but bad idea! by The+Fun+Guy · · Score: 1

      this scheme has some hidden advantages

      Well, they were hidden until I let the cat out of the bag. Doh!

      I forgot to mention that, as for this being an unproven technology, the Spirit and Opportunity systems did almost exactly the same thing with the retrorockets. They lowered the lander out on a tether + umbilical, then fired rockets to bring it to rest ~40m above the surface. Ground-capture imagery let them adjust thrust to counter lateral movement, so it would drop straight down, without a lot of side momentum. I should say, pretty close to rest... there was still some vertical and lateral movement when they cut the tether.

      Granted, they'll need much bigger rockets to slow down 900kg vs. 180kg, but a lot of the 180kg of Spirit and Opportunity was airbag, casing, support stuff. All of MSL will be of instrumental scientific value - a lot more bang for the buck.

      --
      The man who does not read good books has no advantage over the man who cannot read them. - Mark Twain
    29. Re:Cool Movie - but bad idea! by florescent_beige · · Score: 2, Informative

      You can see the pedigree of the concept. The airbag system used a brutal retro-rocket on the teather milliseconds before impact to slow the airbag-lander from smush speed to bounce speed.

      This is similar. The retro rocket is far more gentle and precise but basically we have a last-second retro rocket on a tether dropping the lander onto the surface.

      I presume tradeoff studies were done to find the optimum balance between the amount of crane hover precision and winch control precision for a giving touchdown speed tolerance at min weight.

      As noted, there are a lot of things deploying in rapid sequence, and a winch. Winch bad. Winch have many fiddly bits. I wonder if they also did a tradeoff study of reliability vs capacity of this concept and a brute-force lander.

      --
      Equine Mammals Are Considerably Smaller
    30. Re:Cool Movie - but bad idea! by Digital+End · · Score: 1

      I really don't understand how this type of thing continues to be modded up.

      How f-king arrogent is it to cheer the response of this or any other person on this forum who after glancing at the idea... an idea which many of the best minds in science have dedicated years of their life, working together with the best possible tools with specialized testing equipment and computer simulations...

      ...to think that the initial opinion of someone who glanced at a 3rd person report of the end result (and really just watch a movie), has anything to hold to that? I know it's 'just slashdot', but god damnit is this the respect we have for science today? To encurage that? It's a free internet, and he can say whatever he wants, but it'd have expected better from people modding. More people will likely read this nonsense then will actually GO to the sight.

      Find out WHY they chose this design if you want to learn something... what research was it that made this the best choice. What restriction, what limitation, what pushed this to the front.

      But to sit at your computer with a hand in your pants and a finger up your nose and pass pathetic judgement on people who have done more for human understanding then you ever will... it shouldn't be encuraged.

      (PS; not directed only at you OP, half the thread are worse examples of this which pissed me off, wasn't yours specifically. Yours was just the first 'wrong' response on the list with +5) (PSS; I'll take the karma hit, so tired of seeing them get plus modded for this)

      --
      Beware of he who would deny you access to information, for in his heart, he dreams himself your master.
    31. Re:Cool Movie - but bad idea! by Dripdry · · Score: 1

      My mind has just gone nuts on this one. Keep in mind I didn't get much sleep last night, and have been kinda stressed, but here goes:

      What about sending useful, reusable machinery ahead of us/our probes to Mars?

      Your idea about a machine that puts itself together does sound interesting, although if one mission should fail, does the entire thing fall apart? Would it be worth it to simply send pieces of a unit to Mars which can put itself together over time to create some sort of sustainable power generator? Of course, there must be dirt/dust/environmental issues and other obstacles, but is it possible anyway?

      That way, future vehicles could land (or try to) near the generator and, whenever necessary, plug into it for more power. Perhaps that thing could havelittle bays where the rover could rove (or whatever they do) right into it for protection, or to sit out the Martian winter.

      It sure sounds to me like we've begun littering Mars with dispoasble junk, just like Earth. Why not set a precendent by introducing a sustainable energy source there and allow any nation to simply plug right into it for their missions?

      Could we do this for the moon as well? As stated earlier, landing anything on the moon would be MUCH easier than Mars, so couldn't we have a robot (or pieces of one) build itself into a basic structure or two up there ahead of time? I'm sure it has been thought of, and I know there are issues with moon dust, so perhaps my little day-dream is a little uninformed.

      Should anyone ever decide that Mars is a good place to visit (I think Venus should be first, but IANA Astrophysicist) a scheme like this might give them a place to begin. Sure, the generator might only be able to power a flashlight or two, but it would be a starting point.

      Just a thought from someone who wishes he had a more technical background in this sort of thing.

      --
      -
    32. Re:Cool Movie - but bad idea! by Cheeko · · Score: 1

      You hit this spot on.

      My brother is on the project and we've discussed many times the process they went through to come to this solution. As its been explained to me the scale meant that they needed to move on to something else the airbags were a brilliant idea for their scale, but they reached their limit.

      Another somewhat related topic I found interesting were some numbers he heard some guy run during a talk. He mentioned how this is a good middle step to the sizes of payloads a manned mission would need. Even if you take into account aero braking etc, the atmosphere is too thin to slow heavier crafts (say a human lander) to a speed that would make landing survivable to a person. The shock from mach 1+ chutes would likely kill people, and the amount of fuel you'd need for a pure retro descent is prohibitive. With current tech human landing might not be possible, so this is a good next step since airbags wouldn't be feasible for humans either.

      Incidentally the first bounce from the airbags was something like 3km if i recall correctly.

    33. Re:Cool Movie - but bad idea! by Mr2cents · · Score: 2, Interesting

      Indeed, you are right about Spirit and Opportunity.. I almost forgot.

      I am fairly confident that NASA has made the correct choice about the EDL method, but I really wonder if they are going to be ready in 2009. I haven't seen any photo's of the MSL construction, so I don't even know if they have already started building it or not. Or are they planning to do construction in just a few months? I know the science instruments are all (nearly) finished, but I hardly hear news about the rest of the hardware.

      --
      "It's too bad that stupidity isn't painful." - Anton LaVey
    34. Re:Cool Movie - but bad idea! by Anonymatt · · Score: 1

      Don't you just wish you could be there to see it go down? If it does, that is.

    35. Re:Cool Movie - but bad idea! by genner · · Score: 1

      It sure sounds to me like we've begun littering Mars with dispoasble junk, just like Earth. Why not set a precendent by introducing a sustainable energy

      In space there are no trees to hug.

    36. Re:Cool Movie - but bad idea! by Chris+Gunn · · Score: 1

      You you explain it to us? I don't see the advantage of not landing the rocket. All I see is an extra level of complexity. I don't see how this method saves fuel, or gives a softer landing.

    37. Re:Cool Movie - but bad idea! by GrayNimic · · Score: 1

      As I understand it, the rationale behind this is twofold and actually rather simple:
      1) Hard vs Soft landing: The sensitive equipment is hard/expensive to make able to endure the shocks of a hard landing, like the Spirit/Opportunity "Airbag" landing. MSL will be a "soft" landing, like the Viking landers and Phoenix, putting less strain on its equipment and therefore letting them get more delicate instruments to the surface. (you can do this without a SkyCrane, obviously, but this is the reason for not using a landing system like the Mars Exploration Rovers)

      2) Location: Landing on a boulder = bad thing. That's always one of the dangers of landing - even if you aim for a gigantic open field, you still might hit that one single protrusion that could destroy your lander. The SkyCrane lets you pick your landing spot to a minor degree, meaning that you can even potentially land in a boulder-strewn area (which might be the kind of geology you want to target) and have a dramatically reduced danger of your lander becoming uselessly stuck or destroyed by what it lands on.

      Overall, I do agree that this seems like an excessively complicated system to add-on, and an 'easy' way to add lots of new ways to fail. That said, I can at least sympathize with the rationale for wanting something like this (the above two reasons).


      (There is a third reason they've cited, but this one I don't really understand the logic of - how is the SkyCrane "deploy" any 'better' than egressing a lander?)
      3) "You haven't really landed yet" - with the MER, once they'd "landed" they hadn't really landed - the rover wasn't yet on the surface. When you land on a platform like MER did, you still have a complicated, 'dangerous' process of getting the rover extracted from the lander and onto the surface. By using SkyCrane, this step is removed - once you get to the surface, you're on the surface "for real", and can begin your checkout and setup of the rover proper.

    38. Re:Cool Movie - but bad idea! by khallow · · Score: 1

      I forgot to mention that, as for this being an unproven technology, the Spirit and Opportunity systems did almost exactly the same thing with the retrorockets. They lowered the lander out on a tether + umbilical, then fired rockets to bring it to rest ~40m above the surface. Ground-capture imagery let them adjust thrust to counter lateral movement, so it would drop straight down, without a lot of side momentum. I should say, pretty close to rest... there was still some vertical and lateral movement when they cut the tether.

      Wow, I didn't know about the tether. That makes this much more interesting. Because you are right, the technology has been tested.

    39. Re:Cool Movie - but bad idea! by florescent_beige · · Score: 1

      Intuition tells me there must be advantages to landing a smaller weight. Perhaps it is because some of the touchdown precision can be achieved by winch control instead of flight control. That is, you need a less accurate and lighter flight control system, and, the landing gear can be less robust. Those strike me as second order effects but weight to Mars must be ridiculously expensive.

      --
      Equine Mammals Are Considerably Smaller
  2. WTF: Hyper-realistic? by corsec67 · · Score: 5, Funny

    Almost realistic: the simulation approaches what the same inputs would do to the real system.

    Realistic: the simulation behaves the same way as the real system.

    Hyper-realistic: the simulation is better at realism that they real system?

    What next, über-realistic? Or is profit next?

    --
    If I have nothing to hide, don't search me
    1. Re:WTF: Hyper-realistic? by zappepcs · · Score: 1

      Profit is next actually... I have no idea why the story submitter can't believe this. There are some awesome engineering feats that our species has accomplished here on earth. UAVs are awesome. The Thames flood damn is awesome. ISS is awesome. Comms satellites are awesome. Heavy lift helicopters are awesome. VTO spaceships and fighter jets are awesome. Autonomous gliders launched from weather balloons in near space are awesome. Why is it so difficult to believe this Mars mission? The Lunar lander did similar feats. It's even possible to test this with modified equipment right here on earth. I don't understand why this is so difficult to believe, or why some might call it a bad idea?

      A soft landing is much preferred to a 6G impact any day, or whatever you call it on Mars. Perfecting this technology might even allow for a more precise landing spot... a little extra fuel and you could hover the lander over to the desired location several kilometers away?

      Oh, by the fucking way, that guy who flew his jet powered wing pack over the English Channel is awesome too.

      --
      Support NYCountryLawyer RIAA vs People
    2. Re:WTF: Hyper-realistic? by Anarchitect_in_oz · · Score: 2, Insightful

      I think it's to cover all the storytelling camera movements and focus effects, that go above and beyond the simulation of the concept itself. More fun to watch that way. Like news is more interesting with handheld cameras and fast cuts.

      --
      "Call us when the New age is old enough to drink" Beck
    3. Re:WTF: Hyper-realistic? by zippthorne · · Score: 1

      Like news is more interesting with handheld cameras and fast cuts.

      No, it really isn't. Fast cuts are ok, but if the shaking isn't caused by my own head, I feel like I'm being lead around. It's not very comfortable. I'm talking to you Ronald D. Moore.

      --
      Can you be Even More Awesome?!
    4. Re:WTF: Hyper-realistic? by gnick · · Score: 1

      Why is it so difficult to believe this Mars mission? The Lunar lander did similar feats. It's even possible to test this with modified equipment right here on earth.

      I agree almost 100%. But why must we test the awesome tech we're developing for space exploration in space? It's awesome engineering with a good cause, but we can do the same things here (more or less) at a much reduced cost. I'm convinced that the difference in cost between deploying locally and deploying extraterritorially must exceed any benefits we'll receive from making actual landings. I know slashdot is full of folks who want robots/astronauts actually tromping around, but what's the actual cost/benefit?

      The big push I see is that actual landings, despite making questionable sense from a budgetary standpoint, may be the only way to garner funding for our tech development. That's just too depressing for me to accept...

      --
      He's getting rather old, but he's a good mouse.
    5. Re:WTF: Hyper-realistic? by zappepcs · · Score: 1

      As someone who tinkers around with robots, perhaps I can shed some light on the question you ask:

      I know slashdot is full of folks who want robots/astronauts actually tromping around, but what's the actual cost/benefit?

      There is much to be learned by building robots galore. Intelligent machines can make many tasks much more cost effecting in the 'long run' but will cost much to start, and seem silly for a long while. I say in the long run because what we think we know today is merely the tip of an iceberg. A couple of benefits of robotics engineering experience are: iRobot's vacuum robot and bomb disposal robots for the military and police, the Canadarm on the space shuttle, Automated mechanical assembly (makes things cheaper)

      When you consider the cost of sending an unmanned craft halfway across the solar system compared to cost for a similar manned mission, cost savings are incredible. This is more poignant in view of the fact that we are not sure yet why we'd send a manned mission. If robots can do the work necessary for initial and preliminary discoveries, then the cost is greatly reduced. If we find a chemical on the surface of another planet that not only sequesters CO2 but turns it into useful hydrocarbons by mixing it with seawater and sunlight... that would be worth going after a boatload of the stuff. Perhaps by sending robot explorers we find something that could replace all the predicted oil energy with just 10 trips for the next 75 years? What we don't know is exactly what we'll find and we are kind of running out of time and discoveries on this planet. Time to explore the next great frontier... surface exploration of other solar planets.

      In the meantime, we take baby steps. Vacuums, IED warriers, manufacturing, toys, and other methods of financing further development. BTW, there are many groups around the globe that are experimenting with robotics in their garages. Some of them are pretty fucking awesome. Here are a couple that I've seen close up and personal that are quite impressive http://www.geology.smu.edu/~dpa-www/myrobots.html They won't be exploring Mars anytime soon, but the principles involved in creating these robots apply to exploring mars as well.

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    6. Re:WTF: Hyper-realistic? by Max+Romantschuk · · Score: 1

      Hey! You spelled über correctly! Don't tell me you can pronounce it too? ;)

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    7. Re:WTF: Hyper-realistic? by zappepcs · · Score: 1

      Perhaps I did miss the point? I hope I didn't.

      What we don't know is exactly what we'll find and we are kind of running out of time and discoveries on this planet. Time to explore the next great frontier... surface exploration of other solar planets.

      I don't think that the great explorers of Earth waited for the very best high tech gear that was possible before they went exploring to find new lands and the poles etc. Whether that seems wise or not, you really will have trouble inventing new and groundbreaking diving gear without getting in the water. What you can discover in your backyard pool is good, but it's not quite the same as experimenting at 275 meters.

      Yes, some flight equipment can be tested in Earth atmosphere, yet others can't really be tested except in space, except theoretically. The space race and moon endeavors as well as Mars missions and others have helped add impressive amounts of data to what we do know about space travel. The Voyagers found some interesting information about gravity and our solar system, but that took years. You really can't send men out for that long. We have some information about radiation in space (outside our protective atmosphere/magnetosphere) but more information is needed. Waiting for that information until there are perfected space craft that can't possibly fail will hinder the over-all progress and perhaps cost humanity the chance for a better world. Explorers are not known for their timidity. How many great discoveries by the human species were made while analyzing the failure of other research? Accidents as it were. This is real 'get your hands dirty' science at it's best. Try, experiment, analyze the failures, celebrate the successes, continue to learn.

      Your thoughts on what is out there are fair, but based solely on what we think we know so far. What discoveries have been made by the Mars missions? Water ice? It's confirmed. This helps shape how we look at other planets through telescopes and with sensitive instruments orbiting this planet. Each discovery or confirmation of theory builds a greater base of knowledge for our use. While you speculate that we need to first master fusion reactors, perhaps it will be a discovery in our solar system that allows us to do that. Some material or carbon matter that does not exist in any quantity here on Earth. Think about the KT boundary. It was not created by wind and rain. What else can be created by things we do not have in abundance on this planet? Like lack of heat for instance, or constant bombardment by other small bodies, or by radiation that we are protected from.

      Your line of thinking seems to be: Lets not go into the store until we are sure we have the best shopping cart, and we know exactly what we are shopping for and are certain that it is available for purchase in the store. Thankfully the early explorers on Earth were not so timid.

      From this, I conclude that you are male. I can also conclude that you will probably never run NASA.

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    8. Re:WTF: Hyper-realistic? by Frequency+Domain · · Score: 1

      What next, über-realistic? Or is profit next?

      You want über-realistic? Check out http://www.marsipan.co.uk/index2.php?mission=1170270775

    9. Re:WTF: Hyper-realistic? by rts008 · · Score: 1

      No, I think you go from 'hyper-realistic' to 'OMGZ!!11Ponies!!!'.
      There are only 'hyper-profits' in 'hyper-realistic' worlds...EVERYONE is hyper-rich!!!

      Is this where 'gag me with a spoon' is used?

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    10. Re:WTF: Hyper-realistic? by R2.0 · · Score: 1

      I believe the proper term is ludicrorealistic.

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    11. Re:WTF: Hyper-realistic? by moosesocks · · Score: 1

      What next, über-realistic?

      They've gone to plaid!

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  3. Another slashdown? by Fluffeh · · Score: 1

    I think the site got slashed, I can't view the vids :(

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    1. Re:Another slashdown? by Alpha+Whisky · · Score: 1

      Click on the NoScript icon and select "temporarily allow gizmodo.com"

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  4. Why not use what works? by ryanisflyboy · · Score: 2, Insightful

    Why does NASA have to spend money on new untested methods? If the old baloon method worked well for two previous rovers, why not use it again? It is hard to beat a 100% success rate. Does anyone know why they want to use this over other methods?

    The sysadmin in me says: The more moving parts, the greater the chance something will break.

    1. Re:Why not use what works? by ColdWetDog · · Score: 5, Informative

      Why does NASA have to spend money on new untested methods?

      Trebuchet's don't scale very well. AFAIR, neither did the beach ball. This thing is lots bigger and heavier.

      --
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    2. Re:Why not use what works? by Yvan256 · · Score: 1

      And I can't help but think about all that extra weight that needs to be launched and is useless once the rover has landed, not to mention the cost of the sky crane itself.

    3. Re:Why not use what works? by corsec67 · · Score: 2, Insightful

      True, but how much does a triangular pyramid covered with self-inflating balloons weigh? Plus it had the hinged ramps that would fold down, so the old landing method wasn't completely without complex stuff.

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    4. Re:Why not use what works? by Anonymous Coward · · Score: 5, Informative

      It has to do with mass, the MSL rover, at 900 kg, is much too heavy to land using the airbag methods that landed the 180 kg Spirit and Opportunity rovers. To give a sense of scale, the MSL rover is the size of a minivan, while Spirit and Opportunity are the size of small riding mowers. See:

      http://en.wikipedia.org/wiki/Image:Mars_Science_Laboratory_empty_chassis.jpg

    5. Re:Why not use what works? by Tablizer · · Score: 1

      the MSL rover is the size of a minivan, while Spirit and Opportunity are the size of small riding mowers.

      But they did a fine job nevertheless, for I saw zilch grass in the photos.
               

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    6. Re:Why not use what works? by Somegeek · · Score: 1

      I was just going to use that example but state that therefore it obviously DOES work for much larger payloads!

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    7. Re:Why not use what works? by zbharucha · · Score: 1

      The balloon system cannot be used as the payload's weight increases. This is why even the Phoenix lander had to use rockets. It was just too heavy for the bouncy balloon option. It's really annoying when readers just post their bitchy comments without considering that NASA might have thought of these things before them!

    8. Re:Why not use what works? by david.given · · Score: 1

      That's about twice as big as the Viking landers, which at 570kg are the biggest things to be landed on Mars to date.

      They used an aeroshell for the initial reentry and to slow to 250m/s (are you allowed to call it a reentry if it's the first time you're entering the planet's atmosphere?), a set of parachutes to slow to 60m/s and to descend to 1.5km from the surface, and then rockets for the final touchdown, which happened at 2.5m/s.

      However, I'd imagine that this approach would be totally unsuitable for a rover because you end up with lots of rocket hardware and tankage on the vehicle itself.

      (Trivia: Viking 1 lasted for six years before someone accidentally overwrote the antenna pointing software. Viking 2's batteries failed after about half that time. Both landers were powered with a RCA1802 8-bit microprocessor. The whole project, both missions, cost about $1B in 1978, which is equivalent to about $4B in 2008 --- so the price of a trip to Mars is definitely coming down.)

    9. Re:Why not use what works? by Cheeko · · Score: 1

      I've seen the mockup in person (family member works at JPL). The comparison I was given was to a VW bug (the new one). Its almost identical in size, but taller with masts etc

  5. And by Konster · · Score: 5, Funny

    We've got to flex some of our engineering muscle in front of our Martian friends so they will less inclined to invade us. In this light, clearly this > bouncing beach ball delivery.

    Maybe have an external speaker system that blasts Ride of the Valkyries during descent, too.

    1. Re:And by memristance · · Score: 2, Funny

      In that vein, I propose we scrap the whole robo-probe thing and go straight to a manned lander.

    2. Re:And by TheDarkMaster · · Score: 1

      +5 funny is not enought to this, LOL!

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  6. Who am I to question NASA's physics... by fishinatree · · Score: 1

    I know that Mars's gravity is only about 40% of Earth's, and its atmosphere is less dense. So would a parachute even work? It doesn't seem that a less dense atmosphere would be able to generate the air resistance needed to keep the rover up in the air, especially with all the gas the crane needs as fuel to generate the thrust necessary to hold the rover in the air. I don't know the exact physics of it, but just in terms of a balance of forces, this does not seem extremely plausible.

    1. Re:Who am I to question NASA's physics... by zappepcs · · Score: 2, Informative

      That is the reason for the skycrane. If the air were as dense, a standard parachute landing would be all that is required. The problem is an inability to decelerate to a stop without the sudden stop part. I believe that gliders are also out of the question due to atmospheric conditions. This is a compromise of all known possible options. One that will land the heavier weight, and perhaps give them much greater accuracy in choosing a landing spot... With the speed of the rover hitting the right spot first try can be quite a bit of savings.

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    2. Re:Who am I to question NASA's physics... by fishinatree · · Score: 1

      I see what you're saying, but what about the lack of deceleration that the parachute would provide? If you didn't have enough deceleration from the initial parachute, then the sky crane would have to provide a lot of thrust to overcome the momentum...but then....that's what the retrorockets would be for....I think my only hope is to abandon my current thread of thought and wait for someone to take pity on me and mod me up for being "funny" or at least "interesting"...please?

  7. preposterous by heroine · · Score: 1

    The skycrane seemed preposterous originally & still does. Having said that, autonomous helicopters are pretty germane nowadays & everyone knows about Stanford's aerobatic helicopter so maybe it's not so crazy anymore.

    1. Re:preposterous by dutchd00d · · Score: 1

      Be sure to let NASA know when you've finished your design of a helicopter that can support 900 kg in an atmosphere 170 times less dense than Earth's.

      Preposterous indeed.

  8. turtle on its back by rcallan · · Score: 1

    What are the chances it lands on its side or back? It would be very embarrassing to land the thing on its side or back, with everything otherwise functional and intact, but still completely useless.

    1. Re:turtle on its back by Profane+MuthaFucka · · Score: 4, Interesting

      The video showed the lander dropping straight down on the wheels without any side motion at all. This seems unlikely to me. The rover would be swinging like my dick on those cables unless there were some thrusters used to stop any swinging motion.

      Other than that, it's a pretty neat idea, ESPECIALLY for a spacecraft which is not a rover. A rover can move out of the landing zone, but a stationary spacecraft cannot. It would be sitting on soil which has traces of hydrazine from the landing rockets - but this system would avoid that problem.

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    2. Re:turtle on its back by Mr2cents · · Score: 1

      The rover would be swinging like my dick on those cables unless there were some thrusters used to stop any swinging motion

      Erm.. if you watch the video you'll see the crane has multiple thusters. In fact, without those thrusters MSL would have a real problem landing.

      (Hint: The rockets don't have to be mounted on the lander to counter swinging motions, just by moving the crane you can cancel out the swings - it works both ways).

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    3. Re:turtle on its back by Profane+MuthaFucka · · Score: 1

      After thinking about it for a second, I think you're right.

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  9. Not entirely practical by Chazerizer · · Score: 2, Informative

    As cool as this is, we've succesfully landed rovers on mars (and the moon, though not a robotic system), as well as landing non-motile craft on other planets. All used relatively simple delivery systems, and frankly, worked pretty well. The Apollo system (at 40 years old) landed softly enough not to smash human beings, which can be a lot more sensitive than robots. Maybe this type of technology will have a use in the future (though it's not like it's a super-high-tech idea). All of that being said, GOD DAMN that's cool!

    1. Re:Not entirely practical by DerekLyons · · Score: 4, Informative

      As cool as this is, we've succesfully landed rovers on mars (and the moon, though not a robotic system), as well as landing non-motile craft on other planets. All used relatively simple delivery systems, and frankly, worked pretty well.

      So what? This thing is much larger than anything landed anywhere before, with the exception of the manned LEM.
       

      The Apollo system (at 40 years old) landed softly enough not to smash human beings, which can be a lot more sensitive than robots.

      The Apollo capsule had an atmosphere much thicker (as in height) and much thicker (as in density) than the Mars landers have available. The Apollo LEM could use rocket braking because of the Moon's low gravity.
       
      Mars is a stone cold bitch to land on because the atmosphere is too thin to completely rely on parachutes, and Mars' gravity is too high to rely completely on rockets.

    2. Re:Not entirely practical by nedlohs · · Score: 1

      Apollo had people in control to turn off the rockets so they didn't take off again (well not "land" in the first place). The lander had to hit 0 speed at some distance from the ground, and then stop firing the thruster.

      The "lower by rope" system has the advantage off a much much larger range heights for that 0 speed point. It doesn't have to do a thruster based landing it just to get within [length of the rope] from the ground before it starts going back up.

      This seems a good solution to me - not as cool as a bouncing ball though...

    3. Re:Not entirely practical by Somegeek · · Score: 1

      I don't buy that. If Armadillo Aerospace can design and build a lander that can go from a hover to a soft controlled rocket landing, in Earth gravity, why can't NASA do the same thing in Mars gravity?

      http://media.armadilloaerospace.com/2007_10_21/modFreeFlight.mpg

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    4. Re:Not entirely practical by kdart · · Score: 1

      Probably because 1) the vehicle is not starting from hover, but starting at over 10 km/s when it reaches the atmosphere, and 2) the vehicle will have a mass over 1000 times greater than that demo vehicle.

      That demo vehicle video is very cool, but I noticed it only carried its own fuel. There was no useful payload.

      --

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    5. Re:Not entirely practical by kdart · · Score: 1

      Oh, one other detail. I noticed the demo vehicle also had to have an already prepared slab of concrete to land on. I suspect the crane idea is there to avoid the problem of not blasting a hole in the possibly soft dirt or ice that the rover would have to land on.

      --

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      The early bird catches the worm. The worm that sleeps late lives to see another day.
    6. Re:Not entirely practical by Goaway · · Score: 1

      Of course they can do that. They don't, because it's a bad idea.

      Landing on the surface with rockets kicks up dust, for one, so you need to protect the rover from that with a dustproof shell. Which adds weight, which you can't afford. And then you need to get the rover down on the ground. And so on.

      Is it really so hard to actually consider the fact that NASA may have put some actual THOUGHT to this?

    7. Re:Not entirely practical by Somegeek · · Score: 1

      Is it really so hard to actually consider the fact that NASA may have put some actual THOUGHT to this?

      I understand that NASA has put thought into this. This just seems a very convoluted solution and nobody that I have seen has adequately explained the rationale behind the hovering sky crane piece in a way that explains all of the risks associated with it. I am trying to understand what their thinking is, not deride it. Nedlohs had provided his explanation above, and I countered with why I didn't think that was the real reason for the sky crane.

      Your dust explanation may be closer to the truth but there has to be more to it than that. After all, a protective shell wouldn't have to be 'dustproof'; a simple sheet might do it, and certainly wouldn't add lots of weight. A vehicle this size is going to kick up dust of its own in its travels, so it will be designed to live with that anyway. Also this rover doesn't depend on solar cells that need to remain clean like the current rovers do.

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  10. what I don't understand by the_Bionic_lemming · · Score: 2, Interesting

    We seem to be able to get to mars better, the Russians do land landings better than us.

    why not have them design and build the landing mechanism, and we just fly it there?

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  11. Almost as good as stunt helicopter pilots by TheKidder · · Score: 1

    Remember the last complicated descent method of NASA's that worked so perfectly? The get-caught-by-a-stunt-helicopter-pilot method? Granted, the reason that crashed was fairly mundane, but still...

  12. Half life by greyhueofdoubt · · Score: 1

    Did anyone else get a Black Mesa vibe from the wind sound effect at the end of the video?

    Also, would wind sound like that in an atmosphere like mars'?

    -b

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    1. Re:Half life by Leif_Bloomquist · · Score: 1
      Also, would wind sound like that in an atmosphere like mars'?

      Hopefully, we'll get to find out:

      http://www.livescience.com/blogs/2008/09/18/phoenix-mars-microphone-turning-on-the-robots-ear/

    2. Re:Half life by greyhueofdoubt · · Score: 1

      I never knew about that. Thanks for the heads up.

      -b

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  13. Meh by moniker127 · · Score: 1

    That video was boring. Why dont they just make a mini helicopter to decelerate the thing? Or is the air too thin for that?

    1. Re:Meh by ThePeices · · Score: 1

      The atmosphere is way way too thin for that to be practical. It should be pretty obvious that if there was an easier and more reliable method of landing a 900kg rover, NASA would have gone with that.

      NASA engineers are somewhat of an intelligent bunch methinks...

    2. Re:Meh by Goaway · · Score: 1

      If you were actually as smart as you think you are, you would have gone and found out yourself why they didn't attach landing jets to the rover.

      Instead, you chose to trumpet your own ignorance as if it proved you to be smarter than others.

  14. Its easy to forget how Big MSL is. by mcwiggin · · Score: 1, Redundant

    The reason why airbags won't work is because the MSL Rover is about the same size as a large car. It amazing to think something this large will be traveling around mars. http://en.wikipedia.org/wiki/Image:Mars_Science_Laboratory_empty_chassis.jpg Image of MSL under construction.

  15. simulation? by Goldsmith · · Score: 1

    I don't think that word means what you think it does.

  16. This link explains a lot of your questions. by Fourpole · · Score: 1

    Here is a link to a Universe Today story outlining the difficulties of landing on Mars. This is mostly about a manned mission but it does specifically reference the MSL. http://www.universetoday.com/2007/07/17/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/

    1. Re:This link explains a lot of your questions. by Somegeek · · Score: 1

      Thanks, good link!

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  17. No solar panels? by TheModelEskimo · · Score: 1

    The guy that's been doing the 3D animations for high-profile NASA projects usually goes as close as possible to the reference. There don't appear to be any solar panels on the rover - is it nuclear-powered, or what?

    1. Re:No solar panels? by Concerned+Onlooker · · Score: 4, Informative

      Not exactly. It is radioisotope power but it is not nuclear power in the sense that there is a reaction going on. The simple decay gives off heat. As I recall it's not that much, either. Something on the order of 110 watts. Still, it's much better than relying on solar panels. Here's a nice page of fact sheets for the mission.

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  18. Story? by tsa · · Score: 1

    Who is tagging every post on /. as story and why? I know this is off-topic but I'm so curious. Oh and by the way, this is how to find life on Mars.

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    1. Re:Story? by ceoyoyo · · Score: 1

      If you wave your mouse over it it says it's a type tag. I suspect it's added by the editor who posts the story. Since Slashdot doesn't seem to have anything BUT stories, I'm not sure there's a point to having it, and I'm pretty certain there's no point to displaying it.

    2. Re:Story? by tsa · · Score: 1

      Exactly my thoughts. It's a useless waste of bits! Horrible. ;)

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  19. Is that you Mal? by Wannabe+Code+Monkey · · Score: 1

    Was it just me or did anyone else expect to see Jayne suspended from the bottom of that rover?

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    1. Re:Is that you Mal? by MRe_nl · · Score: 1

      No, but I did expect the word "Bitterman" on the side of the vehicle, in large unfriendly letters.

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  20. Landing on Mars is hard by Animats · · Score: 4, Informative

    The problem with soft-landing heavy objects on Mars is that there's not enough atmosphere for aerobraking and parachutes to do the job, so the approaches used for Earth re-entry won't work. There's too much gravity for landing on rockets. as with lunar landers, without most of the payload being landing fuel. The problem gets harder as the mass goes up. This was realized only about five years ago, to the embarrassment of some within NASA. So there are now various complicated hybrid schemes, like this.

    The scheme with the cables does not look promising. Unlike Luna, Mars has winds and weather. This looks like one of the student lander designs from NASA's high school curriculum.

    One bad feature of this design is that the actual landing forces have to be taken by the rover's suspension. Previous designs had the rover inside the landing module, not underneath it. That approach uses crushable components (air bags, crushable blocks, collapsible legs, etc.) to cushion the landing. With this "flying crane" approach, the autopilot has to do a really, really smooth landing or the rover will be broken.

  21. Anyone know? Audio recordings of Mars? by foniksonik · · Score: 1

    Watching that and hearing the wind blow made me wonder if there have been any audio recordings taken on Mars? I'm sure it would be boring as hell but still that would be really cool for the first minute or so... you know, to listen to Mars (well whatever you can hear in the 1km radius around the rover anyways).

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    1. Re:Anyone know? Audio recordings of Mars? by Somegeek · · Score: 3, Informative

      Just a little longer...

      http://www.space.com/businesstechnology/081001-tw-phoenix-microphone.html

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  22. MSL weight: 1 ton by LordMyren · · Score: 1

    You should point out it weights 1984 pounds... just shy of one ton. It makes the landing system a lot more intuitive.

    1. Re:MSL weight: 1 ton by LordMyren · · Score: 1

      It weights 1984 lbs on earth, hence its mass is 1984 lbs.

    2. Re:MSL weight: 1 ton by LordMyren · · Score: 1

      the inverse would have meant it would have massed nearly 6000 lbs, making it an even bigger crater.

  23. Re:Mars? Bah. Just another Athiest Myth! by Anonymous Coward · · Score: 1, Funny

    Your religion is weak. Forsake your old god and embrace your new faith.

  24. Really Poor Concept by VendettaMF · · Score: 2, Informative

    The whole operation is horrendously complicated, with dozens of potential failures at each point, and no realistic means of allowing for such failures. Every step would have to function perfectly, or we've just sent another multi-billion paperweight to a dead planet.

    Whatever happened to KISS?

    The engineer who proposed this really needs to look into alternate fields of employment. I suggest Fecal Matter Relocation.

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    1. Re:Really Poor Concept by DerekLyons · · Score: 1

      The whole operation is horrendously complicated, with dozens of potential failures at each point, and no realistic means of allowing for such failures. Every step would have to function perfectly, or we've just sent another multi-billion paperweight to a dead planet.

      Whatever happened to KISS?

      In real world engineering it's actually KISAP - Keep It As Simple As Possible. Some complexity is almost always unavoidable.
       
       

      The engineer who proposed this really needs to look into alternate fields of employment. I suggest Fecal Matter Relocation.

      If you have a lighter, fully functional, and better design, feel free to submit it or your resume to the appropriate office.

    2. Re:Really Poor Concept by Klootzak · · Score: 1

      Whatever happened to KISS?

      It's still there, applied by Engineers/Scientists/Technologists and other people who design stuff.

      Unfortunately when you work in projects like this, you need a "Wow, that's cool!" factor for people who grant your funding. My guess is the sky-crane is one of the things providing that factor in this project. Lets face it, the KISS principle provides us with very reliable but (mostly negative wow-factor) technology.

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  25. Re:This is needlessly complicated and HERE is why: by the_other_chewey · · Score: 4, Insightful

    Even in their most recent plan for this Mars descent, their first mode of descent is to drop the module like a stone, using elaborate and expensive heat shielding to protect the even-more-expensive gear. But maybe -- just maybe -- they could take a lesson from Spaceship One and just take their time getting this thing down to the ground.

    Sorry - but you have no clue. Mars' atmosphere at the surface has about 1% of the Earth's density, making something like aerodynamic flying impossible.
    There simply isn't any other way than "dropping like a stone" - even on their parachutes, the rovers did exactly that. Those parachutes were supersonic, and their
    main purpose was trajectory stabilization (although they did of course contribute to the braking).

    Go read this article already linked above for a well written explanation about why
    landing on Mars is actually very hard and cannot in any way be compared to landing on Earth.

  26. Re:This is needlessly complicated and HERE is why: by Somegeek · · Score: 1

    Sorry for being so dense, but I really don't understand.

    At the apogee of its flight, when it starts to descend back down, SS1 is going, well, zero. It's fairly easy to take it slow at the beginning when you start at zero, no?

    When a NASA spacecraft starts down, its going, well, that orbital velocity that you mentioned.

    How can those, basically, conceptually, be the same?

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  27. Why the crane part? by Somegeek · · Score: 2, Insightful

    I'm OK with everything up until they start winching the lander down under the crane. How is that better than sitting the rover on top of the retro rocket module, hovering, then landing, and having the rover drive off the top of the lander?

    The number of failures that could happen to the winching system seems nuts; a line might not lower, or at the wrong speed, or a line could tangle, or a side to side oscillation while descending, or a cable not disconnect, and if any of these go wrong, you have no time to fix it.

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    And as you tread the halls of sanity, You feel so glad to be, Unable to go beyond. I have a message, From another time..
    1. Re:Why the crane part? by n-baxley · · Score: 1

      You make a good point, but I would guess that getting a system to slow the decent just enough to achieve a soft landing is pretty complicated. Plus the whole process has to be automated. This isn't like the moon landings where you have an astronaut controlling things and reacting as things change. The "no time to fix it" you mention is the same no matter how you land. There's like an 8 minute radio delay between earth and Mars, so no chance for humans to be involved.

      Besides, while this is complicated, getting the whole thing to Mars in the first place is a bit complicated and if they can pull that off, they can probably get this figured out as well.

      --

      THIS SPACE FOR RENT
    2. Re:Why the crane part? by James+McP · · Score: 1

      Landing on thrusters with significant gravity and atmosphere is hard. Since the gravity is much greater than lunar landings, it requires a lot of thrust. Then you've got the sudden boost in lift caused by direct ground effect. A big part of learning to land is to deal with the sudden increase in lift b/c the natural response is to power down aggressively, which tends to cause your vehicle to drop ~15' like a rock as you stall. Not fatal most of the time but very hard on vehicles.

      Minor variations on the surface can result in incredibly complicated interactions like reflections, harmonics, and rotation. IIRC, some helicopters can literally have their rotors shattered if they land at the wrong speed b/c a harmonic is created. (I am not a pilot but I love helicopter sims) I've got no idea what the rocket equivalent is but I'm sure it probably exists. IIRC one of the x-prize vehicles had a similar failure with a rocket landing when the pilot flaked out.

      Since the martian terrain is brocken rock and blown sand, the rockets are going to dig into the ground, making it a dynamic landing site. That requires a very complicated pilot, not to mention you have to worry more about rocket-propelled detritus. So I can see how it would be much safer to get the lander to the ground effect zone and just hover there. The rover has to be attached to the lander anyhow and adding ~5m of cabling and a winch is probably less complicated than writing an autopilot. Plus the rocket blast will be angled far enough out that the landing site will be mostly unaffected, aside from blown dust which is an everpresent issue on Mars.

      --
      I've been on slashdot so long I'm starting to get out of touch with the cool stuff if it ain't on slashdot.
    3. Re:Why the crane part? by ChrisA90278 · · Score: 2, Insightful

      I think some one figured out that a winch is ligher weight then a folding ramp. You have to remember that this next rover is the size of a car. Think about how you'd make a folding ramp that would allow a car to drive off a lander. The winch is very compact and light

      A ramp carries a risk too. It would need a set of motoers and gears to make it unfold. If there is anything in spacecraft that will fail it is those kinds of moving parts and they depand on batteries that have beenin space for a year.

      The winch could be a simple fiction device. Not a motor, just a spool of cable that is pulled open by the weight of the rover and some kind of friction device to reduce th speed that the cable can unroll.

  28. fecal matter relocation by weirdo557 · · Score: 1

    i for one do not trust rocket powered cranes hovering above my house while full of fecal matter.

  29. subject by onIXep · · Score: 1

    Very interesting subject. I don't know why but after looking at it, thoughts about life and death visited my mind: Life is fantastic The beauty and sorrow Death is too drastic I can't say goodbye Golden or plastic The joys of tomorrow Life is fantastic I don't want to die

    1. Re:subject by weirdo557 · · Score: 1

      i see that NASA's new mood control experiments are moving along quite nicely.

    2. Re:subject by onIXep · · Score: 1

      it's allways require manual override :(

  30. Re:This is needlessly complicated and HERE is why: by Joce640k · · Score: 1

    Big difference: The space shuttle is going 18,000mph when it starts re-entry.

    Spaceship one isn't, so it can easily do things more gently.

    --
    No sig today...
  31. Zoom, blur, zoom! by Trogre · · Score: 1

    What, did they hire the New BSG CG team for this?

    --
    "Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
  32. Re:This is needlessly complicated and HERE is why: by BiggerIsBetter · · Score: 1

    Sorry - but you have no clue. Mars' atmosphere at the surface has about 1% of the Earth's density, making something like aerodynamic flying impossible.

    O'RLY? http://www.x-plane.com/mars.html

    --
    Forget thrust, drag, lift and weight. Airplanes fly because of money.
  33. Who came up with the name?!? by rts008 · · Score: 1

    href="http://en.wikipedia.org/wiki/Skycrane" title="wikipedia.org">Skycrane has been used before.

    Also, having a n00b on the construction site has been a tradtional excuse to initiate said n00b with a search for either a 'skycrane' or a 'left-handed skyhook'.

    Are the younger generations just lacking in imagination, or just recycling old names/terms to confuse us old geezers...Is it Alzheimer's, or senility....Who's going to know?!?!?

    I'm on to your tricks, you young whippersnappers!
    Now get off my lawn!

    --
    Down With Slashdot BETA!!! I've been around the corner and seen the oliphant; you can only abuse me from your perspecti
  34. Re:900kg? What is that? Like...a ton? by Fred_A · · Score: 1

    A ton would be more like... 1000 kg.

    You're welcome.

    --

    May contain traces of nut.
    Made from the freshest electrons.
  35. Re:Mars? Bah. Just another Athiest Myth! by Big+Hairy+Ian · · Score: 1

    you should listen to this http://www.stablesound.co.uk/mp3/notyourblog.mp3

    --

    Build a Man a Fire, and He'll Be Warm for a Day. Set a Man on Fire, and He'll Be Warm for the Rest of His Life.

  36. Re:This is needlessly complicated and HERE is why: by Fred_A · · Score: 1

    Absolutely ! I'm glad somebody points this out. Not to mention the potential for sightseeing.

    Besides I really don't see why they don't just beam in down from the Enterprise.
    Stupid NASA showoffs.

    --

    May contain traces of nut.
    Made from the freshest electrons.
  37. What happens to it next? by 4D6963 · · Score: 1

    Wait wait I don't get this, what happens to be the big flying thing after it's done delivering? Where does it go and what does it do?

    --
    You just got troll'd!
  38. Camera tracking by PearsSoap · · Score: 1

    It seems like their virtual cameraman had difficulty follwing the aeroshell. I was half expecting the film to switch in and out of focus, or to catch the boom mike in the corner of the frame.
    But, seriously, awesome tech and awesome video. That's the kind of thing that would make me want to become an engineer, and I'm sure that I'm not the only one. If they keep this up, it think it's very likely that everyone will remember how cool space exploration is.

  39. Re:900kg? What is that? Like...a ton? by Goaway · · Score: 1

    Me, I don't seem to recall the Viking landers carrying any one-ton rovers.

  40. amortiguate? by argent · · Score: 1

    Google shows about 26 hits for the word, but no definition or etymology.

    1. Re:amortiguate? by argent · · Score: 1

      Hmmm. Seems to be an anglicization of amortiguar. Verbogeny in action.

  41. Re:This is needlessly complicated and HERE is why: by icebrain · · Score: 1

    Part of the problem with aerobraking at Mars (especially with atmospheric skipping) is not just that the atmosphere is thin, but it changes quite a bit. If you can't reliably and accurately predict how high the atmosphere is, or what the pressure and temperature will be, skip entries are much riskier.

    This is even a factor for aeroshell-and-parachute systems; guess wrong, and you'll either burn up the aeroshell or not decelerate enough and end up using lithobraking.

    --
    The meek may inherit the earth, but the strong shall take the stars.
  42. An Idea for Mars Lab by LifesABeach · · Score: 1

    Given the nature of our curiosity, the availability of Blender3D, and Mars based physics principles. Has anyone considered combining the two? Then anyone could have a Mars Simulator, and imagine or experiment with possible designs. That balloon idea was cool. But how about the mechanics of a Space Elevator? That would be cool to simulate. Simulation of Auto-Assembly Space Platforms could be more easily demonstrated. Given the statistics of ISS, one could infer logistics of actual engineering requirements.

  43. Avoiding contamination by Patchw0rk+F0g · · Score: 1

    Perhaps I missed it, but did anyone think of the benefits of not messing up the immediate area around the lab?

    If the lab is lowered by this (admittedly gonzo) contraption, it would additionally have the benefit of placing the mechanism in a pristine area, uncontaminated and undisturbed by a landing. How many times have we seen rovers etc. having to motor away to find pristine areas to survey? If there's going to be a problem, especially with the drive mechanisms, at least they'd be in a situation whereby they'd have a surveyable area right at hand. This in addition to the foregoing points regarding vehicle weight, previous landing mechanism failures, etc.

    --
    When the going gets weird, the weird turn pro. ~~ Hunter S. Thompson
  44. Re:900kg? What is that? Like...a ton? by RegularFry · · Score: 1

    A ton would be more like... 907.18474 kg.

    You're welcome.

    Fixed that for you.

    --
    Reality is the ultimate Rorschach.
  45. Size maters by ChrisA90278 · · Score: 1

    As an example an ant can fall off a 20 story building and hit the ground so softly that it hardly notices the landing. It just walks away. If you or I fell off the building we'd make a crater. The reason is simple Mass increases with the cube of size. For example a 4 foot ball is 8 times as heavy then a 2 foot ball of the same material. When you double the dimensions of any part it's weight goes up by a factor of eight and it's strenght goes up by a smaller factor So for several reasons you can't simply "scale up" a small design. What happens in the case of the airbag system is that for small payloads the bags weigh less then the payload but for large payloads the bags are a larger fraction of the total weight.

    In space weight drives cost very strongly

  46. Re:900kg? What is that? Like...a ton? by brizzadizza · · Score: 1

    He was speaking about a metric tonne.
    1 metric tonne= 1000kg=1Mg
    There are a bunch of tons. 900kg is a great approximation for the US. Ton, and a decentish approximation for the british long ton and metric tonnes.

  47. Re:This is needlessly complicated and HERE is why: by ceoyoyo · · Score: 1

    You're right. Comparing a suborbital spacecraft to something that has to come down from orbit is ALSO something you should not do.

    Even disregarding how thin Mars' atmosphere is, SS1 doesn't go very fast compared to an orbital spacecraft. The orbital spacecraft has to get rid of all that extra speed. How does it do it? Well, you can take along a bunch of fuel and some really powerful (heavy) engines and blast yourself down to low velocity and glide down like SS1. Or you can take a hunk of ceramic with you and use the atmosphere to slow you down.

    Guess which way EVERY orbital spacecraft we've ever built has used?

  48. Where did super-realistic go? by fantomas · · Score: 1

    Mod parent up! and where did "super-realistic" go, it should be in there between "realistic" and "hyper-realistic" surely? ;-)

  49. Hover and soft landing by Somegeek · · Score: 1

    Nedlohs was speculating that the reason to lower the lander to the ground via the winches was because it was too tricky to some to a soft landing.

    I was refuting that particular explanation by pointing out that if they can come to a hover close to the ground, which it is designed to do, then it is feasible to come to a computer controlled soft landing from that point, as Armadillo has demonstrated.

    re: payload:
    Armadillo's lander carries at least a 25kg payload to satisfy the contest rules, and they have noted that they actually carry "quite a bit" more:

    http://www.armadilloaerospace.com/n.x/Armadillo/Home/News?news_id=346

    re: relative size:
    I'm not sure what you are using as a basis for your 1000 multiple in the mass comparison of the vehicles, but from what I can find Armadillo's vehicle in the example weighs about 200kg. Certainly not as heavy as the Mars lander, but enough for a proof of concept, especially considering the decreased gravity on Mars.

    http://www.armadilloaerospace.com/n.x/Armadillo/Home/News?news_id=347

    --
    And as you tread the halls of sanity, You feel so glad to be, Unable to go beyond. I have a message, From another time..
  50. You know, I have said it before in other words... by Jane+Q.+Public · · Score: 1

    but I am motivated to say it plainly here. Somebody tried to refute my statements using an article that very clearly stated that it was about something that was totally irrelevant to the issue at hand. Obviously, he/she had not even read the thing. And when I called him on it, *I* was the one who got modded down.

    Sometimes the modders around here are a bunch of fucking morons.