Simulation of the Mars Science Laboratory Sky Crane 195
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."
Cool Movie - but bad idea! (Score:5, 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.
Re:Cool Movie - but bad idea! (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.
Re:Cool Movie - but bad idea! (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.
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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 sp
Re:Cool Movie - but bad idea! (Score:5, 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...)
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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? O
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Re:Cool Movie - but bad idea! (Score:4, Interesting)
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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 achi
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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.
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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 equ
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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 moment
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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.
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I don't think so. Cable cutters are very, very reliable. That's the least of my worries.
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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
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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 sou
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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.
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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.
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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.
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You might enjoy reading this paper [ieee.org] on the EDL system.
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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.
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Airbags don't work on something as big as the MSL rover. It's that simple.
MSL weight: 1 ton (Score:2)
You should point out it weights 1984 pounds... just shy of one ton. It makes the landing system a lot more intuitive.
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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 surroundin
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Well if they get wormsign they can always come back and pick up the harvester
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Too bad you weren't on the team so they could hear from a real expert about how to land on Mars!
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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!
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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...
Size maters (Score:2)
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 sim
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Gee, too bad nobody thought of that before they built it!
WTF: Hyper-realistic? (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?
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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 simila
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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/
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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 militar
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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 Eart
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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.
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Hey! You spelled über correctly! Don't tell me you can pronounce it too? ;)
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What next, über-realistic? Or is profit next?
You want über-realistic? Check out http://www.marsipan.co.uk/index2.php?mission=1170270775 [marsipan.co.uk]
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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?
Another slashdown? (Score:2)
Why not use what works? (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.
Re:Why not use what works? (Score:5, Informative)
Trebuchet's don't scale very well. AFAIR, neither did the beach ball. This thing is lots bigger and heavier.
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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.
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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.
Re:Why not use what works? (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
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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 rov
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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
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I was just going to use that example but state that therefore it obviously DOES work for much larger payloads!
And (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.
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preposterous (Score:2)
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.
Not entirely practical (Score:2, Informative)
Re:Not entirely practical (Score:5, Informative)
So what? This thing is much larger than anything landed anywhere before, with the exception of the manned LEM.
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.
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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
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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 [armadilloaerospace.com]
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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?
what I don't understand (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?
Half life (Score:2)
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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Hopefully, we'll get to find out:
http://www.livescience.com/blogs/2008/09/18/phoenix-mars-microphone-turning-on-the-robots-ear/ [livescience.com]
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I never knew about that. Thanks for the heads up.
-b
simulation? (Score:2)
I don't think that word means what you think it does.
No solar panels? (Score:2)
Re:No solar panels? (Score:5, Informative)
Story? (Score:2)
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 [youtube.com] is how to find life on Mars.
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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.
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Exactly my thoughts. It's a useless waste of bits! Horrible. ;)
Is that you Mal? (Score:2)
Was it just me or did anyone else expect to see Jayne suspended from the bottom of that rover?
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No, but I did expect the word "Bitterman" on the side of the vehicle, in large unfriendly letters.
Landing on Mars is hard (Score:5, 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. [thinkquest.org]
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.
Anyone know? Audio recordings of Mars? (Score:2)
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).
Re:Anyone know? Audio recordings of Mars? (Score:4, Informative)
Just a little longer...
http://www.space.com/businesstechnology/081001-tw-phoenix-microphone.html [space.com]
Really Poor Concept (Score:3, 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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In real world engineering it's actually KISAP - Keep It As Simple As Possible. Some complexity is almost always unavoidable.
Why the crane part? (Score:3, 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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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, g
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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
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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 wi
Zoom, blur, zoom! (Score:2)
What, did they hire the New BSG CG team for this?
Who came up with the name?!? (Score:2)
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!
What happens to it next? (Score:2)
An Idea for Mars Lab (Score:2)
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 requirem
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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 tr
Re:turtle on its back (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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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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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...
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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.
Re:This is needlessly complicated and HERE is why: (Score:5, 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 [universetoday.com] 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.
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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 [x-plane.com]
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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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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 y
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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.
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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.
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Thanks, good link!
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A ton would be more like... 1000 kg.
You're welcome.
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A ton would be more like... 907.18474 kg.
You're welcome.
Fixed that for you.
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Me, I don't seem to recall the Viking landers carrying any one-ton rovers.
amortiguate? (Score:2)
Google shows about 26 hits for the word, but no definition or etymology.
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Hmmm. Seems to be an anglicization of amortiguar [wiktionary.org]. Verbogeny in action.