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Seven minutes of Martian terror
June 22, 2012 11:13 AM   Subscribe

Curiosity's Seven Minutes of Terror is a YouTube video guaranteed to get you excited about NASA again. It shows the elaborate process that will get the Curiosity rover onto the Martian surface on August 5. It involves the largest supersonic parachute ever built, multiple vehicles, 76 explosive devices, and a skycrane.
posted by blahblahblah (91 comments total) 38 users marked this as a favorite

 
I decided against throwing a "landing party" at my place because I'm so completely terrified that something is going to go wrong, and I don't want to subject my friends to that particular facet of my Space Madness.

But seriously HOW CAN THIS POSSIBLY WORK? o______o
posted by Narrative Priorities at 11:20 AM on June 22, 2012 [5 favorites]


Goddamn if that thing works it will be awesome. Even the idea of it is awesome.
posted by Aizkolari at 11:22 AM on June 22, 2012 [1 favorite]


They told me at the beginning that it would sound crazy.

It sounds crazy.
posted by Phreesh at 11:23 AM on June 22, 2012 [1 favorite]


My local science museum is holding a live event for the landing. My 10- and 9-year-old kids are totally pumped.
posted by DWRoelands at 11:25 AM on June 22, 2012


As nervous as I was for Spirit and Opportunity, this is pure seat-of-my-pants terror. I'm going to be good and liquored up at landing time.
posted by gsh at 11:26 AM on June 22, 2012 [2 favorites]


Has the makings of a brilliant OK Go video.
posted by localroger at 11:26 AM on June 22, 2012 [6 favorites]


You know, if you simply told me someone at NASA had proposed this idea, I would have then expected you to tell me they were subsequently run out on rails.

I'd really like to know why they are taking this approach, rather than the previous landing schemes used for the Spirit, Opportunity, and Sojourner .
posted by I Havent Killed Anybody Since 1984 at 11:27 AM on June 22, 2012


Spirit and Opportunity's landings were nothing to sneeze at either.
posted by no regrets, coyote at 11:27 AM on June 22, 2012 [1 favorite]


Nothing can go wrong...go wrong...go wrong...go wrong...
posted by Splunge at 11:29 AM on June 22, 2012


I sure hope this goes better than Genesis did.
posted by Clandestine Outlawry at 11:32 AM on June 22, 2012


I'd really like to know why they are taking this approach, rather than the previous landing schemes used for the Spirit, Opportunity, and Sojourner .

From the Scientific American article in the last link:
The airbag landing system isn’t an option for Curiosity. Weighing in at an impressive 1,654 pounds (that’s three-quarters of a ton), it is the size of an SUV.
...
Similarly, a larger parachute to slow Curiosity’s initial descent ... would be too heavy for the launch vehicle and unlikely to fully inflate before its payload reached the Martian surface.
...
The Jet Propulsion Laboratory was also keen to move away from the inevitability of driving a rover off a landing platform as it had with the previous rovers.

It was clear that for NASA to deliver the larger and heavier payload with less room for failures, it would need a new landing system. Enter the Sky Crane.
posted by caaaaaam at 11:34 AM on June 22, 2012 [3 favorites]


"Curiosity's Seven Minutes Of Terror" is the new ride at the cats-only thrill ride park. I'm not sure whether it's a motion simulator ride, or some kind of suspended looping rollercoaster.

Also, anyone who loves the Mars Rover landings and Nine Inch Nails needs to know about this.
posted by hippybear at 11:34 AM on June 22, 2012 [9 favorites]


Well, I Havent Killed Anybody Since 1984, I'm not sure of all the details but it's probably relevant that Curiosity is 900 kg, compared to Spirit's ~150.
posted by introp at 11:35 AM on June 22, 2012


It won't be 7 minutes of terror. It will be 7 minutes of cautious optimism. It only becomes terror when there is no signal after the 7 minutes. Then at the 10 minute mark a signal is received, creating 3 minutes of terror.
posted by stbalbach at 11:41 AM on June 22, 2012 [1 favorite]


I'd really like to know why they are taking this approach, rather than the previous landing schemes used for the Spirit, Opportunity, and Sojourner.

It's just plain too big and too heavy to use the airbag method. The only alternative to the skycrane (which is, seriously crazy and awesome) is to use rockets all the way down like the Viking landers. Which also presents its own problems of weight, contamination, and site risks (i.e. requiring probably an even smoother landing site than the skycrane method).
posted by chimaera at 11:45 AM on June 22, 2012 [1 favorite]


Ok, but what after the Decepticons smash it up after it lands? What is the plan then?
posted by Old'n'Busted at 11:45 AM on June 22, 2012


Ok, but what after the Decepticons smash it up after it lands? What is the plan then?

It's got a nice big-ass laser, normally used to vaporize rock. I guess if it's attacked, it could punch a hole right through a Decepticon.
posted by chimaera at 11:47 AM on June 22, 2012 [2 favorites]


(also if a Mod can fix the date on the OP -- it's August 5, not August 2).
posted by chimaera at 11:48 AM on June 22, 2012


I'm going to be good and liquored up at landing time.

I'll be drinking in both terrestrial and Martian frames of reference.
posted by RobotVoodooPower at 11:48 AM on June 22, 2012


Weighing in at an impressive 1,654 pounds (that’s three-quarters of a ton), it is the size of an SUV.

I didn't even realise how big it was. (I had also forgotten how big Spirit and Opportunity were...) Given nothing to compare it with in the video, I'd thought it was much smaller, maybe a bit larger than the one in the front in that picture. This is insane.
posted by eykal at 11:52 AM on June 22, 2012 [4 favorites]


Did they have to use all the terrible action-movie-trailer cliches? As cool as I'm sure it is, I can't get through the video.
posted by junco at 11:58 AM on June 22, 2012 [3 favorites]


Holy shit that's a well produced video. I've never seen Nasa Engineers so charismatic. (The landing animation is gorgeous too, but that's excerpted from an earlier video). I'm guessing NASA decided they'll never get more funding unless congress thinks they're cool again, so spend the last cent on marketing.
posted by Popular Ethics at 11:59 AM on June 22, 2012 [3 favorites]


[Date fixed, carry on. ]
posted by restless_nomad at 12:00 PM on June 22, 2012


Edit this video down to 30 sec's and run it a few times during prime time with a link to a web site that has the complete 5 min video and I bet the next time NASA's funding is questioned people might actually call their congressman and show their support.

Shit, make the whole thing a reality show and get the public involved and I bet NASA won't ever have to deal with the possibility of defunding ever again.
posted by photoslob at 12:03 PM on June 22, 2012 [4 favorites]


Ok, but what after the Decepticons smash it up after it lands? What is the plan then?

Well, the sky crane has that capability to....

I've said too much.
posted by Kid Charlemagne at 12:08 PM on June 22, 2012


The Mars Exploration Rover (Spirit and Curiosity) payload is about the limit of what you can safely land with the drop & bounce method.
When this problem is first presented to people, the most offered solution, Manning says, is to use airbags, since they have been so successful for the missions that he has been involved with; the Pathfinder rover, Sojourner and the two Mars Exploration Rovers (MER), Spirit and Opportunity.

But engineers feel they have reached the capacity of airbags with MER. “It’s not just the mass or the volume of the airbags, or the size of the airbags themselves, but it’s the mass of the beast inside the airbags,” Manning said. “This is about as big as we can take that particular design.”
If you want to land something larger, you need to come up with an alternative. Thus, the skycrane. For what they're trying to do, it makes a lot of sense. Here's footage of the sky crane drop test.

Which also presents its own problems of weight, contamination, and site risks (i.e. requiring probably an even smoother landing site than the skycrane method).

Yup. You want to minimise the amount of rocket fuel you're spraying over everything. (Preventing the Forward Contamination of Mars: Spacecraft Propellant and By-Products as Potential Contaminants)
posted by zamboni at 12:09 PM on June 22, 2012


I hope those NASA guys know what they're doing. It's not like they can actually test the thing, since the atmosphere & gravity are so different than our own, so they pretty much just have to get the math right.

I've been following Curiosity on twitter & am really pumped. Spirit & Opportunity have been fantastic, and if this one works, it promises to be fantastic x 1000.
posted by Devils Rancher at 12:12 PM on June 22, 2012


"500,000 lines of COD3"

Um.
posted by zippy at 12:13 PM on June 22, 2012


Sorry, L1NES OF COD3

Double-um
posted by zippy at 12:15 PM on June 22, 2012


Wow. I hope this works.
posted by sotonohito at 12:20 PM on June 22, 2012


Did they have to use all the terrible action-movie-trailer cliches?

What, in particular, are you referring to? The visual effects in the animation, phrases like "game over" or the over texts like "1600 Degrees" and "Supersonic Parachute"? While these exist in part to make it seem exciting (You know, like an action-movie-trailer) it's important to note that this isn't just crap some write made up and then one of the producers decided that 900 degrees wasn't impressive enough and added a few hundred degrees to it.
posted by Kid Charlemagne at 12:26 PM on June 22, 2012


Holy cats, this is neat stuff. Thanks for posting it.
posted by jquinby at 12:29 PM on June 22, 2012


that image that eykal posted is in the martian habitat testing area at JPL. Here's when I got to go visit Curiosity's identical twin. Only difference is that power for this one is tethered and not nuclear. You may also notice in photos of the rover, that the wheels have holes in them. Not only will these help calibrate how fast and far the rover is traveling, among of things, they are also an easter egg. In morse code they read JPL. Sneaky nerds :)

I also got to handle one of the mega cutters (real name!) for the sky crane cables. It was a great visit, and I'm really crossing my fingers on this one because Curiosity is totally badass.
posted by Bohemia Mountain at 12:29 PM on June 22, 2012 [1 favorite]


What, in particular, are you referring to? The visual effects in the animation, phrases like "game over" or the over texts like "1600 Degrees" and "Supersonic Parachute"? While these exist in part to make it seem exciting (You know, like an action-movie-trailer) it's important to note that this isn't just crap some write made up and then one of the producers decided that 900 degrees wasn't impressive enough and added a few hundred degrees to it.

Haha, no, I'm not talking about that, obviously. I mean the production design is terrifically juvenile. Repetitive, "tense" music through the whole thing, huge, bold intertitles (not to mention the "L1NES OF COD3" issue), the lights brightening and dimming on the guy's face, the shaky-cam of the CGI, etc., etc. Show me some science, don't try to excite my reptile brain by making me think I'm watching 24.
posted by junco at 12:34 PM on June 22, 2012 [2 favorites]


Unfortunately, it seems to be the reptile brain that decides funding priorities, so they're adapting to what they need to do to survive.
posted by radwolf76 at 12:39 PM on June 22, 2012 [5 favorites]


I have been told that I have no sense of adventure because I don't believe in manned space flight. Well, now I can show this video to people, so they can understand how freaking exciting robotic space exploration can be.
posted by Philosopher Dirtbike at 12:42 PM on June 22, 2012


Show me some science, don't try to excite my reptile brain by making me think I'm watching 24.

You are not their target demographic.
posted by Floydd at 12:42 PM on June 22, 2012 [3 favorites]


As cool as I'm sure it is, I can't get through the video.
posted by junco at 11:58 AM on June 22 [+] [!]

Holy shit that's a well produced video.
posted by Popular Ethics at 11:59 AM on June 22 [+] [!]


This is why I love Metafilter.
posted by euphorb at 12:43 PM on June 22, 2012 [2 favorites]


junco: "Show me some science, don't try to excite my reptile brain by making me think I'm watching 24."

I feel the complete opposite on behalf of all my fellow apathetic taxpayers. Get me excited. Show me footage of the goddamned laser vaporizing some rock and NASA can shut up and take my money.
posted by danny the boy at 12:43 PM on June 22, 2012 [2 favorites]


(This is what the real exciting science looks like behind the scenes.)
posted by ntk at 12:57 PM on June 22, 2012


"Show me some science"... Ok, but don't fall asleep.
posted by spaceviking at 1:03 PM on June 22, 2012 [1 favorite]


Did they have to use all the terrible action-movie-trailer cliches? [...] Show me some science, don't try to excite my reptile brain by making me think I'm watching 24.
Unlike the 99% of other times in our lives that we've seen these dramatic cliches used, this landing actually deserves it.

This landing is the cutting edge of technology, engineering, and ambition for our species. If this is successful, it should merit a national day of celebration with ticker tape parades. You know, if TV fiction hadn't already ruined our appreciation of genuine drama and achievement.
posted by Davenhill at 1:04 PM on June 22, 2012


If it works in Kerbal Space Program — trust me — it'll work on Mars (ploink!).
posted by steef at 1:06 PM on June 22, 2012 [3 favorites]


Seriously, NASA built a nuclear powered robot with a frickin laser attached to its head and they put some poindexter on camera who sounds like he's talking about the colonoscopy he had last Tuesday.

I wanna see them blowing up a boulder with Marvin the Martian painted on it AMERICA FUCK YEAH
posted by danny the boy at 1:07 PM on June 22, 2012 [2 favorites]


"Enter Descent and Landing, also referred to as the Seven Minutes of Terror" ... that's what she said?
posted by bl1nk at 1:15 PM on June 22, 2012


"Show me some science"... Ok, but don't fall asleep.

Thank you! Those instruments are incredibly cool. ("Especially a Remote Micro-Imager (RMI) capable of resolving 1 mm features at a distanceof 10 m, or 200 μm features just in front of the rover"!)

(This is what the real exciting science looks like behind the scenes.)

When I asked for less flashy production values, I didn't mean "take away the tripod"!
posted by junco at 1:21 PM on June 22, 2012 [1 favorite]


Unlike the 99% of other times in our lives that we've seen these dramatic cliches used, this landing actually deserves it.

This landing is the cutting edge of technology, engineering, and ambition for our species. If this is successful, it should merit a national day of celebration with ticker tape parades. You know, if TV fiction hadn't already ruined our appreciation of genuine drama and achievement.


You don't need to try to convince me of that! I'm in complete agreement. I'm just pointing out that I think the video in question is a representation of the decline of the level of public education and engagement. It's very disappointing that we expect so little of the citizenry that anything that doesn't conform to the Hollywood production values for "entertainment" we've come to expect over the past 15 or so years will be ineffective and pointless, and even moreso that we automatically suppose that links to four 2 page, easily understood papers will make a reader fall asleep.
posted by junco at 1:36 PM on June 22, 2012


I was half expecting to see Batman straddling the rover as the big reveal at the end.

I'm excited!
posted by mazola at 1:44 PM on June 22, 2012


Neat. But it makes me a bit queasy to think that NASA has to promote their stuff like it was a summer blockbuster.
posted by DarkForest at 1:47 PM on June 22, 2012 [2 favorites]


I'm overwhelmed by the complexity of it all. I understand (in layman's terms) why the landing sequence is so elaborate but I have a hard time imagining this working in practice. I'm glad others have bigger imaginations than I do because I probably never would have pitched this with a straight face.
posted by dgran at 1:51 PM on June 22, 2012


That laser is really neat. But I'm a little sad that it's not powerful enough to vaporize or explode things. I blame Star Wars (the movies and the top secret military program).

Still, should be exciting to see what Curiosity brings to space exploration and science and if colonization on Mars is possible. I don't want to move to Mars, but it would sure be exciting to see that idea become a reality in my lifetime.
posted by PipRuss at 1:59 PM on June 22, 2012


I probably never would have pitched this with a straight face.

I worked at JPL until 2009 (I worked on Astronomy projects, though, not Mars projects), know many people who work/worked on Curiosity, and I am surprised they pitched it with a straight face. There were quite a few skeptics who surely had to see all of the engineering and testing to be really, finally convinced that it'll work.

Instead of Curiosity, I think they should've called the rover Audacity.
posted by chimaera at 2:00 PM on June 22, 2012 [3 favorites]


"Instead of Curiosity, I think they should've called the rover Audacity."

Yeah that's a better name than my proposal 'Holyshitholyshitholyshit'
posted by PenDevil at 2:08 PM on June 22, 2012 [3 favorites]


It's very disappointing that we expect so little of the citizenry that anything that doesn't conform to the Hollywood production values for "entertainment" we've come to expect over the past 15 or so years will be ineffective and pointless, and even moreso that we automatically suppose that links to four 2 page, easily understood papers will make a reader fall asleep.

I think you're bringing a lot of baggage to a five minute video. The science is cool, but so are the details of the landing, and I think presenting those details viscerally is being true to how the whole thing is going to play out physically. If they were dramatizing soil analysis to that extent, I might be more sympathetic.
posted by invitapriore at 2:27 PM on June 22, 2012


I've got a 12 year old son who has declared his intention to be an astronomer and gotten into building robots, through Dean Kamen's First Lego League. I was overjoyed to send him these videos to watch while I was out running an errand just now -- picking up an NXT kit for his birthday next Saturday. I hope it inspires him.
posted by Devils Rancher at 2:33 PM on June 22, 2012 [1 favorite]


I think you're bringing a lot of baggage to a five minute video.

Perhaps. In any case, if it inspires kids (like Devils Rancher's) to get interested in NASA, then it's doing good, regardless.
posted by junco at 2:40 PM on June 22, 2012 [1 favorite]


I'm overwhelmed by the complexity of it all. I understand (in layman's terms) why the landing sequence is so elaborate but I have a hard time imagining this working in practice.

So do I -- I have never seen a video of the sky crane actually being flight-tested. Animations are all neat and stuff, but I want to see a video of this thing hovering/maneuvering over a piece of the Nevada/California desert before I will start getting excited.
posted by CosmicRayCharles at 3:01 PM on June 22, 2012


You don't need to try to convince me of that! I'm in complete agreement. I'm just pointing out that I think the video in question is a representation of the decline of the level of public education and engagement. It's very disappointing that we expect so little of the citizenry that anything that doesn't conform to the Hollywood production values for "entertainment" we've come to expect over the past 15 or so years will be ineffective and pointless, and even moreso that we automatically suppose that links to four 2 page, easily understood papers will make a reader fall asleep.
There are other, longer, less (or non) dramatic videos about the Curiosity rover, too.

As tastes and levels of interest vary, so should the variety of efforts to promote this particular mission, and science and space exploration in general.

If marketing cliches can get the masses to watch and consume so much culturally irredeemable trash, why not exploit them to steer people towards an interest in science and the wider universe?

I'd even be fine if they hired the "In a world..." movie trailer guy to narrate a video with Larry the Cable Guy as the voice of Curiosity's fire-breathing Martian friend, Mars-a-saurus, capped off with a reminder to watch the landing on August 5th, i.e. "SUNDAY! SUNDAY! SUNDAY!"

:)
posted by Davenhill at 3:11 PM on June 22, 2012


(... if it boosted enough interest in science/space/NASA among kids)
posted by Davenhill at 3:15 PM on June 22, 2012


I want to see a video of this thing hovering/maneuvering over a piece of the Nevada/California desert before I will start getting excited.

Not practical. This vehicle is designed to operate in a gravitational field 1/3 as strong as Earth's.
posted by Devils Rancher at 4:58 PM on June 22, 2012


I want to see a video of this thing hovering/maneuvering over a piece of the Nevada/California desert before I will start getting excited.
I believe this is the closest test they've done.

More NASA/JPL videos here at the official website. Click "All Videos" at the bottom to display, well, all the videos.
posted by Davenhill at 6:10 PM on June 22, 2012


Not practical. This vehicle is designed to operate in a gravitational field 1/3 as strong as Earth's.

So do it on earth first and then divide everything by 3.

(sidenote:My high school physics teacher pulled me aside after a few weeks and said "If I can get you to pass this class, I will have earned my salary for the year" Fortunately for him he didn't put that in writing, as I flunked spectacularly.)
posted by billyfleetwood at 6:10 PM on June 22, 2012


So do it on earth first and then divide everything by 3.

That's really not how it works. In order to counter the fact that the propulsion would need to put out 3 times as much thrust, you'd need larger rockets and more fuel, which increases the weight, which means you need even larger rockets and even more fuel and it just keep spiraling out of control until you've designed a Saturn V that looks and acts nothing like the original design. If you tried to fly the original design on Earth it would just drop like a rock and you wouldn't be able to actually test any of the control systems. Those systems are expecting much less gravity, and they would hopelessly command the thrusters to full thrust as they sensed descent much faster than anything they are capable of handling.
posted by Rhomboid at 6:23 PM on June 22, 2012


About the video style: I once watched a documentary where a botanist had to rappel off the side of a cliff in Hawaii to study a rare flower.

The flower was cool.
Rappelling from the side of an extinct volcano down a sheer cliff 300 feet above the ocean was also cool.
posted by BeeDo at 6:50 PM on June 22, 2012


This, by the way, is why there will never be a manned mission to Mars.

Forget time. Forget cost. Forget will and determination. It's about energy and gravity and human limitations.

The atmosphere of Mars is too thick to be ignored, too weak to help. And no human (riding a vehicle much larger than Curiosity, I would imagine) could ever survive the descent.

This is why I love stories about Spirit, Opportunity and Curiosity. These brave little toasters will inherit the stars.
posted by SPrintF at 8:07 PM on June 22, 2012 [2 favorites]


Never is a very long time, SPrintF.
posted by anifinder at 8:28 PM on June 22, 2012 [1 favorite]


That was the most amazing video I have seen Roving Mars, which everybody else who liked this clip should see immediately. What does NASA cost the average taxpayer, $20 a year or something? This is so worth it so many times over just to see them try something like this. Let alone whether this rover finds some sign of life, this landing is so badass.
posted by Camofrog at 8:51 PM on June 22, 2012 [1 favorite]


SprintF, I think a human may survive the forces Curiosity will go through. In the linked video the guy called 9g "neck breaking", but I swear I just watched an episode of Mythbusters where Adam Savage dropped himself off a building covered in bubblewrap and they considered 10g impacts safe for insurance company purposes.
posted by floam at 8:53 PM on June 22, 2012


Hm, I guess it's all about how long you have to endure 9-10g... a fraction of a second (the bubble-wrap-thingie) or several minutes (descending to mars)...
posted by SAnderka at 4:28 AM on June 23, 2012


or several minutes (descending to mars)...

The 9g force is only experienced when the parachute is deployed and catches the atmosphere for the first time. At that point, the momentum of the descending capsule will be cut dramatically, which is where the high g-force moment comes from. After that, the parachute will continue to slow the craft, but any experienced g-forces by anything in the system will be dramatically lowered, as it will all be descending at the same, slowing rate and there won't be any sudden yank caused by further parachute deployment.
posted by hippybear at 5:34 AM on June 23, 2012


That was the most amazing video I have seen Roving Mars, which everybody else who liked this clip should see immediately.

I recommend the Roving Mars book for anyone interested in this stuff. The book is by the rover scientist (geologist) Steven Squyres who first proposed the mission and led the entire development and operation. You can learn so much from it about how science actually gets done and about the design decision process that engineers go through. A great gift for any science- or engineering-loving high school or college student.
posted by neuron at 5:48 PM on June 23, 2012


9 gravities is at the limit of what fighter pilots are expected to be able to remain conscious for, using modern equipment and training. If the 9-g phase of a Mars landing is brief and the human passengers don't have to actively pilot during it, it's probably doable.
posted by hattifattener at 2:35 AM on June 24, 2012


But, everyone, this is for a entry vehicle the size of an SUV.

Unless you intend a manned mission to Mars to be a suicide mission, with no expectation of return, then no human can ever walk upon Mars with the expectation of coming home.

The beautiful silver spaceships of Ray Bradbury's Mars stories simply won't work. And this breaks my heart, because I grew up with them and the hope they represented.

Mass. Gravity. Energy. The cold equations say no, not now. And, probably, not ever.
posted by SPrintF at 3:57 PM on June 24, 2012


SPrintF, we could build return capable vehicles. They'd just be bigger and a lot more expensive than the rover.

As for Mars, if you offered me a one way ticket and some living space I'd take it in a heartbeat.
posted by sotonohito at 4:50 AM on June 25, 2012


Rather than send a big heavy thing that requires you to invent a new landing system that puts all your eggs in one basket, why not send 3 (or 10 or 100) little tiny ones? You can use one of (or several of) the proven landing methods and be assured that by chance at least some of your little guys will survive. Assign a tiny portion of the mission to each probe and you know at least some of your science will get done.
posted by DU at 4:56 AM on June 25, 2012


Rather than send a big heavy thing that requires you to invent a new landing system that puts all your eggs in one basket, why not send 3 (or 10 or 100) little tiny ones?

The MSL mission brief is to assess the habitability of the landing site. It needs to look at the climate and geology over the whole area. It uses various tools to investigate what it finds - the science payload. There are ten separate instruments, some of which require considerable power, and they need a way to be moved around Mars. If you want to achieve what MSL is designed to do, dividing up the payload isn't practical.

MSL is an intentional attempt to land a heavy payload on Mars, and as such, is a stepping stone to later exploration and sample return missions.

The shotgun approach of multiple redundant vehicles working in conjunction is a good approach for other missions- for instance, the Finnish Meteorological Institute's proposed MetNet, and to a lesser extent, ESA's proposed Mars Science Network.
posted by zamboni at 8:35 AM on June 25, 2012


Ridiculous ideas.

Absurd that it got launched.

This is a prime example of what the best engineer I know calls "optimising a sub-optimal solution". I'm sure that it's brilliantly designed, built and operated but the whole idea is over-complicated and has just far too many failure points. This would be a bad idea for something you could monitor in real time, or get access to; as a solution for an environment which has no access, no monitoring and a lot of unknown unknowns...

KISS dudes. Keep It Simple, Stupid.
posted by BadMiker at 8:49 AM on June 25, 2012 [1 favorite]


If you want to achieve what MSL is designed to do, dividing up the payload isn't practical.

This is a non-sequitor in your paragraph. Why isn't it practical? More specifically, why is making the entire thing hinge on a big iffy step more practical?

Or as BadMiker put more simply: KISS. Redundancy and KISS.

posted by DU at 9:49 AM on June 25, 2012


Why isn't it practical?

The sentence before your quote explains exactly why.
posted by localroger at 10:55 AM on June 25, 2012


No it doesn't. We've already had mobile robots on Mars for some time using existing methods, so the "need a way to be moved" explains nothing. These robots also required power and had multiple instruments, so again, no explanation. The only possible explanatory word there is "considerable" and that's only because it's so vague.

Are the power requirements so high that the solar panel(s) alone forces them use this method?
posted by DU at 11:29 AM on June 25, 2012


Curiosity has several instruments which require more power than solar panels can provide, not to mention all the trouble solar panels caused with regard to survivability for Spirit and Odyssey, so Curiosity has a nuclear power source (RTG). Even if you launched separate rovers for the different instruments some of them would be too heavy for the airbag system. You'd have multiple rovers instead of one, with many more failure points and more driving and more testing and more of everything, including more Plutonium being launched which some people don't like on principle.
posted by localroger at 12:13 PM on June 25, 2012


For those of you interested in this type of thing, there was a meeting about concepts and approaches to Mars exploration a few weeks ago - and the abstracts and reports are all online, as well as the talks. So check it out.
posted by spaceviking at 2:05 PM on June 25, 2012 [1 favorite]


You get certain things from one big rover that you don't get from multiple little ones.

Size: Curiosity can clear obstacles up to 75 cm (30 in), and can travel up to about 200 meters (660 feet) per day. A Mars Exploration Rover (Spirit/Opportunity) has a 30 cm clearance.

Power: The MMRTG powering MSL should generate 2.5 kilowatt hours per day, year round. At peak, a Mars Exploration Rover's solar panels generated ~0.9 kilowatt hours per day, which quickly dropped due to dust and seasonal variation.

Precision: The powered landing means you can choose sites with a higher degree of accuracy, allowing you to choose locations that aren't safely accessible by the airbag method. MER-A had an estimated landing ellipse of 80 km by 30 km, MER-B 360 km by 30 km.*

Redundancy:

For the multiple vehicle approach, you need to duplicate at least the following for each vehicle: MSL has 80 kg of scientific payload. MER had 6.8 kg. If you could somehow split up the instruments between a fleet of RTG powered MERs, you'd need to launch twelve of them, land them, reunite them, and coordinate them. To properly study a sample, you need to run all your tests on it, and you can't do that when the instruments are miles apart.

Sure, it's complex. There's been numerous cost overruns, window slips, etc. Perhaps they should have picked a different mission, something easier, with less risk and reward. But for difficult problems, there often isn't a simple solution. Rice still plays Texas, and MSL is going to Mars.
posted by zamboni at 2:12 PM on June 25, 2012


The assumption here that is going unchallenged is that you in fact need all of the instrumental complexity to answer the important scientific questions.

I would argue that instead of learning more about one spot on Mars, we need to learn a little about a lot of spots on Mars. Sampling the diversity is a much better way of answering the big science questions like: Was Mars warm and wet, or were there habitable environments.

We often land on Mars only to discover that the landing site we picked wasn't like we thought it would be. Nobody thought Gusev crater would be largely composed of lava flows.

We have a lot of instrument complexity on MSL but may have picked a landing site that doesn't contain the type of rocks that the instruments are looking for.
posted by spaceviking at 2:26 PM on June 25, 2012


SPrintF: Part of the deal with this was that they didn't want to disturb the landing site too much, by exposing it to the rocket flames and thrust. If you were landing humans, you would probably tolerate more of a mess.

The moon, after all, does not have an atmosphere at all, and we were able to land there. So "too weak to help" isn't that big of a deal. You don't need atmosphere to slow you down if you have big rockets. "Too thick to ignore" just means that you want to start decelerating before you get into the atmosphere so that you don't burn up and you need a heat shield, but we do that when we land on Earth. So you need some kind of hybrid approach, a heat shield and controlled entry like you have on earth, but also rockets for deceleration (rather than a glider) like you use on the moon. That's exactly what they're doing here, with the "protect the landing site" skycrane twist.
posted by OnceUponATime at 4:34 PM on June 25, 2012


So "too weak to help" isn't that big of a deal.

Actually, it is. First, Mars has considerably higher gravity than the Moon, which means you need lots bigger rockets for both landing and liftoff. The Apollo moon lander got away with some hijinks that won't work on Mars precisely because of the atmosphere; on Mars there isn't enough atmosphere to slow you down all that well, but there is enough to fry you from entry heat, so you need a heat shield and considerable aerodynamic design which the Lunar Lander could ignore. If you slow down far enough up to avoid this heat problem you're wasting a lot of fuel on descent compared to what you could get by with if Mars had no atmosphere at all and you could use an optimum descent trajectory.
posted by localroger at 4:56 PM on June 25, 2012


As for Mars, if you offered me a one way ticket and some living space I'd take it in a heartbeat.

Hey, you're in luck! That's not only been proposed, but there are groups working toward it. Here was one featured in an FPP not too long ago!

And here is NPR reporting on the same concept, only a bit more seriously.
posted by hippybear at 6:56 PM on June 25, 2012


I want a to build a SkyCrane CatCopter that lowers a mouse manned RC car.
posted by Sprocket at 2:03 PM on June 26, 2012


Emily Lakdawalla steps through the landing system in "excruciating detail": Part 1, Part 2.

Landing accuracy:
In its tilted state, the spacecraft does not fall like a rock. It actually generates lift. It will literally be flying in Mars' atmosphere, not falling. It can, in theory, even rise in elevation at some points during the deceleration phase (though it probably won't need to, given how low-elevation Gale Crater is). It will use an inertial measurement unit (which contains gyroscopes) to detect its path through the atmosphere, and will change its pitch (the angle of the cone) and also bank left or right as needed, making S-shaped curves, in order to deliver the spacecraft to a targeted spot at a targeted velocity for parachute deployment. This guided flight phase is what makes Curiosity's landing ellipse so much smaller than previous landers'. The atmosphere will still have an opportunity to move the rover around while it's under parachute, but Curiosity will be able to fly out almost all other sources of landing inaccuracy in this guided phase.
The parachute:
Another concern after the parachute inflates is something called "wrist mode oscillations." This is where the spacecraft spins underneath the parachute. Here's an interesting sentence from Ravi's article: "Historical attempts to bound the wrist mode behavior and its time evolution following parachute deployment have failed to bound the behavior during flight (e.g. MER-B)." Translation: we're trying to figure out ways to make our computer simulations produce the same behavior we observe in reality, but we're not there yet. Without an understanding of why this oscillation happens, it's really hard to engineer a system that prevents it.
posted by zamboni at 8:08 AM on June 29, 2012


If you have an Xbox 360 and a Kinect, you can download the free NASA game Mars Rover Landing, available as of today.
posted by hippybear at 9:47 PM on July 16, 2012


Nasa may miss Curiosity Mars rover's landing signal: Nasa might not be able to follow the progress of its big Mars rover all the way to the surface when it attempts to land on the planet on 6 August (GMT).
posted by homunculus at 12:18 PM on July 17, 2012


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