Curiosity – coming to Mars – maybe

When I was in Washington a couple of weeks ago for ICCC6,

I took the family to the National Air and Space Museum on the mall. While everyone was gazing at rockets and other bus-sized hardware of glory days past, off in the corner I noticed this, roped off, without a placard even:

What was it? A full sized mockup of the new Mars Science Lab explorer known as Curiosity. Apparently, it would serve as a backdrop to this announcement I found out later.

About the size of a Jeep, it looked ready to rumble on the red planet. I figured they would use the air bag bouncy deployment system that worked so well for Spirit and Opportunity, just super-sized.

But after learning a bit more about how Curiosity will be landed, and watching a video from NASA JPL on the mission sequencing, I was surprised to learn they weren’t using that method, but rather a series of mechanical, dangling drops by wire, and rocket maneuvers, that look more than a bit worrying due to the complex synchronization that must occur. Watch this video:

This artist’s concept animation depicts key events of NASA’s Mars Science Laboratory mission, which will launch in late 2011 and land a rover, Curiosity, on Mars in August 2012.

My view: there’s a lot more that can go wrong. One thruster rocket failure, or a tangled drop wire, is all it would take to doom the mission. Mars is known for eating missions, with an over 50% failure rate, so adding to the complexity during landing, especially that dangling rover under a hovering rocket, looks mighty failure-prone.

More on the mission here at NASA JPL.


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Brian H

And how are they planning to get all those whooshing and sputting and popping sounds in the vacuum of space?
It’ll never work, I tell ya.


It’s basically the same way Phoenix probe has already successfully used for landing – but Phoenix was not mobile so all the balast in empty tanks and no longer useful thrusters did not matter. For a rover it’s better if they are detached for further operation.


Sound-effects in space really get under my skin!

Tom Buckley

As an engineer I am constantly amazed at how my fellows take a perfectly good system, proven to work, and “improve” it.

Rube Goldberg works for NASA now?

You are assuming they actually mean to implement the Curiosity mission. I’ll believe it when I see it. The way things are now, I wouldn’t be surprised if the exhibit were not just an imaginative display, done to soothe starry-eyed visitors and keep the public from realizing just how far they are going to be pulling in their horns, with regard to further space adventures. Or maybe they will do it, but subconsciously want it to fail, and so make awkward plans as you point out — it is hard to tell, with their mental state looking so lame, and their reason for being having been suborned to the latest political cash-cow (“global warming”). Obama is presiding over a third-class mindset of haplessness, social injustice and perennial victimhood of most “folks” (as he calls us, not realizing in his cluelessness that the “f” word begins to resemble the “n” word, with both now meaning “victims”, to those who don’t remember “ask not what your country can do for you; ask what you can do for your country”).


Curiosity is five times the mass of Spirit or Opportunity. Plutonium is heavy. That’s why the airbag thing will not work for this mission. They cannot be scaled up to match the size of curiosity and still fit in the launcher.

John Marshall

Jems tPL have certainly forgotten KISS– Keep It Simple Stupid.
Too many inherant problems to cause failure. Another $5B lost.

Neil Jones

Looks as though they are test-bedding tech for a manned landing as well as putting the probe down. Too many targets on one mission?

David Schofield

Let’s hope Walowitz isn’t driving it.

wayne Job

Heath Robinson would be proud.

Michael D Smith

Seems like a long way to fly for muslim outreach. Has NASA lost its way?


The Great Galactic Ghoul ( is generally credited with the loss of so many Mars missions.
I share your concern about the sky crane, especially with no way to test it in a realistic Martian gravity scenario. “Works first time” is not a plan. I wish Curiosity the best, but I’m also glad that Opportunity is still roving and is within weeks of stealing Curiosity’s thunder by finding the first phyllosilicates on Mars, at Endeavour Crater.

Luther Wu

Just getting it there in the first place… what’s a little tight- wire act at the end?
But really, the big deal is- just think of all of the carbon pollution from planning- to- launch. We continue to exploit the atmosphere, but think of the poor developing nations which should be receiving the money, instead. Why is NASA still reaching into space? Isn’t their mission to reach out to the developing Muslim world, instead?
How dare they?!

Ian W

Is Curiosity a ‘shovel ready project’?
With the NASA confusion over FPS and MKS expect it to land at a few meters per second rather than feet per second – then they won’t need any shovels.

Leon Brozyna

Mr. Murphy will have the final say on this project.


Sadly, some folks can’t have a serious discussion of a NASA mission, of ANY type, without dredging up pointless canards like “muslim outreach”.
This program was under development long before the current administration and is scheduled for launch this Fall. I believe it is currently going through launch vehicle integration and testing.
I agree with those who feel the complexity of the launch sequence is worrisome, but as Symon notes this is a much larger vehicle. I’m hoping the engineers dotted their i’s and crossed their t’s.
Re: the sounds in space. Most Americans have no idea how laughable this is, and would probably complain about “no sound!” during most of the video. NASA is trying, I guess, to do a better job of PR to the masses, so “sounds in space” is what we get…

Now that NASA has adopted the metric system, what could go wrong?
“NASA lost a 125 million Mars orbiter because one engineering team used metric units while another used English units for a key spacecraft operation…”
Assessment of NASA’s Use of the Metric System
Oh wait…
“NASA criticised for sticking to imperial units”


They want to reduce the weight of the rover by jettisoning the rocket assembly. They have traded the complexity of the bouncing balloon for the cable descent. Not sure the cable descent is inherently more complex.

Bruce Hall

Mr. Goldberg would be proud.

Steve Fitzpatrick

It seems to me unlikely to be funded, but if it ever is, they should re-think the landing: too much risk of a (very expensive) crash and burn.

>Sound-effects in space really get under my skin!<
Because 2001: A Space Odyssey was so technically accurate? A movie that showed a moon bus cruising laterally over the surface, rather than making parabolic hops? A movie that showed fill light in the shadows a Discovery out in deep space? A movie that showed the suspended animation beds in the accelerated living area, rather than the free-fall area of the ship, which would wear less on the sleepers?

Patrick Davis

If you scream in space, does anyone hear your screams?

General P.Malaise

at least you will know when it contacts the surface of Mars.
…because the transmissions will stop.


[Snip. Use of the d-word is not tolerated here. Read the site Policy. ~dbs, mod.]

richard verney

Leon Brozyna says: July 25, 2011 at 4:49 am
Mr. Murphy will have the final say on this project
Or, perhaps lady luck!
Seriously, there does appear a lot to go wrong, and if it successfully lands (without damage), that is a monumental achievement in itself that the designers and engineers can rightly be proud of. I wish them all the best.

I watched this amazing video many months ago when it was presented on DVD at a meeting of our local astronomy club. I bet the contraption will work — any takers? 😀


MSL is indeed ready (although barely). Its cost is a little north $2B. It is the last “BIG” mission that NASA is going to launch for the foreseeable future due to budgetary constraints. There is going to be lots of layoffs at JPL after this because there is nothing else in the pipeline. This had had cost overruns like most NASA missions but when you do one of the kind/first of the kind engineering that is what you get. There is no prototyping and it is very hard to test the equipment in conditions that it will operate, especially with regards to low gravity environment. We do thermal/vac tests as well as vibration tests to see if the spacecraft can survive the outer space and its launch, orbit insertion or landing but things can go wrong.
The metric/British thing was because JPL (which is mandated by NASA and Congress to use metric system) was working with a contractor (Lockheed Martin) that had a DoD heritage British system. Because of this we lost MCO but now the whole thing is rectified.
A few fun facts about the NASA’s capability to track deep-space spacecraft:
We know where a spacecraft is to about +/-10m with respect to its distance to Earth. That is over hundreds of millions of kilometers. We know where the spacecraft IS. Of course this only matters during the cruise for MSL as after it lands we know where Mars is.
The power that the spacecraft has to transmit is typically equal to that of household light bulb (35W to 100W typically). The signal that we receive on the ground is something like 10^-13 (very strong signal) to about 10^-19 Watts. This is after the signal is captured by our 34-m diameter and 70-m diameter antennas at the Deep Space Network. At the high end of that power range we can communicated at about 10 Mbps. That is because we keep our receivers cooled to about 4.7 Kelvins.
We are a victim of our own success. We have so good at doing the near impossible that right now failure is not an option. This has led to cost overruns because we have to bullet proof everything. That is why Mars rovers have lasted close to eight years when they were only planned to operate for only 90 days.
For the record: I am a JPL hack and this is my personal opinion and does not present any position of either NASA or JPL.

Doug in Seattle

Looks like a grand plan. The likelihood of it being built though, let alone launched, is pretty small given the current fiscal problems facing the nation.
Perhaps in 5 to 10 years we can revisit this idea.


they won’t use air-ballons, rather it is lowered down in a controlled fashion. The air bags didn’t work perfectly either in that subsequent testing of that technology had shown that they may rip quite badly. Call it luck 🙂

Douglas DC

“Everything is expected to work perfectly.”-Dr Rube Goldberg NASA engineer…

Alan the Brit

Bet it will never leave the ground! Besides, how on Earth will they get it there? NASA doesn’t do “space” any more. It probably results from a European Study (I jest) that found that competition was too frightening for some people, & they just couldn’t grasp the vastness of space & the spirirt of adventure & exploration, so much so that it hurt their brains! Therefore, all 27 member states will all make a joint sharing caring group hug multi-cultural contribution on the new space project to Mars, budgetted at 500Bn euros over the next 10 years. 30 years later, at 20 times the original estimate, having wasted billions on test programmes because the chief-scientist said they mustn’t interpret the results of said tests in case it upset somebody somewhere, & achieved nothing, nothing has been built passed a cardboard model gathering dust in a cupboard somewhere (hey but the computer generated imagery is fantastic), the French are insisting that 30 cases of Chateau Lafite ’73 should be allocated along with 500 kilos of Camembert in the stores section of the spaceship, the Germans are demanding it should be 300 cases of Moselle instead with bratverst, the Italians want to take mixed cases of Frascati & Barollo along with copious amounts of anchovies & parma ham, the Brits are bogged down in the engineering with some brilliant ideas but have run out of money with no manufacturing base with which to finish them off, have thrown in the towel & gone down to the only pub left open to sup on an insipid euro-approved low alcohol ale, & are terrified the thing will end up with French auto-electronics to run the life-support & guidance systems. The Germans are crafting a marvellous space frame & rocket engine system from the finest space steels, but insist that the firing sequences must be written in Gothic-German, the Italians have designed the space suits (by Gucci), which frankly my dears are to die for (they don’t work!) Reminds me of the Euro-fighter! The rest are just peed off at being bystanders with their hands in their pockets trying to find some more cash. Come on you colonials out there, get NASA back into space where they belong, stop worrying about AGW leave that to the lunatics in Disneyland!

The whole point of Skycrane is to be able to land in very rough terrain, to avoid boulders, canyon walls, etc., within the landing elipse. So, instead of landing at an interesting spot it was designed for, such as Mawrth, shown in the animation, or the river delta in Eberswalde crater, they are going to land in a very large, very flat, very windy Gale Crater, where they are mainly going to be able to look at the same global dust as every other mission. A huge waste of capability. Just like the Spirit, sent to land on what was very obviously a lava flow and not lucrustine deposits like it was sent for – fortunately that rover went far further than intended and found some of what we were looking for.


Lets hope the Martians don’t throw a Jeep size ballistic size object back at us.

Classic JPL digging for dollars. Honestly, a little competitive spirit is needed, but to throw out a tried and true landing concept so we can throw billions of dollars into a better mouse trap (Rube Goldberg style) is just another waste.
Fact is JPL wants more money than just the low cost of another airbag system.
They aren’t going to get it because this thing will never make it past the Mission Review process which balances cost & risk. I know, having been in on those reviews.
Sadly we paid for the mock up and video.

So how did the Viking landers land? Why not use that method? Weren’t they fairly large and heavy?


The air bag approach has it’s own major concerns, even though it has been proven to be a workable design. I’ve not worked those programs but I would guess the main problem with the air-bag approach is that your vehicle must then be designed to survive significantly greater dynamic forces than this design for MSL. When you have to make your vehicle tough, you add weight in the form of structure. Added weight means more power consumption to move robot arms/legs/wheels around. This MSL has no solar panels shown, so they’re likely going with something nuclear. Nuclear is nice in that it is more reliable than Solar (gee where have we heard that before?), but unless you’ve got a full steam-engine reactor, you’re talking about a radioisotope thermoelectric generator. Those worked great for the Voyager and Galileo probes, but they are VERY LOWER POWER output. In a gravity well, when you’re trying to move around, this means you have to save weight any way you can. Basically the design here is to go for a mars rover that will maybe last as long as Voyager has. It might seem higher risk, but the rewards are greater because you’d maybe have a rover on Mars for 10-20 years, instead of 5-6.

Brian H

I’m just as interested in the SpaceX COTS launches to ISS this year for NASA. 3 are scheduled, 2 more demos, 1 live. In 2012, 3 live.
Interesting that the Falcon Heavy will have 2X the payload lift capacity of a Shuttle. First test launch late 2012.
Launch Manifest.

The final separation of the landing rocket frame from the rover is where I would expect a failure to occur.


while its landing does the initial pod with the parachute land on all the other equipment? Why not just use a parachute ?


Good thing they’ve scheduled the landing for the weather window of no severe winds that could tangle the payload in the wires or flip it.


Why all this angst and pessimism? How are we to learn anything if we don’t try?
If the majority attitude of ‘it’s to complex and not yet proven thus it will fail and is a waste of money’ were applied in the early ’90s as Pathfinder was being developed, the ‘safe’ airbag landing method would have been lauded as utter foolishness. I’ll note as one who as followed NASA’s mars program closely for the past 15 to 20 years, the airbag approach is impossible with MSL as Symon noted, and is to this day anything but a ‘safe’ landing method itself. We are VERY blessed to have both MERs survive – research their development.
JPL’s only mars lander failure in the past 35 years or so is as Ian W noted, MPL (Mars Polar Lander) in ’98 which itself was not a result of the the humiliating metric conversion error. Rather, it’s landing computer though it had contacted the surface when in fact the sensors ‘felt’s the jolt of the legs deploying, a failure mode not detected thanks in large part to the prevailing “faster, better, cheaper” development philosophy at the time. For the record that is six for seven, a nearly 86% success rate, with most employing some need for “works the first time” technology, including the first successful mars landing ever with Viking Lander 1.
Stop with the lemming-like nay saying attitude and don’t confuse nay saying with skepticism. Both are foolishness and are an embarrassment to this fine site. Research before you type!

M.A.DeLuca II

I find that video works best with Raymond Scott’s “Power House” playing in the background.


The airbag system was pushed to it’s limits to land Spirit and Opportunity. It would NOT scale up.
The airbag system may have LOOKED simple, but tell that to the people that had to make it work…oh yes those are the people at JPL, the people some of you seem so eager to mock, and call fools.
Yes, Mars eats spacecraft. Do you think this is news to the people that designed this system? Or rather is it their unending, all pervasive nightmare?
Who here thinks that the Apollo missions were simple? Or that they were cheap?
What is being attempted with MSL is an order of magnitude or three bigger and better than anything tried before.
You know what I think?
It’s crazy, it’s brave, and it’s glorious, and I hope with all my heart that it succeeds brilliantly.

Eric Anderson

Anthony, this is a (slightly modified) previously used approach. The bouncing balloon bags worked so well with Spirit and Opportunity that it is tempting to think that is the only way to go, but that approach was by no means a sure deal either. Agreed, Mars is known as a tough place to do a mission, but I think this approach has been relatively well thought out and has as good a chance for success as other landings.


I disagree completely. Synchronization is actually easy. These electro-mechanical systems are extremely reliable. It should be quite obvious that the bouncy airbag idea is actually much more risky ( bag getting tangled in the vehicle machinery, landing in an uncontrolled way and hitting a bad spot, excessive g forces on equipment and structures ) . The only advantage of the bouncy airbag idea is that it is very inexpensive to implement – a beautiful idea for cheaply deploying small and extremely robust gear.


>>My view: there’s a lot more that can go wrong.
I fail to see how all that parachutery, in an almost airless atmosphere, can weigh less than taking more fuel for the retro-rockets. I would like to see the weight comparison.


Over at there were some videos from the recently completed Atlatis mission. One part showed video from the SRBs with audio. Really cool shots. There were very interesting clunks and lower frequency ringing sounds. All this from the vacuum of space. Clearly, the sounds were conducted through metal. See at about 4 min.
I first watched the Curiosity landing video a few months ago, and yes is seems far too complex and more prone to failure. It also seems silly they don’t have a second launch planned to up the odds of success and cut the cost of the second mission.
If the Curiosity landing is successful, you’ll have back-slapping congratulations. But that’s a big $2.3 billion gamble. If they are successful, they might start taking even bigger risks. We should be spending for exploration and developing space technology. It’s funny sometimes what people do with other people’s money. At least there are no human lives riding on this one.

Eric Anderson

I should add that NASA is a huge organization, with lots of different teams working on lots of different items, together with outside contractors. No-one who has spent years designing and building a spacecraft is going to do anything that they think will possibly kill their baby. There are risk/cost/spec tradeoffs in any design, but there is a lot of thought that goes into the best way to make the mission a success.
It’s good to be skeptical, but let’s not let James Hansen and his ilk automatically taint our view of all the hard working men and women at NASA who are doing real applied science (i.e., engineering).


The whoosing sounds are part of artist’s imagination, not of the technical specification. It works for many other projects (including about any space movie) so I don’t think they are a real problem here. Anybody who does not like the unrealistic sound effects in the animation (and sure enough none of them are realistic) can just mute the sound.
Regarding the rube-goldberg scheme, yes I agree the mechanism seems to be complicated. But I’m sure people at NASA are not stupid and they discussed many possible solution variants before choosing this. The braking mechanism has already been proven working on the Phoenix probe so it’s not something that hasn’t ever been tested in real conditions – and for the control system it does not really matter whether it zeroes out on zero or any positive height. The main problem is that the rover really needs to get rid of all the balast it doesn’t need to carry along and leaving it above and then throwing away is IMO really the safest way. Even with additional weight for fuel reserves, spare thrusters and the towing mechanism it’s still going to be lighter than the airbag structure, too. Plus the system can visually navigate to a spot that seems to be most suitable for landing pretty much the same way moon landing was done, instead of blind crash landing with airbags.
Regarding the airbags idea, I just think there is a big problem with scaling. A toy car can withstand quite a lot of crashes to a brick wall which destroy a normally-sized car on first attempt at the same relative speed. The requirements on the container and airbag structure stability and toughness don’t raise linearly with scale. And there is still the chance that the airbag structure may get stuck somewhere from which it may not be able to get out or unfold.
Yes, there is a whole lot of things that can go wrong and there is a whole lot of things that went wrong in past missions. Basically each of them was the ‘must work on first attempt’ to some extent too because we don’t have Mars gravity or several kilometers of Mars atmosphere available here on Earth to test everything. That’s the risk of the project. And as the funds are getting limited, the task is not only to find the single safest way of getting the machine there but also doing so within available budget. Personally I believe a lot of technology that’s going to be used in this project was already quite thoroughly tested in real Martian environment during past missions, so there will not be as much of the ‘must work on first attempt’ untested technologies as some may think.