NASA’s Curiosity Mars rover is to use a unique system called a “sky crane” to touch down next year on the Red Planet. Engineers at the Jet Propulsion Laboratory have just released a video of this previously untried mechanism under test. (UPDATE: it all worked perfectly, for more detail see how did NASA do it?)
A UFO hovers in the Martian sky (Image credit:NASA/JPL)
The car-sized Mars Science Laboratory Curiosity is too heavy to slam into the rocky plains of Mars encased in airbags like its predecessors, so this imaginative and complex system was devised instead. Like many previous successful missions, Curiosity is being built at NASA’s Jet Propulsion Laboratory, and staff there have created this fascinating video documenting a test of the deployment mechanism.
All being well this will all happen for real in the Martian sky in August 2012.
Update:Curiousity was successfully launched on 26 November 2011.
All I hear about is that this design is to avoid a top heavy and thus unstable “table with legs” type Lander and the difficulty of shutting off rocket engine nozzles simultaneously. I would hope some control of the deployment speed of the cable would add greater control of the descent speed, but IòÀÙve not heard much about that advantage of the design and even if there is anything more than a constant speed winch deploying the cable(s). Is there more to the cable deployment than I’ve read?
yes. there is a huge benefit to the cable drop system. the short answer is weight. the cable drop method eliminates the weight of lander legs, a platform for Curiosity, and two ramps for it to roll off of (two for redundancy in case one is on a rock). remember that Curiosity already weighs 900kg, so the legs, platform, and ramps would have to be strong enough to hold that weight. that strength would require heavy materials. additionally, every additional pound you launch into outer space means that the rocket you use will require more fuel. every pound of fuel the rocket has to life reduces the payload you can put into space, so reducing weight is critical in keeping launch costs reasonable.
I’ll be honest and say I don’t know the answer. Perhaps you could contact the author of http://www.engineeringchallenges.org/cms/7126/7622.aspx and he could help?
It is quite shocking how difficult it is to land on Mars (see http://www.universetoday.com/7024/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/). At the moment we have no idea how we could land a crewed mission there!
Is there a video anywhere on the internet of a test of the “sky crane” rockets? Was this tested at all, or did they only test the lowering mechanism?
Why would the send a $Billion payload out without testing the delivery/landing system?
Seems fishy to me.
Dear James, thanks for your question. I have not found any videos online of the sky crane rockets (which were 8 Aerojet MR-80B units) being tested but you can read about their development and testing in the document Monopropellant Hydrazine 700 lbf Throttling Terminal Descent Engine for Mars Science Laboratory (link).
Obviously every element of the landing system was tested on Earth, but since our planet’s gravitational pull is about three times that of Mars, it was not possible to test the entire system here. The assumption had to be made that the entire system would work as designed, that is absolutely normal for planetary missions. Since the Curiosity rover was successfully landed this philosophy proved satisfactory.
I hope this answer has helped you.
P.S.
I’ve seen a lot of cartoons of the proposed landing, but no real video of a test.
It appears NASA employs a lot of animation people. Wouldn’t it have been better to save that money (spent on animation) and spend it on testing and actual videography?
Dear James, I would have thought that the cost of producing an animation was minuscule compared to the cost of developing the actual hardware so I assume that isn’t really an issue.