typodupeerror

## Getting the Latest Rover To Mars191

derGoldstein writes "New Scientist has a great video up detailing every step of how the latest Mars rover will reach its target and get deployed. It's drastically different than the bouncing air-bag delivery system previously used (YouTube video)."
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## Getting the Latest Rover To Mars

• #### Re:The difference is size (Score:2, Interesting)

<mosb1000@mac.com> on Monday July 25, 2011 @02:54AM (#36868148)

Space is not entirely soundless. If you were to put a microphone nearby a rocket nozzle, or thrusters firing, you would record sound. Likewise, if the microphone were attached to the vehicle while it was undergoing stage separation you would record sound. I'm not gonna say the video was perfectly technically accurate, but you can't just say "no sound in space" either.

• #### Re:Dibs on crash (Score:4, Interesting)

on Monday July 25, 2011 @07:09AM (#36868998)

Unless Calculator has failed me, a 1 million part machine (with each part having a 1 in a million fail rate) has around a 63.2% chance of failing.

No need for a calculator. This type of problem (1 in n chance of an event occurring, what are the odds of it occurring in m trials, when n=m?) converges to 1 - 1/e. The total number of failures adds up to 100% (it has to be to maintain the original odds), but some of those outcomes are multiple failures (i.e. 2+ parts failing on your million part machine). If you have 100 letters which you randomly put into 100 mailboxes, some of those mailboxes will get 2+ letters, meaning obviously that some mailboxes will not get any letters. As it turns out, it's 1/e mailboxes which get no letters, and 1 - 1/e mailboxes which get at least 1 letter.

• #### Doomed to become a statistic (Score:4, Interesting)

on Monday July 25, 2011 @07:22AM (#36869046)

I counted 8 systems where any problem at all would kill the mission:

Heatshield that has to protect, then deploy (or fall off in non-techno speak)
Guidance rockets that have to work just right
A parachute that mustn't rip or tangle
A hovering system that must balance,irrespective of any storms it may encounter
A winch that must not jam (after 40+ weeks in cold and vacuum)
... and pay out slowly enough
... and detach when the lander is down safely
and finally the hovering platform that must not run out of fuel and drop onto the lander, or think it's detached and fly off with the lander in tow (If they got that on video, I'd laugh for a week)

In short there are far too many ways it can fail, and far too many things that have to work perfectly. I think there's a bad case of hubris from having 2 landers out of 2 that not only survived the trip, but exceeded expectations. Sadly, I think this thing will even up the score.

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