Mars helicopter phones home after 63 days of silence NASAs Ingenuity Mars Helicopter has phoned home, more than 60 days after last establishing contact. mars China space agency reckons Zhurong Mars rover has probably been done in by dust READ MORE Ingenuity's last flight was on April 26, when the rotorcraft took to Martian skies for 139 seconds and hopped 363 meters. The …
It's very easy to make sure a one off prototype product lasts well past it's minimum required lifetime since the material cost of exceeding engineering requirements is relatively minor compared to the engineering costs and related expenses. For mass produced consumer goods, material costs starts getting counted in fractions of cents, overengineering is no longer an option and things get cost optimized to the point that roughly 95 to 99% of products will last a minimum of the warranty period (The myth that they get engineered to fail just after is false, but optimizing to last a minimum of the warranty but with no "unnecessary cost" means that they're likely to fail very shortly after warranty so the effect is about the same).
It's in the maths. I've said it before but here goes again... if you want to make sure that the thing as a whole will last the initial mission duration with 95% probability, then each subsystem (let's say six of them) needs a 99% chance of getting there. In which case there's an 80% chance (whatever) of lasting ten (whatever) times longer. Particularly with the rovers - jammed wheel? Drive backwards.
Obvs helicopter more of a go / no-go situation.
Still, it's marvellous that a technology demonstrator has been turned into a useful instrument.
Many years ago, at university, I was one student in a room full of mechanical engineering students who had to sit and listen to a management lecturer tell us that car manufacturers deliberately design in rust spots.
Needless to say, we had very little respect for him before that lecture, because his entire course (compulsory to engineering students) was trying to teach us meaningless management-speak, and after that particular lecture, he had absolutely no respect from us at all.
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