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Celebrating Spirit, The Mars Rover
4

Celebrating Spirit, The Mars Rover

Celebrating Spirit, The Mars Rover

(OP)
She doesn't answer any more but she ran years past her design life.  Nice job on the engineering and design.  A salute to all the men and women involved.  

Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.    

RE: Celebrating Spirit, The Mars Rover

Or arguably, she was well over designed/engineered (if you want to argue the term look here thread1010-292852: The term 'Over engineered') for the original requirement and presumably there fore more expensive than necessary.

As a tax payer I want a refund.

winky smile

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RE: Celebrating Spirit, The Mars Rover

Note that Spirit's sister rover, Opportunity, is still going strong and sending pictures back to Earth on a daily basis:

http://marsrover.nasa.gov/mission/status_opportunityAll.html#sol2600

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.
 

RE: Celebrating Spirit, The Mars Rover

Kenat, consider Opportunity's successful longevity as payback rather than refund.

"Art without engineering is dreaming; Engineering without art is calculating."

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RE: Celebrating Spirit, The Mars Rover

Oops, insert tongue above.

"Art without engineering is dreaming; Engineering without art is calculating."

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RE: Celebrating Spirit, The Mars Rover

(OP)
Dear Kenat:

From your posts I always assumed that you were the type of person who enjoyed designing / building something that outperformed while coming in at or under all budgets.   

I think that is what happened here.  

Tom

 

Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.    

RE: Celebrating Spirit, The Mars Rover

Hey Tom, I put a "winky smile".

You should know I'll often play devils advocate just to make sure people have really thought through their own position, not necessarily because I disagree with their position.

It really is an achievement, plus as long as they're gathering useful data then even if arguably more expensive than needed for their original requirement, they may well be a worthwhile investment.

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RE: Celebrating Spirit, The Mars Rover

(OP)
Dear Kenat:

I am aware of your propensity for playing Devil's Advocate.

I very much admire your ability to broaden issues in an entirely relevant manner.  

I am also an admirer of yours and you do strike me as someone who takes great pride in the quality he delivers.

I agree with you about the added expense.  But it is still a really cool thing.

Tom

Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.    

RE: Celebrating Spirit, The Mars Rover

"She doesn't answer any more but she ran years past her design life."

Sounds like my wife - but she is still alive!!!

RE: Celebrating Spirit, The Mars Rover

Quote (KENAT):


...even if arguably more expensive than needed for their original requirement...

Of course you do have to take into consideration that we're talking about conditions on the surface of MARS so I would suspect that the specifications that they were working from had a bit more latitude than what most engineers are presented with when they are starting a new design for some Earth-bound application.  Besides, since making on-site service calls were going to be a bit impractical, I assume that this was justification for spending a bit more on redundant systems winky smile

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.
 

RE: Celebrating Spirit, The Mars Rover

To some degree, there is no overdesign.  Designing for a 3-month minimum life is like trying to design a system with a minimum of 64k DRAM.  

At this point in history, designing for that minimum would actually cost you more money, because parts that bad or small don't even exist anymore, except in surplus stores, or in some hideous reclamation yard in China or India.  So, you build to the smallest DRAM you can find, which is around 256 MB, which is 4000 times your requirement.  

Likewise, most electronics, except the stuff that we buy, already far exceed 3-month (5-σ) reliability.  Even in the 1980s, there were semiconductor companies with processes so reliable, they didn't even include test devices on their wafers.

So, in actually, to design for a 3-month life, only, could actually have been more expensive design alternative.

TTFN

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RE: Celebrating Spirit, The Mars Rover

Kenat,

Were you even a US resident, much less a citizen, when Spirit was designed and built?

I don't think you're entitled to one penny of that refund.

RE: Celebrating Spirit, The Mars Rover

Not to minimize this extraordinary work but--come on- throw infinite money at  it and you are bound to get great designs. I know from the LEM days.

RE: Celebrating Spirit, The Mars Rover

I wonder what the actual design life (MTBF) was? Obviously 90 days was no good, as that would give a 50% chance of failing to meet its necessary life span, that's no good. Given the typical failure curve for a complex electromechanical system, choosing the reliability of each component (offset against weight and redundancy)must be quite a trick.

Cheers

Greg Locock


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RE: Celebrating Spirit, The Mars Rover

Greg, you aren't kidding!  I've burned almost a full (slow) Friday reading that blog.  Really interesting and enjoyable to read.  Make me wish I was over at JPL (yeah, like that would ever happen!).

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