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Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

nytimes.com

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Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#62
post #31

Is it possible for someone other than NASA to send a message to the rover? I'd be happy throwing a little money at a project to ping it monthly to see if there is a response.

It's physically possible but I'd have to imagine there's a security key required for the Rover to accept a message and there's no way in hell NASA would give you that key.

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#63
post #18

And it was supposed to last 90 days...

It wasn’t supposed to last only 90 days, the initial mission specifications were for a 90 day mission. While it’s an engineering marvel no one thought that it would last only 90 days if it successfully landed and deployed, the 90 days was a minimum figure for the design and also the initial operating budget for the mission.

It wasn't actually expected to last much longer than 90 days, that it did was essentially a miracle, not just good engineering.

At the time the MER vehicles were built we knew enough about Martian dust to know that it would be a severe limiting factor on solar powered vehicles, but we didn't have enough experience with long lived solar powered vehicles to know all the details. We didn't know about "cleaning events" which were too irregular to fully plan for anyway. Ultimately, we got lucky, and we were able to take advantage of that luck on the fly. For example, we found that even with heavy dust accumulation the rovers could survive with careful power management during Summer, and during Winter we could conveniently park them on a South facing incline to maximize power.

Nevertheless, it is telling that for both rovers the thing that did them in was the thing that was always expected to limit their longevity: solar power generation. Spirit had a wheel get stuck and then couldn't park at a good angle during winter, and the absence of cleaning events during that time resulted in power generation falling below a critical threshold at that time. Opportunity got done in by an epic planet wide dust storm, which blocked sunlight long enough for the batteries to run out and for the vehicle to get dangerously cold (likely resulting in critical equipment failures).

Before we had that experience we had no idea that these things were possible, and nobody in their right mind would have bet money that the rovers would have been able to survive for years on Mars.

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#64

Was looking through Opportunity's Wikipedia page, and found this cool comparison of the embedded systems used in Mars rovers: https://en.wikipedia.org/wiki/Comparison_of_embedded_compute... That lead me to the RAD6000 page, which was new to me: https://en.wikipedia.org/wiki/IBM_RAD6000 "Reported to have a unit cost somewhere between US$200,000 and US$300,000, RAD6000 computers were released for sale in the general co…

My understanding is that most of that is setup costs for retooling a fab, which requires moving around and recalibrating some very specialized equipment. The numbers I heard were dozens of engineers working a total of one to two thousand man hours to set up the process, make and verify the chips, then switch the fab back to the processes their other customers usually order. Since these semiconductor fabs have high upfront and fixed operating costs, they need to have a high utilization to be profitable - preventing anyone from having a specialized fab that makes only RAD hardened chips.

AFAIK the lower cost VORAGO designs require far less retooling so they're a lot cheaper with existing processes.

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#65

Earlier quoted context omitted.

Also a testament to the value of under-promising. :)

Then that was the mother of all under-promises!

If they make it over 9000 days, they can state the just did a error on the exponent

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#67
post #41

Was looking through Opportunity's Wikipedia page, and found this cool comparison of the embedded systems used in Mars rovers: https://en.wikipedia.org/wiki/Comparison_of_embedded_compute... That lead me to the RAD6000 page, which was new to me: https://en.wikipedia.org/wiki/IBM_RAD6000 "Reported to have a unit cost somewhere between US$200,000 and US$300,000, RAD6000 computers were released for sale in the general co…

Low yields, low volume, high development cost, high certification costs, strict QA. Vorago makes a cheaper option these days at $800 a chip: https://www.voragotech.com/products/va10820-radiation-harden...

They're not comparable chips. The RAD6000 has a thousand times more RAM, for starters.

Re: Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission

#68
post #41

Was looking through Opportunity's Wikipedia page, and found this cool comparison of the embedded systems used in Mars rovers: https://en.wikipedia.org/wiki/Comparison_of_embedded_compute... That lead me to the RAD6000 page, which was new to me: https://en.wikipedia.org/wiki/IBM_RAD6000 "Reported to have a unit cost somewhere between US$200,000 and US$300,000, RAD6000 computers were released for sale in the general co…

Low yields, low volume, high development cost, high certification costs, strict QA. Vorago makes a cheaper option these days at $800 a chip: https://www.voragotech.com/products/va10820-radiation-harden...

That's a Harvard architecture microcontroller, a bit different from the POWER CPUs in the rovers.

Still subject to the same engineering constraints, but significantly less complex.

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