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Fraser
2007-Jan-04, 01:54 AM
Consider this for a moment. NASA's Mars Exploration rovers are nearing their third anniversary of crawling around the surface of Mars. Spirit arrived on January 3rd, 2004, and Opportunity showed up 21 days later. ...

Read the full blog entry (http://www.universetoday.com/2007/01/03/mars-rovers-learn-some-new-tricks/)

John Mendenhall
2007-Jan-04, 06:40 PM
This is an interesting approach. In designing future remote vehicles, considering the enormous amounts of data storage and processing available now, it might be a good idea to allow for major re-programming over the life of the vehicle. Because of the design lead times of 10 years or so, this was a problem on the early robotic explorers, Pioneer, Voyagers, etc.; by the time they were launched, they were badly outdated. And there was no easy way to update, their computer systems were limited.

Remember. that desktop that you have in front of you is probably as good as the first generation Crays. And keep in mind the critical date;the computer designers estimate that by 2015 the average desktop will be as smart (whatever that is) as the average human. Won't that be nice to send to Mars? Will it be the first Martian?

01101001
2007-Jan-04, 07:37 PM
And keep in mind the critical date;the computer designers estimate that by 2015 the average desktop will be as smart (whatever that is) as the average human. Won't that be nice to send to Mars?

Which of course will happen well after the 2015 human-level smarts (of which I'm skeptical).

Space.com: Thinking on Mars (http://www.space.com/businesstechnology/mer_computer_040128.html)


[Mars Exploration Rovers'] RAD6000 microprocessors are radiation-hardened versions of the PowerPC chips that powered Macintosh computers in the early 1990s, with 128 megabytes of random access memory (RAM) and capable of carrying out about 20 million instructions per second. A critical feature of the spaceworthy chips -- developed jointly by BAE systems, JPL and the Air Force Research Laboratory -- is the radiation shielding, which uses a series of resistors and capacitors to ground harmful radiation before it can damage onboard electronics.

Association for Computing Machinery: A Conversation with [OS Dude] Mike Deliman (http://www.acmqueue.org/modules.php?name=Content&pa=showpage&pid=227&page=2) (page 2)


MD Hardening a spacecraft is much easier than hardening a processor. The steps to harden a processor can take years, and it requires testing and reworking, iterated several times to create a processor that is both radiation-hardened and functional. This is a costly and time-consuming process. These are the reasons why rad-hard processors are so far behind consumer-grade processors. For instance, the current [October 2004] state-of-the-art rad-hard processor is a PPC750-based chip that runs at 130 megahertz, whereas you can buy consumer-grade PPC750s that run at well over 1,000 megahertz.

ToSeek
2007-Jan-04, 09:38 PM
I remember people wondering why they were installing a 386-based computer in Hubble some years ago at a time when the Pentium was state-of-the-art.

John Mendenhall
2007-Jan-05, 05:24 PM
Interesting about the radiation hardening. As a computer professional, I can assure you that you get some strange looks when you tell people that an infallible computer cannot be built, because eventually a cosmic ray will arrive with enough energy to flip a critical bit, and then it's crash time.