stevech 
2nd generation NASA Apollo nav computer. Got us to the moon and back.
Could an AVR do it? See enclosure to this posting.
Ah, the rub: The Apollo computer had 2K of RAM.
Tell that to the code-bloat kiddies in Redmond.
[credit: SparkFun website and they from http://mitpress.mit.edu/catalog/... ]
farang 
The Apollo landing was in 1969. There were no single chip microcontrollers at that time. No doubt an AVR could achieve that functionality today.
Your point on efficient use of RAM is noted and apprieciated.
But would an AVR be able to stand up to the rigors of space flight? I don't think there are radiation hardenend AVRs available. IIRC the super slow rca1802 was used for a very long time just because of this.
bobgardner What does radiation do to silicon? Once upon a time I thought it produced current in emmitter-base junctions, which could burn out bipolar transistors. I thought cmos was not susceptible to this?
http://en.wikipedia.org/wiki/Radiation_hardened tells you all.
It seems CMOS is less susceptible, not immune.
KillerSpud But would an AVR be able to stand up to the rigors of space flight? I don't think there are radiation hardenend AVRs available. IIRC the super slow rca1802 was used for a very long time just because of this.
That's just radio power.
Not cosmic rays, solar particles, neutron or gamma radiation and whatever other scary phenomena that exist ;)
If just a metal box would be sufficient then why does rad hardening exists and are SEEs a real problem?
Especially with the ever smaller geometries it's easier to upset a chip.
laker Just an interesting factoid. I read somewhere that they've recently discovered that 'Hard' cosmic radiation is in fact less problematic to electronic components then 'Soft' radiation. they have spent the past years concentrating on making rad-hard components stand up to as much cosmic radiation as possible, but it turns out that by raising the bar as high as you can you let through the softer, more harmfull to electronics, radiation. So even the guys at the top of their game are still getting caught out on what can and cant survive the riguers of space.
But my opinion, for what its worth, is that an AVR with enough IO could land a space mission! So long as the space weather was nice and calm, and your circuits were well screened from harmfull spacey... stuff. (technical terminology!)
Watch out for those solar winds!
