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The 100-Million Mile Network
mykepredko writes "eWeek has an article on the network and radio topography of the two Mars rovers and how they communicate with satellites in Mars' orbit as well as the Earth. The article ends by giving four rules for maintaining a space network, a) Automate processes, b) Bulletproof your gear, c) Be persistent and d) Simulate potential problems, which are probably good rules for any network."
They're using RAD6000 processors which are modified chips used to run old Macs from the early nineties. Each rover has 384 megabytes of RAM, the extra 256 is for images.
The operating system is VxWorks.
Not to nitpick but,
<nitpick>
The RAD6000 is a radiation hardened RS/6000 PowerPC chip from IBM. A similar chip was used in Apple Macintoshes, but Apple is not the source of the RAD6000 chip.
</nitpick>
I love my Mac as much as everybody else, but it's just not the case that the RAD6000 is a 'mac' chip. It's an IBM chip, a cousin of those used in macs.
UHF is not that old... most public service (save the boomtowns like LA and NYC) are still on VHF-lo/hi. My county fire (in CA) does digital telemtry over a 159mhz (VHF) freq to track all the apparatuses around the county. With the low bandwidth allowed and general problems that come with VHF, it is a fight. A good thing about UHF is its relative line of sight path while still penetrating/bending around slight obstructions and keeping a good digital signal. Higher frequency signals coming from an omni-directional antenna would die out pretty quick if anything more than dust was in the way. To get around really big obstructions lowband is the way to go... there is a reason CA Dept. of Forrestry and CA Highway Patrol still maintain their 30mhz radio nets around the state. But to go digital you need clean signals, so 800+mhz is the way to go there. What, you want both? Oh, UHF-T band then, 400mhz. Enjoy.