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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."
Apparently, they run VxWorks
Wait a minute. I got it. You could play with your magic nose goblins.
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.
A satellite that could bounce signals to the far side of the sun at Mars orbit would have to be much bigger than the International Space Station, be somewhere in the orbit of Jupiter and have enough fuel to reposition itself hundreds of millions of miles for several years to be economically viable.
More info on communications between Mars/Earth and the DSN (Deep Space Network):
- NASA's MER2004 Communications with Earth Overview
- DSN (Deep Space Network) Main Page
- Wikipedia entry on Deep Space Network
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For news, status, updates, scientific info, images, video, and more, check out:
(AXCH) 2004 Mars Exploration Rovers - News, Status, Technical Info, History.
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.
Deep Space Network website:
http://deepspace.jpl.nasa.gov/dsn/
Not very detailed but a nice overview of the setup.
Well, actually it's right, and it implies that the average house internet connection is 1.0mbps.
Do the math...
1000000 bits / 8 = 125000 bytes/s 125000 bytes / 1024 = 122.0703125 kb/s 122.0703125 / 1024 = 0.1192092mb/s That means it's a 0.1192092mb/s line to mars, and probably with brutal latency. Let's just hope that they're not serving up warez from it...or that slashdot doesn't link to a webserver hosted on it...
Canadian Cynic, canadian politics is less boring than you
That was a different warp scale, apparantly they changed it sometime after the TNG timeline, to account for faster ships. The old warp scale was some kind of logarithmic scale, with warp 10 as infinite speed. This led to faster ships reaching warp 9.9, 9.99, 9.99999, etc. The new scale was used to stretch out the range a bit.
God i feel like a geek.
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.
Well, actually it's right, and it implies that the average house internet connection is 1.0mbps. Do the math... 1000000 bits / 8 = 125000 bytes/s 125000 bytes / 1024 = 122.0703125 kb/s 122.0703125 / 1024 = 0.1192092mb/s That means it's a 0.1192092mb/s line to mars, and probably with brutal latency. Let's just hope that they're not serving up warez from it...or that slashdot doesn't link to a webserver hosted on it...
You have confused your units. Network speeds are reported in bits, not bytes -- an average cable modem is around 1.5Mbps, not 1.5MBps.
ZFS: because love is never having to say fsck