Slashdot Mirror
The Tech Aboard the International Space Station
CNETNate writes "With its own file server for uploaded Hollywood blockbusters, a 10Mbps Internet connection to Earth, and around a hundred IBM ThinkPad notebooks, the consumer technology aboard the $150 billion International Space Station is impressive. It's the responsibility of just two guys to maintain the uptime of the Space Station's IT, and they have given CNET an in-depth interview to explain what tech's aboard, how it works, and whether Windows viruses are a threat to the astronauts. In a related feature, the Space Station's internal network (which operates over bandwidth of just 1Mbps) and its connected array of Lenovo notebooks is explained, along with the tech we could see in the future."
It's been done: http://www.nasa.gov/home/hqnews/2008/nov/HQ_08-298_Deep_space_internet.html
rewriting history since 2109
Space pirates!!
Not necessariily; they could be getting the movies with the MPAA studios' blessing. It's only "piracy" if the copyright holder doesn't give permission.
I know, "woosh" and all that.
Free Martian Whores!
Once upon a time, large portions of the internet were "store and forward."
"I'd rather be a lightning rod than a seismometer." -Ken Kesey
"mankind's first permanent space colony"
Someone needs to tell Mark Harris that the ISS is scheduled to be deorbited 1Q 2016 before he moves in to his condo there.
http://en.wikipedia.org/wiki/International_Space_Station
-- Terry
OK you get two points for +1crazy. Point 1; the ISS completes an ENTIRE orbit in 90 minutes. That means that if you had an antenna pointed straight up, and say you used a moderate gain antenna with a 5 degree beam, you will get just over ONE minute of access before you need to adjust the antenna. You would need a pretty sophisticated ground tracking mechanism to have any hope of keeping the connection alive for more than a minute.
On to 2. WiFi uses an ack timeout in the microsecond range. This means that for a typically configured transceiver, you are racing the speed of light with that timeout window. The practical limit happens to be around 20 miles, or 32 kilometers. Not quite enough to get you to the ISS.
Good luck, though!
So is there a network of geosynchronous satellites that provides its 10 mbps link to the ground?
http://en.wikipedia.org/wiki/Tracking_and_Data_Relay_Satellite_System
Up to 48 megs. My guess is 10 megs came about because someone told a journalist, "its about as fast as old fashioned thinnet" whom thought to himself, thinnet is 10 megs, so the journalist says 10 megs.
And/or there may be a critical link in the path that is, literally, a piece of thinnet coax, or an old fashioned 10 meg only cat5 cable, so the overall path cannot exceed 10 megs.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
As someone who works in space flight hardware, I will state what I think is obvious to most slashdotters: These are not just "consumer grade electronics." True, they were based heavily or solely on an existing consumer product, but they have to meet a very stringent set of requirements to operate in space. *They need to cool themselves effectively despite having no gravity, which means heat doesn't rise and you lose all naturally convective heating *They need to be radiation hardened to mitigate against bit flips and the like due to radiation particles *They need to meet specific reliability and usability requirements driven by spaceflight And lastly, with everyone complaining about how the government wastes money, do you really expect that it would be better for NASA to contract out development, design, testing and building of a one-off product (laptop, camera, MP3 player, camcorder, PDA, etc) where it isn't necessary?
Actually I am sure that the ISS is using TDRS or it's replacment for their link. I would bet that the ISS has at least one geosynchronous bounce at all times.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
FTFA:
"You'd be surprised at how many computers would survive on the ISS. I can't think of an occurrence when we've have a computer fail from the radiation itself. It may reduce the lifetime of how long we can keep the equipment in orbit, but most of the time the failures are just like the ones here on the ground -- we'll have a hard-drive failure or we'll have an application problem and end up reloading the machine."
It's going to vary since both Earth and Mars orbit the Sun. The closest distance is around 55 million km. The furthest is around 400 million km. At 55 Mkm, it's about 3 minutes. At 400 Mkm it's about 22 minutes.
NASA requires you to use the thinkpads. Not that they are anything special other than they have gone through a battery of tests and have a few mods to help with cooling and power requirements. Offer them all you want for free and they'll say no. The main reason for so many are that each one more than likely is dedicated to a single use. If you have 60 experiments, then you have 60 laptops. It's quite a bit of effort and paperwork to certify that any application you need to run on a laptop plays nicely with everything else. Even if your program is a whopping 100kb controller for some piece of equipment. This is done because you typically don't have a whole lot of overlap between who is supplying the experiments so cross testing is difficult. The last thing you want to do is try to fire up an experiment, not have it work and then have to waste everyones time figuring out what isn't playing nice with what. It's just easier to dedicate a whole laptop.
"One thing that really impacts the crew's day-to-day operations is if the file server itself fails. This forces them to reload the hard drive and re-establish all the network drives and all the apps. They actually have to get out the media and load the image to the hard drive. That's a significant hit for the crew because we can't do everything for them from the ground.
Jesus Christ, given the cost per minute keeping those guys up there, I'd think they'd at the very least have redundant servers with redundant media.
Take a look at this video. The Thinkpads are scattered across the whole space station. And as you can see they are pretty much mounted on racks doing something specific.
By the way, am I the only one thinking the ISS seems to be pretty huge?
I thought it was closer to 90 minutes...
With a martian 1.666 AU x 1.381 AU orbit, and our own slight eccentricity, we could simplistically expect a separation of between 0.365 and 2.682 AU, so with 499 light-seconds in an AU we'd get 182 to 1338 seconds (3:02 to 22:18).
Funny, but I recall having heard 90 minutes as well (in the form of news reports discussing the time it would take for reports of successful probe landings to be radioed back), but with a speed limit of 7.2 AU/hr, Jupiter is never even an hour away. 90 minutes is about right for worse case Saturn, so perhaps it was the Huygens landing that stuck in my mind.
We consistently get 650ms latencies on our satellite network hitting a Geo stationary satellite. I imagine with the proper setup they could see latencies as low as 150ms witch is very reasonable. Even with a 650ms latency you can barely tell the lag on a phone call
The distance from Earth to Mars varies between 3 and 22 light minutes.