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Hackers In Space: Designing A Ground Station
An anonymous reader writes with some new information on the happenings of the Hacker Space Program. From the article: "At the Chaos Communication Camp 2011 Jens Ohlig, Lars Weiler, and Nick Farr proposed a daunting task: to land a hacker on the Moon by 2034. The plan calls for three separate phases: Establishing an open, free, and globally accessible satellite communication network, put a human into orbit, and land on the Moon. Interestingly enough, there is already considerable work being done on the second phase of this plan by the Copenhagen Suborbitals, and Google's own Lunar X Prize is trying to spur development of robotic missions to the Moon. But what about the first phase? Answering the call is the 'Shackspace,' a hackerspace from Stuttgart, Germany, who've begun work on an ambitious project they're calling the 'Hackerspace Global Grid.'"
Otherwise, why call this hacking?
Engineering, anyone?
Simple question: where are they going to get the billions of dollars required to put a man on the moon? The physical world isn't like the software world, where things are often shared freely. Perhaps it'll be a little different in 2034, but I doubt anyone's going to build a lunar module with a 3D printer and some free plans from the internet.
"A week in the lab saves an hour in the library"
disclaimer: I'm a satellite telecom engineer.
What these guys don't know about satellite telecom could fill a swimming pool. "A open, free and globally accessible satellite communications network"? Sure. Except for the free part, it already exists. With a properly designed VSAT terminal (either C or Ku band) anywhere that's not beyond 83 degree latitude can get broadband net access. Why is VSAT service not cheap? It costs $200 million to launch a 6000 kilogram satellite into geostationary orbit, and the satellites lasts on average 12 to 16 years. The $200m satellite has less aggregate data capacity than a fiber optic cable the diameter of a pencil. Installing a 1.2 meter Ku-band VSAT terminal with DVB-S2 compliant TDMA modem (iDirect Evolution series, for example) is not rocket science, but proper service starts at $400/month and up.
If they're trying to push a large amount of bandwidth through small, cheap low earth orbit satellites I believe they're going to run into some fundamental engineering constraints (satellite power budget, shannon limit, the fact that two axis tracking antennas are expensive).
Step #1) Improve HAM bandwidth for data transmissions to/from space.
On a good day my old 14.4k modem is faster then the throughput I can get on packet radio.
"The price good men pay for indifference to public affairs is to be ruled by evil men." ~Plato (427-347 BC)
... see, children, the difference between nerds and non-nerds may be as small as the one between 'ck' and 'g'.
you used the word "kilogram". Everybody knows that only Americans launch stuff, and they launch pounds. Except for Mars explorers, then they launch bricks.
-- Terry
Don't think of this as 'free internet in space.' The internet model, with it's simple dumb-endpoint packet-switching, isn't going to work. It's massively inefficient: Every time someone in the UK wants to view a webpage on a US server it gets send, possibly billions of times, through the oceanic fiber. If there is to be hope of getting any more than text through bidirectionally (And it must be bidirectional: Having one operator decide who gets precious capacity isn't in the hacker spirit) then it's going to mean some serious rethinking of networking fundamentals.
There is an advantage to be had with modern technology though. Storage is cheap. Cheap as dirt. Want to put a few gig in every ground station? Easy. Want to put a few terabytes in the larger ones? Compared to the cost of the radio gear you need anyway, barely adds anything. So I think what should be looked into is trying to shift the internet further towards content-addressible networking and caching (Proper content-addressible hash-based caching, not the evil that is trying to cache HTTP where every access needs to ask the server if the content has changed). Such technologies would reduce the need for expensive bandwidth by orders of magnitude, at the expense of consuming far cheaper storage at every caching node. Magnet links are a good place to start.
"At the Chaos Communication Camp 2011 Jens Ohlig, Lars Weiler, and Nick Farr proposed a daunting task: to land a hacker on the Moon by 2034.
I'll be more impressed if they can get someone back from the moon.
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
The moons orbit is oblong, so you'd have to have some method by which the cable length could change. You need a cable strong enough to support its own weight. Gravity drops off as altitude increases by the formula g = 9.8 m/s^2(r/r+h)^2 (r is the radius of the earth and his your height), so it's 100% at the surface (very slightly less if you're at the equator), 96.937% 100 km up, 94.012% 200km up, 85.990% 500km up, 74.730% 1000 km up, 57.955% 2000 km up 37.770% 4000 km up, 19.678%. 8000 km up and so on. Even at geosynchronous orbit altitude (which may or may not be relevant depending on how this cable is being managed) where gravity is 2.287%, the average weight of the 35,800 km of cable to that point is about 15.172% of its Earth weight. Out at 325,000 km, which is about the distance of the L1 point between the Earth and the moon the gravity is .037% of what it is on Earth (not at the actual L1 point where it's cancelled by the moons gravity, this is just an approximation, not taking all forces into account) the average weight of the 325,000 km of cable is still about 1.932% of its Earth weight. So, if you need to stretch a tether out to Geosynchronous orbit, it needs to be strong enough to hold 15.172% of the Earth weight of 35,800 km of material. If the tether masses 1 kg per kilometer, that means it has to be strong enough, at that thickness, to hold the Earth equivalent of .15172*35,800=5431.576 kilograms. Tapering the tether can help, of course, but we still don't have any materials strong enough. For the L1 point, it's equivalent to holding 6279 kg on earth with that size cable.
Then there's the problem that the moon isn't in a geosynchronous orbit, so you can't tether the cable at a stationary point on earth. The poles aren't stationary, so the best you can do is anchor to tower, built on a train on a huge circular track around one of the poles.
Of course, the cable doesn't actually need to be a straight line to the moon. If you could make a tether to geosynchronous orbit, you could then have another tether from there to the moon. For that matter, you might be able to build a 60,000 mile tether that circles the earth at slightly greater than orbital speed (maintained by propellant brought up from earth on the space elevator) then attach multiple secondary tethers that loop around the earth towards the poles where they connect to smaller tether rings suspended above each pole with a station suspended in a web in the middle and a variable length tether that need only be a 100 km long or so (and could be supported by dirigibles through a good portion of the atmosphere) that tethers to a polar base station. You could take an elevator up at the pole, then down along one of the loops to the equatorial ring. From the equatorial ring, you could suspend another ring further out, or perhaps just spokes out to additional stations. From one of those, you could potentially even build a tether all the way to the moon and set it up on an orbit that jump ropes the Earth. Of course, the tether all the way to the moon would hardly be necessary. Once you're out to the orbital ring, if it's fast enough, you can just drop off and fall toward the moon, it would be a heck of a lot faster than pulling an elevator car along 400,000 kilometers of tether. At the moon end you could have another space elevator. The one at that end could use the same equatorial ring with polar elevator trick, but the moons smaller size and lower gravity mean that you could actually have a plain old space elevator right to the surface.
Of course, the above idea might have a lot of problems. Getting that giant orbital lasso trick to actually work might be next to impossible. Also, such a long tether going around the entire Earth is going to have to be carefully designed. It could run into some really interesting electrical effects that could instantly fry it. On the other hand, they could also be used as a method of powering the whole thing. In any case, it's a massive endeavour. You would have to start