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Space Tugboat to Refuel Satellites
Faeton sent in this article about a proposed space tugboat to refuel aging satellites. Looks like they're just going to bolt on some extra thrusters with a new fuel supply, guidance system, etc.
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The title calls this a "tugboat", but as far as I can see from the article, it is really just an extra fuel tank and set of rockets.
A real tugboat would be very cool indeed -- something which could grab a satellite, move it up back into the correct orbit, and then let go and move on to the next satellite -- but it looks like this is rather less so.
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I guess I'm just feeling nitpicky today. Other than that, this sounds like a great idea. Then again, I'm usually hyped about any space program. We've got less than 5 billion years or so to find a new home out there... :(
"To confine our attention to terrestrial matters would be to limit the human spirit." -Stephen Hawking
I thought that ion thrusters have proved themselves multiple times already for meneuvering in space. You can use the sun to power them and not have to worry about running out of liquid fuel.
What am I missing? Do they need *sudden* changes of direction? We are not talking about spy satellites.
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... can't they just put newer, smaller, niftier satellites about ten klicks behind the first one in its orbital path?
Isn't all the money spent just getting there?
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This article saddens me in this way: Technology such as this should be the natural, and MUNDANE, result of an "agressive space exploration policy". But its not, because the new machines we build for space are few and between. AND this lack of 'space ware' makes this FERRY newsworthy on /. .
I guess it just saddens me that we dont go out and make this solar system ours(humankinds).
but not Microsofts.
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This sounds remarkably like the first step in George William Herbert's "Phobos on the Cheap" paper, here.
The basic idea of the paper is that you could fund the development of these things by doing satellite maintenance and related things, then use one of them as the propulsion system for a trip to Mars orbit.
So I wonder if this is that project.
Do you think this company is gonna charge the extra 40 cents per gallon for full-serve? If so, they better at least wash the windows and check the oil in the satellite.
It looks like they ARE using ion drives + solar panels. I wouldn't trust it, but it looks like they will be selling this as a fully insured package...
But the thing is... old satellites don't die. They just sit up there, cluttering up the orbital space. The GPS system, for example, expects to retire satellites at a regular rate into "parking orbits". In fact recently, as this article in Space Daily shows, it was discovered that the parking orbits chosen will degrade and pose a threat to the operating GPS satellites in 20 to 40 years. This is a long-term problem that is only getting worse.
Refueling satellites at least gives us the control of them needed to take them out of orbit if required.
Anna B
Both of the articles mentioned that fuel is not the only problem, the rest of the satellite has degraded as well. So, why don't they come up with a good garbage collection method to periodically get rid of the old sattelites. This could also partially answer the problem that it's starting to be pretty crowded there in the orbit already.
I'm curious why they haven't started using something like this to remove old satellites. A remote controlled vehicle equipped with a mass delivery system (rail gun, propellent, hell it could even ram them) that would deliver enough force to knock the old satellites out of orbit and maybe on a vector towards the sun where they will be quietly taken apart into component atoms.
Any atronomists/physicists know what the gravitational pull of the earth is in orbit and how much force would be necessary to kick, say, a 2000 lb satellite to escape velocity?
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It seems to me that there's a lot of hardware in orbit and that our modern complex society is dependent on this hardware. We also have a permanent space station up there (Alpha or ISS or whatever it's called). What say we use Alpha as a base for repairing and upgrading satellites as well as cleaning up orbital debris? What it would need is a space craft, kind of a tow truck in space. A couple of astronauts could take this tow truck to a satellite and reposition its orbit and make repairs. It would always be in space so it would be cheaper than having to send the shuttle up every time you want to repair a satellite. And it could find space junk and send it to burn in earth's atmosphere. This could be a real commercial role for Alpha. Combine this with tourism and Alpha might actually be a viable commercial entity.
The Moore-Murphy Law: The number of things that will go wrong will double every 2 years.
This is grabbing the hammer by the head, not the handle.
The problem is the total cost of launching a satellite - most of which is the cost of boosting it into orbit. To correct that, you don't need tugboats or shuttles, you need cheap lift systems.
You need to make the cost of putting a bird up low enough that you can plan on a controlled deorbit at end-of-life. Right now, the bird's owner will squeeze every last second of use out of the bird because it is so damn expensive. So they won't plan to save the last N kilos of fuel to deorbit it - that fuel translates into another year of operation.
The problem of boosting a bird into orbit can be split into three parts: initial lift, orbital insertion, and orbital circularization.
For initial lift, you just need a rocket that gets about 90% of the work done. If it gets 85% done, or 95% done, you can correct that in the next phase. As a result you don't need a complicated first stage. What I suggest is a rocket made out of a renewable resource for the casing, coupled with a simple propellant.
That's right, I am suggesting a big Estes rocket. A rocket with a casing made of paper, and solid fuel. A rocket that can set on the shelf for months before use, rather than a liquid fuel rocket that requires constant maintainance before launch. A rocket that is cheap enough to throw away - remember that every kilo you add to the rocket to be able to reuse it is over ten kilos of fuel, or a kilo of payload GONE. I call this the BPR - Big Paper Rocket concept.
For the second part, orbital insertion, you need a rocket that is controllable so you can make up the last 5-15% of the boost. Again, use a cheap system - solid fuel, liquid oxidizer. You throttle the rocket by controlling the oxidizer feed, but the fuel is solid. This has many of the advantages of the BPR - longer shelf life, simpler to make.
The last part, orbital circularization, requires a light motor - it's staying up with the bird, so we need to shave kilos. This is where a high specific impulse system like ion drive or liquid fuel is worth its mass in gold, quite literally.
Make the system cheap enough that you can launch a bird for less than a couple of million dollars, and the owners will not have a problem with deorbiting a bird before it is completely dry.
This way, you avoid having old birds with less than state-of-the-art systems cluttering the sky, taking places that a new craft could do twice the work in. This way, you avoid complex docking manuevers. This way, you bring the cost of getting stuff into space down where it is USEFUL to have a space station. This way you pave the way for Moon and beyond.
OK, that's my opinion. Pick it apart. Or, if you think I'm on to something, start beating on the Planetary Society, the National Space Society, vulture capitalists, NASA, and your congressmutants to make it happen.
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When I studied satellite communications in grad school, the comment was always that the life span was to long on most communications satellites, not to short. We were shown graph after graph that illustrated that by the time the damn things were half way through their life cycle, a better model was available that handled a lot more traffic, better quality, half the size/price, or whatever. So you had a precious GEO slot taken up by a bird that was obsolete, while your competitor has a new one about to launch.
These things probably only have two useful applicaitons, orbital repair (not repair in orbit, but of the orbit), and de orbiting something to salvage the GEO slot. Not to say that the technology isn't great on its own merits.
Unfortunately, you can only refuel one satellite per launch of the space tugboat. Then you have to destroy it or end up with billions of space tugboats.
Check out the DARPA project for more info. Do a Google search on "orbital express" for other links and news.
~afniv
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One of the first applications of the Shuttle back in the 70s/80s was that it would carry a SpaceTug to retrieve satellites from orbits higher than the shuttle to travel.
Does anyone know if Challenger had an impact on why it's taken so long to return to this, or was this one of those "oh YEAH, we promised this to Congress back in 1978" deals?
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It looks the moderators left their brains at home this morning, so let me be the next guy to blow his karma in a desperate plea to the moderators to mod this guy up. He's not a troll at all. If you'd just read what he wrote (as well as the grandfather post) you will understand that.
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Okay. Hindsight is 20-20. But clearly future satellites should have the facility to get electricity from an external source.