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Space Science

Space Tugboat to Refuel Satellites 113

Posted by michael from the regular-or-unleaded dept.
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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Space Tugboat to Refuel Satellites More

Space Tugboat to Refuel Satellites

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  • Darnit (Score:3, Funny)

    by Com2Kid ( 142006 ) <com2kidSPAMLESS@gmail.com> on Thursday September 05, 2002 @12:44AM (#4198718) Homepage Journal
    There goes any more chances for free tacos.
    • I'm out of mod points this week, so I can't mod the parent up, but I thought I'd explain why this joke is funny and on-topic. Maybe somebody with mod points left can bump it up.

      Back about a year ago, Taco Bell offered to give free tacos for a day if the Mir space station (then decomissioned) hit a particular target (floating in the ocean... Pacific Ocean, I think, but maybe Indian Ocean) when it fell out of space.

      The joke was that if they strap boosters onto satellites, then one would assume that no satellites will fall, thus there's no chance for free tacos in the future. Of course, this really doesn't affect satellites that are decomissioned for other reasons, like obsolescence, nor was the Mir a satellite. Regardless, though, it's funny, if a bit inaccurate. :-)

      • 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.

        Oh well, it's no use. Nobody will read this message.
    • The even funnier thing...is that they missed the huge Taco-raft. Eh, I'm going to start to watch out when these satellites start reaching their deorbit years. Eek, I can see my sailing classes right now...

      "Jordan! Satellite on your right! Quick...oh well, too late."
  • Now we won't have to keep replacing them, just keep refuling them. But wont the sattellites lose speed in docking?

  • Is it really a tugboat? (Score:4, Insightful)

    by cperciva ( 102828 ) on Thursday September 05, 2002 @12:53AM (#4198741) Homepage
    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.
    • From http://www.orbitalrecovery.com/about_us.html [orbitalrecovery.com]:

      The SLES also can be used to rescue spacecraft that have been placed in a wrong orbit by their launch vehicles, or which have become stranded in an incorrect orbital location during positioning maneuvers.

      They don't say anything about what happens after the SLES has moved the misplaced spacecraft. I suppose it would really depend on the needs of the rescued craft -- ie, whether it has enough on board fuel to maintain and adjust its attitude, or whether the SLES needs to hang around to help it.

      As for a business model, well, how many satellites need rescuing? I would think that they're right to focus on the predictable market of sats that run out of juice instead of relying on error (human or mechanical) to create opportunities for them. At least, in the short-term. Once they've got their birds flying and have some real world experience, maybe they'll start getting creative with them and send them on "Extended Missions" once the sat-moving job is done.
    • "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"

      Will they let Lance Bass be the captian ;-}
    • And everyone knows that tethers tug!

      Read about tethers here. [tethers.com]

  • The image, or drawing, of the thing has a very major flaw. Judging by the size of the blue planet in the background, I'd say they were about 90,000 KM away from Earth. I think that's a wee bit too far... :P

    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... :(

    • I'll nitpick too (Score:1, Informative)

      by Anonymous Coward
      Let A be the distance from the camera to the Earth.
      Let B be the distance from the camera to the satellite.

      The picture only gives you the ratio A/B, you can't "judge" the value of A alone.

    • Re:Laugh at the image... (Score:1, Funny)

      by Anonymous Coward
      Not 100,000 KM ?

    • Re:Laugh at the image... (Score:1, Informative)

      by Anonymous Coward
      > We've got less than 5 billion years or so to find a new home out there... :(

      Actually less than 500 million years before the oceans vaporise. Still, I don't think you should worry that much, we probably have that technology 1000 years from now. :)
    • Maybe its just very big?...
  • 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.

    • Re:What ever happened to ion drives? (Score:4, Informative)

      by mumkin ( 28230 ) on Thursday September 05, 2002 @01:20AM (#4198803) Journal
      Wha? They're using them:

      from http://www.orbitalrecovery.com/faq.html [orbitalrecovery.com]

      Attitude control for the SLES and the telecommunications satellite to which it is mated is handled by ion thruster packs mounted on deployable booms. These booms are extended to provide sufficient thruster impulse for control of the SLES/telecom satellite combination.

    • Re:What ever happened to ion drives? (Score:4, Interesting)

      by zenyu ( 248067 ) on Thursday September 05, 2002 @01:30AM (#4198827)
      ION drives require power. The idea is to design newer satelites with larger solar arrays so they can last 20 years up there instead of 10. If you're going to add a booster you don't want it to have solar panels because they would be unlikely to work with all those old satelites without a redesign based on where the existing solar panels are on each one. Plus it might not make sense economically to add a 20 year propulsion system to a satelite with 10 years left in it.

      As for wanting a "real tugboat" that attaches to multiple satelites... well the biggest problem is the docking, when we've had these working long enough to have confidence in automatic docking, then we can think about a general purpose tugboat. Remember it would have to dock with each satelite many times over a 10 year span, and transit between all the satelites it wants to service. Perhaps an ion based one could have a 25-30 year life span, but then you'd be testing two undertested technologies at once instead of just the docking. I'm not even sure they should be allowed to do this in geosynchronus orbit before it is tested in other less essential orbits; it's going to cost $$$ for the shuttle to go up there and clean up the mess when one of these fails.
      • 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...

      • Re:What ever happened to ion drives? (Score:4, Informative)

        by ender81b ( 520454 ) <wdinger@g m a il.com> on Thursday September 05, 2002 @02:09AM (#4198904) Homepage Journal
        Actually the shuttle is incapable or reaching GeoSynch orbit w/o substantional modifications - and dangerous ones (like a fuel tank in cargo bay, extra SRB, etc) or refueling at the ISS if that ever becomes a possibility. The highest altitude a shuttle has ever achieved, IIRC, is around 490 miles.

        So if there really was a mess in GeoSynch they would just be screwed...

        • Re:What ever happened to ion drives? (Score:4, Funny)

          by clickety6 ( 141178 ) on Thursday September 05, 2002 @03:33AM (#4199041)
          The highest altitude a shuttle has ever achieved, IIRC, is around 490 miles.

          Rubbish. I saw a documentary only last week where a suttle left the Earth's orbit and went thousands of miles out into space to land on an asteroid. They didn't have extra fuel tanks in teh cargo bay eitehr, cos it was full of these neat, large-wheeled, big trucks fitted with drills and machien guns and everything - they could even jump mile wide cnayons. You just ask the leader of the mission, Harry S. Stamper , a rough-neck, Texas oil man and his team of expert oil drillers if it ain't so!
  • We don't want to refuel old crappy satellites!

    Please let them * burn * and then launch new generation satellites build on nanotechnology - they will be small and efficient!

    • 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 [spacedaily.com] 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

      • Re:Old satellites never die... (Score:1, Informative)

        by Anonymous Coward
        Generally it is very difficult to land a satellite that was not built with the intention of being landed.

        You cannot just let them burn up in the atmosphere, because parts could survive re-entry, and cause major havok when they crash back to earth.

        However, it *is* possible to capture a satellite which is in orbit, and bring it back to earth, but that is by no means a trivial operation, although if you don't care about damage to it, (you probably don't), it would be doable as a clean-up operation.

        What should be done, but is very expensive, is to build the capability in to all new satellites to be landed when they are no longer required. That is the real way to solve the problem, however it is *very* expensive.
  • ... 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?
    • " ... can't they just put newer, smaller, niftier satellites about ten klicks behind the first one in its orbital path? "

      Do you have any idea how crowded it already is up there? Or how crowded it would become if they do that?
      • Common myth. Let's look at the geostationary orbit (where most TV, telecom and weather satellites nowadays are) which is ~36000 km above the surface, i.e. it has an diameter of nearly 85000km and a length of over 265000km. So even if you require a minimum safety distance of 50km between satelites in geostationary orbit, there's place for over 5000 satellites.

        Currently there are less than 300 AFAIK. (Here's a list [satsig.net] of most of them). Please note that satellites which that are put put out of service usually will be parked in a "graveyard orbit" above the geostationary orbit - if there's still enough fuel and the motors still work of course.

        The lower orbits (LEO, ~150-500km), where most military satellites, GPS, GLONASS, IRIDIUM and the like are placed is less problematic, since they are 'self cleaning' from old satellites: Objects there will deorbit sooner or later (the larger the sooner) since those orbits aren't very stable (due to earth's irregular shape) and the very thin atmosphere there reduces the orbital speed. That's why spacestations like Mir or ISS have to be boosted from time to time to higher orbits by a docked spacecraft.

        The space debris problem is not caused by dead satellites, it's caused by all those tiny nuts and bolts left over from stage seperations, solar panel releases and so on which are affected much less by those deorbiting effects. Satellite and launch system designers nowadays take more care of this as they used in the 60-70s, e.g. the parts of the fairing which protects the payload of a launcher, are kept together connected by a wire or something after the fairing is ejected - the fairing just used to be blown up in seperate pieces by small pyros before.
        • To get away with using a small antenna to receive from a satellite you need about 3 degrees of separation between them to avoid interference. The closer together the satellites the larger the dish required to recieve from them without interference from neighbor satellites. So you won't ever get close to your 5000 satellites.

          Co-location of satellites to allow multiple satellites to be received by a single antenna is common in the TV broadcast business however each satellite requires a different set of uplink / downlink frequencies so there is a limit to the number of satellites that can be used in a particular position.
    • I know jack about hauling stuff to space, but I would venture it might be more economical to use 50Kg of fuel to move a 500Kg satelite to a stable orbit. Assuming a newer satelite will weigh more than 50Kg. I don't know how likely that scenario is. Once in space even 5Kg of fuel could move a satelite, just not very fast depending on the size.
    • From the article:

      Nevertheless, Orbital Recovery is upbeat about the prospects. It thinks it can save satellite operators money because the cost to launch a small tugboat would only be a fraction of a large, new satellite.

      Reading the article gives you alot of information...
  • It attaches and "uses its own independent on-board attitude control system, thrusters and fuel load to keep the telecommunications spacecraft at the desired orbital position and altitude."

    http://www.orbitalrecovery.com/faq.html

  • 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.
    • Time to step out of your Star Trek fantasy world and have some respect for how vast space is. There's nothing but junk in our solar system, and we aren't going to other stars any time soon.

      Personally I think we have plenty of problems down here that need to be addressed first.

  • I wonder... (Score:3, Interesting)

    by cgreuter ( 82182 ) on Thursday September 05, 2002 @01:22AM (#4198812)
    This sounds remarkably like the first step in George William Herbert's "Phobos on the Cheap" paper, here. [retro.com]

    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.

  • Refueling (Score:3, Funny)

    by MalleusEBHC ( 597600 ) on Thursday September 05, 2002 @01:34AM (#4198833)
    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.

  • Garbage collection (Score:4, Insightful)

    by jukal ( 523582 ) on Thursday September 05, 2002 @02:49AM (#4198951) Journal
    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.

  • getting rid of old satellites (Score:3, Insightful)

    by forkboy ( 8644 ) on Thursday September 05, 2002 @02:55AM (#4198966) Homepage
    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?

    • I think it would take less force/momentum/energy/whatever to give it a kick in the opposite direction and let it burn up in the earth's atmosphere.

      Getting it in an elliptical orbit with one part skimming the upper atmosphere would be good enough. It then only takes some patience to watch the satellite slowly getting into lower orbits and finally burn up (similar to aerobreaking at Mars, except for the final stage).

      • Don't some satellites have nuclear power sources though? The radioactive particles entering our atmosphere can't be good. Plus there's the chance that all of the satellite won't burn up upon re-entry and you have to worry about dropping a big wad of semi-molten metal on someone's house, head, or dog.

        • Well, when they do a controlled deorbit, they typically aim it at the ocean which has a notable lack of dogs, houses, and people's heads. If it's out of control then it falls where it falls.

          Most sats use solar but I suppose there may be a few with RTGs and maybe a handful with nuclear reactors. The RTGs are designed to survive reentry _intact_ so they don't spread radioactivity anywhere. I believe an RTG from a satellite launch accident in 1968 (Nimbus?) was actually recovered from the ocean and reused.

          Now a nuclear reactor reentry might be more of a problem. I think the couple that are up there from the 60's are parked in orbits that won't decay for thousands of years.
      • I think it would take less force/momentum/energy/whatever to give it a kick in the opposite direction and let it burn up in the earth's atmosphere.
        I think you should review how geostationary [bldrdoc.gov] satellites work. Geostationary satellites orbit at 35,787 kilometers above mean sea level.

        Mir, Spacelab, and thousands, or tens of thousands, of other satellites we put in low Earth orbit have burned up as their orbits degraded.

        There is a big difference between LEO and GEO. There is no cutoff between where the Earth's atmosphere ends and the vacuum of space begins. Friction with the tenuous remaints of the atmosphere do cause the orbits of satellites at 100 km to degrade within years or decades. Friction at 36,000 will be a lot less. But even if it was as great, that disposal burnup would still be tens of millenium away.

        If a geostationary satellite had enough fuel to change its orbit so it skims the atmosphere, so it burns up, it could use that fuel to remain in orbit for ages longer. When it is short of fuel, using the remaining fuel to kick it up just a touch would be plenty to keep it from being a danger to satellites that still had fuel.

    • The thing you have to think about is that even a misguided stray fleck of paint can potentially obliterate another satellite on impact. The growing amount of obital material also increases the potential for destructively colliding objects in orbit. Such a chain reaction which could effectively create a wall of space debris, preventing safe and economical space flights for the foreseeable future. It's just like the old analogy of dropping a penny off a 10 story building, except in this case you don't have air resistance to limit the velocities involved. In otherwords, moving another satellite into any new vector is necesarily a very delicate precision operation.

      -Guanno

  • 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.

  • 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.

  • Someone missed their market research (Score:3, Interesting)

    by color of static ( 16129 ) <smasters@@@ieee...org> on Thursday September 05, 2002 @07:22AM (#4199342) Homepage Journal
    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.

  • Sounds similar to Orbital Express (Score:3, Informative)

    by afniv ( 10789 ) on Thursday September 05, 2002 @08:04AM (#4199458) Homepage
    Check out the DARPA project [darpa.mil] for more info. Do a Google search on "orbital express" [google.com] for other links and news.

  • Old Concept (Score:3, Interesting)

    by LittleGuy ( 267282 ) on Thursday September 05, 2002 @08:06AM (#4199472)
    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?
  • A couple of years ago they would have had money thrown at them just because the have "powered by php" and "powered by MySQL" on their homepage and they're running an Apache webserver. Everyone would have assumed that they were open source friendly and just thrown their money at them. Now people are actually looking at the technology, isn't it wonderful!!!

    However, it is cool that they are running open source software for their presence. I wonder if the on-board computers are running Linux or *BSD :-)

  • It has been pointed out that many satellites couldn't benefit all that much by being rescued, and put back into orbit, if their solar panels, batteries, etc, were also worn out. It has been pointed out that these satellites weren't designed to have their batteries supplemented by an external source.

    Okay. Hindsight is 20-20. But clearly future satellites should have the facility to get electricity from an external source.

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