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How big this orbit difference is? Would adjusting the orbit be an option at all? Does anyone know? Just curious.

JshWright 12y ago
The 5 degree inclination change would likely burn through most, if not all, of the maneuvering fuel onboard the satellites. That's not accounting for the peri/apoapsis adjustments. If they do get them to a usable orbit, they won't have enough fuel to last long.
- lucb1e 12y ago
  And refueling is not an option? There are also people on the ISS for example, when the crew refreshes they could do that "on the way there"... yeah I don't know anything about space, just an idea.
  - jeroen94704 12y ago
    No, refueling is not an option. - There is no way for the satellites to reach the ISS - There is no way for the ISS or the crew to reach the satellites - The ISS does not carry equipment to refuel satellites - The satellites are not equiped to be refueled in space etc...
    - jbuzbee 12y ago
      Wait, I saw this movie called "Gravity" where the heroine used a fire extinguisher to propel herself through space and went all over the place. It was easy. Maybe the ISS folks should try that to get the the satellites! ;-)
      - CamperBob2 12y ago
        This thread is exactly why I called BS early and often on Gravity, despite being downvoted in numerous places for doing so and being told "It's just a movie, lighten up." A movie that leaves everyone who sees it a little bit dumber. Yes, it was "just a movie," but you know what? Reality is pretty goddamned interesting, too. Hollywood should try it sometime.
        seanflyon 12y ago
        I have yet to meet someone who was left dumber by seeing Gravity.
        CamperBob2 12y ago
        Read the comment I replied to. I'm pretty sure s/he was being sarcastic, but I'm also pretty sure a lot of kids now think of a fire extinguisher as a useful tool for navigation in gravity wells.
        TeMPOraL 12y ago
        Sure, but the thing is, Gravity was like five orders of magnitude less dumb than anything else about space. Despite all my undying love to that show, you'll not get any smarter if you watch Star Trek instead. Gravity is probably the closest Hollywood ever got to the real deal.
        CamperBob2 12y ago
        Star Trek didn't pretend to be a realistic portrayal of current technology.
        TeMPOraL 12y ago
        Still, we should learn to appreciate a thing that's better than everything even if it's still bad, instead of dismissing as not perfect. Incremental improvements, things like that...
  - sharth 12y ago
    This picture may help: https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)#mediaviewer/File:Comparison_satellite_navigation_orbits.svg https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)... Note that the Galileo satellites orbit somewhere around 18000 miles higher than the ISS.
    - Zikes 12y ago
      Always blows my mind how relatively "close" the ISS orbit is.
      - NoMoreNicksLeft 12y ago
        It's a roadtrip away. If there were roads there.
  - Zikes 12y ago
    I think in order to perform a refueling you would have to match orbits first. Given the expense of getting the necessary fuel up there (even if ISS uses fuel on-hand, it would have to be replenished at expense), matching orbits, and correcting the orbits, it would probably be easier to just launch new satellites.
    - JshWright 12y ago
      Many orders of magnitude easier... The amount of energy required to get the ISS to same inclination and orbit as these stranded sats would be stupendous... _Well_ beyond its capabilities.
  - krastanov 12y ago
    That is plain impossible. To change the shape or the inclination of the orbit takes a lot of fuel (change of 1km/s is a good order of order of magnitude even if it is more of an upper bound). Moreover, if you have to carry fuel for somebody else it gets that much harder to accelerate/decelerate like that.
    - ForHackernews 12y ago
      The Tyranny of the Rocket Equation: http://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html http://www.nasa.gov/mission_pages/station/expeditions/expedi...
      - clebio 12y ago
        What an excellent read. Thanks so much for the link!
  - Ezra_Weedin 12y ago
    Hypothetically, rather than trying to refuel the satellite, what if something were launched as a "tug" to push/pull the satellite into orbit? I'm sure there's no time to design something like that, but maybe someday something like that will exist to correct orbits.
    - Tuna-Fish 12y ago
      Generally, it's cheaper to launch a new satellite than to do that. For a good intuitive idea of how hard that would be, I strongly recommend kerbal space program.
      - XorNot 12y ago
        KSP is really really good for this stuff. I never really grokked orbital mechanics till I played it, but a lot of the weirdness of how space missions are designed makes perfect sense once you have an actual feel for how orbits react to velocity changes.
        antimagic 12y ago
        I wrote a small 2D game once, where the Earth is attacked by a swarm of satellites in polar orbits. Your ship is launched from the surface, but after that it's up to you to put yourself in orbit, using thrusters. Thinks Asteroids with gravity. It really taught me a lot about how an orbit's shape changes when thrust is applied in different directions, at different points in an orbit. For example, a good way to circularise an orbit from an elliptical, a small tangential thrust at apogee during each orbit would eventually place the spacecraft in a circular orbit with a radius roughly equal to the apogee distance of the elliptical orbit... or to say it another way, perigee would increase until it equalled apogee... Anyway, the point being that I never would have understood any of this no matter how many times I read 2010, until I wrote that little game. Some things need to be experienced to really grok.
        Xorlev 12y ago
        Orbiter too. It's incredibly difficult to make your orbit. You really have to get it right from the get go on the ground. If you have to do an orbit transfer, that can sometimes be a huge amount of your fuel just to line up for the transfer before even breaking orbit. I gained a true appreciation for difficulty of the kind of maneuvers that are common place in science fiction after spending time with Orbiter.
  - twistedpair 12y ago
    How? Space is not like driving a car. To go higher you've got to burn fuel to gain velocity and altitude, do go lower you've got to burn fuel to slow down. If you're going the wrong direction or angle, you've got to burn a ton of fuel to change that (i.e. if at 90deg to ISS, you've got no velocity vector in common). And that's just my armchair assessment that ignores the myriad complications of spaceflight. This is a common misconception, however. For example, people want to know why Columbia didn't just buzz over and hook up with the ISS rather than burning up. They were at a different altitude from ISS and could not have made the jump with available fuel.
    - XorNot 12y ago
      Conversely this is why space mining is kind of a big deal. If we could get large quantities of pretty much anything that works as a propellant without launch costs, that would change a lot of things.
      - TheLoneWolfling 12y ago
        Even aluminum mined on the moon would be potentially useful. And due to the oddities of space travel, it costs a lot less delta-v to go from the Moon to Earth orbit than it does from Earth to Earth orbit, especially if you do aerobraking.
    - lucb1e 12y ago
      > How? Space is not like driving a car. Isn't it? You drive, you burn fuel. You take more fuel with you, it costs more fuel to get going. Some vehicles (spacecraft or car) require more fuel to drive the same distance than others. Sure, space flights are much, much more expensive, but I don't see how it's so different. If it's not worth it to spend the extra fuel to get there, refuel, and continue to the original destination, then just say so.
      - twistedpair 12y ago
        > Isn't it. You drive, you burn fuel. I'd refer you to the Rocket Equation [1]. 1. http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
  - ChuckMcM 12y ago
    No, for two existing reasons; the satellite has no capability for on orbit refueling, there is no rocket available to do that. In this situation, an on-orbit refueling capability and a tug, a ship which can pick things up and change their orbit, and refuel itself would be worth the cost of these satellites because it would take currently unusable satellites and turn them into usable ones. Not clear what the salvage rights in space are yet. United Launch Associates (ULA) has some great work they have done on making a practical on-orbit refuelling capability but nobody has stepped up to pay for it. This is something I am hoping SpaceX will do. Elon is the type of person who might fund that on the expectation of making back the investment in saving satellites. [1] [1] I would charge the satellite insurer 1/2 the value of the satellite to put it into its proper orbit. Which saves the insurer from paying out the full amount.
    - TeMPOraL 12y ago
      I hope someone will do that. One could imagine such satellite-recovery company to bundle several repair operations together, to minimize fuel costs of repeat orbit changes.
  - wlievens 12y ago
    That would probably require almost as much fuel as sending a new one and obviously the ISS doesn't have that fuel on board.
  - jbrooksuk 12y ago
    I think that's literally rocket science.
  - lucb1e 12y ago
    Since I cannot edit this post anymore I'll comment on myself: I really do appreciate the downvotes, but could anyone comment why? Because I may be unknowledgable about space flight, but I'm not trying to troll or anything.
- jeroen94704 12y ago
  AFAIK, it was already established they do not have enough fuel to circularize the orbit at the correct altitude, let alone correct the inclination (which takes large amounts of fuel).
- hawkw 12y ago
  If there's one thing I've learned from Kerbal Space Program, it's that inclination changes are Hard and Scary...
  - kd0amg 12y ago
    In low orbit, sure, but if you're coming from outside the SOI, you can burn retrograde at periapsis just enough to be captured, then make a very inexpensive inclination change at apoapsis (my usual procedure for deploying a kethane scanner).
    - hawkw 12y ago
      Yeah, that's a good trick - I was thinking specifically of the benefits of launching into an inclined orbit vs. the incredibly painful process of gravity turn, circularize, change inclination, and circularize again...

The 5 degree inclination change would likely burn through most, if not all, of the maneuvering fuel onboard the satellites. That's not accounting for the peri/apoapsis adjustments. If they do get them to a usable orbit, they won't have enough fuel to last long.

lucb1e 12y ago
And refueling is not an option? There are also people on the ISS for example, when the crew refreshes they could do that "on the way there"... yeah I don't know anything about space, just an idea.
- jeroen94704 12y ago
  No, refueling is not an option. - There is no way for the satellites to reach the ISS - There is no way for the ISS or the crew to reach the satellites - The ISS does not carry equipment to refuel satellites - The satellites are not equiped to be refueled in space etc...
  - jbuzbee 12y ago
    Wait, I saw this movie called "Gravity" where the heroine used a fire extinguisher to propel herself through space and went all over the place. It was easy. Maybe the ISS folks should try that to get the the satellites! ;-)
    - CamperBob2 12y ago
      This thread is exactly why I called BS early and often on Gravity, despite being downvoted in numerous places for doing so and being told "It's just a movie, lighten up." A movie that leaves everyone who sees it a little bit dumber. Yes, it was "just a movie," but you know what? Reality is pretty goddamned interesting, too. Hollywood should try it sometime.
      - seanflyon 12y ago
        I have yet to meet someone who was left dumber by seeing Gravity.
        CamperBob2 12y ago
        Read the comment I replied to. I'm pretty sure s/he was being sarcastic, but I'm also pretty sure a lot of kids now think of a fire extinguisher as a useful tool for navigation in gravity wells.
      - TeMPOraL 12y ago
        Sure, but the thing is, Gravity was like five orders of magnitude less dumb than anything else about space. Despite all my undying love to that show, you'll not get any smarter if you watch Star Trek instead. Gravity is probably the closest Hollywood ever got to the real deal.
        CamperBob2 12y ago
        Star Trek didn't pretend to be a realistic portrayal of current technology.
        TeMPOraL 12y ago
        Still, we should learn to appreciate a thing that's better than everything even if it's still bad, instead of dismissing as not perfect. Incremental improvements, things like that...
- sharth 12y ago
  This picture may help: https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)#mediaviewer/File:Comparison_satellite_navigation_orbits.svg https://en.wikipedia.org/wiki/Galileo_(satellite_navigation)... Note that the Galileo satellites orbit somewhere around 18000 miles higher than the ISS.
  - Zikes 12y ago
    Always blows my mind how relatively "close" the ISS orbit is.
    - NoMoreNicksLeft 12y ago
      It's a roadtrip away. If there were roads there.
- Zikes 12y ago
  I think in order to perform a refueling you would have to match orbits first. Given the expense of getting the necessary fuel up there (even if ISS uses fuel on-hand, it would have to be replenished at expense), matching orbits, and correcting the orbits, it would probably be easier to just launch new satellites.
  - JshWright 12y ago
    Many orders of magnitude easier... The amount of energy required to get the ISS to same inclination and orbit as these stranded sats would be stupendous... _Well_ beyond its capabilities.
- krastanov 12y ago
  That is plain impossible. To change the shape or the inclination of the orbit takes a lot of fuel (change of 1km/s is a good order of order of magnitude even if it is more of an upper bound). Moreover, if you have to carry fuel for somebody else it gets that much harder to accelerate/decelerate like that.
  - ForHackernews 12y ago
    The Tyranny of the Rocket Equation: http://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html http://www.nasa.gov/mission_pages/station/expeditions/expedi...
    - clebio 12y ago
      What an excellent read. Thanks so much for the link!
- Ezra_Weedin 12y ago
  Hypothetically, rather than trying to refuel the satellite, what if something were launched as a "tug" to push/pull the satellite into orbit? I'm sure there's no time to design something like that, but maybe someday something like that will exist to correct orbits.
  - Tuna-Fish 12y ago
    Generally, it's cheaper to launch a new satellite than to do that. For a good intuitive idea of how hard that would be, I strongly recommend kerbal space program.
    - XorNot 12y ago
      KSP is really really good for this stuff. I never really grokked orbital mechanics till I played it, but a lot of the weirdness of how space missions are designed makes perfect sense once you have an actual feel for how orbits react to velocity changes.
      - antimagic 12y ago
        I wrote a small 2D game once, where the Earth is attacked by a swarm of satellites in polar orbits. Your ship is launched from the surface, but after that it's up to you to put yourself in orbit, using thrusters. Thinks Asteroids with gravity. It really taught me a lot about how an orbit's shape changes when thrust is applied in different directions, at different points in an orbit. For example, a good way to circularise an orbit from an elliptical, a small tangential thrust at apogee during each orbit would eventually place the spacecraft in a circular orbit with a radius roughly equal to the apogee distance of the elliptical orbit... or to say it another way, perigee would increase until it equalled apogee... Anyway, the point being that I never would have understood any of this no matter how many times I read 2010, until I wrote that little game. Some things need to be experienced to really grok.
      - Xorlev 12y ago
        Orbiter too. It's incredibly difficult to make your orbit. You really have to get it right from the get go on the ground. If you have to do an orbit transfer, that can sometimes be a huge amount of your fuel just to line up for the transfer before even breaking orbit. I gained a true appreciation for difficulty of the kind of maneuvers that are common place in science fiction after spending time with Orbiter.
- twistedpair 12y ago
  How? Space is not like driving a car. To go higher you've got to burn fuel to gain velocity and altitude, do go lower you've got to burn fuel to slow down. If you're going the wrong direction or angle, you've got to burn a ton of fuel to change that (i.e. if at 90deg to ISS, you've got no velocity vector in common). And that's just my armchair assessment that ignores the myriad complications of spaceflight. This is a common misconception, however. For example, people want to know why Columbia didn't just buzz over and hook up with the ISS rather than burning up. They were at a different altitude from ISS and could not have made the jump with available fuel.
  - XorNot 12y ago
    Conversely this is why space mining is kind of a big deal. If we could get large quantities of pretty much anything that works as a propellant without launch costs, that would change a lot of things.
    - TheLoneWolfling 12y ago
      Even aluminum mined on the moon would be potentially useful. And due to the oddities of space travel, it costs a lot less delta-v to go from the Moon to Earth orbit than it does from Earth to Earth orbit, especially if you do aerobraking.
  - lucb1e 12y ago
    > How? Space is not like driving a car. Isn't it? You drive, you burn fuel. You take more fuel with you, it costs more fuel to get going. Some vehicles (spacecraft or car) require more fuel to drive the same distance than others. Sure, space flights are much, much more expensive, but I don't see how it's so different. If it's not worth it to spend the extra fuel to get there, refuel, and continue to the original destination, then just say so.
    - twistedpair 12y ago
      > Isn't it. You drive, you burn fuel. I'd refer you to the Rocket Equation [1]. 1. http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
- ChuckMcM 12y ago
  No, for two existing reasons; the satellite has no capability for on orbit refueling, there is no rocket available to do that. In this situation, an on-orbit refueling capability and a tug, a ship which can pick things up and change their orbit, and refuel itself would be worth the cost of these satellites because it would take currently unusable satellites and turn them into usable ones. Not clear what the salvage rights in space are yet. United Launch Associates (ULA) has some great work they have done on making a practical on-orbit refuelling capability but nobody has stepped up to pay for it. This is something I am hoping SpaceX will do. Elon is the type of person who might fund that on the expectation of making back the investment in saving satellites. [1] [1] I would charge the satellite insurer 1/2 the value of the satellite to put it into its proper orbit. Which saves the insurer from paying out the full amount.
  - TeMPOraL 12y ago
    I hope someone will do that. One could imagine such satellite-recovery company to bundle several repair operations together, to minimize fuel costs of repeat orbit changes.
- wlievens 12y ago
  That would probably require almost as much fuel as sending a new one and obviously the ISS doesn't have that fuel on board.
- jbrooksuk 12y ago
  I think that's literally rocket science.
- lucb1e 12y ago
  Since I cannot edit this post anymore I'll comment on myself: I really do appreciate the downvotes, but could anyone comment why? Because I may be unknowledgable about space flight, but I'm not trying to troll or anything.
jeroen94704 12y ago
AFAIK, it was already established they do not have enough fuel to circularize the orbit at the correct altitude, let alone correct the inclination (which takes large amounts of fuel).
hawkw 12y ago
If there's one thing I've learned from Kerbal Space Program, it's that inclination changes are Hard and Scary...
- kd0amg 12y ago
  In low orbit, sure, but if you're coming from outside the SOI, you can burn retrograde at periapsis just enough to be captured, then make a very inexpensive inclination change at apoapsis (my usual procedure for deploying a kethane scanner).
  - hawkw 12y ago
    Yeah, that's a good trick - I was thinking specifically of the benefits of launching into an inclined orbit vs. the incredibly painful process of gravity turn, circularize, change inclination, and circularize again...