Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Space Launch from the Arctic

  1. Jun 9, 2004 #1
    Thinking that there is quite a bit of junk orbiting around the equator, what would be the disadvantages (if any) of conducting a launch from the Arctic/North Pole?

    Any comments on launching from the Magnetic North Pole?
  2. jcsd
  3. Jun 9, 2004 #2
    Well for one, you would lose the ‘boost’ of the Earth’s rotation that you get near the Equator, thus meaning your rocket would need to carry more fuel and less payload to get it into orbit.
    While the bulk of space junk is probably concentrated near the equator, this is simply because all orbiting debris crosses the equator twice during their orbit.
    Anyway, the orbits of satellites are selected to achieve a certain goal. Placing a satellite in a polar orbit specifically to shield it from space junk isn’t very efficient.
  4. Jun 9, 2004 #3


    User Avatar
    Science Advisor

    A polar orbit would still past through the equatorial belt of junk twice per orbit. Any collision that did occur in one of those encounters would of necessity be a high-speed one. When an object is in a west-to-east orbit, at least it is going the same direction as most of the other stuff there, so a collision with a tiny bolt might not be catastrophic.
  5. Jun 9, 2004 #4
    I was thinking of a launch completely into space, not orbit. It seems like everything is launched into some sort of earth or sun orbit. I know a gravity slingshot is a good way to save fuel, but is it always required?

    I guess I’m wondering if there have ever been anything ever launched from the poles... besides ICBMs in the 80's :(
  6. Jun 9, 2004 #5
    If that's the goal then all you need is a rocket powerful enough to accelerate your cargo to Earth escape velocity, 11km/s.

    And there have been rockets launched from near the poles. There are a few launch facilities in Alaska if I'm not mistaken.
  7. Jun 9, 2004 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    The reason you wouldn't want to launch from the poles has already been mentioned here.

    The orbit has to pass over the equator twice per orbit. Since your orbit must also pass (more or less) over the point you launched from, that limits your choice of inclination for the orbit to anything higher than your launch latitude. At the poles, you've only got the option of a 90 degree inclination orbit. Since most sites you'd want to visit outside of LEO are in the ecliptic at 23.5 degrees, you'd need to do an immensely expensive (fuel-wise) burn to change your inclination. Think: spend 9.2 km/sec dV to get into orbit. Then burn ~6-8km/sec to stop that polar motion and ~6-8km/sec to start going in the ecliptic direction. All that and you haven't even fired off the "leave Earth vicinity" burn. Wasteful.
  8. Jun 9, 2004 #7


    User Avatar

    Staff: Mentor

    Gravity slingshots and leaving earth's gravity are only applicable to deep-space probes. There have only been a couple of dozen. There are thousands of satellites and they must be in orbit to be useful.
  9. Jun 12, 2004 #8


    User Avatar
    Science Advisor

    I don't know of any such launches, probably because by launching from the equator you get about a thousand mph for free. It is possible to launch from elsewhere, but very expensive and innefficient.
  10. Jun 12, 2004 #9
    LURCH said, "I don't know of any such launches, probably because by launching from the equator you get about a thousand mph for free."

    Actually from Florida, where most (all?) of our satellites are launched you probably only get about 500mph for free. Even in low earth orbit a satellite has to be going around 18,000mph. I suppose every little bit helps, but if there were a good reason to launch farther north, I don't think that losing the free 500mph would be a deal breaker.
  11. Jun 18, 2004 #10


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Israel launched its first satellite 'backward', IIRC; against the Earth's rotation - they were concerned that if the launch failed the fallout over nations to the east would be unmanageable.

    Polar LEO orbits are a good idea if you want hi-res coverage of the whole globe, e.g. for mapping (or spying) purposes.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook