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Why can't Jet planes fly in space?

  1. Sep 10, 2011 #1
    Why can't Jet planes fly in space?

    Is is because it doesn't get lift or is it due to the absence of atmosphere?
     
  2. jcsd
  3. Sep 10, 2011 #2

    Borek

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    What is a jet engine? How does it work?
     
  4. Sep 10, 2011 #3

    D H

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    And wings. How do they work?
     
  5. Sep 10, 2011 #4

    Borek

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    That's the difference between chemist and physicist :rofl:
     
  6. Sep 10, 2011 #5
    I guess you guys have not seen "Airplane II" :smile:
     
  7. Sep 10, 2011 #6

    phinds

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    What is the relationship between lift and atmosphere. Your statement seems to imply that they have nothing to do with each other. Is that what you believe?
     
  8. Sep 10, 2011 #7

    HallsofIvy

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    Of course, you don't really need "wings" or "lift" in space. What you need is thrust. The difference between a jet engine and a rocket engine is that the rocket engine contains its own oxygen (perhaps in the form of a chemical) while a jet engine gets its oxygen out of the air.
     
  9. Sep 10, 2011 #8
    A jet could fly in space. It couldn't produce thrust, maneuver, or keep the cabin pressured in space. Use a rocket to put it into orbit and it will fly until gravity eventually pulls it back down. The strict definition of flying is to move through the atmosphere and there is most certainly atmosphere in orbit.
     
  10. Sep 10, 2011 #9

    phinds

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    Depends on how high the orbit is. Above the atmosphere, it would be in a ballistic trajectory and I don't think traveling in a ballistic trajectory is considered flying. It would no more be flying than the moon is flying.
     
  11. Sep 10, 2011 #10

    Pengwuino

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    The heights that satellites orbit have almost no atmosphere. That's actually one of the points, with minimal atmosphere, satellites don't need to carry as much fuel to compensate for constant frictional forces slowing it down.
     
    Last edited: Sep 10, 2011
  12. Sep 10, 2011 #11
    If oxygen is the problem, what if we use some other fuel that doesn't require oxygen for burning? Could we fly the jet plane in space?
     
  13. Sep 11, 2011 #12

    russ_watters

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    No. They don't carry enough fuel, have enough thrust or the ability to maneuver in space.
     
  14. Sep 11, 2011 #13
    Greetings Arjun Ar,

    Jet engines employ an “open system” method of propulsion therefore they require the high velocity airflow of atmosphere through their turbine engines from which they make use of its oxygen to allow combustion with the fuel the carry. Additionally, airflow is required to produce lift as well as provide axis control of the jetliner.

    Conversely, a spacecraft employs a “closed system” method of propulsion whereby all the elements necessary to produce thrust for acceleration and axis control of the spacecraft are self-contained aboard the spacecraft thereby making its ability to traverse a desired expanse of space 100% independent of its surroundings.
     
  15. Sep 11, 2011 #14
    It depends on what you qualify as "space."
    The US has developed the SR-71, which allowed the pilot to see the curvature of the earth and the blackness of space. There was still, admittantly, a little atmosphere left.
    :D
     
  16. Sep 12, 2011 #15
    At the point that you carry all your fuel on board, the "jet engine" becomes a rocket.

    The broad definition of a jet engine DOES include a rocket engine, however, so yes, a "jet" engine could indeed fly in space. However, not the more specific turbofan or turbojet that you're thinking of, whose operations rely on an atmosphere with oxygen.
     
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