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Thread: why the space shuttle landing on water is difficult than on the regular runway

  1. #1
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    why the space shuttle landing on water is difficult than on the regular runway

    or it is possible only after applying the space shuttle a big float when it will land on the sea. I think it would be more safe on landing the space shuttle on the sea water, because there is no such botheration about the demarcation line of the last point of landing strip, and there will also not be a fear to scratch with the strip due to a fast landing. ?

  2. #2
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    It is simply because the shuttle is designed to land on a runway, not in that water. If the shuttle came in fast enough that it was liable to overrun the end of the landing strip or damage it in any way then it probably wouldn't survive a water impact either.

  3. #3
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    The shuttle lands at about 220 mph, much faster than a jet airliner. At that speed water is hard as concrete. Even jet airliners often breakup upon water landing due to the structural forces. Here's a video of one breaking up when trying a water landing: http://www.youtube.com/watch?v=PfxvkYeuXG0

    The shuttle is going much faster. Kinetic energy increases as the square of the velocity. So 220 mph might not seem that much faster than 150 mph, but it results in TWICE the kinetic energy of an airliner of similar mass. That energy must be dissipated on landing which results in the vehicle disintegrating.

    NASA has modeled ocean ditching by the shuttle and it's not generally survivable. That's why after the Challenger disaster, they added bailout capability.

    Any scenario requiring an ocean ditching would result instead in a bailout. Here's how that works: http://www.batnet.com/mfwright/shuttlejump.html

  4. #4
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    Is 220 mph much faster than the landing speed of a fighter jet?

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    Yes, the Shuttle lands faster than just about any fighter. There may be exceptions, such as a fighter that couldn't lower its flaps or an F-111 trying to land with the wings swept backwards.

    Simply put, the Shuttle was designed to land on land. Even if it could manage to survive impact with water without breaking into pieces, you'd have a massive amount of damage to the structure and especially to the thermal protection tiles. Salt water corrosion would be a problem, as would water damage to things that aren't supposed to get wet.

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    Besides, the pontoons probably wouldn't survive reentry.

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    Quote Originally Posted by joema View Post
    The shuttle lands at about 220 mph, much faster than a jet airliner. At that speed water is hard as concrete. Even jet airliners often breakup upon water landing due to the structural forces. Here's a video of one breaking up when trying a water landing: http://www.youtube.com/watch?v=PfxvkYeuXG0
    Was there EVER a successful (as in "not everyone died") landing of a passenger airliner on water?

  8. #8
    Quote Originally Posted by Ilya View Post
    Was there EVER a successful (as in "not everyone died") landing of a passenger airliner on water?
    In the jet airliner age there have been several water ditchings in which there were survivors however most of these could not really be called successful landings. The most famous was the hijacked Ethiopian 961 Boeing 767 which ran out of fuel and ditched. Of the 175 people aboard 52 survived. A Garuda Indonesia Boeing 737 ditched into a river on Java in 2002. Of the 60 on board only 1 died.

    Source: Wikipedia

  9. #9
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    Quote Originally Posted by Waspie_Dwarf View Post
    ...The most famous was the hijacked Ethiopian 961 Boeing 767 which ran out of fuel and ditched. Of the 175 people aboard 52 survived...
    The above-listed video is that incident. The 767 lands at about 150 mph, vs the shuttle's 220 mph. The shuttle orbiter and 767 have very roughly the same empty (no fuel) weight. Because kinetic energy increases as the square of velocity (KE=1/2*m*v^2), the shuttle has about TWICE the kinetic energy.

    Despite the 767 having 1/2 the kinetic energy, the vehicle broke up and most passengers died. The orbiter isn't structurally designed for a water landing, and anything heavy in the payload bay would possibly come crashing through the crew cabin due to the deceleration. That's a key reason NASA added bailout capability after the Challenger disaster -- so scenarios where an abort or contingency landing site is unreachable, there's a better option than ocean ditching.

  10. #10
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    There was a mitigating factor in that 767 ditching - the hijacker was fighting the pilot the whole time! That's why one wing dipped, causing the plane to tear apart. Odds are the pilot would've made a much better ditching and had far fewer casualties if he didn't have a madman in the cockpit.

  11. #11
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    That and the fact that the actual touchdown velocity as recorded on radar was well above 200 knots...

    The aircraft was never configured for landing, but only in part because it had run out of fuel (it still had an APU). No flaps, slats, etc.

    All modern airliners can ditch with a very high success rate, provided the airplane systems are working fine (hydraulics). Unfortunately, by the time a pilot makes a decision to ditch, it's usually because two or more engines are out, they're out of fuel, severe weather is at hand, etc.

    So, it's almost always the other less than ideal conditions which create the hazards in ditching, not the ditching itself.

    For more, the difference between crashing and ditching

  12. #12
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    Quote Originally Posted by joema View Post
    The shuttle lands at about 220 mph, much faster than a jet airliner. At that speed water is hard as concrete. Even jet airliners often breakup upon water landing due to the structural forces. Here's a video of one breaking up when trying a water landing: http://www.youtube.com/watch?v=PfxvkYeuXG0
    I think it could have resisted the splash if it wasn´t that banked.

  13. #13
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    It may be possible for smaller aircraft, presumably going slower that an airliner, to survive a water landing. See: http://www.micom.net/oops/WetLanding.jpg

    JOhn

  14. #14
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    I recall in my youth a JAL pilot who landed short at SFO here. Ended up in the bay. As I recall it was the second time he had done that, the first time in a airport in Japan where he also ended up in the water. He commited suicide shortly after the second time.

  15. #15
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    I remember that also. The aircraft was repaired and may still be flying.

    http://www.airliners.net/articles/read.main?id=1

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