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Aren't Space Rockests Rubbish

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    #11
    Originally posted by TimberWolf View Post
    Don't forget 9 tenths of the energy needed to get the satellite in orbit is kinetic (its orbital speed) with only a tenth potential (its height). So most of the energy given to the rocket from earth must be to push it tangential to the earths surface, not straight up. If you push straight up, it will come back down when you turn off the power. In fact any ballistic path (fired in any direction like a cannon) will return to earth unless escape velocity is reached (which would need more energy, and a rocket that won't come back).

    It's amazing not only how old the technology is (though to be fair you can't change the laws of physics) but how ineffficient rockets are. To get 1Kg orbiting at 100km only needs 31,816,706 Joules. Which is about what's contained in 3 kg of petrol. I hope I got my sums right there, but it is small. Admittedly a substantial proportion of these losses may be inevitable since we have an atmophere, unless a Jacobs ladder or somesuch is used instead of brute force.

    I'd also like to see more use made of the atmosphere (contains fuel in the form of oxygen and reaction mass to push with), and perhaps rail guns too. Though this would need work on high temperature materials since the atmosphore will make things rather toasty, though it does on the way down too.
    So the weight of the package is 1kg for the payload plus 3 kg for the fuel plus the weight of the craft to carry the payload and fuel...

    So the energy required to launch that lot is...

    Your sums is sh!te!

    Comment


      #12
      Originally posted by Churchill View Post
      So the weight of the package is 1kg for the payload plus 3 kg for the fuel plus the weight of the craft to carry the payload and fuel...

      So the energy required to launch that lot is...

      Your sums is sh!te!
      My calculation was for the miniumum amount of fuel, you can use as much as you like. For example firing ballistically or climbing a ladder does not require you to carry fuel with you. As you say, with a rocket you also need fuel to carry the fuel to carry the fuel and integration is required. Rockets are by no means fuel efficient, wot I said.

      Comment


        #13
        Originally posted by Churchill View Post
        So the energy required to launch that lot is...

        Your sums is sh!te!
        I don't think sh!te will do the job. You'd need a lot of dried cowpats to launch a rocket.

        Instead, couldn't we put lots of hose pipes up cow's bottoms to gather the methane and pipe that into the top of the rocket, then light the bottom (so to speak) of the rocket.

        One mega cow-fart-launched firework to the moon. A Frisian Fart Blaster.
        My all-time favourite Dilbert cartoon, this is: BTW, a Dumpster is a brand of skip, I think.

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          #14
          Originally posted by RichardCranium View Post
          I don't think sh!te will do the job. You'd need a lot of dried cowpats to launch a rocket.

          Instead, couldn't we put lots of hose pipes up cow's bottoms to gather the methane and pipe that into the top of the rocket, then light the bottom (so to speak) of the rocket.

          One mega cow-fart-launched firework to the moon. A Frisian Fart Blaster.
          Yup CH4 is your saviour!!!

          All hail the mighty fart!

          Comment


            #15
            Originally posted by zeitghost
            God preserve us, you'd have to be brave to ride that thing... the bearded twat can't even run trains properly.
            The guys who build the things (Scaled Composites) are very, very bright cookies.

            Comment


              #16
              Originally posted by zeitghost
              Somehow, I really don't find that very reassuring...
              Why?

              The technology is proven.

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                #17
                Branson - "Never trust a hippy" It's true now as it was then.
                How did this happen? Who's to blame? Well certainly there are those more responsible than others, and they will be held accountable, but again truth be told, if you're looking for the guilty, you need only look into a mirror.

                Follow me on Twitter - LinkedIn Profile - The HAB blog - New Blog: Mad Cameron
                Xeno points: +5 - Asperger rating: 36 - Paranoid Schizophrenic rating: 44%

                "We hang the petty thieves and appoint the great ones to high office" - Aesop

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                  #18
                  I could simulate the flight for free at the gym: Strap on some 100 kilo weights and get on the vibrating machine thingy (this can take fillings out). After a few minutes turn off the lights and jump into the pool. Float around for a bit (you might want to take off the weights at this point) and get back onto vibrating machine, turn on ipod for screaming noises, get in sauna and after 30 seconds ignite big petrol bomb. For a successful trip, you obvious don't need a petrol bomb.

                  Comment


                    #19
                    Originally posted by Spacecadet View Post
                    Try reading
                    The Fountains of Paradise by Arthur C Clarke
                    or
                    The Mars Trilogy by Kim Stanley Robinson

                    They've nicked your idea!!
                    The technology to build a space elevator may be developed in twenty years or so.

                    http://en.wikipedia.org/wiki/Space_elevator
                    Down with racism. Long live miscegenation!

                    Comment

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