• Cethin@lemmy.zip
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      1 day ago

      Realistically, it’s technically sideways. To reach orbit you need to go sideways, not up. Theoretically you could escape Earth’s gravity influence by going straight away from it, but it’s not the realistic way that works.

      • crapwittyname@feddit.uk
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        6 hours ago

        Actually, you go up. The earth rotates beneath you, turning your up into sideways.
        E: then of course you have to turn east

        • Cethin@lemmy.zip
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          12 hours ago

          No, not really. The velocity needed for low Earth or it is 7.8 km/s. The speed of rotation on the surface of earth is 0.46 km/s. You need to go sideways a lot more than you need to go up. You do need to go up some, but it’s pretty minor in comparison. Watch a rocket launch. They go up at the start, but start burning toward the horizon pretty quickly.

          • crapwittyname@feddit.uk
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            6 hours ago

            It’s a major enough speed boost that it’s cheaper to launch rockets from the equator than anywhere on the European mainland.

            • Cethin@lemmy.zip
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              5 hours ago

              Yeah, 1/16th isn’t nothing. However, the point is you’re mostly accelerating sideways, not up. If that were a significant part of the launch then we’d launch from mountains, but we almost always launch from the lowest points possible, at sea level.

              Yes, the Earth is rotating, but most of your orbital velocity is added during the launch. The altitude is pretty minor. It’s why very few rockets have been launched from planes, that can give a significant portion of the altitude with very little cost. Altitude is just a small enough portion of the launch that the extra complications don’t give it an edge.

              • crapwittyname@feddit.uk
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                1 hour ago

                I guess it also depends on your definition of “leave Earth”. If you’re in orbit, you’re still kind of tethered to Earth. Quickest way to leave the gravity well is straight up, although escape velocity in most directions will get you there.

        • Natanael@infosec.pub
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          24 hours ago

          Technically a spiral because you start with orbital momentum just from standing still on the surface of earth when starting. You’d have to intentionally offset that to go straight but that’s not the most efficient way