• Rivalarrival@lemmy.today
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    1 month ago

    You can (theoretically) reach “space” with a single impulse from earth’s surface, but you cannot achieve earth orbit that way. To make orbit, you need a circularization burn at apogee to raise your perigee above the atmosphere. Otherwise, its ballistic trajectory will cause your spacecraft to re-enter the atmosphere.

    • JohnDClay
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      1 month ago

      Yeah, this is just a first stage replacement. You still need a rocket to get most of the way into orbit.

      • NobodyElse
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        1 month ago

        The first stage counts for the bulk of the fuel and total mass, so this would still be a big deal.

        • JohnDClay
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          1 month ago

          Yeah definitely. The way the rocket equation works out, the second stage gives most of the Delta V, but the first stage needs to be much bigger because it needs to lift itself and the second stage.

    • Agent641@lemmy.world
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      1 month ago

      In theory, with an impulse hard enough to reach the moons orbital altitude, you could get a slingshot maneuver that leaves your object in a highly elliptical orbit around earth without burning fuel, but it would eventually be unstable from the moons gravitational pull changing it.