MoreAmphibians [none/use name]

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Joined 4 years ago
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Cake day: February 6th, 2021

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  • I’m not an expert but I’ve played a good amount of KSP. It looks like India is using a periapsis kick. Instead of one burn at periapsis (bottom of the orbit) it uses a bunch, once for each orbit. This lets them use a weaker engine which lets them save weight. You want to do most of your burns at the periapsis because that’s when the spacecraft is moving fastest and that makes burns more efficient because of the Oberth Effect. Burning only at periapsis is what makes orbits shaped like that, when you do an orbital burn the shape of the orbit near where you’re burning barely changes and the biggest change is 180 degrees from where you are.

    When the probe is orbiting the moon it does the same process in reverse. Repeated burns at periapsis to lower the apoapsis (highest part of the orbit) until the orbit is low enough to do a single burn to land the probe.