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launch him anyway (mander.xyz)

submitted 8 months ago by [email protected] to c/[email protected]

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[–] [email protected] 17 points 8 months ago (1 children)

Why cancel the angular momentum when we can utilize it?

[–] [email protected] 6 points 8 months ago (2 children)

i may be mistaken but I don't think it can be utilized to descend toward the sun

[–] BluesF 2 points 8 months ago (1 children)

Still this approach seems wasteful. Just making it sufficiently far from the surface travelling in the right direction should be enough... As long as you aren't in a rush.

[–] [email protected] 1 points 8 months ago

Yeah it just depends on whether the goal is to launch the child into the sun or just in an orbit with a low periapsis

[–] [email protected] 2 points 8 months ago (1 children)

It's the foundational principle of "Launch Windows." Because the earth rotates the sun and also spins on an axis, we can launch at a time of day that gives us time to accelerate and then leave earth orbit in the direction of earth's orbit around the sun with minimum amount of energy required. The majority of energy used is simply to escape Earth orbit. Once orbiting the sun, comparatively very little energy would be required to approach it utilizing it's own gravity.

During Perihelion the sun is 147100632 KM away, as the distance from the sun is not constant for earth's orbit.

[–] [email protected] 4 points 8 months ago (1 children)

It requires energy to shrink an orbit just as it does to grow it. Since we're launching from Earth, we start with Earth's orbit around the sun, and we have to burn enough to bring the perihelion of our launched child's solar orbit to within the sun itself. We could use Venus or Mercury for gravity assists but the angular speed of the orbit does have to be mostly cancelled to hit the sun

[–] [email protected] 2 points 8 months ago (1 children)

It's still a lot cheaper than instantaneously cancelling angular velocity.

[–] [email protected] 2 points 8 months ago* (last edited 8 months ago) (1 children)

well the other stipulation was that it has to happen from a single kick

[–] [email protected] 1 points 8 months ago* (last edited 8 months ago)

Yes the source of thrust is still cheaper using a launch window. Basically, you don't need to kick directly to the sun you just need the child to land somewhere below a maintainable orbit given their velocity. The closer they get the more gravity will effect them and do more work that we don't have to do.