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Interstellar Flight: Perspectives and Patience

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93 points JPLeRouzic | 2 comments | 25 Jun 25 16:35 UTC | HN request time: 0.511s | source
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KineticLensman ◴[25 Jun 25 17:40 UTC] No.44379911[source]▶
> those of us with an interstellar bent naturally start musing about ‘sundiver’ trajectories, using a solar slingshot to accelerate an outbound spacecraft, perhaps with a propulsive burn at perihelion. . The latter option makes this an ‘Oberth maneuver’ and gives you a maximum outbound kick.

You can't do a solar slingshot like you can with (say) Jupiter because the sun is essentially at rest with respect to the rest of the solar system. You could still do an Oberth manoeuvre.

replies(2): >>44380434 #>>44380993 #
1. ta1243 ◴[25 Jun 25 18:29 UTC] No.44380434[source]▶
If you unfurl a solar sail after perihelion, presumably you get more energy while nearer the sun, giving more of a "kick", and lower in the gravity well (would oberth still apply for solar sail)

Your speed once you get to 1AU would I assume be far higher than if you had simply started at Earth

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2. KineticLensman ◴[25 Jun 25 18:47 UTC] No.44380638[source]▶
But getting to the sun in the first place (from Earth) is a massive hassle as you have to lose the Earth's significant orbital speed to 'fall' inward [0]. Perhaps better just to use that fuel to head out. Operating a solar sail really close to the sun would also be challenging because of the massive heat.

[0] https://www.nasa.gov/solar-system/its-surprisingly-hard-to-g...