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Interstellar Flight: Perspectives and Patience

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94 points JPLeRouzic | 3 comments | 25 Jun 25 16:35 UTC | HN request time: 0.001s | source
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os2warpman ◴[25 Jun 25 17:54 UTC] No.44380049[source]▶
>To get around thousand-year generation ships, we are examining some beamed energy solutions that could drive a small sail to Proxima in 20 years.

The odds of a spacecraft hitting a single particle of dust while in space are 100%.

A spacecraft hitting a single particle of dust at 0.2c will impart tens of millions of joules into the body of the spacecraft, the equivalent of getting hit with hundreds of pulses from the most powerful laser ever created by humanity-- simultaneously.

Or concentrating several kilogram's worth of TNT into the size of a particle of dust and detonating it.

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1. naasking ◴[26 Jun 25 01:29 UTC] No.44383426[source]▶
Perhaps, some fraction of the laser energy beamed to move the sail is redirected directly in front of the spacecraft to vaporize any dust particles in its path. Fragments of a circular sail could be angled in the right way so as to take some fraction of the light's momentum in its desired direction with the rest reflected at an angle to clear the opposite side of the sail. For a circular sail you'd then get a circular "clearance beam" of sorts.
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2. sfink ◴[26 Jun 25 05:25 UTC] No.44384411[source]▶
You're avoiding the energy that would be imparted by hitting the dust spec by... adding energy to the dust spec? Perhaps splitting it so it damages a larger area? It seems better to let it plow as small a hole as possible in the sail.
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3. naasking ◴[26 Jun 25 14:29 UTC] No.44387800[source]▶
1. Dust specs would respond to momentum imparted by the light much more quickly, which would reduce the momentum difference between the ship and the specs.

2. Enough incident light could vaporize the specs entirely leaving only gas or plasma, which doesn't carry the same danger to the ship.