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Interstellar Flight: Perspectives and Patience

(www.centauri-dreams.org)
93 points JPLeRouzic | 1 comments | 25 Jun 25 16:35 UTC | HN request time: 0.232s | 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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archermarks ◴[25 Jun 25 18:07 UTC] No.44380200[source]▶
Only true if the dust grain is stopped by the craft. For a thin lightsail the grain will probably pass right through without depositing much energy
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1. os2warpman ◴[25 Jun 25 18:27 UTC] No.44380414[source]▶
I wasn't even considering the sail.

Most of the designs for a system like this are "chip" designs where a single 1cm x 1cm silicon wafer is towed by the sail.

This design prevents the need for lasers so large that they create enough ozone to kill the entire human race.

The contents of the chip vary, based on who is speculating, but tend to contain exotic, uninvented, circuitry capable of both harvesting energy from the laser and doing "something" of use besides zipping by the target at 0.2c deaf, dumb, and blind. Sometimes it's even an AI-enhanced swarm! (Shoulda figured out how to work blockchain in there, post-doc guy)

Regardless, during the 40 trillion kilometer voyage to Proxima Centauri, that 1x1cm silicon wafer (and the sail) will hit space dust, and numerous other atoms and molecules (including carbon rings) because empty space... isn't.