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Feasibility study of a mission to Sedna – Nuclear propulsion and solar sailing

(arxiv.org)
200 points speckx | 1 comments | 01 Jul 25 14:08 UTC | HN request time: 0.521s | source
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myrmidon ◴[01 Jul 25 15:08 UTC] No.44434668[source]▶
This direct fusion drive is a really interesting concept. Maybe something like this could be used for interstellar travel in a century (or five), it is very encouraging that there is active research on it. ~5kg of thrust is not a lot, but over time...

This sounds significantly more feasible than nuclear pulse propulsion ("project orion" style) which I used to think was the only feasible approach to get to another star.

One thing that was unclear from the paper to me: How does the fusion drive "pick" D/He3 fusion over D/D? Can this be "forced" by just cranking the plasma temperature way up? Or do you still just have to deal with a bunch of neutrons from undesired D/D fusion?

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floxy ◴[01 Jul 25 15:12 UTC] No.44434709[source]▶
Roundtrip Interstellar Travel Using Laser-Pushed Lightsails

https://ia800108.us.archive.org/view_archive.php?archive=/24...

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1. pavel_lishin ◴[01 Jul 25 17:19 UTC] No.44436095[source]▶
> This paper discusses the use of solar system-based lasers to push large lightsail spacecraft over interstellar distances. The laser power system uses a 1000-km-diam. lightweight Fresnel zone lens that is capable of focusing laser light over interstellar distances. A one-way interstellar flyby probe mission uses a 1000 kg (1-metric-ton), 3.6-km-diam. lightsail accelerated at 0.36 m/s2 by a 65-GW laser system to 11% of the speed of light (0.11 c), flying by a Centauri after 40 years of travel. A rendezvous mission uses a 71-metric-ton, 30-km diam. payload sail surrounded by a 710-metric-ton, ring-shaped decelerator sail with a 100-km outer diam. The two are launched together at an acceleration of 0.05 m/s2 by a 7.2-TW laser system until they reach a coast velocity of 0.21 c. As they approach a Centauri, the inner payload sail detaches from the ring sail and turns its reflective surface to face the ring sail. A 26-TW laser beam from the solar system, focused by the Fresnel lens, strikes the heavier ring sail, accelerating it past a Centauri. The curved surface of the ring sail focuses the laser light back onto the payload sail, slowing it to a halt in the a Centauri system after a mission time of 41 years. The third mission uses a three-stage sail for a roundtrip manned exploration of e Eridani at 10.8 light years distance.

Very cool.