3 ms·

Pellet beam propulsion can allow fairing efficient travel at 10% c, fast enough to reach Alpha Centauri in a human healthspan, when combined with interstellar p

Pellet beam propulsion can allow fairing efficient travel at 10% c, fast enough to reach Alpha Centauri in a human healthspan, when combined with interstellar plasma braking.

blincoln 3y ago
I can only find very high-level descriptions of the pellet-beam approach. What's the advantage of accelerating the pellets after launch via laser ablation versus using a more powerful mass driver to launch the pellets and omitting the laser?
- taneq 3y ago
  It’s more cost effective, assuming the mass driver is taking most of your budget. Both driver length and force required scale with the square of launch velocity.
- Robotbeat 3y ago
  Laser beams are only one method of acceleration for the pellets, and not necessarily the most efficient option.
readyplayernull 3y ago
Got me thinking whether capturing asteroids, mining them and shoting pellets with a solar powered automated facility will drive future space exploration. Seems easier than other challenges like terraforming.
jrumbut 3y ago
But what about navigating on the other end? It would make a terrible first impression if our probe smashed into their version of Voyager. Hopefully we come up with a good way to test the brakes.
- kevinventullo 3y ago
  This sounds like a great sci-fi premise. We think we’re being attacked by intergalactic missiles but they’re really just probes sent by a more advanced, albeit clumsy civilization in an attempt to move fast and break things in the name of discovery. Humanity vehemently debates the meaning of the “attacks” but ultimately decides we must go to war with these aliens. Eventually the aliens do arrive, interested only in peaceful communication. They disarm our arsenal trivially, but understand why we wanted to fight them and apologize for the misunderstanding.
  - saiya-jin 3y ago
    Or after series of misunderstandings they hit the big reset button, sterilize Earth and move on from those aggressive apes.
  - mminer237 3y ago
    A bit of a spoiler, but something similar to this happens in Ender's Game.
- Robotbeat 3y ago
  The interstellar void is not a pure void but is filled with diffuse plasma, the Interstellar Medium. Which, because plasma is electrically conductive at large length scales, you can brake against using gargantuan superconducting coils producing a magnetic field (which induces eddy currents in the plasma, producing a force opposing the direction of motion), slowing down like a magnet dropped into a vertical copper pipe: https://youtu.be/uh0bbW6S3BY?si=kE-1jYagQxGHIVMA https://youtu.be/uh0bbW6S3BY?si=kE-1jYagQxGHIVMA

Pellet beam propulsion can allow fairing efficient travel at 10% c, fast enough to reach Alpha Centauri in a human healthspan, when combined with interstellar plasma braking.

blincoln 3y ago

I can only find very high-level descriptions of the pellet-beam approach. What's the advantage of accelerating the pellets after launch via laser ablation versus using a more powerful mass driver to launch the pellets and omitting the laser?

taneq 3y ago
It’s more cost effective, assuming the mass driver is taking most of your budget. Both driver length and force required scale with the square of launch velocity.
Robotbeat 3y ago
Laser beams are only one method of acceleration for the pellets, and not necessarily the most efficient option.

readyplayernull 3y ago

Got me thinking whether capturing asteroids, mining them and shoting pellets with a solar powered automated facility will drive future space exploration. Seems easier than other challenges like terraforming.

jrumbut 3y ago

But what about navigating on the other end? It would make a terrible first impression if our probe smashed into their version of Voyager. Hopefully we come up with a good way to test the brakes.

kevinventullo 3y ago
This sounds like a great sci-fi premise. We think we’re being attacked by intergalactic missiles but they’re really just probes sent by a more advanced, albeit clumsy civilization in an attempt to move fast and break things in the name of discovery. Humanity vehemently debates the meaning of the “attacks” but ultimately decides we must go to war with these aliens. Eventually the aliens do arrive, interested only in peaceful communication. They disarm our arsenal trivially, but understand why we wanted to fight them and apologize for the misunderstanding.
- saiya-jin 3y ago
  Or after series of misunderstandings they hit the big reset button, sterilize Earth and move on from those aggressive apes.
- mminer237 3y ago
  A bit of a spoiler, but something similar to this happens in Ender's Game.
Robotbeat 3y ago
The interstellar void is not a pure void but is filled with diffuse plasma, the Interstellar Medium. Which, because plasma is electrically conductive at large length scales, you can brake against using gargantuan superconducting coils producing a magnetic field (which induces eddy currents in the plasma, producing a force opposing the direction of motion), slowing down like a magnet dropped into a vertical copper pipe: https://youtu.be/uh0bbW6S3BY?si=kE-1jYagQxGHIVMA https://youtu.be/uh0bbW6S3BY?si=kE-1jYagQxGHIVMA