An Interstellar Laser Cutter For Long-Distance Massless Transit
I’ve been wanting to write up various ideas I’ve come up with. Depending on motivation levels, this might become a series.
This idea is, I would say, the optimal approach for long-distance space travel, given our current understanding of physics. It lets you travel at the speed of light, plus some constant overhead.
The basic idea is that you use an extremely powerful laser to burn and cut a distant planet, moon or asteroid, thereby (somehow) bootstrapping artificial life. The main downside is that it’s a “post-singularity technology,” which is to say it’s not useful without being able to create general artificial intelligence or biological life from scratch.
The laser would have to be in space, to avoid atmospheric distortion, and a target would need to be chosen without an atmosphere and with some sort of suitable surface material. It would probably emit something much higher energy than visible light.
- Close to theoretically optimal because only photons are sent
- Laser travels at the speed of light
- Can be massively parallel with fixed up-front costs (one laser)
- Doesn’t require any advances in physics or materials science
- Lasers are also useful for signaling, after some sort of colony is built
- Close to zero cost of failures
- Requires much less energy than accelerating mass over long distances?
- Could be improved to use less energy as we refine our techniques
- Information-only: Regardless of what the laser cutter can manufacture, only information can be transferred. That means this approach is primarily useful after brain uploading or strong AI has been developed. Considerable autonomy is necessary due to latency for long distances.
- Manufacturing capability: A laser would only be able to heat, melt and cut things. All materials would have to be available on the surface of the target planet or asteroid, and no parts could be moved or assembled. Research would need to be done to develop a suitable bootstrapping process, and some creativity would be needed to adapt to local conditions.
- Bootstrapping process: Even after the laser has successfully built something, it might take a lot of time and steps to go from “what the laser can make” to something useful (for example, a robot, 3D printer, or another laser). This process could even take years, regardless of the distance traveled.
- Accurate control: High precision is necessary in order to productively manipulate the business end of the laser several light-years away.
- Atmospheres: The laser would probably have to be space-based in order to avoid problems caused by Earth’s atmosphere. Similarly, asteroids or planets without significant atmospheres would have to be chosen as targets.
- Dispersion: The laser beam needs to stay focused over very long distances to have a usable “tip.” We can see stars fairly sharply, so it seems like sending a fairly sharp laser should be equally possible.
- Space dust: Laser power would have to increase for larger distances, and there is probably a limit on the maximum feasible distance.
- Energy: It would take a lot of energy. If the laser is in space, it might need a large number of solar panels to power it, or we could beam power to it from a secondary ground laser.
- Suitable targets: Targets must be within a reasonable distance (probably less than 10 light-years), must not have an atmosphere, and must have suitable surface minerals for melting. Considerable searching might be necessary to find suitable targets.
- Feedback lag: For a target 4 light-years away, it would be 8 light-years before we could determine what happened. For this reason we’d probably need to do highly accurate simulations up front, and work on hundreds or thousands of attempts (on the same or different targets) in parallel.
- Telescopes: We need to be able to detect suitable targets (e.g. asteroids) from several light-years away. Then we need to be able to monitor our own progress.
I’ve posted cynical things about space exploration[#] before. I think that as long as our ideas and technology are rapidly improving, the fastest approach is to wait. That said, a giant space laser will still require conventional rockets, so I’m not opposed to multiple approaches being tried in parallel.