Recent content by schplade

I might be misunderstanding something still. Let's say the spacecraft is 5 light-minutes away from the telescope/laser. You might be able to see it, but you won't see it at its current location. You'll see where it was 5 minutes ago, right? You can't know with certainty what its current...

You're still thinking in terms of wafer-sized spacecraft . I was thinking of something that's more comparable in mass to our current space probes, pushed by an extremely powerful laser. Something that would take a long time to accelerate. We obviously can't aim a laser to hit a departing object...

Obviously you would need to aim the laser at the spacecraft to get things started, but from that point forward, couldn't the spacecraft make adjustments of its own to stay on the beam? It should be relatively easy for the spacecraft to detect when it's moving off the center of the beam...

That's part of why I think it might actually be easier to build the telescope in space. This would definitely NOT be a short-term project. What if the beam needs to be aimed at the spacecraft for days, or even weeks at a time? It's just hard for me to imagine how you could ever aim a laser so...

I've been wondering lately about the challenge of building a giant laser-projecting telescope, like the one mentioned earlier. How does it compare to the challenge of building a giant light-gathering telescope of the same size? At our current level of technology it's a little ridiculous to talk...

Am I using the evolving beam width equation correctly? I have no idea if it's reasonable to assume something close to an ideal Gaussian beam in this case. If the math is right, then it suggests to me that you would need to focus the laser through a telescope with a 713.65-meter aperture to...

I used the Gaussian equation for evolving beam width to figure out how wide the beam would need to be for a given distance and wavelength. https://en.wikipedia.org/wiki/Gaussian_beam#Evolving_beam_width Hopefully I'm not misusing the equation. All of this assumes an ideal Gaussian beam. For...

In this paper James Benford argues that microwaves are the most cost-effective for propelling a sailcraft, although they might be at a disadvantage for missions that require long acceleration times. https://arxiv.org/ftp/arxiv/papers/1112/1112.3016.pdf I guess this shows you where I got the...

I've often read that beam-powered propulsion is the only basic interstellar propulsion concept without physics problems. To me, that doesn't seem far from the truth. However, for a long time I've felt that the biggest obstacle to overcome is the beam divergence problem. Most of the concepts I've...