alt Hacker NewsThoughtful intuitions all around. My understanding is that lasers don't necessitate the big reception dish, but instead have a 1m or smaller reflective telescope. The laser setup is lighter, lower power and gas precedent in modern space missions.
Probes I suspect would realistically have to be large enough to send strong signals over long distances, so weightier than a few grams.
I think 99% downtime is an existing paradigm for lots of space stuff, e.g. NASA's DSOC and KRUSTY, so room for optimism there.
Though I think I agree with you that an energy payload as well as general hardware reliability are probably the bottlenecks over long distances. I have more thoughts on this that probably deserve a seperate post (e.g. periodic zipper-style replacements that cascade through the whole relay line) but to keep this on honoring the Voyager, I will say for the Voyager is at least for me huge for opening my imagination for next steps inspired by it.
I also spend far too much time wondering about sending out swarms of probes and if you could somehow rendezvous them and add fuel midjourney and so on!
The problem I see is that lasers are still subject to diffraction, and this is worse the smaller the aperture is relative to wavelength. Due to the small probe mass which you need to split with observation equipment, support systems and presumably some microscale nuclear power supply, you could maybe with a few breakthroughs in engineering manage a wispy affair on the order of a metre at most. It it scales with diameter and mass scales with diameter squared.
So the beam divergence of a visible light laser end with a diameter of over 18 million km over 4 light years. With 100W of transmission power, that's 0.1pW per square kilometer of receiver. Which isn't nothing, but it's not huge either.
I really don't see how the Starwisp type microprobes will actually work on a practical level at any time in the foreseeable future, even if the propulsion works. Not only is the communications a problem, but so is power, computational resources, observation equipment, radiation shielding and everything in between. But anything massier than that requires mindboggling amounts of fuel. And the problem is so much worse if you want to stop at the destination rather than scream past at a modest fraction of c and hope to snap a photo on the way past.
It really seems (sadly, in a way) that building gigantic telescopes will be a lot more instructive than any plausible probe for quite some time. An gravitational lens telescope would be a far better, and probably almost as challenging, project for learning about exoplanets. Not least it would be about 3 times further from Earth than Voyagers.