The proposal here is very similar to the Breakthrough Starshot initiative that wants to send a probe to Alpha Centauri, the nearest star system to our sun.
Basically the idea is to take a very small (i.e. low mass) craft with a large solar sail and accelerate it to a significant fraction of the speed of light using very powerful ground-based microwave laser arrays. The neat thing about this concept is that all of the technology essentially exists already — it’s just a matter of scaling up existing concepts and miniaturizing existing sensors.
The black hole rendezvous suggested in this paper is a lot more ambitious than Starshot, targeting a distance of 20-40 light-years (for comparison Alpha Centauri is only about 4 light-years away) and a max speed of 30% the speed of light (vs a speed of ~10% c targeted by Starshot). I think the main problem here (other than the requirement of building what essentially amounts to a microwave death ray) would be developing an antenna that’s both small enough to fit under the strict mass limits and powerful enough to broadcast the data 20+ light-years back to Earth. Maybe space-time lensing effects around the black hole itself could be used to amplify the signal? Another problem is that even at extreme speeds, this is a multi-decade mission — like 70+ years. Considering the travel delay involved in sending back a signal, it’ll be a century at least before any data would arrive at Earth. Unfortunately, century-long projects are an extremely hard sell for the people who hold the scientific purse strings.
Oh, also… We don’t currently know of any BHs within the target range, and the paper’s author even admits that any targets more distant than 50ish light-years are basically unreachable. The current closest-known BH is more than 1000 light-years away, so we’ve still got a lot of work to do in finding a suitable target. Fortunately the field of black hole detection is advancing quickly, and the new Vera Rubin observatory is very likely to spot many previously-unknown black holes in the coming years. Hopefully some of those will be close!
The problem with these long term journeys is that it’s entirely possible that the probe could get half way there by time we develop the technology to make another probe that’s twice as fast and cheaper. Or maybe we make other discoveries and find that we don’t need the data the probe is equipped to gather. We’re not really near the limits of propulsion and space engineering yet so it doesn’t make a ton of sense to invest in something with such a distant payoff when it’s somewhat likely to be outdone before then.
Along with the antenna, there’s another problem to solve - power. The probes need a power source that, after the better part of a century, can still output enough power to send a signal home. That doesn’t leave a lot of options. RTGs will not do for this, their power output is too low. It’s theoretically possible to build a battery large enough, but it’ll add tens of tons to the probe’s mass. A nuclear reactor would probably be lighter, but has the same problem as an RTG, in that its fuel supply will decay along the way. And if you need to make course correction maneuvers on the trip (cause let’s face it, we’re not going to bullseye a dwarf planet sized target from lightyears away), the probe has to stay powered for the entire time, so the propulsion system doesn’t freeze up. And now you need to worry about propellant losses.
EDIT: Finally got around to reading the article and I’d love to know what the author of this idea considers unrealistic if decelerating from 0.3c into orbit around a black hole >20 lightyears away sounds plausible.
That’s a pretty good idea, especially when you consider another problem that needs to be solved by any fast-moving spacecraft: dust.
If a spacecraft hurtling through interstellar space at .3c encounters even a tiny grain of dust, the energy released by the collision is going to be enormous — more than enough to destroy the ship entirely. So far, the best strategy anyone has come up with to mitigate this risk is to just… send a shitload of probes all at once. Basically shotgun blast tiny craft at the sky in hopes that at least one of them makes it to the final destination unscathed.
I imagine it wouldn’t be too hard to modify this strategy and stagger the launch times somewhat to create more of a ‘caravan’ of probes that could also double as a signal relay.
Wouldn’t the trajectory from here to a single blackhole be so tight — like < 1 degree of the night sky — that if any probe were to vapourize at 10% the speed of light, the dust debris would likely destroy any craft that follows behind it, even if it were months behind?
I thought that was the whole point of starshot (and similar). Sending multiple little crafts to act as relays and backups. Also because we can’t slow down at the destination. So we’d have multiple fly-bys to get more data.
I also remember reading about the theorized micro black holes. The fraction of a millimeter in diameter to quantum scale. If we were somehow able to create a process to reliably produce holes of micro size we might be able to send a small probe into one.
I keep coming back to this whole endeavor might be pointless as not even light can escape, how would we retrieve any information? Even if we somehow were able to get some info how could we guarantee the information is in a complete state? Maybe a lazer broadcast of info till right before the event horizon if the probe was strong enough to withstand the gravitational extremes. We might just get an understanding of how close probe x could get before destruction.
I guess if we could consistently reproduce black holes we could send enough probes to retrieve enough information in parts to understand more than we do.
The proposal here is very similar to the Breakthrough Starshot initiative that wants to send a probe to Alpha Centauri, the nearest star system to our sun.
Basically the idea is to take a very small (i.e. low mass) craft with a large solar sail and accelerate it to a significant fraction of the speed of light using very powerful ground-based microwave laser arrays. The neat thing about this concept is that all of the technology essentially exists already — it’s just a matter of scaling up existing concepts and miniaturizing existing sensors.
The black hole rendezvous suggested in this paper is a lot more ambitious than Starshot, targeting a distance of 20-40 light-years (for comparison Alpha Centauri is only about 4 light-years away) and a max speed of 30% the speed of light (vs a speed of ~10% c targeted by Starshot). I think the main problem here (other than the requirement of building what essentially amounts to a microwave death ray) would be developing an antenna that’s both small enough to fit under the strict mass limits and powerful enough to broadcast the data 20+ light-years back to Earth. Maybe space-time lensing effects around the black hole itself could be used to amplify the signal? Another problem is that even at extreme speeds, this is a multi-decade mission — like 70+ years. Considering the travel delay involved in sending back a signal, it’ll be a century at least before any data would arrive at Earth. Unfortunately, century-long projects are an extremely hard sell for the people who hold the scientific purse strings.
Oh, also… We don’t currently know of any BHs within the target range, and the paper’s author even admits that any targets more distant than 50ish light-years are basically unreachable. The current closest-known BH is more than 1000 light-years away, so we’ve still got a lot of work to do in finding a suitable target. Fortunately the field of black hole detection is advancing quickly, and the new Vera Rubin observatory is very likely to spot many previously-unknown black holes in the coming years. Hopefully some of those will be close!
The problem with these long term journeys is that it’s entirely possible that the probe could get half way there by time we develop the technology to make another probe that’s twice as fast and cheaper. Or maybe we make other discoveries and find that we don’t need the data the probe is equipped to gather. We’re not really near the limits of propulsion and space engineering yet so it doesn’t make a ton of sense to invest in something with such a distant payoff when it’s somewhat likely to be outdone before then.
Along with the antenna, there’s another problem to solve - power. The probes need a power source that, after the better part of a century, can still output enough power to send a signal home. That doesn’t leave a lot of options. RTGs will not do for this, their power output is too low. It’s theoretically possible to build a battery large enough, but it’ll add tens of tons to the probe’s mass. A nuclear reactor would probably be lighter, but has the same problem as an RTG, in that its fuel supply will decay along the way. And if you need to make course correction maneuvers on the trip (cause let’s face it, we’re not going to bullseye a dwarf planet sized target from lightyears away), the probe has to stay powered for the entire time, so the propulsion system doesn’t freeze up. And now you need to worry about propellant losses.
EDIT: Finally got around to reading the article and I’d love to know what the author of this idea considers unrealistic if decelerating from 0.3c into orbit around a black hole >20 lightyears away sounds plausible.
Maybe we could extend the range of transmission by sending multiple radio relay’s in sequence behind the initial probe.
A game of cosmic telephone.
That’s a pretty good idea, especially when you consider another problem that needs to be solved by any fast-moving spacecraft: dust.
If a spacecraft hurtling through interstellar space at .3c encounters even a tiny grain of dust, the energy released by the collision is going to be enormous — more than enough to destroy the ship entirely. So far, the best strategy anyone has come up with to mitigate this risk is to just… send a shitload of probes all at once. Basically shotgun blast tiny craft at the sky in hopes that at least one of them makes it to the final destination unscathed.
I imagine it wouldn’t be too hard to modify this strategy and stagger the launch times somewhat to create more of a ‘caravan’ of probes that could also double as a signal relay.
Wouldn’t the trajectory from here to a single blackhole be so tight — like < 1 degree of the night sky — that if any probe were to vapourize at 10% the speed of light, the dust debris would likely destroy any craft that follows behind it, even if it were months behind?
I thought that was the whole point of starshot (and similar). Sending multiple little crafts to act as relays and backups. Also because we can’t slow down at the destination. So we’d have multiple fly-bys to get more data.
I also remember reading about the theorized micro black holes. The fraction of a millimeter in diameter to quantum scale. If we were somehow able to create a process to reliably produce holes of micro size we might be able to send a small probe into one.
I keep coming back to this whole endeavor might be pointless as not even light can escape, how would we retrieve any information? Even if we somehow were able to get some info how could we guarantee the information is in a complete state? Maybe a lazer broadcast of info till right before the event horizon if the probe was strong enough to withstand the gravitational extremes. We might just get an understanding of how close probe x could get before destruction.
I guess if we could consistently reproduce black holes we could send enough probes to retrieve enough information in parts to understand more than we do.