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.
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.