Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

Breaking that down: Voyager itself couldn't have reduced velocity, it had nowhere near enough reaction mass to do that. Hypothetically a spacecraft could but you might be talking about orders of magnitude more reaction mass. (Which means multiples more of the fuel to launch and accelerate that mass itself, which could quickly escalate beyond any chemical rocket capabilities.)

It also likely wasn't possible to get to Pluto on some future Pluto orbital pass. The limiting factor is likely that Voyager's incoming trajectory to Neptune was already too far beyond solar escape velocity to get into that narrow elliptical orbit you propose. (You'd have to slingshot so close to Neptune's center that you'd hit the planet instead.)

Designing from the beginning to come in slower to Neptune and adjust to encounter Pluto on some future Pluto orbital pass was probably possible, but yeah you might be talking about time scales of Pluto's entire orbit or even multiples of that. (We do similar things for inner solar system missions, like several encounters with Venus separated by multiple Venus-years, but that's on the order of single-digit years and not hundreds.)

The common answer to a lot of these outlandish slingshot questions is usually, yes it's eventually possible by orbital mechanics, but it gets so complicated and lengthy that you may as well just build another separate spacecraft instead. We talk about Voyager's grand tour alignment because it's captivating, but realistically if that hadn't happened we would have just done separate Jupiter-Uranus and Jupiter-Neptune missions instead.

The sun's motion relative to the galaxy doesn't matter for any of this - nothing else in the galaxy is remotely close enough to affect anything, the nearest star is still over 1000x Voyager's distance.

> New Horizons nearly did.

New Horizons didn't nearly overtake Voyager. It's currently traveling about 4 km/s slower, and as it's still closer to the Sun, it's also decelerating more.

> We're shutting down sensors on Voyager because there just isn't much to see.

That's not why Voyager's sensors are being shut down, they're being shut down because the probes no longer have the power to run them.

>Nothing lasts forever, and if you don't figure out when it's going to fail, it's going to be sooner rather than later.

You might be surprised about the reality of the situation.

I had a professor who worked on the design and fabrication of the Apollo Guidance Computers, which likely was a somewhat similar process to the one being discussed here. It's been quite a few years since his lecture on it, but the process went something like this:

They started with an analysis of the predicted lifetime/reliability of every chip type/component available to potentially include in the design.

The design was constrained to only use components with the top x% of predicted life.

Then they surveyed each manufacturer of each of those component types to find the manufacturer with the highest lifetime components for each of the highest lifetime component types.

Then they surveyed the manufacturing batches of that manufacturer, to identify the batches with the highest lifetimes from that manufacturer.

Then they selected components from the highest lifetime batches of from the highest lifetime manufacturers of the highest lifetime components.

Using those components, they assembled a series of guidance computers, in batches.

They tested those batches, pushing units from each batch to failure.

They then selected the highest quality manufacturing batch as the production units.

When he gave this talk, decades after the Apollo era, NASA had been continuing to run lifetime failure analyses on other units from the production batch, to try to understand the ultimate failure rate for theoretical purposes.

Several decades after the Apollo program ended, they had still never seen any failure events in these systems, and shortly before the time of his lecture, I believe NASA had finally shut off the failure testing of these systems, as they were so remote from then "modern" technology (this was decades ago, hence the quotes around "modern").

This is what happens when you have the best minds committed to designing systems that don't fail. Yes, the systems probably will fail before the heat death of the universe. No, we don't have any idea when that failure time will be. Yes, it's likely to be a very long time in the future.

(And, of course, this is typed from memory about a lecture decades ago on events happening decades before that. This being HN, someone here probably worked on those systems, in which case hopefully they can add color and fix any defects in the narrative above).

Yes, I wrote that short for brevity. If you must have the full thing spelled out: New Horizons nearly got enough velocity at Jupiter to eventually overtake Voyager. 4 km/s is "nearly" in astronomical terms. New Horizons wasn't really trying to optimize for speed at Jupiter (its closest approach was over 10m km), and a spacecraft that did could easily overtake Voyager using Jupiter alone and not need an alignment with Saturn or anything else.