I'm looking forward to lifting fuel into orbit as the next major progress item for this. A lot of the math changes if you lift fuel into orbit. Our mindset is currently very confined by the need to launch everything in one shot. I'm not sure exactly how fast you could get to the outer planets, but I expect it's at least enough that you would no longer need a "grand tour" to do it. (Also depends on whether you just get there fast as a fly-by or whether you want to go into orbit, I'm sure.)
Honestly kind of unsure why we're not hearing more about this already. The costs of it are an increasingly small fraction of what we're spending on these probes anyhow.
Honestly kind of unsure why we're not hearing more about this already. The costs of it are an increasingly small fraction of what we're spending on these probes anyhow.