But it is in fact different than other ash.
This ash come from Tombaugh's corpse. Other ash came from some other place.
That is not a scientific difference. Can you show how we can distinguish ashes from Tombough from other ashes?
Or, are you saying that someone pulled a switch and substituted sand for Tombaugh's ashes?
That wouldn't be too far-fetched. Other sources are more readily available, and they would need some for tests anyhow. And who would know?
Is it that you can't understand that memorials to people who do these things encourage people to try to do great things, or even do small things that matter?
Oh, I understand. And that it's a personal and/or religious thing, not something the public should pay for. If a group wanted to ship Clyde Tombaugh's remains out to outer space, and his family were good with that, let them fund it. But don't force the rest of us to pay for what's basically magical thinking.
There's not much logical difference between this and putting Lenin's corpse up for display. Except that Lenin's corpse has a higher probability of actually containing some of Lenin's remains, and those who are morbidly inclined can actually go visit it at times.
Focus on what made Tombaugh do great (or not so great) things, and not a random bit of his carcass (will those 7 grams contain more ear or more penis?). Wenerating dead bodies through public funding is religious symbolism and of no scientific value, unless someone actually studies its effect on people.