Im curious - if you destroy ur palace or rushbuild a settler to disband ur capital, does it provide you with a safeguard against corruption and rioting like it protects you in the space race?
Absolutely not. One of the main purposes of a capital is to establish the reference distance for corruption/waste in the lower forms of government.
Specifically, there are 4 governments that rely on the capital to compute corruption: Anarchy, Despotism, Monarch, and Republic.
In late game, however, you should be in Commuinsm, Fundamentalism, or Democracy. None of those governments will lose production or trade by having no capital, since corruption/waste is not a factor.
To my knowledge, having a capital or not does not affect the riot factor; but if you lose a capital in republic, your corresponding loss of trade due to corruption may cause a city to become unhappy. But the city does not "riot" merely because you have no captial.
Just to keep the perspective here, in the vast majority of circumstances, a player will not have a need to destroy their own capital. It would pretty much need to be a very close space race, with an AI (or human) that was ready, willing, and able to come after your capital after your SS was launched.