Paying space pirates with cryptocurrency

Thought of an amusing scenario the other day. Suppose there was a future world with reasonably common space travel, and actual space pirates. So you’re out there braking into Mars orbit when the pirates launch from the far side of the planet and come out to ambush you.

“Yo ho ho. Pay us the booty or face the wrath of our railguns!”

Basically, the pirates offer you the opportunity to immediately pay them in bitcoins or some other cryptocurrency so they don’t have to waste propellant chasing you down. The catch is, they want to confirm payment so they can shut off their engines right away, but the nearest transaction clearing node is back at earth.

Is there any cryptocurrency scheme that would let you immediately confirm the transaction in a remote scenario, where you can’t contact a central server due to speed of light delays?