This is for an application in cryptography. There is a concept called "time based cryptography", where a message can be decrypted only after a certain time, Say "12/12/2060, 12:30 GMT". There are some ideas based on "proof-of-work" but they have many problems. Is it possible to use quantum mechanics to do this in a nicer way?
The only related idea I'm aware of is position based quantum key distribution, which means that you can only distribute keys to a partner located in a specific place. But they only work as long as eavesdroppers have limited resources. You can find more information in "Position-Based Quantum Cryptography: Impossibility and Constructions" (http://arxiv.org/abs/1009.2490)
Well, this should be feasible.
You generate entanglate EPR pairs of qubit. For each pair you keep the qubit A, you send the other qubit B on a spaceship one light-year away. You have to prepare that in advance because it will take more than one year to reach this place.
Today you mesure your qubits and XOR your message with the result to encode it. The spaceship was programmed to mesure its qubit the same day, and send back the measurement to earth. Everyone will be able to decode the message, but only in a year.
Of course, you have to know the spaceship was not compromised before reaching its destination.