An unmanned cargo ship loaded with emergency supplies — including Japanese whisky — successfully docked at the International Space Station early Tuesday, officials said.

But thirsty astronauts will have to keep their hands off the golden tipple — it’s a science experiment.

Drinks giant Suntory sent the booze to space so it could test how time in a zero-gravity environment affects its flavour.

Researchers for the company have said that storing the beverage in an environment with only slight temperature changes and limited liquid movement could lead to a mellower flavour.

The cargo was placed inside the 5.5-tonne vessel Kounotori, which blasted off from southern Japan last Wednesday attached to an H-IIB rocket.