Astronauts onboard the linked space shuttle Endeavor and the International Space Station on Wednesday collect ed recycled urine samples from their $250- million water recovery system, to be returned back to Earth for further testing.

The urine recycling equipment went operational Tuesday after long hours of tinkering by astronauts. It was delivered on November 16 by the space shuttle Endeavor and will be a crucial part in increasing the number of astronauts on board the ISS from the current three to six.

Flight director Holly said the astronauts have to fill at least six one-liter containers of urine and condensation that Endeavor will bring back to Earth for more studies to determine if it is fit for human consumption.

The next shuttle flight scheduled in February will bring back more samples from the ISS.

NASA is hoping recycled urine from the ISS will be ready for drinking by ISS astronauts by spring.