ISS toilet. Photo: NASA TV/Spaceflight Now

The Atlantis astronauts, awakened at 7:55 p.m. EDT by a Russian recording of a tune called "Kombaht" beamed up from mission control, geared up for a busy day in orbit this evening, assembling the international space station's zero-G toilet, installing a final battery and transferring fresh water and supplies into the outpost.

The toilet, which gets more than its fair share of attention in the media, will not be used or even tested during Atlantis's flight. The space station's first crew, scheduled to arrive in early November, will complete the toilet's activation and use it for the first time.

"It's much like you'd find on a camper or out on a boat," said William Shepherd, commander of the station's first three-man crew. "This one's a little bit different, though, because it's got airflow and that keeps all the wastes going in the right direction.

"We have a container below the toilet and when we're finished, every once in a while we take these containers, put them in our cargo vehicles and send them back to the surface of the Earth."

The international space station docked to Atlantis. Photo: NASA TV/Spaceflight Now

It's not quite that bad. No longer needed, trash-filled cargo vehicles - and their contents - burn up in Earth's atmosphere and do not actually reach the ground.

Phil Engelauf, lead flight director for Atlantis's current mission, said the astronauts will do little more than hook up the toilet's basic plumbing, starting around 4:15 a.m. EDT Thursday. The work will take about one hour.

"There's a tank and a hose connection," he said early today. "We're discussing right now possibly filling the tank with water and adding a preservative that eventually is used for preserving the wastes."

Along with hooking up the toilet, the overnight flight plan calls for Atlantis's crew to:

• Install a new battery in the Russian Zarya module to provide a full complement of six new powerpacks
• Transfer more supplies and equipment into the space station from the shuttle and a Progress supply ship docked to Zvezda's aft port
• Transfer nearly 400 pounds of fresh water from the shuttle to the station
• Install a battery charger/discharger that will be used by visiting Russian Progress and Soyuz spacecraft