Staying fit in space is about to get easier now that astronauts on the International Space Station have finished building a new zero-gravity treadmill named after TV comedian Stephen Colbert.

Dubbed COLBERT after the host of Comedy Central's "The Colbert Report," the new exercise treadmill is now awaiting a series of tests to make sure it's working correctly before astronauts can begin running on it.

"It's done, and we're looking at it right now," space station flight engineer Nicole Stott said Monday via a video link.

The $5 million space treadmill was unpacked on the orbiting lab in September, but took about 20 hours for astronauts to put it together from more than 100 pieces. Four of the station's six astronaut residents wore broad smiles as they piled onto the treadmill for an impromptu "test run" last week, but spun their legs in weightlessness since the exercise machine was not yet ready for full operations.

Officially called the Combined Operational Load-Bearing External Resistance Treadmill (or COLBERT), the hardware got its name as a consolation prize for Mr. Colbert, who won an online NASA contest for the naming rights to a new space station module set to launch next (NASA opted to name the new module Tranquility instead).

"It's all put together in its rack but it hasn't been checked out yet," NASA spokesman Kelly Humphries told SPACE.com. "The team is working on it. They'll evaluate the data and the crew will be given a "go" or "no go" to run on it."

The treadmill is one of a suite of instruments spaceflyers use to fight the bone loss and muscle decay associated with space travel. The COLBERT treadmill should provide a better workout than the existing treadmill on the station, though both will continue to be used, Humphries said.

"They can have increased force as their foot falls as they hit the treadmill and that's what really helps with maintaining their bone density," Humphries said. "It's a commercial off-the-shelf treadmill that's been outfitted especially for spaceflight."

To keep from floating away while running on it, astronauts will have to attach themselves to the treadmill with elastic straps on their shoulders and waists.

"It's actually a beautiful piece of hardware," Stott said. "I think it's going to be a really excellent piece of exercise equipment. We're actually really looking forward to getting to run all over COLBERT."

The hardware is also specially designed to spread a minimum of vibrations through the space station, so as not to disturb the sensitive science experiments and instruments onboard.

Now that it's built, the COLBERT should only need an occasional greasing of its bearings to stay operational. The treadmill is built to handle 150,000 miles of running, NASA officials said.