The seven-man crew was spending the day conducting pre-landing systems checks and completing other chores, along with participating in televised interviews.
Early weather forecasts looked good for Wednesday morning's planned touchdown at Kennedy Space Center in Florida, NASA said.
If the weather changes, however, Atlantis will aim for the backup touchdown site in California to give the military time enough time to shoot down a damaged spy satellite without endangering the shuttle.
Atlantis commander Stephen Frick said the crew hopes the weather cooperates for a Florida landing.
"All our families are waiting for us there," he told ABC News. " ... We miss them very much and are looking forward to getting home."
After leaving the international space station on Monday, Atlantis' crew inspected their ship one final time to ensure it's prepared for the fiery descent through the atmosphere.
The astronauts used a laser-tipped boom to hunt for possible micrometeorite damage to the shuttle's wing and nose that might have occurred while the shuttle was docked to the space station.
NASA was finishing up its analysis of the latest laser data and expected to let the astronauts know later Tuesday if they are cleared for landing.
The prelanding check has become standard procedure ever since Columbia was destroyed during re-entry.
Atlantis is ferrying home astronaut Daniel Tani, whose mother died during his four-month stay at the space station. Tani told CNN he believes he has processed the grief of losing her but is not sure how he'll feel when he lands.
"Like a lot of things you just deal with what you're given," said Tani, whose trip home in December was delayed by Atlantis' fuel gauge problems. "My job had me on the space station, and life happens. Great things happen and terrible things happen."
During their nine days of joint operations, the shuttle and station crews devoted almost all of their time together to the European Space Agency's $2 billion Columbus lab.
The astronauts conducted three spacewalks to install the module, attach science experiments to its exterior and replace a station nitrogen tank.
"It's arguably one of the most successful docked missions we've had," said LeRoy Cain, a mission manager.
For more information, visit the STS-122 mission page on the NASA Web site: www.nasa.gov
By Liz Austin Peterson