Astronauts Sandra Magnus and Douglas Hurley used the station's robot arm to attach a bus-size container filled with food and other supplies to the outpost. Clothes also were stuffed inside the Italian-built cylinder, named Raffaello, as well as spare parts for the station.
It was a double dose of good news for astronauts.
Flight controllers were worried a piece of space junk from an old Soviet satellite might get dangerously close during a spacewalk tomorrow, but on Monday, they determined it will remain a safe distance away.
Space junk is said to be the No. 1 threat facing the space station in the coming decade. More than 500,000 pieces of orbiting debris are being tracked, according to NASA.
Two weeks ago, the space station residents had to seek shelter in their lifeboats when a piece of junk came within 1,100 feet - the closest encounter yet.
This is the last shuttle mission for NASA. Atlantis is due back on Earth late next week.
All 10 astronauts will spend the next week unloading the contents of Raffaello and filling the chamber back up with packing material, and space station garbage and old equipment.
The Associated Press contributed to this report.