A code of conduct to govern how countries manage equipment and travel in space is a step closer.
The United States has agreed to a code, being formulated by the European Union, aimed at tackling space junk and other problems.
Currently, there are more than 10,000 pieces of junk orbiting Earth, including spent rocket bodies, discarded satellites and thousands of spacecraft fragments.
In a statement, Secretary of State Hillary Clinton said that unless these challenges are addressed, the environment around our planet will become increasingly hazardous to human spaceflight and satellite systems.
However, she said the United States would not enter into an agreement that "in any way constrains our national security-related activities in space or our ability to protect the United States and our allies."