NASA's defunct Upper Atmosphere Research Satellite is expected to plunge into the Earth in an uncontrolled fall in late September or early October, officials said Wednesday. Though the 6.5-ton satellite is expected to burn up as it enters the atmosphere, NASA doesn't rule out the possibility of solid pieces touching the ground.

NASA will take necessary measures to keep the public informed about the fall of satellite and about the potential risks involved.

It is too early to say exactly when UARS will re-enter and what geographic area may be affected, but NASA is watching the satellite closely and will keep you informed, NASA said in a statement.

UARS was launched Sept. 12, 1991, aboard space shuttle mission STS-48 and deployed on Sept. 15, 1991. It was the first multi-instrument satellite to observe numerous chemical components of the atmosphere for better understanding of photochemistry.

UARS data marked the beginning of many long-term records for key chemicals in the atmosphere. The satellite also provided key data on the amount of light that comes from the sun at ultraviolet and visible wavelengths. UARS ceased its productive scientific life in 2005.

According to a computer analysis of satellite re-entry survivability for UARS components, about 150 component types, including the parent body of the satellite, will disintegrate during re-entry, but 12 types would endure the fiery fall to Earth.

The risk to public safety or property is extremely small, and safety is NASA's top priority, NASA said. Since the beginning of the Space Age in the late 1950s, there have been no confirmed reports of an injury resulting from re-entering space objects. Nor is there a record of significant property damage resulting from a satellite re-entry.

According to NASA, on UARS re-entry day, if you find something you think may be a piece of UARS, do not touch it. Contact a local law enforcement official for assistance.

NASA will host a media teleconference Friday to discuss the anticipated re-entry of the satellite and its implications.

The agency will post updates weekly until four days before the anticipated re-entry, then daily until about 24 hours before re-entry, and then at about 12 hours, six hours and two hours before re-entry.