NASA UARS artist concept
This conceptual image shows the Upper Atmosphere Research Satellite, launched on Sept. 15, 1991, by the space shuttle Discovery. Originally designed for a three-year mission, UARS measured chemical compounds found in the ozone layer, wind and temperature in the stratosphere, as well as the energy input from the sun. Together, these measurements helped define the role of Earth's upper atmosphere in climate and climate variability. The 35-foot-long, 15-foot-diameter UARS was decommissioned on Dec. 14, 2005. NASA

Warning sky gazers: Equip yourselves with umbrellas and other protective gears later this month and in early October as a massive, 7-ton defunct NASA satellite is set to re-enter Earth's atmosphere and will possibly rain down debris on our planet as it disintegrates during re-entry.

NASA warned Wednesday that it's too early to tell when the defunct, 35-foot-long, 15-foot-diameter Upper Atmosphere Research Satellite (or UARS) will make the final plunge but the U.S. space agency has predicted that the satellite will re-enter earth's atmosphere sometime in late September or early October.

The bad news is that during re-entry, the satellite could rain down debris as it disintegrates upon coming in contact with earth's atmosphere.

"Although the spacecraft will break into pieces during re-entry, not all of it will burn up in the atmosphere," NASA has warned.

A Russian news report has predicted that Moscow was "in the zone of risk" but NASA said it's too early to predict the orbital path which, however, will become more refined as the days pass.

UARS, which was deployed from the shuttle Discovery on Sept. 15, 1991 to study Earth's atmosphere and help scientists understand how different gases helped protect earth from the harsh environment of space, had provided conclusive evidence that atmospheric chlorine, originating from human-produced chlorofluorocarbons, was responsible for the formation of polar ozone hole, NASA said.

The satellite was originally planned to operate for just three years but the $750 million mission continued for an additional 10 years before UARS was finally decommissioned on Dec. 14, 2005.

NASA, which had once suggested that it would re-enter the Earth's atmosphere in 2009-2010, said it will post updates on UARS's orbital path status on a weekly basis till about 24 hours before its re-entry. Thereafter, updates will be posted 12 hours, four hours and two hours till re-entry.

NASA said UARS, based on current orbital flight path and inclination, is expected to re-enter the atmosphere somewhere between 57 degrees north latitude and 57 degrees south and the debris could rain down on the Earth's surface stretching about 500 miles.

The Joint Space Operations Center of the U.S. Strategic Command at California's Vandenberg Air Force Base is monitoring UARS' status around the clock, the U.S. space agency said.

"The risk to public safety or property is extremely small, and safety is NASA's top priority. 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," NASA said.

However, NASA has cautioned the public not to touch or tamper with the fallling debris. "If you find something you think may be a piece of UARS, do not touch it. Contact a local law enforcement official for assistance," it said.

NASA will host a media teleconference at 11 a.m. EDT on Friday. For live audio streaming of the teleconference, click here.

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