A mysterious breakup of a decades-old American spy satellite has sent debris hurtling through low-Earth orbit, with the U.S. Space Force now tracking the fragments for potential threats to other spacecraft, according to Space-Track.

The satellite, known as USA 32, came apart on September 13 at approximately 5:13 p.m. ET, according to U.S. Space Forces-Space. Officials have not publicly determined what caused the nearly 40-year-old spacecraft to suddenly fragment.

"All tracked debris are being incorporated into routine conjunction assessment screenings to support spaceflight safety," U.S. Space Forces-Space said in a notice. "No immediate threats have been identified; further analysis is ongoing."

USA 32 had been circling Earth since the final years of the Cold War.

The National Reconnaissance Office satellite blasted into space aboard a Titan II rocket on September 5, 1988. Public records identify the spacecraft as an electronic and signals intelligence satellite designed to collect information from orbit.

USA 32 has also been identified as FARRAH III, part of a secretive family of American intelligence satellites whose name was inspired by actress Farrah Fawcett.

The satellite was traveling in an orbit roughly 480 miles above Earth when it broke apart. Officials have yet to disclose how many fragments were produced.

That uncertainty matters because debris traveling at orbital speeds can pose a hazard to functioning satellites even when the individual pieces are relatively small. Space Force tracking systems routinely monitor objects around Earth and screen their trajectories for possible collisions.

Exactly what happened to USA 32 remains a mystery.

A collision with an untracked object is one possible explanation for an unexpected satellite breakup. Aging spacecraft can also fragment because of failures involving batteries, pressurized tanks or other components. There is currently no public evidence establishing any of those scenarios as the cause of USA 32's demise.