USA 32 was launched in 1988 on a top-secret mission to monitor Soviet radars from orbit. It was part of a series of satellites named after the actress Farrah Fawcett. This one was Farrah III, shaped, ironically, like
a squat cylinder. The "tuna can" form allowed it to rapidly spin and sweep its antennas across the ground below. The NRO fully declassified the program only this year.
There may be nothing sinister about this event. Old spacecraft carry batteries and leftover propellant. After 38 years of heating and cooling, a pressurized tank or a battery cell on USA 32 may have simply ruptured. This is a leading suspicion, although it is too soon to rule out a meteor strike or ASAT.
Other satellites may be in danger. USA 32 broke up in a crowded shell of low Earth orbit. Within 50 km of its altitude are more than 200 active satellites, including the entire Iridium NEXT constellation. Even before USA 32 broke up, this region was extremely cluttered. NASA identifies a major debris-density peak already there from the Iridium 33/Cosmos 2251 collision in 2009. The collision threat is real.
Analysts are carefully tracking the fragments and measuring their individual trajectories. Soon, they may be able to "run the clock backward" to see how the explosion began.