On December 9, 1965, what was described by some eyewitness as a “fireball” was reported streaking across the skies of six U.S. states and Canada. At a sharp angle the “bright light” crashed into a forest outside of Kecksberg, Pennsylvania.
Astronomers postulated that it was a meteor. At the other end of the spectrum, Ufologists said it was an extraterrestrial spacecraft.
Before being quarantined, there were several reports of what was described as a crashed “acorn shaped” object with hieroglyphic type inscriptions in the forest. A la Roswell, without doubt, something crashed, and debris was secreted away, this time on a flatbed U.S. Army truck.
A very plausible explanation that was floated for the “Kecksburg incident” was the theory that it was a retrieved Russian satellite. The hieroglyphic type writing reportedly seen by some wasn’t alien but Cyrillic.
However, according to the declassified files made available in 2015, the object wasn’t Soviet, but a prototype of an ICBM manufactured by General Electric known as the Mark 2, a re-entry vehicle. On December 7, 1965, a missile launched from Vandenberg Air Force Base, California had veered off course and the “acorn” shaped craft made two earth orbits before crash landing in a forest outside of Kecksberg, PA. Due to the nature of the experiment, it was classified.
Not that we can take at face value everything the government tells us, but in this particular case, it does seem to explain the incident. John Ventre of MUFON has extensively researched this incident and accepts this explanation.