There was a significant increase in satellite breakups during 2006. That’s the word from orbital debris experts at NASA’s Johnson Space Center in Houston, Texas.

Although no satellite breakups were detected for nearly a year during the period from June 2005 to the first of May 2006, the remainder of last year witnessed eight satellite breakups for a rate of one per month.

Not since 1993 had so many breakups occurred in one year.

Contributing to the peppering of space with human-made junk: one Japanese and two U.S. rocket bodies, as well as a 7 metric ton Russian spy satellite.

Surprisingly — after its remaining fuel had been vented — a U.S. Delta II second stage that had been adrift for 17 years went kaBoom! Potential reasons for the unexpected breakup, including impact by another object, are under evaluation, according to the January issue of Orbital Debris Quarterly News.