For awhile there was speculation this was a returning Apollo-era S4B stage,
but more recent measurements seem to lower the chances of that...


Earth's "Other Moon"
April 17, 2007
by Roger W. Sinnott

http://skytonight.com/news/Earth_Sec...?showAll=y&c=y

Last September, when a tiny asteroid drifted into Earth's vicinity, our
planet's gravity captured it. The meter-size object, designated 6R10DB9, is
now making its third wide swing around Earth. It was quite faint, magnitude
19.3, when discovered September 14th with the 0.68-meter (27-inch) Schmidt
telescope of the Catalina Sky Survey in Arizona, and it won't get much
brighter than that. ... more