I'd check anything with a Geiger counter before touching it.
The shuttle may have been using radioactive decay for power
(http://www.jpl.nasa.gov/news/fact_sheets/future.html)
or may have been doing experiments for the Nuclear Systems Initiative (http://www.space.com/news/nasa_nuclear_020205.html). Neither of
these is mentioned in the official list of experiments
(http://spaceresearch.nasa.gov/sts-107/107_payload.pdf).
