The Pittsburgh Post-Gazette has an article on Tessellator, a robot that was developed by CMU to inspect and waterproof the heat shield tiles on the Space Shuttle. The robot was briefly tested by NASA in 1994-95 but they decided it didn't do the job as well as humans. Tessellator now sits abandoned in a corner of the CMU Robotics Institute, just a footnote in the Space Shuttle program. And, if you're interested in a footnote to the footnote, don't miss the story of the Tessellator's run-in with dumpster divers in The Great Drivertrain Robbery.