1742: English astronomer Edmond Halley, who discovered the comet that now bears his name, died. 1873: "Celluloid" was registered as a trademark by John Hyatt. 1934: French scientist Paul Vieille, inventor of smokeless gun powder, died. 1943: American biochemist Shannon Lucid, who stayed aboard the Russian space station Mir in 1996 for a women's record-breaking 188 days, was born. 1981: The FCC freed stations to air as many commercials an hour as they wish. 2005: The Huygens space probe landed on Titan, Saturn's largest moon.