Letters to the Editor Humans Letters from the September 10, 2005, issue of Science News By Science News September 6, 2005 at 1:27 pm - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to print (Opens in new window) Print Pennies in heaven? Why slam a copper impactor into Comet Tempel 1 (“A Grand Slam: In a winning move, NASA probe burrows into a comet,” SN: 7/9/05, p. 22)? Wouldn’t copper vapor contaminate the spray? Why not a high-temperature ceramic? P.M.