NEW YORK (TheStreet) -- Shares of Lockheed Martin Corp.a are down 1.58% to $172.75 in afternoon trading Tuesday following the company's disappointing sales forecast and itsamixedathird quarter earnings report this morning. The Bethesda, MD-based company said sales in 2015 will decline at "a low single digit rate from 2014 levels" with a total business segment operating margin of 11.5% to 12%, based on the U.S.