The U.S. government's growing acceptance of commercial military satellites is opening the $20 billion-a-year market to new companies and forcing big arms makers such as Lockheed Martin and class="mandelbrot_refrag"> Boeing to change how they operate. U.S. officials are trying to boost security of U.S. military and intelligence satellites, with an eye on risks from space debris and the proliferation of space-faring countries that could target U.S. satellites in a war. Officials hope the booming commercial satellite market can help the government obtain simpler and cheaper satellites, lower the cost of launching and create more options in other areas. After years of talk, U.S. budget cuts and changes in technology have started to alter a market long dominated by big contractors like Lockheed. "The space market is changing dramatically," said Henry Obering, senior vice president with Booz Allen Hamilton and former Missile Defense Agency director. "T