Welcome to today's Space Briefing, a biweekly roundup of the latest national security space news. Top Story Harris, Leidos, Northrop and Raytheon win HBTSS prototype contracts The Missile Defense Agency has selected Harris, Leidos, Northrop Grumman and Raytheon to develop prototype designs for the Hypersonic and Ballistic Tracking Space Sensor program -- a project formerly called the Space Sensor Layer -- to develop a network of orbiting satellites optimized to continuously track long-range missiles from launch to impact. News &...