Space Development Agency awards roughly $3.5 billion to 4 companies for 72 missile tracking and warning satellites  Spaceflight Now Lockheed Martin secures Tracking Layer contract from Space Development Agency  Lockheed Martin SDA Hands Out $3.5B for 72 New Missile Tracking and Defense Satellites  Air & Space Forces Magazine U.S. Space Force awards $1.6 billion in contracts to South Bay satellite builders  Los Angeles Times US Space Development Agency places $3.5 billion order for 72 satellites  Reuters