https://www.spaceforce.mil/About-Us/Fact-Sheets/Article/2197774/defense-support-program-satellites/
Defense Support Program Satellites United States Space Force Fact Sheets
U.S. Space Force-operated Defense Support Program (DSP) satellites are a key part of North America's early warning systems. In their 22,300-mile,...
united states space forcedefense support programsatellitesfactsheets