What is the primary function of Defense Support Program (DSP) satellites?

The primary function of Defense Support Program (DSP) satellites is to detect missile launches and nuclear detonations. These satellites play a critical role in national security by providing early warning of possible missile attacks. They are equipped with advanced infrared sensors that can identify the heat generated by a missile launch or nuclear explosion. This capability allows defense organizations to respond promptly to potential threats, making DSP satellites essential for maintaining situational awareness and strategic defense.

The other options pertain to functions handled by different satellite systems. For instance, communication with astronauts is typically managed by other dedicated communication satellites, while GPS functionality is provided by the Global Positioning System satellites. Weather tracking is the responsibility of meteorological satellites designed specifically for that purpose. Each of these systems serves a distinct role, underscoring why the DSP satellites are uniquely focused on detecting missile launches and nuclear events.