DSP-6

The "Phase II" block of DSP satellites, comprising Flights 5 through 7 launched between 1975 and 1977, featured upgrades such as increased on-orbit design lifetime, weight, and solar panel output compared to the "Phase I" series. These satellites retained the same basic spacecraft design but included additional packages, notably an experimental Above-the-Horizon (ATH) array sensor on Flight 6. They can be identified by two electronic packages located 180 degrees apart on the satellite's conical section.