A 1976 NASA satellite carries a Sagan-designed plaque that timestamps Earth through deep time

NASA’s LAGEOS-1, launched in 1976, is a bare-bones, durable satellite designed to reflect laser pulses for geodynamics research. It carries two Carl Sagan–designed stainless-steel plaques with three maps showing Earth’s continents 268 million years ago (Pangaea), at launch in 1976, and about 8.4 million years in the future—the latter date aligned with the satellite’s expected re-entry. The plaque is not targeted at aliens but serves as a timekeeping message, dating itself via continental drift while the satellite—an electronics-free sphere studded with reflectors—awaits eventual opening when it returns to Earth.