Science

LCS 1

Radar Calibration Sphere (Oldest Continuously Used Spacecraft) · MIT Lincoln Laboratory (Rohr Corp.)

LCS-1 (Lincoln Calibration Sphere 1), launched May 6, 1965 and, remarkably, still the oldest continuously used spacecraft in orbit today — over 60 years later. LCS-1 is nothing more than a hollow, precisely machined aluminum sphere 1.12 meters across, built by MIT's Lincoln Laboratory with absolutely no power, electronics, or fuel of any kind. Its entire purpose is to give ground-based radar systems a perfectly known reference target with a fixed, precisely measured radar cross-section, allowing radar operators worldwide to calibrate their instruments against it. With a predicted orbital lifetime of roughly 30,000 years, LCS-1 will very likely outlast every other object humans have ever put into space — including, quite possibly, humanity's own written record of having built it.