Probe Launched In 1978 Coming Close To Home - But We Can’t Talk To It | Orbit Diagram

The International Sun-Earth Explorer Cometary Explorer (ISEE-3 / ICE) – launched in 1978 – makes its closest approach to Earth in August 2014, but engineers have lost the ability to command it to perform science. It studied the solar wind from a stable orbit Lagrangian point between Earth and the Sun (L1) and later was redirected to study 2 comets.

credit : NASA