Fifteen years ago today — August 25, 1997 — the Advanced Composition Explorer was launched from Cape Canaveral by a Delta II rocket.
(ACE. NASA image.)
The ACE spacecraft carried “six high resolution spectrometers, each designed to provide the optimum charge, mass, or charge-state resolution in its particular energy range,” in order to collect data on energetic particles from the Sun and other sources.
ACE is in a halo orbit around the L1 Lagrange point, between Earth and the Sun. According to the CalTech ACE mission site, the spacecraft “has a prime view of the solar wind, interplanetary magnetic field and higher energy particles accelerated by the Sun, as well as particles accelerated in the heliosphere and the galactic regions beyond,” and has enough fuel to maintain that orbit until 2024.by