Advanced Composition Explorer, Space Radiation Laboratory, California Institute of Technology
Data Center Description
The Advanced Composition Explorer (ACE) is an Explorer mission that was managed by the Office of Space Science Mission and Payload Development Division of the National Aeronautics and Space Administration (NASA). More on the ACE personnel, including scientific Co-Investigators can be found here.
The Earth is constantly bombarded with a stream of accelerated particles arriving not only from the Sun, but also from interstellar and galactic sources. Study of these energetic particles will contribute to our understanding of the formation and evolution of the solar system as well as the astrophysical processes involved. The Advanced Composition Explorer (ACE) spacecraft carrying six high-resolution sensors and three monitoring instruments samples low-energy particles of solar origin and high-energy galactic particles with a collecting power 10 to 1000 times greater than past or planned experiments.
From a vantage point approximately 1/100 of the distance from the Earth to the Sun ACE performs measurements over a wide range of energy and nuclear mass, under all solar wind flow conditions and during both large and small particle events including solar flares. ACE provides near-real-time solar wind information over short time periods. When reporting space weather ACE can provide an advance warning (about one hour) of geomagnetic storms that can overload power grids, disrupt communications on Earth, and present a hazard to astronauts.
ACE orbits the L1 libration point which is a point of Earth-Sun gravitational equilibrium about 1.5 million km from Earth and 148.5 million km from the Sun. With a semi-major axis of approximately 200,000 km the elliptical orbit affords ACE a prime view of the Sun and the galactic regions beyond. The spacecraft has enough propellant on board to maintain an orbit at L1 until ~2019.