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.


[Summary provided by the California Institute of Technology.]

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