spase://CNES/Observatory/CDPP-AMDA/ACE

Advanced Composition Explorer (ACE) observes particles of solar,
interplanetary, interstellar, and galactic origins, spanning the energy range
from solar wind ions to galactic cosmic ray nuclei.
The Advanced Composition Explorer (ACE) spacecraft carries six high-resolution
sensors and three monitoring instruments that sample 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.

The prime objective of ACE is
to measure and compare the composition of several samples of matter,
including the solar corona, the solar wind, and other interplanetary particle populations,
the local interstellar medium (ISM), and galactic matter. While there has been great progress
addressing these objectives, the changing conditions over the solar cycle present new opportunities.
In addition, new observations and theoretical advances, new missions, and the evolving goals of NASA
and the Sun-Solar- System Connection (S3C) Theme have introduced new challenges, including the goal
of achieving the scientific understanding needed to forecast space weather in the coming years when
humans will venture beyond Earth's protective magnetosphere.