The following was reported by CNN Interactive, March 7, 2000.
(www.cnn.com/2000/Tech/space - More stories "European satellite quartet to plumb...")
Mission to the magnetosphere:
Satellite quartet to decode mysteries of space weather
March 7, 2000
(CNN) -- The magnetosphere protects life on Earth from countless billions of charged solar
particles blasted continuously from the sun. That much we know, but there are plenty of
questions about the planet's natural barrier still to be answered.
To that end, European Space Agency plans to send a flotilla of identical satellites skimming
in formation through the magnetosphere this summer. The quartet will collect data and map
Earth's magnetic field, providing a critical tool in the relatively young field of space weather
forecasting.
Though the magnetosphere normally acts as a shield against the solar wind, it can be
breached by high-energy particles (mainly protons and electrons) during periods of increased
solar activity. "It's like a never-ending football game," Cluster II project scientist Philippe
Escoubet said in a statement. "The sun is kicking particles toward us, like footballs. The Earth
is the goal, and its magnetic field is the goalkeeper." When particles score goals, they disrupt
the Earth, producing electrical currents that can shut down power grids, interrupt short-wave
radio communications or damage communication satellites.
Cluster II is scheduled for launch this June and July, just in time for the Solar Maximum, a
peak in the 11-year cycle of solar activity. The four robotic satellites, each about the size of
a
Volkswagen Beetle, will be lofted into orbit in pairs by two Soyuz rockets fired from the
Baikonur cosmodrome in Kazakhstan.
Each satellite is identical in design and carries the same payload: 11 instruments designed to
study all aspects of the Earth's electrical and magnetic environment. The probes' most
striking visual features are the booms that extend into surrounding space, sweeping through a
sea of charged particles as each spacecraft rotates. The quartet will fly as a group, collecting
data simultaneously while circling the Earth in an oblong orbital trajectory.
"The spacecraft will give us four viewpoints -- like having one camera behind the game at a
football match and three others at different angles," Escoubet said. "It will be the first time
this has been done in the Earth's magnetic field."
If successful, the mission will mark the first time ESA has built spacecraft in series
production and operated them as a single group. The mission is a duplicate of the original
Cluster project, lost during the explosion of the Ariane-5 demonstration flight in June 1996.
Cluster II uses some of the original spare parts from Cluster I, and its scientific objectives
remain unchanged, according to ESA.
Over their two-year mission, the spacecraft will sail through the various layers and
boundaries within the magnetosphere and cross over the edge of Earth's magnetic bubble into
interplanetary space, where the solar wind blows full force. Scientists hope to use the data to
create the first detailed, three-dimensional map of the magnetosphere, which would be an
invaluable tool for understanding and predicting the effects of space weather.
