NASA will launch two identical probes into the
radiation belts to provide unprecedented insight
into the physical dynamics of near-Earth space, where
violent space weather can affect astronauts,
satellites and even ground-based technologies.
Researchers and engineers at Johns Hopkins' Applied
Physics Laboratory and a number of other
institutions have begun detailed design of NASA's Radiation
Belt Storm Probes Mission, or RBSP. APL
will build and operate the twin probes, which are scheduled
for a 2011 launch and a primary mission of
two years.
"We're excited to move into the detailed planning,"
said Rick Fitzgerald, RBSP project manager
at APL. "The Laboratory has a long-standing history in
radiation science, so it's a natural fit for us to
be building these two spacecraft to investigate how the
radiation belts are created and change over
time."
The radiation belts are two doughnut-shaped regions,
encircling Earth, where high-energy
particles are trapped by the planet's magnetic field. Most
Earth-orbiting spacecraft pass through the
belts, and when the energy and density of the particles
increase, it becomes more likely that an
astronaut or spacecraft will be affected.
High-energy particles striking human tissue can alter
the chemical bonds within cells, damaging
or destroying them. When a particle strikes a satellite, it
can overwhelm sensors, damage solar cells
and degrade wiring and other sensitive electronics. Large
changes in the magnetic field near Earth's
surface associated with space weather storms can induce
currents that flow through — and affect the
operation of — railroad systems, power transmission
lines and pipelines.
The RBSP mission seeks to resolve decades-old
scientific mysteries of how these particles
become energized to such high levels, and how the radiation
belts vary so dramatically with changing
conditions on the sun.
"The radiation belts were a scientific curiosity when
they were discovered 50 years ago by
James Van Allen, who was one of the founding members of
APL," said Barry Mauk, project scientist
for RBSP. "But the belts are becoming very important
because we have people and machines operating
in them. That region of space is now part of our technology
infrastructure. If we can understand the
radiation belt environment and its variability, we can
apply this knowledge to improve our spacecraft
operation and system design, mission planning and astronaut
safety."
The probes will measure the particles, waves and
magnetic and electric fields that fill near-
Earth space to improve our understanding of how the sun's
changing energy flow affects them. These
observations will help researchers understand not only how
charged particles are energized at Earth
but also the processes that create particle radiation
throughout the universe in stars, interplanetary
space and distant nebulae.
These observations also will help researchers develop
various models for the radiation belts
that will be used by engineers to design radiation-hardened
spacecraft, and by forecasters to predict
space weather phenomena and alert astronauts and spacecraft
operators to potential hazards.
"We're now moving from figuring out what we're going
to build to how we're going to build it,"
said APL's Doug Eng, RBSP's system engineer. "Our biggest
technical challenge is to develop
observatories that can survive the severe radiation belt
environment for a two-year mission. RBSP
operates in a place most spacecraft missions want to
avoid."
The instruments will be provided by broad teams
managed by Boston University, the universities
of Iowa and Minnesota, New Jersey Institute of Technology
and the National Reconnaissance Office.
The RBSP mission is part of NASA's Living With a Star
Geospace program in the Heliophysics
Division of the Science Mission Directorate. The program
explores fundamental processes that
operate throughout the solar system; in particular, those
that generate hazardous space weather
effects near Earth and phenomena that could affect solar
system exploration. The Living With a Star
program is managed by NASA Goddard Space Flight Center.
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