Two NASA Probes Tackle New Mission: Studying The Moon
WASHINGTON -- Two small NASA probes that had been used to study spaceweather now are orbiting the moon to study its interior and surface composition.
The spacecraft, called Acceleration, Reconnection, Turbulence and
Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS),
began their journey away from Earth's orbit in July 2009. The first
spacecraft entered lunar orbit on June 27, and the second on July 17.
Engineers used complex orbit maneuvers to relocate the spacecraft to
their new locations. The journey required many gravity assists from
the moon and Earth and used minimal amounts of fuel.
The probes will now approach the moon's surface to within sixty miles
once per orbit. The data will provide scientists with new information
about the moon's internal structure for the next seven to 10 years.
"This is a good example of how additional science can be achieved with
the innovative use of existing spacecraft," said Dick Fisher,
director of Heliophysics for NASA's Science Mission Directorate in
Washington. "The quality of the original design and construction of
the spacecraft creates a double win: a new research opportunity for
the space science community with no additional cost to the nation's taxpayers."
Both spacecraft were previously in areas called the Lagrangian points,
areas on either side of the moon, where the moon and Earth's gravity
balance perfectly. These locations were ideal spots to study Earth's
distant magnetic field and how the solar wind, made up of ionized gas
known as plasma, flows past the moon and tries to fill in the vacuum
on the other side.
The ARTEMIS mission was made possible by repurposing two spacecraft
that would otherwise have ceased operations in 2010. The spacecraft
were part of NASA's Time History of Events and Macroscale
Interactions during Substorms (THEMIS) mission launched in 2007.
"From their new orbits about the moon, ARTEMIS will collect important
data about the moon's core, its surface composition, and whether it
contains pockets of magnetism," said Dave Sibeck, ARTEMIS and THEMIS
project scientist at NASA's Goddard Space Flight Center in Greenbelt,
Md. "ARTEMIS also will provide information needed to understand the
moon's magnetic environment in space and its relationship to events near Earth."
The THEMIS mission consisted of five identical spacecraft that studied
the magnetic environment around Earth, the aurora, and how these are
affected by the sun. The other three THEMIS probes continue their
original science mission. Substorms are atmospheric events visible
near the poles as sudden increases in the brightness of the aurora.
The findings from the mission may help protect commercial satellites
and humans in space from the adverse effects of particle radiation.
The ARTEMIS mission is a joint effort among Goddard, NASA's Jet
Propulsion Laboratory in Pasadena, Calif., the Space Sciences
Laboratory at the University of California, Berkeley, and UCLA.
Goddard manages the program for NASA's Science Mission Directorate.
THEMIS was the fifth medium-class mission under NASA's Explorer
Program. The program, managed by the Explorers Program Office at
Goddard, provides frequent flight opportunities for world-class space
investigations in heliophysics and astrophysics. Berkeley's Space
Sciences Laboratory managed the project development and operated the
THEMIS mission. ATK Space (formerly Swales Aerospace) of Beltsville,
Md., built the THEMIS satellites.
For more information about the ARTEMIS mission, visit:
http://www.nasa.gov/mission_
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