NASA’s THEMIS Satellites Given New Moon Mission


Two of the five small THEMIS satellites NASA launched in 2007 to study the Earth’s magnetosphere began a new mission the week of Oct. 25 studying how solar wind electrifies, alters and erodes the Moon’s surface.

The repurposed satellites, originally built by ATK Space Systems of Beltsville, Md., for the Time History of Events and Macroscale Interactions during Substorms, or THEMIS, mission, were carefully repositioned by NASA over the past year to provide a two-point view of the Moon’s space environment.

One of the satellites reached the L2 Lagrange point on the far side of the Moon Aug. 25. The other satellite entered the L1 Lagrange point on the Earth side of the Moon Oct. 22. After spending six months at the Lagrange points, the spacecraft will maneuver within 100 kilometers of the Moon’s surface.

“From point-blank range, the spacecraft will look to see how the solar wind impacts a rocky world when there’s no magnetic field to protect it,” NASA said in an Oct. 27 press release announcing the new mission called ARTEMIS, or Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun.

The mission is a joint effort among NASA’s Goddard Space Flight Center, Greenbelt, Md., NASA’s Jet Propulsion Laboratory, Pasadena, Calif., the Space Sciences Laboratory at the University of California at Berkley and the University of California at Los Angeles.