The Magnetometer - Electron Reflectometer (MAG/ER) instrument on Mars Global Surveyor was built and run from NASA Goddard Space Flight Center. The image shown here was published as Figure 1 of the article: Connerney, J.E.P., M.H. Acu�a, P.J. Wasilewski, G. Kletetschka, N.F. Ness, H. R�me, R.P. Lin, and D.L. Mitchell (2001) The Global Magnetic Field of Mars and Implications for Crustal Evolution. Geophysical Research Letters, 28, 4015-4018. The image is public domain.