On Oct. 23, NASA's 2001 Mars Odyssey space probe entered a highly elliptical orbit around Mars as planned. The craft was to continue to perform a series of aerobraking maneuvers, skimming the atmosphere of the planet to slow itself and so circularize the orbit.The investigators plan to begin Odyssey's mapping mission in February. They have tested Odyssey's high-energy neutron detector, neutron spectrometer and thermal emission imaging system.The Jet Propulsion Laboratory of Pasadena, Calif., manages the Odyssey mission and will control the spacecraft's operations with Lockheed Martin Astronautics of Denver. Researchers at Arizona State University in Tempe, the University of Arizona in Tucson and NASA's Johnson Space Center in Houston will operate the probe's instrument package.