MARS HAS A MAGNETIC FIELD. The field, measured by the Global Surveyor spacecraft newly arrived at Mars, is much weaker than Earth's, but might (at an earlier epoch) have afforded hypothetical life forms on Mars a small buffer against lethal incoming solar wind particles. The Global Surveyor will now put itself into a circular orbit by using Mars' tenuous atmosphere as a brake during successive passes. (Science News, 20 Sept. 1997.)