SOJOURNER: An Insider's View of the Mars Pathfinder Mission

Millions of viewers watched in fascination in July 1997 as the Mars "rover" Sojourner (named after Sojourner Truth) maneuvered around the Red Planet's surface like an interplanetary dune buggy, sending back pictures of rocks and boulders that were given whimsical names by mission scientists (e.g., Yogi, Scooby-Doo). Mishkin, senior systems engineer at NASA's Jet Propulsion Laboratory, where the rover was developed, chronicles the years of trial and error to create a vehicle that would be the right size for the Pathfinder lander and could withstand the temperature extremes on the Martian surface while maneuvering around rocks without getting stuck or driving over the edge of an abyss. It takes 40 minutes for a signal to travel from Mars to Earth and back, so JPL scientists had to make the rover's navigational systems as self-sufficient as possible. The author details how software and hardware teams often clashed over the best ways to solve the problems they encountered during development. Mishkin himself discovered a potentially fatal error shortly before launch: a wrong parameter in the computer clock would have woken Sojourner in the middle of the night instead of in the morning, but the robot needed sunlight to function. Mishkin's detailed history undoubtedly will interest engineers and dedicated science techies, but readers looking for an account of Sojourner's accomplishments on Mars will be disappointed—the rover's 80 days of exploration are given one quick chapter. Nevertheless, Mishkin has written a valuable chronicle of one of NASA's only mission in the past decade to have captured the public's imagination. Photos not seen by PW. Agent, Agnes Birnbaum. (Dec. 2)