ASTRONOMY BY SATELLITE Dreams of Other Worlds: The Amazing Story of Unmanned Space Exploration. By Chris Impey and Holly Henry (Princeton University Press, Princeton, 2013). Pp. 450. $35. ISBN 978-0-691-14753-6.Should scientists write history? Most of the time, I don't think so. This is one of those times. Chris Impey is a very fine astronomer who has been involved in many space science investigations over the years. His co-author, Holly Henry, is a professor of English and therefore knows how to tum a phrase. Neither is an historian, nor should they pretend to be. Overall, the narrative presented here is a mission-by-mission summary of individual efforts, all but one of them from NASA, and a summation of what was learned from the effort. That is fine as far as it goes. But, the reality is that there is little context offered for why those missions were undertaken, the questions that they pursued, the breadth of effort necessary to execute them, and the place of those missions in larger stories of solar system science and knowledge production.As only one example, after a breathless introductory chapter that ranges from the ancients to the space age, the authors pursue two chapters on Mars missions, one on the Viking missions of the 1970s and another on the Mars Exploration Rovers (Spirit and Opportunity) that landed in 2004. The authors exploit the longstanding fascination humans have harboured for Mars, invoking gentleman astronomer Percival Lowell and the he claimed to see. Lowell argued that Mars had once been a watery planet and that the topographical features known as canals had been built by intelligent beings, created as a planetary-wide effort to bring precious water from the poles to inhabited parts of Mars nearer the equator. This concept dominated studies of the Red Planet until the space age although many scientists remain convinced that Mars was once a watery planet and NASA's official strategy, Follow the water, has guided its efforts since the 1990s.Where this book fails is concerning the cul-de-sacs and contours of the history of science and technology. Using the Mars example, Impey and Hunter fail to appreciate the nuances of this effort. Discussions of personalities, planning, politics, budgets, decisionmaking, setbacks, and coups are conspicuous by their absence.One example of this problem will suffice. In 1967 the Mars scientific community pursued a planetary lander. In response, NASA's Office of Space Science formulated a $2 billion program (in 1960s dollars) to search for life on Mars. …