When Sally Ride died on July 23, 2012, her obituary surprised space fans in more ways than one. No one outside her immediate circle had known she was ill with pancreatic cancer, and as she was only 61, her death came as a shock. But admirers were just as surprised by the sentence in her obituary acknowledging her female partner of 27 years, Tam O’Shaughnessy. As it turns out, even some of Sally Ride’s closest friends hadn’t known about her relationship either, and Lynn Sherr ’63 was among those left in the dark. Sherr first met Sally Ride when she was covering the space program for ABC News; when a new group of astronaut candidates was chosen in 1978 (the first group to include nonpilots, nonwhites, and women), Sally Ride was among them. The two women hit it off, both as interviewer/interviewee and as friends. They remained close, even after Sherr was no longer reporting on spaceflight and after Ride had left NASA. So it was bewildering to Sherr to learn that she had been left out of such a significant part of Ride’s story as her life partnership.

As a result, the questions that drive Sherr’s new biography, Sally Ride: America’s First Woman in Space, are real questions, much to the benefit of the book. With the full support of O’Shaughnessy and the Ride family, Sherr sought out the insights of Ride’s childhood friends and teachers, NASA coworkers and crewmates, friends and former lovers. The picture that emerges is complex and nuanced. Fellow astronauts remember her unfailing competence and intelligence. Her younger sister remembers her competitiveness and determination. Several friends remember being frozen out after overstepping unspoken boundaries. Her first girlfriend remembers Ride’s warmth and her lack of anxiety over finding herself in a same-sex relationship. Her former husband, fellow astronaut Steve Hawley, remembers her resentment at having to play the dutiful spouse during his own launches into space.

Most astronaut biographies are part hagiography, part advertisement for NASA, and understandably so. Those who have risked their lives in order to reach into the unknown are among the few people we can still comfortably acknowledge as heroes. When an astronaut does break the code and give writers fodder for sensationalism, the incidents draw flurries of coverage but few thoughtful responses.

But astronauts have private lives as well as public accomplishments, and 31 years after her historic first flight, we may be ready to examine the complexities of Sally Ride’s personality and legacy. The tidbits we look for in traditional biographies are present here—Ride’s experiences in orbit, her service on the investigation boards after the losses of Challenger and Columbia, her run-in with Billie Jean King as a teenager on the junior tennis circuit, her reaction to first hearing her name in a Billy Joel song on her car radio. What lingers is an image of a brilliant scientist who never lost the joy of discovery, an educator who dedicated her life to sharing that joy with others, and an introvert who might have been crippled by her fame but instead harnessed it to help further her dearest values. The book never becomes a tell-all, though, or devolves into celebrity gossip-mongering, and for those of us who want to be able to keep respecting our heroes even while learning more about them, that is a great gift.

Sherr’s biography makes an implicit case for complexity in biography: Not all questions are answered, not all details accounted for. There are contradictions and loose ends, incidents unexplained and details that don’t quite fit. The result is a full and moving picture of a person’s whole life—public, private, and secret—and that is precisely what puts this book on the short list of the finest astronaut biographies written.