Roberts soon wrote back, offering to help, and he became my unofficial career counselor. But then the Mars-bound intern captured headlines for a different reason: In the summer of 2002, he stole more than $20 million worth of moon rock and Martian meteorite samples from under NASA’s nose. He was caught in an FBI sting in Florida and spent six years in prison.

The heist sabotaged not only Roberts’s own goals of space travel but also those of his accomplices: fellow NASA interns Tiffany Fowler, then 22, and Shae Saur, then 19. “Being an astronaut is something I had planned to do and aspired to do my entire life,” Saur told the Houston Chronicle before she was sentenced. “My own actions have shattered that dream.” The two Texan women were given three years’ probation and required to repay NASA $9,000 in damages.

In the years since, Roberts has received a great deal of media attention, including a TEDx talk based on a book he wrote in prison and the writer Ben Mezrich’s version of the tale, Sex on the Moon: The Amazing Story Behind the Most Audacious Heist in History. Million Dollar Moon Rock Heist, a documentary by Icon Films, aired on the National Geographic channel in 2012. In contrast, Fowler and Saur have faded from public sight.

Why the two women joined him remains unclear; neither could be reached for comment. But accounts over the years suggest that Roberts was talented in recruiting others to accompany him in sometimes risky exploits. One of the FBI officers interviewed in the Icon Films documentary said of the court ruling, “I think the judge was very sympathetic. She realized that Thad manipulated them and that this was out of character for them.”

Recently, I interviewed Roberts to ask him myself why he stole moon rocks from NASA. His story still haunts me because I was part of its prequel: Before he apparently charmed Fowler and Saur, he charmed me.

Thad’s first email came a few days after my Science Day visit to the University of Utah, in 2000. “I heard from Oliver that you have some questions about becoming an astronaut. Feel free to ask me anything you like,” he wrote. Even digitally, Thad exuded confidence, from his “astronaut_thad” Yahoo handle to the three inspirational quotes on his automatic signature. One was unabashedly his own: “Passion is the essence of the human soul, to be truly alive is to kindle that fire within and explore your passions. —Thad Roberts.”

In the flurry of emails that followed that winter, Thad asked whether I wanted to visit the moon or Mars as casually as asking whether I wanted a hamburger or a hot dog. Because he was still an intern, alternating semesters between NASA and the University of Utah, he encouraged me to join him in learning skills he felt would give us an edge in applying for full-time positions at NASA. Learn Russian and Japanese, he said. Start attending astronomy nights. Get your pilot’s license.