One afternoon two summers ago, Kathleen Rubins, a principal investigator at the Whitehead Institute for Biomedical Research, gathered her lab members for a quick meeting. The Rubins lab  usually met at 9 a.m., so this was unusual. "Have we done something wrong?" Judy Yen, the lab manager, recalls thinking. Then it struck her: A while ago, her boss had mentioned that she was applying to astronaut training. Rubins had downplayed her chances of getting in, so no one gave it another thought. Yen's intuition -- that Rubins must have heard from the folks at NASA -- was correct: Rubins had been selected to be part of the class of 2009. She was an "ASCAN ."
The decision to shut shop wasn't easy. "When I was in grad school, I wanted to be in academia forever," she says. In 2007, she became a Whitehead Fellow . The 5-year fellowship gave her the resources to run her own lab immediately after her Ph.D., priming her for a top faculty position. Her research centered on poxviruses: she studied their workings at the molecular level and was collaborating with the U.S. Army to develop clinical therapies for the infectious disease Ebola. There were more than 15 people in her team, including three postdocs. "How was I going to walk away from all this?" she remembers thinking.
But the desire to be an astronaut went back even further. It was a childhood dream.
Rubins had just 2 months to shut down her lab. Pardis Sabeti, a geneticist at Harvard University who took in four of Rubins' lab members, says that being an astronaut means being an elite athlete. Mentally, physically, and emotionally, an astronaut must be "a bit of a superhero," Sabeti says. "Kate embodies all of that."
Some of Rubins' research colleagues -- those directly affected by the transition -- were stunned by her decision to join NASA. Even to casual observers, the timing seemed less than propitious. The shuttle era was coming to a quiet close, with no replacement vehicle on the horizon. Why become an astronaut now?
They may not have a homegrown carrier, but astronaut-scientists still have a place to go: the International Space Station  (ISS), which will remain in operation until at least 2020. "The shuttle could carry seven astronauts and provided opportunities for short-term visits. That will no longer be available," says John Logsdon of the Space Policy Institute at George Washington University in Washington, D.C. But, he points out, the United States controls three of the ISS's six spots, and the crew changes every 4 to 6 months. Until alternative transportation becomes available, astronauts (and cosmonauts) will travel to the station aboard the Soyuz. Fluency in Russian is a requirement for graduating from astronaut candidate school.
Rubins' classmates at NASA have dubbed her BOLA, which is short for Ebola. It's her call sign. Following an outbreak of monkeypox, a simian disease and close cousin of smallpox that was spreading in human populations in the Democratic Republic of Congo, Rubins' Stanford University team went to a bare-bones hospital at the edge of the rainforest to collect DNA samples from quarantined patients.
As a graduate student at Stanford, she wore a biosafety level 4 suit -- often called a "space suit" -- while working to understand how the smallpox-causing virus routs immunological defenses in host cells. "She spent long hours in isolation, and in demanding conditions, relishing the challenge," David Relman, her Ph.D. adviser, says.
"But the real space suit is a different beast altogether," Rubins says. The pressurized suits worn by space-farers weigh approximately 136 kilograms in Earth's gravity and can make the wearer feel like a basketball.
Astronaut candidates also learn to fly T-38 supersonic jets. In a high-pressure environment, they learn to communicate as a crew and to react quickly in critical situations. "You have to be able to think at the speed of light," Rubins says. "Out there, you could kill yourself in the blink of an eye."
For Rubins, the ultimate prize is the chance to work in the ISS, that world-class scientific facility. More than 1000 investigations were performed while the ISS was being assembled, but this represents only 20% of the research proposed for the coming years, Rubins says. The ISS offers scientist-astronauts like Rubin the opportunity to be full-fledged scientists operating labs in space for several months at a stretch.
Presently, prospects look good for scientists to hitch a ride to the ISS. Until 2009, the ISS usually hosted only two or three crewmembers, and much of the crew time was dedicated to assembly, says Tara Ruttley, associate program scientist for the ISS. Today, the optimal crew size is six. With the ISS construction approaching completion, more crew time can be devoted to research.
To realize the full potential of the orbiting research platform, scientist-astronauts will be sought after, says Peggy Whitson, chief of the Astronaut Office at NASA. Scientists on the ISS must perform a host of duties to maintain the full functionality of the station, but research will be their primary focus.
"I can't imagine a more exciting opportunity than to work with hundreds of principal investigators and their top-notch research teams around the world, in this exceptional and incredibly special laboratory," Rubins says. "This is such a unique environment to make new scientific discoveries."
Vijaysree Venkatraman is a Boston-based science journalist.