John Grunsfeld, NASA's new chief scientist, isn't merely passionate about space science: “I've been willing to risk my life to do science,” he says. From others, that statement might sound boastful or delusional. But it is true enough in Grunsfeld's case — he has travelled on the space shuttle four times, including a 16-day research flight in 1995 and two trips to upgrade the Hubble Space Telescope.

Grunsfeld took over this month as NASA's fourth chief scientist since former administrator Dan Goldin created the position ten years ago. Since then the job has carried little political clout and no budgetary authority. But these are turbulent times at the space agency, with major decisions about its future goals looming large on the horizon. Grunsfeld — an astronomer who succeeds two biologists in the position — might just be the man of the moment, observers of the space agency say.

Space man: John Grunsfeld's own missions have convinced him that human spaceflight is vital. Credit: NASA

He brings to the job a solid research background. A 44-year-old native of Chicago, he obtained a doctorate in physics from the University of Chicago and did postdoctorate work there and at the California Institute of Technology (Caltech) in Pasadena, before beginning his astronaut training in 1992.

A specialist in γ-ray and X-ray astronomy, he has worked at the Very Large Array in Socorro, New Mexico, as well as on spaceborne instruments such as the Hubble and the Compton Gamma Ray Observatory. He has published his work in places such as the Astrophysical Journal — no mean feat considering the time demands of shuttle training.

Anneila Sargent, an astronomer at Caltech, says that researchers should find Grunsfeld easy to talk to. “I see John as approachable,” she says, adding that he talks scientists' language. As chief scientist, he will be responsible for advising NASA administrator Sean O'Keefe on the agency's entire research portfolio — not just astronomy but also Earth science, as well as the biological and materials-science experiments planned for the International Space Station.

Grunsfeld says that he is well aware of scientists' scepticism about the space station (see Nature 418, 263; 200210.1038/418263a), but thinks that it is unfair to judge its usefulness while it is still under construction. He says that critics of the station may have the wrong idea about it because of their own backgrounds: laboratory scientists, he points out, are used to working in fully controlled environments. “Field scientists have a more accurate idea of how much scientific return we can get,” he says, as they are used to unpredictability and to handling logistical challenges. Doing science in space, he contends, is more akin to “an athletic event”.

His two successful Hubble missions are his proudest achievements as an astronaut, Grunsfield says, adding that the telescope-servicing operations were a 'poster child' for cooperation between NASA's astronaut programme and its scientific projects. Furthering such endeavours, he says, will be “absolutely top of my list” of priorities as chief scientist. In the past year he has been involved in planning for future space telescopes that could be serviced by a combination of humans and robots — just the sort of human-spaceflight objective that NASA badly needs in the wake of the Columbia accident.

Such projects will need large infusions of money, as well as advocates like Grunsfeld, if they are to come to fruition. If NASA pursues an ambitious programme of human exploration, says Joe Alexander, director of the National Academy of Sciences' Space Studies Board, Grunsfeld's talents as an astronaut and astronomer could prove to be a useful combination.