There is something unsettling about an astronaut in his underpants. Here is the American hero, the icon. He inhabits the rarefied realm of popes and kings. You expect to see him in parades and CNN feed. You do not expect to see him in his Thermal Comfort Undergarment.
The ungarbed astronaut is Chris Hadfield, a 38-year-old former engineer and fighter pilot from Canada. He is standing around in his underwear because he needs help getting dressed. You would, too, were you about to don a 250-pound space suit. The suit will be worn for an underwater training session in NASA's neutral buoyancy tank, part of the Sonny Carter Training Facility at Johnson Space Center in Houston. (It contains 6.2 million gallons, so "tank" is something of an understatement. The public affairs office waxes biblical: "It took three days and three nights to fill.")
The tank, formally known as the Neutral Buoyancy Laboratory, or NBL, is NASA's gravitational approximation of outer space. Floating around fully suited in a pool is one of the ways astronauts train for floating around fully suited in space, which they will be doing in unprecedented amounts during the upcoming construction of the International Space Station (ISS). The station is too big to launch fully assembled and in one piece. Instead over 100 pieces will be launched and put together in space, one at a time, like an extremely complicated Erector set. ISS astronauts will spend an estimated 1,100 hours in open space assembling the craft. (NASA's term for a space walk is Extravehicular Activity, or EVA.) That is more than twice the total EVA hours of all U.S. space mISSions to date.
The tank must be huge so that mock-ups of ISS piecesoupon which astronauts rehearse their outer space construction tasksocan be completely submerged. Before the first NBL was built, in the 1970s (the current tank dates to 1996), EVA rehearsals were done in the ocean, in a lagoon in the Bahamas, a situation wistfully recalled by NASA personnel. This morning's session takes place on a full-size model of a section of the space station's truss, a 350-foot cat's cradle of crISScrossing I beams that will serve as the station's main support structure.
Hadfield's primary task in space will be to unfold and install the ISS's 60-foot-long robotic armoa remote-control helper designed to inch its way around the station exterior, moving bulky items and carrying out simple hookups. Anything complex or detailed will still have to be done by spacewalking astronauts. As Hadfield puts it, "It's like here on Earth. There are some things you can do with a backhoe and some things you need a wrench for."
