ON A SWELTERING SUMMER AFTERNOON, Dave Akin, an associate professor of aerospace engineering at the University of Maryland, heaves open a thick steel door and directs me to a stairwell inside a red brick monolith called the Neutral Buoyancy Research Facility, part of the school’s Space Systems Laboratory in College Park. The building houses a 367,000-gallon cylindrical fiberglass tank of sparkling blue water used to conduct experiments under weightless conditions, or as close as we can get to weightlessness here on terra firma.
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Akin is clad in sandals, cargo shorts, and a souvenir T-shirt from NASA’s nearby Goddard Space Flight Center that’s stained with barbecue sauce from a school picnic he attended at lunch. Plump, bald, and bespectacled, he greets me with a husky handshake and a warm smile, then bounces up five flights of stairs to the top-floor control room, where a team of grad students is about to lower the Ranger space robot into the water.
Autographed astronaut posters adorn the walls of the room; junk food is strewn across a long conference table. Near the door is a dinged-up computer that’s missing its front panel. This is Ranger’s main processor. A thick gray cable snakes from the box through a hole in the wall and into the water tank, where it’s plugged into a data port on Ranger. “That’s his brains,” says research engineer Stephen Roderick when he catches me tapping on the box with my pen.
Minutes later Akin is outfitted in scuba gear and hovering 25 feet down near the bottom of the tank as Ranger slowly swings its arms to and fro, pivots at the waist, rotates its wrists, and, like an irate lobster, clenches and opens its steel pincers.
Akin began building underwater robots like Ranger in the 1980s as part of a NASA-funded effort to learn how robots could help astronauts do their work in orbit, including servicing the Hubble Space Telescope.
So far, Ranger has struggled with its mission du jour: inserting a model of the Hubble’s Wide Field Camera into a drawer-like slot that matches the one on the actual telescope. Akin is busy snapping pictures with a digital camera and hardly notices when his 2,000-pound robot suddenly jerks backward after one of its joints gets jammed.
Roderick, who everyone calls “Kiwi” because he’s from New Zealand, operates Ranger via joystick and keyboard commands while watching its movements over TV monitors linked to five underwater video cameras. At least twice during the three-hour experiment, Ranger contorts itself into yoga-like positions that confound Roderick. Bubbles trickle from its housing, indicating leaks. And during the transition between certain movements, Ranger twitches unpredictably. But when Akin surfaces, he’s beaming. “That went really well,” he says, “considering that was the first time Ranger tried those moves.”
This all happened last summer, at a time when official government interest in space robotics had reached a historic high. Six months earlier, NASA Administrator Sean O’Keefe announced he was canceling a long-planned shuttle mission to replace Hubble’s aging batteries and gyroscopes and install an advanced camera and spectrograph. Worried about astronaut safety following the Columbia tragedy, O’Keefe wasn’t willing to risk lives to upgrade the telescope for the fifth time, no matter how much astronomers or the general public wanted it.
So the call went out to industry: NASA wanted to know if a robotic spacecraft could be built to carry out the servicing mission sans humans before 2008, the year in which the telescope’s batteries and gyroscopes are expected to fail. Akin, whose Ranger had been practicing some of those very tasks for years, answered NASA’s call. So did robotics experts from labs elsewhere in the United States, in Canada, and around the world.
MDRobotics in Brampton, Ontario, submitted one of the most promising proposals. The company had finished construction of Dextre (the nickname for “special-purpose dexterous manipulator”), a remotely operated two-armed robot already ordered to help astronauts service and maintain the International Space Station (ISS). NASA project managers knew that to launch a repair robot by the 2008 deadline, there was no time for research and development. So the agency asked MDRobotics to begin production of a second Dextre that could be launched on an unmanned rocket, then deployed in orbit to complete the tasks originally intended for the shuttle astronauts. Dextre would replace the Hubble’s batteries and gyroscopes, install the spectrograph and camera, and attach a rocket-equipped module that could deorbit Hubble and safely steer it into the ocean at the end of its life.