As NASA sets its sites on manned missions back to the moon and as far away as Mars, the space agency is participating a series of tests this week to determine if robotic technology is the key to providing adequate medical care for its astronauts during such extended spaceflights. On board a military C-9 aircraft flying in parabolic arcs over the Gulf of Mexico, four surgeons and four astronauts are performing simulated surgery by hand and using a robotic device developed by SRI International to determine if the robot's software can compensate for errors in movement that can occur during turbulence and under varying gravitational conditions.
The test flights last as long as three hours and soar up to 32,000 feet (9,755 meters) or dip as low as 24,000 feet (7,315 meters). The plane's nose is kept at a 45-degree angle during ascent and descent, simulating a microgravity environment by creating short periods of weightlessness alternating with stronger gravity during which time the surgeons practice making incisions and suturing them shut by hand as well as by using SRI's M7 robot on a special six-inch (38.7-centimeter) square of multilayer material designed to resemble human skin. They also attempt to cut through the "skin" to the fascia—a fibrous network of tissue between the skin and underlying muscle and bone—and then stitch up their incisions.
After the test flights wrap up on Friday, NASA, SRI and researchers at the University of Cincinnati will study the synthetic skin models and review video of the test runs.
The M7's robotic arms each weigh about 10 pounds (4.5 kilograms) and are about the same size as a human arm. The device is bolted to the aircraft's cabin, sits about 2.5 feet (0.76 meter) off the floor and is powered by the same system used to power the aircraft. It can be operated by a single physician, who views the procedure through a camera mounted between the arms and uses a remote control to manipulate them. "As the surgeon moves the controller, the robot follows," says Thomas Low, director of SRI's medical devices and robotics program. "If there's an accidental movement, the robot will compensate."
The M7 debuted in 1997 as a device for testing how robotic equipment could assist with the care of soldiers on a battlefield, Low says. This latest round of experiments includes software designed to allow the M7's robotic arms to compensate for sudden and severe changes in movement. "The robots are not just mimicking the surgeons' movements of their hands," Low says. "We have created an algorithm to adjust for accidental movements that the surgeon might make as a result of the change in their environment, such as a change in the movement of the plane."
The C-9 on Tuesday flew 60 parabolas in an effort to determine the impact of movement and gravity variations on the M7 and the surgeons. "This is essentially to get enough zero-gravity time for the experiment to be relevant," says Low, an amateur pilot who flew on the C-9 during the tests. "Our goal is to show that a robot can do procedures in a rough environment where a surgeon could not. The hypergravity is more difficult to deal with. If you move your head quickly, it's very easy to get nauseous."
