Whalen built a prototype treadmill that pressurized the upper body by placing it in an airtight fabric bubble made from very thin sail cloth coated with urethane. The astronaut would be inside the inflated bubble from the waist up with the bubble tethered by straps to the treadmill while the air pressure inside the bubble pushed the body down onto the treadmill. "The upper body system also has complete freedom of motion at the waist given the lateral degrees of freedom afforded by the tethering straps, which makes this method a very good simulator of gravitational loading during gait," Whalen says.
Brought down to Earth
Once Whalen had created the downward pressure device, it was not a great leap to create a device that could do the opposite. "Lessening the load evolved from the original idea pretty quickly," Whalen says. "If you could push someone down, you could also push them up."
Whalen's gravity differential technology, which he patented in 1992, eventually was mothballed due to a lack of interest from NASA in the loading treadmill model. Whalen had begun working with the U.S. Department of Veterans Affairs (VA) to give rehabbing soldiers access to the unloading model, but "unresolved differences between NASA's and the VA's human subjects regulations" prevented him from continuing that work, he says.
The technology remained fallow until Sean Whalen, Robert's son, took a special interest in the prototype treadmill stored in the family garage. Sean, himself a Stanford engineering student, was in search of a project idea for his Department of Management Science and Engineering class on technology venture formation, and decided to take the idea of a treadmill capable of simulating a reduced gravity environment and run with it.
The project was a success, and Sean licensed his father's patent in 2005 so he could start a company that would help rehabilitate patients needing support as they learned (or re-learned) to stand, walk and run. This attracted the attention of legendary marathon runner Alberto Salazar, who e-mailed Sean that year to inquire about the treadmill. Salazar had recently been hired by Nike as part of its Oregon Project to train elite athletes, who of course were expected to win while wearing the company's attire. Nike ended up buying six unloading treadmills. "It was really just full speed ahead from there," AlterG's Barfod says. Nike has used his company's technology as part of the training regimen for a number of athletes, including two-time U.S. Olympic marathoner Dathan Ritzenhein, who placed eighth in last weekend's ING New York City Marathon.
Most of AlterG's research and development today involves improving the treadmill's software, according to Barfod. The company is also taking a close look at the neoprene shorts. Barfod says they work well at keeping people on the treadmill stable and creating an airtight seal, but he admits (and Sgt. Warren agrees) that the formfitting outfit could be easier to get into and out of, particularly for those suffering from leg and hip injuries.
The company is also considering a feature that would enable doctors and physical therapists to reach into the treadmill's lower chamber and manipulate a patient's legs without losing air pressure. A prototype of this feature, which Barfod expects to be available by early next year, has a neoprene sleeve that extends toward the patient's legs. When not in use, the sleeve would be sealed by an airtight cap. When a doctor needs to use the sleeve, however, he would remove the cap and extend an arm into the sleeve. The air pressure around the doctor's arm in the bag would form a seal around the sleeve so that no air escaped while the doctor worked. AlterG is also working on a lift system to help patients with more severe disabilities get on and off the treadmill.
Robert Whalen continues to work for Ames, most recently on projects that plan for the need to send medical devices with astronauts on long-term missions. Whalen believes that long-duration deep-space exploration is in humanity's future, even if it is two or three decades away. Such missions, he adds, would require that astronauts equip their ship with a medical clinic of sorts.
When Whalen thinks about the company his son co-founded with the help of technology he developed decades ago, "I just shake my head in amazement," he says. "I don't pinch myself—well, maybe I do. I told my kids just to have fun with whatever they do and learn from those experiences."
View a slide show of the Anti-Gravity Treadmill's development