Imagine being onboard that first human expedition to Mars. Representing all of humankind you take your historical one small step, one giant leap onto the surface...only to find your legs give way and you wind up flat on your backpack in front of a worldwide television audience.
On extended space treks crews are subjected to a number of physiologic effects due to exposure to microgravity. Since the earliest days of plotting out human space exploration goals, the detrimental impacts of weightlessness on the human body have long been a worry.
Now a new NASA/university collaboration will systematically study how artificial gravity could be a way to beef up the overall health of crews on future space exploration jaunts.
Once again, NASA is in a spin regarding the use of artificial gravity. This latest inquiry supports the space agency's Artificial Gravity Biomedical Research Project.
For the first time, researchers will systematically study how artificial gravity may serve as a countermeasure to prolonged simulated weightlessness.
The new work will soon start at the University of Texas Medical Branch (UTMB) at Galveston, overseen by NASA's Johnson Space Center (JSC) in Houston. At the core of the investigation is a short-radius centrifuge, utilized to evaluate the protection of normal human test subjects from deconditioning when confined to strict bed rest.
"People have been talking about artificial gravity at NASA since 1959," said Bill Paloski, NASA principal scientist in JSC's Human Adaptation and Countermeasures Office and principal investigator for the project. "At about every 10 years there's a big swell of interest...a big workshop...and they come back with exactly the same questions that they had 10 years before," he told SPACE.com.
One subject on each arm
This time around, a partnership has been set up between NASA, the National Institutes of Health (NIH), UTMB and Wyle Laboratories of El Segundo, California.
For the initial study this summer, Paloski said that 32 test subjects will be placed in a six-degree, head-down, bed-rest position for 21 days to simulate the effects of microgravity on the body.
Half that group will spin once a day on the centrifuge to determine how much protection it provides from the bed-rest deconditioning. The 'treatment' subjects will be positioned supine in the centrifuge and spun up to a force equal to 2.5 times Earth's gravity at their feet for an hour and then go back to bed.
The centrifuge was built to NASA specifications by Wyle Laboratories and is comprised of two arms with a radius of 10 feet (3 meters) each. The centrifuge can accommodate one subject on each arm.
"It took a fair amount of technical innovation to make it all come together," Paloski said. "That's really what our program is after...getting answers to the question of what are the bounds for human adaptation in a rotating environment," he explained.
Psychological and physiological screening
Paloski said that previous studies have focused on the cardiovascular system, or on the bone system, or in some cases the muscle systems, "but not looking at all the body systems at once."
In the near future, there will be a general call for bed rest subjects for the artificial gravity study effort.
For somebody who completes all aspects of the study, the pay is about $6,100, Paloski noted. "It's not going to get people to quit their day jobs to come and do this," he said, underscoring the fact that those wishing to take part must first pass rigorous psychological and physiological screening.
"We're looking for people who want to go to bed...and have a number of tests done on them," Paloski said.
Putting your feet up
The Wyle centrifuge was delivered to UTMB last year. It will complete design verification testing, validation of operational procedures and verification of science data this spring.
The research itself will take place in UTMB's NIH-sponsored General Clinical Research Center. It is a unique setting for this kind of work, not only for the UTMB, but rare across academic medical centers, said Adrian Perachio, executive director of strategic research collaborations at UTMB.
You wouldn't think that putting your feet up on the job would lead to humans strutting about on other worlds.
Perachio said that bed rest can closely mimic some of the harmful effects of weightlessness on the body that have shown up in space travelers: muscle atrophy, weakening of the heart, demineralization of the weight-bearing bones. It's also a very good analog for the conditions that crop up in patients that are hospitalized for long periods of time, he said, with the new work possibly yielding insight into osteoporosis too.
Given NASA's on-again/off-again attraction to artificial gravity, turning up the spin-dial on research this time is due to President George W. Bush's action-packed agenda to return humans to the Moon and make trips to Mars and beyond. That national impetus has put artificial gravity studies in high-gear.
"There are a lot of unknowns," Perachio told SPACE.com. Countermeasures have not been fully developed, and the health risks associated with long term human space travel are not negligible, he said.
"They can be mitigated to a certain extent. But that's relatively easy to say when you've got people that are in low Earth orbit...or in a lunar colony," Perachio noted. A lengthy roundtrip between Earth and Mars, on the other hand, remains a daunting biomedical challenge, he explained.
"I think now there's much more of a determination to come up with meaningful countermeasures," Perachio concluded.
Prolonged stays on the Moon by returning astronauts is viewed by Paloski "as an opportunity." Since it's only one-sixth of Earth's gravity, "we'll get some indication of what's going to happen to people on Mars," he said.
Testing of intermittent artificial gravity exercise devices within a lunar setting would also give NASA a leg up on the red planet, Paloski added. "We'd learn how to do it right...to protect people in that environment, so we have a safe and well-tested device for use on Mars."
Looks good in the movies
Early visions of space stations had them as large, rotating, wheel-shaped facilities to provide artificial gravity.
"Artificial gravity has for too long remained in the domain of science fiction. The large rotating torus is neither feasible nor necessary," said Larry Young, Apollo Program Professor of Astronautics and Professor of Health Sciences and Technology at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts.
Young has long been a research advocate for artificial gravity. He notes that a short radius centrifuge spinning at high rates -- upwards of 180 degrees per second - while practical, has its challenges too.
At MIT, under National Space Biomedical Research Institute sponsorship, Young and his research colleagues have shown that astronaut surrogates can adapt to the initially sickening Coriolis effects of head turns during centrifugation, even at high speeds.
"It now remains to see whether the periodic exposure to short radius centrifugation will be sufficient, with or without exercise, to overcome the debilitating effects of weightlessness," Young added. "By using bed rest as a model, the project put together by JSC with MIT at UTMB will be a beginning."
Young said that once experience is gained with intermittent centrifugation and its beneficial aspects, then investigators can work toward determining practical values of speed, duration and exercise for intermittent centrifugation. "Then it's on to space validation before a trip to Mars."