THE challenge of sending humans to Mars and beyond usually keeps the fine minds at NASA focused on the heavens.
Yet recently the US space agency lent its medical expertise for a more earthbound challenge: keeping the 33 trapped Chilean miners alive and well during their 10-week ordeal underground.
It turns out the conditions for the miners, trapped 700m underground, had a lot in common with those on the International Space Station about 350km above it.
"There are quite a lot of similarities between the miners and astronauts on the space station," says Michael Duncan, the inter-agency liaison specialist at NASA.
"In the mine it's isolated and you cannot communicate rapidly to the surface. It's an austere environment with certain dangers. In a space flight environment . . . the communication is better but it's nonetheless a remote, isolated, austere environment."
The main difference, Duncan says, is that the space station is climate controlled, so conditions are fairly comfortable, while the miners were routinely subject to temperatures above 30C and humidity above 90 per cent.
Duncan and colleague James Polk, NASA's chief of space medicine, were part of a team that visited Chile and the mine site from August 31 to September 4.
The Chilean government asked them to consult on the medical treatment for the miners. Polk says this included advice on what to feed the miners after several weeks of starvation, because NASA had previously run simulations on how to treat astronauts stranded on a space station with dwindling food supplies.
In fact, from blood analysis to robotic surgery, many of the discoveries made from studying the human body in space have applications for general medicine, and not just for people trapped in a mine. Moreover, as commercial operators such as Richard Branson's Virgin Galactic begin sending civilians into space routinely, the understanding of the effects of space flight on humans will undergo further shifts.
In April, US President Barack Obama committed NASA to sending humans to orbit Mars by the mid-2030s. The biggest hurdle to success is the health toll of being in space for long periods.
Some of the problems, such as decreased cardiac function and loss of muscle mass, can be offset by exercise, but others cannot.
The micro-gravity conditions cause loss of bone density of about 1 per cent a month and the resulting excretion of calcium means a higher risk of kidney stones. Astronauts also are exposed to higher levels of radiation, especially once they get above the Van Allen belt, a protective layer of plasma held in place by the planet's magnetic field.
To make the Mars dream a reality, extensive medical research needs to be done during the next 25 years, according to Texas-based Mark Campbell.
A general surgeon who worked for NASA and on Russia's Mir space-station program in the 1990s, Campbell chairs the Commercial Space Flight Working Group of the Aerospace Medical Association and is a former president of sub-group the Space Medicine Association.
He says some problems with long-term space flight have emerged only in the past few years while studying astronauts on the International Space Station.
"They've put this Mars thing off for a decade or so because of the world economy and that's probably a good thing because our knowledge of space medicine is actually very embryonic," Campbell says.
He claims the "big, hot topic in space medicine" right now is that in the past year they've discovered that missions into space cause retinal changes and deterioration in visual acuity.
Another recently observed problem is that returning astronauts have a risk of rupturing a disc in the neck or back that's four to five times greater than in the general population.
"We think it's because with weightlessness the discs expand and get real soft and then when they come back to gravity there's a lot of pressure on those discs and they rupture.
"We have a very high incidence of slipped discs in astronauts right after they come back from space and we only just published data on this last year," Campbell says, adding that the same problem has been observed on Earth with people who are put on bed rest for several months.
A huge amount of space medicine is about preventive testing and care. And NASA's Polk says this is the source of some of the biggest benefits for the general population. One example is research on blood analysis that doesn't require a blood sample from a needle.
"I'm sure you've seen a Pulsox where you put this device on your finger and it can tell you how much oxygen is in your blood. They use those on ambulances and in hospitals," he says.
"NASA researchers and folks that work with NASA are working to take that even further to identify different electrolytes and even glucose, without having to puncture someone, just by using different light spectrums across the skin.
"You can imagine what a [positive] cascade that would have for diabetic patients who have to stick themselves multiple times a day."
Equipment developed for space flight can also have practical uses here on terra firma. For instance, NASA has been working on closed-circuit ventilators that can extract oxygen from the air.
For NASA the advantage is that it eliminates the need to send costly and bulky oxygen tanks into space, but Polk says this could also help developing countries that are unable to afford oxygen tanks in their hospitals.
Even with all the preventive care in the world, sometimes things can go wrong in space, especially when looking at missions that may last a year or more.
With that in mind, Duncan says work continues on remote robotic surgery, some of it in partnership with the US National Oceanic and Atmospheric Administration in Florida.
"If or when we go on expeditions to other planets we'll need to have additional medical capability," he says. "There's been some testing in an analogue environment, such as an undersea environment, on how to do robotic surgery. There's been no experimenting on humans or animals but we've been doing the modelling for robotic surgery, especially with long time lags such as a 20-minute delay."
Some medical personnel, such as an anaesthetist, would still need to be physically present, but the surgeon would not.
Duncan says the Canadians are particularly interested in the terrestrial applications of robotic medicine, as it would let surgeons in big towns and cities operate remotely on patients in clinics in isolated parts of the country.
Astronauts with NASA and their counterparts across the world are selected rigorously. From thousands of applicants, about 15 are selected.
Shortlisted applicants are put through about a week's worth of medical tests and those who make the cut are given extensive medical monitoring throughout their five to seven years of training, not to mention pre-flight, in-flight and post-flight. Sometimes medical problems are detected and corrected, while other health problems may mean aspiring astronauts don't make the cut.
Commercial space flight will blur the lines between astronauts and civilians and could transform our understanding of the effects of space flight on the human body.
The Russians have already taken so-called space tourists on flights, which Duncan says has greatly informed the field of space medicine.
But the real shift will come when commercial operators make regular space tourism flights.
Virgin Galactic reportedly has several hundred people on a waiting list willing to pay $200,000 or more to fly into space.
Even sub-orbital or low-orbital flight has radically different effects on the human body compared with commercial airline travel.
Campbell says space tourists will go through a launch sequence with about 6Gs acceleration -- six times normal gravity -- for three or four minutes, followed by 15 minutes of weightlessness.
Re-entry is just as demanding and the whole experience stresses the cardiovascular and neuro-vestibular systems.
"It's a whole different program because you're trying to be inclusive, whereas NASA is exclusive," he says.
"These people are obviously very wealthy. They tend to be older people and they're going to have some chronic medical problems, like hypertension, maybe some mild emphysema. Some of them may have had coronary artery disease in the past, there are going to be diabetics. We're going to find things out that we didn't know about before and there's no question there's going to be some increased risk."
Clearly, there are many biological lessons yet to be learned, whether humanity sends astronauts to Mars or civilians to gawk at Earth from space. Is it worth the effort? Ask the Chilean miners.
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