UW scientists try to solve health hazards of space
The one thing you could always say about Capt. James T. Kirk is that as soon as he arrived on a planet, he was ready to romance the nearest attractive alien.
There’s a reason they call it science fiction.
The fact is, if he traveled under the conditions as we understand them today, Star Trek’s Capt. Kirk would have trouble even getting a date. Imagine being on the welcoming committee when this guy arrives on your planet and immediately starts vomiting—as he falls over in front of you.
Even if Kirk gets a date, there wouldn’t be much he could do. Heaven forbid they go dancing. Kirk would flop all over the dance floor, unable to keep his feet steady. The merest twist and turn could shatter his hip bone, left fragile by bone demineralization.
And any long-term relationship would have to take into account the fact that Kirk would likely be sterile and a terminal cancer patient—following months of bombardment from deadly radiation in space.
It’s estimated that astronauts on a mission to Mars would lose a fifth or more of their bone mass.
What’s Kirk’s problem? Each one of us has grown up with gravity shaping our form. Our body, for example, has grown a framework of muscles and bones to hold us up under constant downward force of gravity. If you remove this force during space travel, the body logically concludes that it should no longer spend nourishment on unneeded muscle and bone. It’s estimated that astronauts on a mission to Mars would lose a fifth or more of their bone mass. So that’s why Kirk would likely break some bones following a long trip.
Similarly, without any gravity, your muscles rightfully conclude they can ramp down. Astronauts return from long trips in space with muscles so atrophied that they cannot stand. Zero gravity also challenges one’s sense of balance: nausea is a common problem.
People around the world dream of seeing someone step onto Mars in 15 to 20 years. Before anyone can do so—and live to tell about it—a lot of work needs to be done. That’s the reason that NASA and other federal officials created the National Space Biomedical Research Institute, based at the Baylor College of Medicine in Houston. The University of Washington recently became one of the consortium’s 12 members. Its goal is to prevent or cure the diseases of space, making discoveries that will benefit those of us left on Earth.
Scientists and astronauts say they have no doubt that we can figure out a way to travel in space. It was only decades ago that experts said the body would disintegrate in zero gravity, or if pushed to the speed of sound.
“By and large, all the effects of space travel so far seem to be reversible. But we need to know a lot more before we send anyone to Mars. ”
Dr. Martin Kushmerick, UW professor
“By and large, all the effects of space travel so far seem to be reversible. But we need to know a lot more before we send anyone to Mars. We don’t want someone to arrive on Mars and then collapse. We want them to come back, and we want them to come back alive,” says Dr. Martin Kushmerick, a UW professor of radiology, bioengineering, physiology and biophysics, and head of the UW space medicine team.
Consider what happened to astronaut David Wolf, who spent four months on the Russian space station Mir in 1998. Back on Earth, Wolf quickly realized that if he tried to turn a corner, his ankle would simply roll under him, recalls Michael Anderson, ’81, one of the astronauts who brought Wolf home. The muscles that link something as basic as our foot and leg had atrophied. Wolf spent many weeks in rehabilitation, such as a swimming pool that helped support his newly regained weight. He later told TV viewers, “It feels like a house has been dropped on you at first.”
Yvonne Cagle
“The muscles and nerves have to relearn the language of gravity,” explains Yvonne Darlene Cagle, ‘85, an astronaut who got her M.D. from the UW School of Medicine.
With a mission to Mars, we will expect astronauts to travel perhaps six months in zero gravity, and then land on a planet with about one-third of Earth’s gravity. True, a 200-pound person would weigh only 74 pounds on Mars. But that is enough to strain someone who’s been living in no gravity and then has to put on a heavy spacesuit and perform strenuous explorations. This person would then have many months of zero gravity in a spaceship before returning to the gravity of Earth.
“The challenge is that on Mars, you won’t be landing someplace where organized medical staff can put you through a sophisticated rehabilitation program,” says astronaut Bonnie Dunbar, ’71, ’75, one of seven UW alumni who have flown in space.
Kushmerick says what goes for people on Earth goes for astronauts as well: your odds of staying healthy are better if you exercise. Healthy muscles make for a healthy person. Anderson took 45-minute stationary bicycle rides on his trip into space, pedaling to the sounds of Acoustic Alchemy, Earl Klugh and gospel music. The Russians developed something called the “penguin suit” that has proven partially effective. It’s an all-body suit that is filled with powerful bungee cords. If the astronaut does not resist, he or she snaps into a fetal position. You have to exert force to assume a normal posture and wear it during your daily routine—just as you exert force every day under gravity. However, the suit is not a big hit with astronauts and only seems to partially solve the degeneration problem, Kushmerick says.
One intriguing idea is to have at least partial gravity on the flight to Mars—scientists are looking for ways to accomplish that as well.
“Arthur C. Clarke may have had the right idea all along,” Kushmerick says, referring to the science fiction author who’s written of ships with artificial gravity. But science fiction does not need to count the practical costs of such a design, which at present would be enormous.
Overall, there are four big issues facing long-term space flight, says the space medicine institute’s associate director, Ronald White. Those are radiation, psychological issues, musculoskeletal degeneration and what to do in case of illness or injury.
Artist’s rendering of the completed International Space Station in 2006. Image courtesy of NASA.
Some other conditions are a little less understood; we know astronauts return from long trips with depressed immune systems, but we do not know why.
We do know that space travelers don’t have Earth’s geomagnetic field to protect them from galactic cosmic rays and solar radiation. One might think the answer is to put up a shield, like the lead used when we get an X-ray. But in space, this cure is actually worse than the problem. Heavy ion particles would hit the shield and generate secondary particles that would fill the spacecraft and penetrate through the crew’s suits and bodies.
The solution might include a special sort of shield or treatment. This could have a big benefit on Earth as well. Currently, radiation therapy for cancer kills not only the tumors but also healthy tissue. It would be wonderful for cancer patients if science could find a way to protect the healthy tissue with these types of shields.
The psychological issues are a little trickier to put your finger on. A mission to Mars might involve two years of isolation. That’s an awfully long time to be cooped up with a few other people in a small room, with no place to go for a ‘time out’ or escape. So scientists are studying how they can screen and evaluate candidates for the mission to minimize any problems in advance.
“It’s really the same in space as it is on Earth: prevention is the key.”
Yvonne Cagle, '85, astronaut
This is typical of the approach to space medicine, which emphasizes trying to solve problems before they start. “It’s really the same in space as it is on Earth: prevention is the key,” physician/astronaut Cagle says.
UW’s research is at the heart of the ultimate in prevention. The institute wants scientists to come up with a “digital human,” with the goal of modeling how the body will respond to space flight. Kushmerick is team leader of nine studies, some at UW and some at other institutions, with the title of Integrated Human Function.
While some research areas look at one body system, the integrated human function program takes a more holistic approach. Its goal is nothing less than understanding how the body works, from molecules to entire body systems. Having a digital human would allow researchers to predict potential problems, simulate health conditions and allow researchers to predict problems.
“In space, they won’t be able to say, ‘Oh, I’ve got an emergency so let’s turn back.’ We need to know how the body works so that one can anticipate the effect of something without actually doing it,” Kushmerick says.
The team is beginning its modeling in studies of cardiac and skeletal muscle. Scientists know that the protein myosin is the main molecular motor of muscle. And scientists know a lot about muscle mechanics and blood flow. What’s missing is a solid model of the connections in between.
“We will build a model, from molecules to the larger structure, of the muscle. We want to know what microscopic properties of the internal structure are related to being able to do a certain level of muscle performance,” Kushmerick says.
“We’ll solve this question, just as we solved the problem of getting into orbit. People forget how far we have come.”
Bonnie Dunbar, ’71, ’75, astronaut
White compares the digital human approach to a famous scene from the movie Apollo 13. The astronauts faced problems removing carbon dioxide after an accident forced them to live in the lunar module. On Earth, engineers dumped out a box of parts that were available to the astronauts and had to come up with a solution. They tested several ideas and found that by using plastic bags, cardboard and tape, they could hook up canisters from the damaged command module to the lunar module’s air system.
The ‘digital human’ would allow scientists to do the same thing with the human body. “The problem on Apollo 13 was solved by people on Earth who had a model of the system to tinker with, and try solutions on. If something goes wrong on a trip to Mars, we will need a model of the human body that we can tinker with, and that will give us realistic responses,” White says. “We need something that can take everything we know—all biological and physiological information—and the individual elements of a person.”
Kushmerick’s group will be in contact with other researchers, at UW and elsewhere, with a similar goal. Many groups making use of information from the Human Genome Project are engaged in digital human projects, hoping to discover the keys to preventing or treating various illnesses.
But prevention can only go so far. The truth is that on a long mission, there is a solid chance that someone could get crushed by a piece of machinery, be diagnosed with cancer, or suffer any number of possible nasty surprises. The space medicine institute has also created the Smart Medical Systems team.
“The astronauts will need to bring a hospital along with them,” says UW’s Lawrence Crum, principal physicist of the Applied Physics Laboratory, who is one of the team’s associate leaders. His group is creating an ultrasound device that would stop internal bleeding, a major cause of death after trauma.
This machine would be perfectly at home in Capt. Kirk’s world. Most of us associate ultrasound with detection and diagnosis. We can see grainy pictures of a baby in the womb, or of a blocked artery. And the UW machine would provide diagnostic images as well. It would use ultrasound to locate, say, the precise location of internal bleeding in a liver.
But then the machine would use an even higher frequency, high intensity sound to generate heat, and cauterize a wound or blast a cancer. It can aim its energy to burn precisely at the spot that needs it, deep within tissues, without damage to the intervening skin and tissues. It would be, in effect, bloodless surgery without the need of an incision. When the machine is tested on a bovine eyeball, you watch as a teardrop-shaped lesion appears as if by magic in the middle of the eyeball, aimed at a precise point. In theory, you could place the machine on the patient. The machine would almost automatically recognize the diseased area and then treat it.
“It’s ‘point and shoot’ surgery,” says Michael Bailey, a postdoctoral research scientist in the Applied Physics Lab. “This is Star Trek stuff.”
Artist’s rendering of the completed International Space Station in 2006. Image courtesy of NASA.
Internal bleeding is a very real risk in space. While gravity is not an issue, nothing has repealed inertia. A heavy piece of machinery could still crush an astronaut’s organs. Such accidents also take place on Earth. APL scientists think the machine could also have big benefits on Earth to treat people with certain conditions and who cannot easily reach a doctor.
A crew to Mars would almost certainly have a physician. Of course, that physician could be the one who gets sick. On Earth, a team of other medical experts will be on hand to offer advice. But the farther one gets from Earth, the more of a delay there will be in transmissions to and from the ship; whoever is providing medical care will have to weigh the need to stabilize and treat, in between getting advice from home.
On his Space Shuttle flight in 1998, Anderson was part of a telemedicine experiment that sent all of his body signals to Earth. The equipment was so portable that it could fit into your carry-on airplane luggage, he says.
“I had every test you would get at a standard trip to the doctor’s office,” he says.
When Cagle was at the UW School of Medicine, she participated in a program that sends doctors to the farthest corners of the Northwest. She delivered babies in the remotest corners of Alaska. She refers to a trip in space as the “ultimate house call” and says practice on Earth is great training in developing the judgment physicians will need: “You can’t get much more remote than space.”
It’s this combination of earthly experience and high-tech experimentation that has people confident that we will go to Mars and beyond. “We’ll solve this question, just as we solved the problem of getting into orbit. People forget how far we have come,” Dunbar says. “When I was growing up, people seriously thought that the body could not function in zero gravity. When I was in high school in Eastern Washington, our physics textbooks still said that the human body could not hold together at the speed of sound.”
In space, Dunbar helped examine Russian astronauts on the Mir and noted how well they had adapted to the gravity-less environment. She herself has found readjusting to zero gravity is easier each of the five times she has been in orbit, for a total of 51 days.
“It probably takes two days for the average person to get adjusted. Then it takes less time with each flight. It’s a lot like playing sports—at first, you have to think about what you are doing, and then, after practice, you just reach out and catch the ball,” Dunbar says.
So while the zero gravity confuses the body, the body adapts. Kushmerick says that the study of space medicine is an exploration into yet another amazing aspect of this most amazing of all machines: “Humans have evolved for hundreds of thousands of years. There has been life for billions of years, and no one has been exposed to zero g. Never.
“And yet we respond in an appropriate way. How come our systems are smart enough to do that? This is the central scientific fascination of space medicine.”
From fiction to fact: Space Station Alpha
By the standards of Earth orbit, the traffic outside the International Space Station may resemble the congestion found on the 520 ramps to and from Montlake Boulevard. More than 40 flights are scheduled in the next few years to turn the space station into a dorm and laboratory orbiting 250 miles above our heads.
If all goes according to schedule, the space station will be completed in 2006. It will stretch longer than a football field. The station’s total cost has been estimated at $96 billion, including all the construction flights.
The space station is considered a vital part of space medicine research. Even on the first mission, astronauts are monitoring each other for changes in their bodies because of space.
“We expect to be a big user of the space station, come 2004 and 2005,” says Ronald White, associate director of the National Space Biomedical Research Institute in Houston.
Scientists want to study the effects of zero gravity on humans, such as the loss of bone density and muscle mass. They also want to test many of the methods that might be used for alleviating some of these problems.
For one thing, a centrifuge on board will allow researchers to simulate the gravity conditions that would be found on Mars, which has a little more than one-third of Earth’s pull. So the space station is seen as a crucial place for training and rehearsing for a Mars expedition.
Sixteen countries are cooperating to build and staff the station. The station will have more than half an acre of solar panels to power the station. It will have six times more electrical energy available than its immediate predecessor, the Russian Mir. Two computers on board are in charge of keeping the station on the right course and altitude as it orbits the Earth every 90 minutes.
By the time it is finished, the space station will have 46,000 cubic feet of living and working space—more than the volume of the passenger cabin and cargo hold of a Boeing 747-400, says the Boeing Co.
Boeing is well qualified to make that claim, as it is the station’s prime contractor. Boeing built Unity, a connecting module that is in orbit today. All future U.S. segments of the station will be attached to Unity. Earlier this year, the space shuttle Atlantis delivered Boeing-built Destiny, a laboratory that will allow scientists to study how materials form in zero gravity.
It’s possible that the space station will become a departure and return point for future astronauts going to Mars. “We might someday use the space station as a weighing-in spot—no pun intended—for astronauts coming to and from other places,” says Yvonne Darlene Cagle, ‘85, a physician and U.S. astronaut.