 I'm ready. Future explorers will venture in harsher environments than ever before, at distances never encountered in human history, for durations never achieved by any space program. A future mission to Mars could take as long as three years. Astronauts would work for years at a lunar base. Three Americans undertook the first long duration mission in 1974, returning safely to Earth after 84 days aloft. Two Soviets have spent a year in space. Both programs have shown that there is much yet to learn to enable astronauts to undertake long missions, to keep them healthy physically and psychologically, to provide them with medical care and life support, and to protect them from the hazards of the space environment. When astronauts travel beyond the sanctuary of the magnetic field surrounding our planet, they're no longer protected from cosmic rays and solar flare radiation. Without shielding, an astronaut exposed to a solar flare event would become ill with radiation sickness. Chronic exposure to cosmic radiation could increase an astronaut's risk of developing cancer. Before explorers can undertake long missions far from home, life sciences researchers must find out more about the hazards of space radiation. High on a hillside, overlooking the university campus in Berkeley, scientists use an accelerator to whip tiny fragments of matter faster and faster to higher and higher energies and then hurl them at a target to simulate space radiation. On Earth, this is the only way we have to learn more about how space radiation damages living cells. Greg Nelson of the Jet Propulsion Laboratory uses this unique facility at Berkeley to irradiate microscopic roundworms. It's a nematode or a roundworm called senorabditis elegans. And what we actually look for after the worms have been exposed to these artificial cosmic rays is the presence of mutations or damage to known populations of cells in the worms' bodies. Our ultimate goal is to be able to use our model animal, C. elegans, to extrapolate to the cancer risk for human beings. Earth-based experiments can only simulate space radiation. Soon, scientists will have the opportunity to study the effects of long-term exposure to the real space radiation environment, flying roundworms and insects, plants, and human cells aboard NASA's LifeSat. What we learned will help physicists as they investigate the different spacecraft materials that will protect our astronauts from space radiation. Developing shielding is a difficult task. The shield, the skin of the spacecraft, has to be thick enough to stop micrometeorites, but not too thick. Because when high-energy particles collide with the shield, the collisions produce secondary particles that can also damage the cells of an astronaut's body. The thicker the shield, the more collisions, the more damaging secondary particles are produced. Shielding has to be thin enough to hold down the effects of the collisions and still protect the craft. With real data, LifeScience's researchers will set radiation exposure limits that will drive the development of new shielding materials and other protective measures so that our explorers can safely undertake extended missions beyond Earth's magnetic sanctuary. For most astronauts, microgravity is fun once they get used to it. Virtually all of the body's systems, systems that have evolved for millions of years in the presence of gravity, begin adapting to the absence of gravity within hours of liftoff. But these changes in the body can cause problems. When an astronaut's skeleton is no longer needed to support his body, his bones grow thin and porous. Muscles that on Earth work against the downward tug of gravity to remain strong, atrophy if not used. The heart shrinks when it no longer has to pump blood from the feet to the head against the pull of gravity. Because of these and other changes, astronauts on an extended mission would lose the strength and stamina needed to return to Earth or explore the surface of another planet. Chief of the LifeScience's division at NASA's Ames Research Center, Joan Vernacos. When they return to Earth, even with all the exercise and countermeasures they do, Romanenko, for instance, and other Soviets. So they cannot walk unassisted for at least 48 hours. Well, you can't do that on landing on Mars. You have to be able to either egress rapidly, in case of emergency, or get out in this relatively alien environment and build a shelter or a habitat before you go exploring around the Martian surface. And therefore, you cannot afford to be weak or unable to move. To help our astronauts overcome space deconditioning, researchers at the Johnson Space Center are developing countermeasures. Chief of the Medical Operations Branch, Jeff Davis. On the space shuttle, we employ countermeasures that range from things as simple as fluid loading to replace volume that's lost during flight to exercise for a cardiovascular conditioning and muscle strength to the use of a G-suit to help the body overcome the forces of gravity during entry. During a recent space shuttle flight, Bonnie Dunbar tested a countermeasure device that could help an astronaut prepare for the return to gravity. Completely enclosing her lower body, the device uses a partial vacuum to pull blood down to the feet in the same way that gravity does on Earth. For space station, we'll be interested in looking at research into areas such as bone loss and the potential use of medications as a countermeasure to diet and dietary supplements. High school teacher Vincent Dew is in perfect health. But beginning today, he'll be confined to bed for the next 17 weeks. He'll never get up or sit up, even to eat. Keeping his feet higher than his head shifts fluids to his upper body and takes the stress off his muscles and bones to simulate the changes that astronauts experience in the absence of gravity. Through bed rest studies like this one conducted at the Ames Research Center, scientists can experiment with different combinations of diet, medication, and exercise to offset the effects of space deconditioning. For Vincent, the experiment ends with a ride in a centrifuge to simulate an astronaut's rapid return to gravity. Since Vincent had no problem with his re-entry, these same countermeasures might work to keep an astronaut in good condition during an extended mission. Exercise has been an effective countermeasure for Soviet cosmonauts. But near the end of an 11-month stay aboard the Soviet space station Mir, cosmonaut Yuri Romanenko was working out as much as four hours a day, severely limiting the time he could devote to his mission. So in a parallel effort, NASA researchers are investigating the benefits of the artificial gravity produced by centrifugal force, such as the gravity produced by the spinning spacecraft of science fiction. Scientists don't yet know if artificial gravity will work, or if it does, just how much is needed. Would an hour a day spend in a small exercise centrifuge keep astronauts fit? Or would the entire spacecraft have to rotate 24 hours a day? Answers to these questions will significantly influence the design and cost of the spacecraft that will carry our astronauts further into the space frontier. A spacecraft bound for Mars will be so massive that it won't be launched from Earth in one piece. It will be assembled on orbit. To do the job, our astronauts will spend many long hours working EVA. So biomechanics engineers at the Johnson Space Center are working to make sure that the tasks they'll be performing don't ask more than an astronaut has to give. Tests are conducted in simulated weightlessness, underwater. The crank measures how much strength a space-suited astronaut can exert. Underwater video captures the action. Sensors record which muscles produce the motion. Engineers analyze the data and determine how much force an astronaut can deliver. They then develop computer models of human capabilities. These smart tools will help researchers see how astronauts will work in environments that don't even yet exist. Real requirements can then be set to make sure that tasks can be accomplished a million miles in space. When Gene Cernan, Ronald Evans, and Jack Schmidt departed Earth on the last and longest Apollo mission, they took some 500 pounds of air, food, and water with them. Were those same three men to go to work at a lunar outpost for a two-year tour of duty using the same life support system we have today, each man's provisions would require a dedicated launch, a prohibitive expense. What's needed is a life support system that can recycle food and air, water, and waste. In a closed system, astronauts will grow their own crops, just like the wheat grown in this environmentally sealed chamber at the Kennedy Space Center. With this component of a closed life support system, researchers here are demonstrating the feasibility of using plants to provide fresh air, clean water, and nutritious food. By carefully controlling the nutrient solution, the moisture in the atmosphere, and exposure to simulated sunlight, this biological system is proving to be very reliable. But will it work as well without gravity? The space station freedom will serve as a test bed to qualify the life support system that will sustain our space explorers on long missions, far from home. For researchers in the Antarctic, it is difficult to handle a medical emergency. In this remote corner of the globe, the nearest medical care is hours away. On an expedition to Mars, when an emergency occurs, there is no place to go. Crews must handle medical emergencies and treat routine illness themselves. So doctors and engineers at the Johnson Space Center are putting the capabilities of an emergency room, a medical laboratory, and an x-ray facility into a compact clinic for use in space. Four tightly packed racks of specially engineered medical equipment and supplies will provide what's needed to perform diagnostic tests, treat injuries and illness, and keep track of patient records. But medical systems and procedures for use in space must be more than compact. They must work without gravity. And so they're tested by a team of doctors and technicians in a very unusual test facility. Research engineer Terry Gess. Just like a roller coaster, the KC-135 flies in a parabolic flight path. As the plane reaches the peak of its path, it starts to nose over. And at that point, you get 25 to 30 seconds of zero gravity. This doesn't sound like a lot, but it's the only way we have on Earth of simulating zero gravity. Performing medical procedures without gravity requires an entirely different approach to medical care, with much development and testing yet to be done. Astronauts may seem very different from aquanauts. But this diver experiences some of the same psychological stress from isolation and confinement that an astronaut will on a long mission. The diver works for weeks at a time cut off from family and friends. He lives in a facility that is cramped and close, with a tiny kitchen and living area, and six bunks stacked three on a side. It is a habitat for aquanauts, not unlike that of astronauts, which is why human factors researchers study the diver's behavior. How do people handle the isolation, the lack of privacy, and the prolonged confinement? How do different personalities mix? How does the group function as a whole? Continued human factors research with divers and others at work in remote environments will determine selection criteria and training and psychological support techniques that will help ensure the well-being of future space travelers. Life sciences researchers are at work on a variety of fronts, studying the physical and psychological impacts of extended missions. This research is critical if we are to sustain, nurture, and protect our space explorers. It is this research that will turn our dreams of space exploration into reality. I believe that this nation should commit itself to achieving the goal before this decade is out of landing a man on the moon and returning him safely to the Earth. I believe that before Apollo celebrates the 50th anniversary of its landing on the moon, the American flag should be planted on Mars. The goal is clear. The challenge is upon us.