Better still, you have a partial source of nutrition.

It turns out that if you grow 10,000 wheat plants, you can generate more than enough oxygen to breathe while removing the human waste gas of carbon dioxide. One involves a grow-your-own approach to life support and nutrition. But there is no easy way to resupply a team traveling to Mars, and so a number of ingenious solutions to this problem have been proposed. How do we invent a system that can keep a crew of four alive for nearly three years?įor space stations, breathable oxygen requires electrolyzing a steady supply of water. There are a number of formidable problems that accompany long-stay missions. >Deprived of the need to work against the force of gravity, the body becomes deconditioned - taking athletes and turning them into couch potatoes. Immunity suffers, wound healing slows, and sleep is chronically disturbed. Red blood cell counts fall, inducing a sort of space anemia. There are other, less well-understood alterations. As a result, the essential role they play in delivering a finely calibrated sense of motion is often overlooked. These organs are not considered “vital” in the sense that they are not required to keep the human body alive. The system of accelerometers in our inner ear, the otoliths and semicircular canals, are engineered to provide the finest detail about movement, sharing their inputs and outputs with the eyes, the heart, the joints, and the muscles. When deprived of the need to work against the force of gravity, the heart and its system of vessels become deconditioned - slowly taking athletes and turning them into couch potatoes. When we’re standing up, our heart, itself a muscle pump, has to work against gravity, pushing blood vertically in the carotid arteries that lead away from our heart toward our brain.

The biological adaptations to gravity don’t stop there. Medical students remember this list as: “bones, stones, abdominal groans, and psychic moans”. And because 99 percent of our body’s calcium is stored in the skeleton, as it wastes away, that calcium finds its way into the bloodstream, causing yet more problems from constipation to renal stones to psychotic depression. Deprived of gravitational load, bones fall prey to a kind of space-flight-induced osteoporosis. But at the microscopic level, it is far more dynamic: constantly altering its structure to contend with the gravitational forces it experiences, weaving itself an architecture that best protects the bone from strain. We tend to think of our skeleton as pretty inert - little more than a scaffold on which to hang the flesh or a system of biological armor. Our bones, too, are shaped by the force of gravity. In experiments that charted the changes in the quadriceps of rats flown in space, more than a third of the total muscle bulk was lost within nine days.

That's why the mass of flesh that constitutes the bulk of our thighs and works to extend and straighten the knee are the fastest-wasting group in the body. These muscle groups are sculpted by the force of gravity, in a state of constant exercise, perpetually loaded and unloaded as we go about our daily lives. Without the quadriceps, buttocks, calves, and erector spinae that surround the spinal column and keep it standing tall, the pull of gravity would collapse the human body into a fetal ball and leave it curled close to the floor. Fong worked with NASA’s Human Adaptation and Countermeasures Office at Johnson Space Centre in Houston and the Medical Operations Group at Kennedy Space Centre in Cape Canaveral. He is an honorary senior lecturer in physiology at University College London as well as founder and co-director of its Centre for Altitude, Space, and Extreme environment medicine. () is a doctor of medicine who also holds degrees in astrophysics and engineering. But we are constantly sensing the effects of gravity and working against them, largely unconsciously.

Mars density