JAXA Japan Aerospace Exploration Agency

Space is a very interesting place. The space environment has significant effects on living organisms. If we were to go to Mars without the appropriate preparations, we might eventually become Martian-like creatures.

Even a healthy man would lose 6 to 7 per cent of bone density in a six-month space trip. Suppose that rate of loss continues in linear fashion. That means he would lose 20 to 25 per cent of bone mineral density, and might become a mollusk-like creature similar to this Martian. Even from the point of view of such apparently simple things as bones, long space flight is extremely difficult indeed.

Even if we use the moon as a place to conduct various kinds of experiments for future manned flights to Mars, we need to deepen our understanding of life science and medicine, test our methods of sending living organisms from Earth to outer space, and study the resultant phenomena through experiments on the International Space Station (ISS). The ISS is in circumterrestrial orbit about 400 kilometres from the surface. That means it has a zero-gravity environment, in which things don't fall. We can only create this environment in orbit or at the Lagrangian point, where the gravitational fields of two celestial bodies are in balance. For this reason, the ISS plays a very important role as a laboratory in orbit.

At the ISS, we conduct various kinds of experiments in the microgravity environment, where the level of gravity is nearly zero. By working with centrifugal force, we can create any level of gravity we want. The ISS is a very important facility to study the effects of the microgravity environment, which is available on Earth for only very short periods.

As the level of gravity increased, the objects that had been floating gradually started to sink. Sheets of paper attached to the wall with Scotch tape started to droop down with the weight of the paper. Every time I released a ball-point pen from my hand, the speed of its fall increased. It was very interesting to observe falling objects on my way back to Earth. When we landed, I felt relieved, but also a little sad.

People often ask me what I think was the most interesting thing in space. The most interesting thing actually happened not when I was in space, but when I returned to Earth. Though I went to space in order to look at Earth from there, the difference between what I had expected to see and what I actually saw was relatively small, since to some extent I had managed to imagine the beauty of Earth seen from space and the fascinating aspects of the zero-gravity environment even before my flight. But when I came back to Earth after two weeks in space, I realized that what I had taken for granted before my flight was actually extraordinary: things released from my hand fell down. As I had spent time in a world where things didn't fall, the fact that they did could only be described as phenomenal.

Can you see what's inside this basket? (refer to the left image) There is a blue filter here, so we cannot see the blue object inside the basket. If we remove this blue filter, we can see a blue bird. Suppose this filter represents gravity, and the blue bird represents our world and the phenomena that happen here. We can see how difficult it is to study these phenomena through the filter of gravity. Geniuses like Einstein and Newton didn't have to go to space and take off their "blue glasses" to understand the causes of these phenomena - that's how strong the power of imagination can be.