Flying, and Going to Space

Akiko Matsuo (Professor, Department of Mechanical Engineering)

Today, people can fly. And it is not prohibitively expensive. For less than 10,000 yen per flight, you can not only go above the clouds but also reach your destination in no time. However, it is also true that this has become so commonplace that we have forgotten the wonder and excitement of going above the clouds. With today's science and technology, it is possible not only to fly above the clouds but even to go into outer space. However, flights to outer space are not accessible to the general public; space tourism is a privilege reserved for the world's wealthy.

Going to outer space is far removed from our daily lives. To enter an orbit that continuously circles the Earth (becoming an Earth satellite), one must reach a minimum speed of 7.9 km/s. This is a speed at which one can travel 7.9 km in a single second. While this is slow compared to the speed of light at 300,000 km/s, it is incredibly fast from the perspective of our daily lives. In other words, to reach a space station to leisurely view the Earth from space, one must travel in an ultra-high-speed vehicle. In reality, due to factors like air resistance and gravity, a vehicle capable of reaching about 10 km/s is needed to account for various losses. Reaching outer space in such a fast vehicle and then viewing the Earth from space—this sense of romance has a scale that cannot be experienced in daily life, a romance felt every time one looks up at the sky. For some, their main interest becomes looking at the stars, and they may become astronomers. Those who truly want to go to space might become astronauts, while others might aim to become wealthy enough to take a tourist trip to space. As for me, I became interested in the means of going to space—the equipment itself. I believed that by creating better vehicles, it would become easier to go to space, and they would become a mode of transportation for humanity.

Our ticket to space was secured in the early 20th century when the Russian Konstantin Tsiolkovsky conceived of rocket propulsion. While various types of rockets exist, chemical rockets are typically used for launches into outer space, and even today in the 21st century, air-breathing engines are not used for this purpose. Furthermore, there are no prospects for the practical application of any innovative space propulsion systems. In that case, I thought, why not try something interesting? I am currently researching an unprecedented propulsion system that uses a form of combustion called detonation (which travels at 2 km/s). This new engine, called a detonation engine, is being diligently studied by many researchers around the world. If, in 20 or even 30 years, you happen to hear the words "detonation engine," I hope you will know that we have succeeded.