As a professor at ISAS/JAXA and the University of Tokyo, he has been joining and conducting many of research programs for space science and technology such as launch vehicles, new transportation systems, planetary entry and reentry, and so on, since 1980th. Among many achievements, he has been active about reusable space transportation system. Not only doing system studies, but carrying out flight demonstration of winged space vehicle and vertical landing vehicles. Vision for the future vehicles were pursued by him as a studies of space tourism, which stimulates general public by shedding the light toward the future of rocketry. Another highlight is a sample and return mission from asteroids. A returning capsule of the first Hayabusa mission was developed and made successful flight for the first time in the world by his team.

After finishing executive positions at ISAS, he is now active for stimulating the commercial sector activities such as promotion and new market development of passenger carrier of space tour and Point-to-Point highspeed transport as it is done in the civil aviation today. He plays the role of stimulating commercial space tourism activities and of acquiring government support for many aspects such as cutting-edge technology research, legal frameworks to be built for tourism-based space flight and safety, and so on. Promoting studies and activities for sustainable human presence in space is also one of his current activities. Being a board member of Moon Village Association, he serves as a Moon Village evolution coordinator to think about the future of human presence and activity on the Moon. He also serves as a leader of Japanese study team of highlighting and discussing broad issues in building and operating the “human society on the Moon” on many aspects, such as architecture, business, legal issues, life science and humanity related issues, all of which are concerned about the future of human presence in outer space.