JAXA Japan Aerospace Exploration Agency

Q. When you were trying to avert the crisis, did you have any fears that there was no back-up plan if this method didn’t work?

Asteroid Itokawa. In the center of the image is the shadow of HAYABUSA.

I always had fears, but I just felt I had to try my best no matter what. We don’t get many chances in life. This was a chance I had made myself. When I was asked to put ion engines on HAYABUSA, if I had said, "I can’t do that," I could have lived a pretty ordinary life without feeling any nervous excitement. But that would have meant my life would not have taken a leap forward. This was the first time anywhere that a planet explorer was equipped with microwave discharge ion engines, so there were no examples to study and we had many difficulties. We performed two 20,000-hour consecutive-operation tests on the ground. I often spent nights in my laboratory and was leading an unhealthy life. After completing these experiments, I had many crises with respect to providing the engines with the desired performance by the scheduled delivery date. In addition, there were many troubles after launch, as I mentioned. Each time, I was battling fear, but when I look back now, I think these were very interesting experiences for me.
Just like at school, if the problems you’re given are too hard to solve, it’s no fun. When you manage to solve a problem that’s in a range that you think you can handle but at the same time seems impossible, you feel a sense of fun. In that sense, the failures during the HAYABUSA mission were difficult, but I think the part where we were somehow able to solve them because we all worked hard was interesting for me.
Also, since the mission was a very challenging one, people both abroad and in Japan were saying HAYABUSA would never reach Itokawa. And all the more so, nobody really thought it would return to Earth. I had to have a very firm frame of mind, trying to deal with all these negative opinions. I wasn’t the only one - I think everyone on the project team had the same feelings. I went through some tough times, but as a result the HAYABUSA mission was very interesting work for me. I was very lucky to be given such an opportunity, and to be able to live up to the expectations that were placed on me.

Q. Looking back at the HAYABUSA project, what impressed you the most?

Professor Kuninaka and John McKevett, Operations Manager of the Royal Australian Air Force’s Woomera Test Range, shake hands after the capsule is discovered

There were so many things. It’s hard to choose one, but the one that really stands out in my mind is the time when all the engines stopped in November 2009, and we overcame the crisis.
When HAYABUSA started to travel back home in 2007, I was in charge of coordinating various things for its return to Earth. Dropping the capsule in another country’s desert is an issue related to that nation’s security, so we had to negotiate with the Australian government. We also needed to make import/export arrangements in order to bring the recovered capsule back to Japan, but these arrangements were completely different from the field I’d been working in, the space technology field, so almost everything was a first experience for me, and I was learning one new thing after another. To be honest, by November 2009, negotiations with the Australian government hadn’t progressed very much, and most of the preparations for the capsule recovery were not finished, so I was anxious about the success of this mission. I can say this now, but at the time I was so frustrated, I thought I would bring back the capsule in my own suitcase if the talks didn’t work out. I was under increasing pressure on this front when the propulsion system broke down and I was told that HAYABUSA’s return to Earth was hanging by a thread, so it was a pretty tough time for me.
However, once HAYABUSA’s propulsion system recovered and the explorer resumed its flight back to Earth, the door of opportunity suddenly sprang open. At last, everyone started to take seriously the idea that HAYABUSA would return to Earth, and from that point negotiations with the Australian government went more smoothly. In one stroke, everything started to move forward, and I felt like HAYABUSA had awakened the world.

Q. What was the international response to HAYABUSA’s return to Earth?

The AIAA 2010 Electric Propulsion Outstanding Technical Achievement Award

Not long ago, I was invited to a NASA workshop called Exploration of Near Earth Objects Objectives, and made a report on the HAYABUSA mission. I was very surprised at the project’s solid reputation. Last spring, President Barack Obama suggested that the United States would aim for a manned asteroid mission by 2025. Even though HAYABUSA was a robotic exploration, not a manned one, it successfully completed an interplanetary voyage and landed on an asteroid. In this sense, I think America’s interest in HAYABUSA is huge.
In addition, the American Institute of Aeronautics and Astronautics (AIAA) honored HAYABUSA’s ion engine team with the 2010 Electric Propulsion Outstanding Technical Achievement Award. This is to recognize our achievement of a return-trip space mission using electric propulsion. Before HAYABUSA, electric propulsion was used mostly for orbital control of geostationary satellites circulating around Earth; we used it for an interplanetary trip for the first time. I was honestly happy about this award honoring our newly paved road. It showed that HAYABUSA’s return to Earth is highly regarded overseas as well, and I think people now recognize that Japan is ahead of the West in unmanned space exploration.

Q. How would you like to develop this ion engine technology further?

Ion engine during a beam exhaust test

In order to keep this microwave discharge ion engine alive, I would like to "industrialize" it. A space mission such as HAYABUSA can only be launched every 10 years or so. Technologies expand when we use them regularly, but if we use them only once every 10 years, they cannot be developed - we have to start from scratch every time. In order to improve the technology incrementally, we need to use it - to install it on more spacecraft. Thus, I would like to industrialize the technology by finding uses for it abroad. Currently, there are some discussions with other countries about putting ion engines on geostationary satellites, or providing ion engine technology.
For a developer, a new technology is like a child. It cannot develop itself, so it has to be raised by a parent. The parent of the microwave discharge ion engine is me, so I’d like to do my best to expand its use. If it is industrialized, business gets involved, so I’d like to see manufacturers take the lead, and I’d like to provide support on the technical side.

Q. How do you want to utilize HAYABUSA technology in future space missions?

Asteroid explorer HAYABUSA-2 (Courtesy of Akihiro Ikeshita)

HAYABUSA was a very challenging mission, we had many crises, but the engineers and operators stuck with it to the end without giving up. I think the reason everyone’s hearts didn’t break was because the project was so interesting. By interesting, I mean the opportunity to open up a new world - to reach an unseen asteroid and come back to Earth using a method no one had ever used before - is naturally interesting. It is important that we continue to plan missions that we think are interesting, but I’d like to make these missions interesting for the public as well - although I hope there is not as much drama as we had with HAYABUSA. From the point of view of a scientist, I think it’s preferable that missions proceed more smoothly and on schedule.

Q. What are your goals for the future?

I would like to increase the number of explorers and satellites that carry electrical propulsion engines. First of all, I have to industrialize HAYABUSA’s ion engine. I’d like to maintain this technology and somehow develop it further. My second goal is deep-space engine navigation. This was achieved by HAYABUSA, but I’m aiming for even better performance, such as upgraded propulsion. In the future, I’d like to use an electrical propulsion engine for a mission to Jupiter. If we can make it to Jupiter for a swing-by, we can reach anywhere in the solar system, so Jupiter for us is like the Cape of Good Hope during the Age of Exploration in the 15th century. For this reason, I’m very eager to open up a route to Jupiter.
Thirdly, I’m looking for ways to make bulk space transportation possible. For example, if we send manned missions to the Moon or Mars, we have to deliver food, water and fuel before humans get there. I think humans should make quick return trips to space, but it is better to deliver supplies with the much efficient of electrical propulsion engines, even it takes more time. But considering my age, I may not reach this third goal of mine, so I’d like to train younger generations and let them contribute to such a goal. I hope today’s students will try to do something new.