Interview with Prof. Saku Tsuneta

Brief Personal History

1. You must be very proud of your scientific heritage. Can you tell us was there any crucial juncture that determined your interest and direction of research interest in the Sun?

When I entered the graduate course in astronomy in 1978, Japan did not have any world-class, large astronomy facilities. I was interested in astronomical magnetohydrodynamics; and the Sun, because of its proximity, is a good target to study the interaction between the magnetic fields and plasmas. 

Astronomy develops through larger photon collecting area (larger telescopes) and higher spatial resolution. Any future facilities which bring new discoveries have to go in that direction. I thought that the Sun is bright enough that we can concentrate on high spatial resolution without need of a large instrument. My strong scientific interest was to understand the magnetohydrodynamics of the Sun, such as coronal heating, solar flares, dynamos, and solar wind.  I also had a strong interest in building something that no one else had ever realized. These multiple factors drove me to pursue the solar observations from space. 

Incidentally the late Prof. Minoru Oda, a prominent X-ray astronomer, and his x-ray astronomy group at the Institute of Space and Astronautical Science (ISAS) developed a plan to image solar flares in hard X-rays with the modulation collimator that Prof. Oda invented. I was fortunate enough to be invited to participate in the team as a graduate student. So, pieces of the puzzle fit themselves together, and this set the stage for my career over the subsequent 40 years. That hard X-ray solar observation satellite Hinotori (firebird) was launched in 1981 and successfully imaged many solar flares in hard X-rays for the first time. 

2. Your impressive scientific leadership and management roles cover both JAXA in space science and NAOJ in astronomy. You must have a very unique understanding of science making or making science. So, can you tell us if science is driving technology, or technology is driving science with the three great observatories (Subaru, ALMA and TMT) in mind?  

Personally, I wanted to analyze the data to find something new from instruments that I developed myself. This is ambitious and maybe a bit arrogant on my part. Obviously, this is becoming difficult these days. It is clear to me that the big questions in science drive everything else and should come first. In this regard, science is driving technology.

But the story may not be so simple. Scientists and engineers may develop some very interesting technology and instruments, which led to new discoveries in astronomy. History tells that this is the case. It is important to have strategic technology development programs based on science questions. We also need to pay attention to seemingly unrelated developments in the private sector which may drive science. 

3. JAXA's exploit of solar system exploration in a cost-effective manner is legendary. Can you tell us your secret recipes that we always want to know? 

When I assumed the position of director general of ISAS, there were multiple pillars for the institute: solid booster development, planetary exploration, and astronomy. ISAS had a long history for developing solid boosters for launching the scientific satellites, and this brought the glorious success of ISAS in the 1980s - 2000s. I tried to change ISAS from an ‘institute for booster development’ to an ‘institute for planetary exploration’ with an eye towards the future of ISAS and JAXA. This meant that the institute put more emphasis on planetary exploration where scientific professors and engineering professors can work together. 

This led to the development of a series of planetary science missions such as Hayabusa2 for asteroid sample return, Arase for geo-space observations, SLIM for precision Moon landings, MMX for Phobos sample-return, DESTINY for 3200 Phaethon flyby with interplanetary dust-observations, and the construction of the new deep-space antenna. ISAS is becoming an institute for solar system exploration with related research areas such as astronomy, while the vehicles are mainly developed in another division of JAXA.    

4. May we ask what might be the most serious crises (if any) in your scientific projects or space missions? How do you overcome them? 

I happened to be in my office on one Saturday to do some paperwork. It was a sunny, comfortable afternoon. A phone rang, reporting to me that there was no telemetry signal from the newly-born X-ray astronomy satellite ASTRO-H Hitomi during the scheduled contact time, and there might be some ground system problem. Ninety-six minutes later, there was another call that there was again no signal from the satellite. With that phone call, I declared an emergency following the predetermined procedure. People tried to recover the satellite without success. 

I tried to clarify the root causes of the problem, and in the process established a better system for the development of complicated, first-of-their-kind scientific satellites and probes. I do hope that as the result of this tragedy, ISAS and JAXA became stronger. While considerable money was lost, my biggest regret is the wasted time and effort of people in the US and Japan. A considerable number of people had been working on the project for more than 10 years, some of them as long as 20 years. No effort should be spared to prevent any failure in space programs.

5. It is wonderful that Japan and China are working together on the Thirty-Meter Telescope project together with the United States, Canada and India. Do you see any potential joint projects beyond TMT in near future, either on the ground or in space?

The world is advancing and changing rapidly right now. No one can predict what the future will bring. But when we look at current projects, there are certainly many examples of astronomy working across political boundaries in the Asia-Pacific region.

You mentioned the optical-infrared telescope TMT. Also, radio telescopes in China, the Republic of Korea, and Japan are working together in the East Asia VLBI Network to conduct high-resolution observations that no one partner could achieve alone. Through the East-Asian ALMA (the Atacama Large Millimeter/submillimeter Array) Regional Center (EA-ARC) located in Tokyo, scientists in Taiwan and the Republic of Korea are participating in ALMA in Chile. The East Asian Observatory (a collection of five institutions in East Asia) is now operating the James Clerk Maxwell Telescope in Hawai`i. If funding and other circumstances allow, I would certainly like to see collaborations like these continue.

6. The mutual understanding and trust among young people, especially young scientists, are the basis of long-lasting cooperation and friendship, and hence stability and sustainability in the scientific and social environments. The promotion of such spirit is the main task of ISSI-BJ. Any advice on what we should do more so that our program can be more effective in this aspect? 

Science advances through the exchange of ideas. At the same time, space science is funded by national budgets as part of a national strategy. So, in this era of turbulence in the world, the relationships between nations must necessarily have an impact on space science collaboration between countries. When the international situation is such that research exchange and collaboration for the mutual benefit of both nations is possible, we appreciate such good relations that allow collaboration in space science. We first need to foster an environment conducive to such collaboration. That is how the world should be, how I feel it must be.

Toward such direction, it is important to maintain communication channels across the political boundaries. International workshops and lectures play an important role in helping young scientists to network. I have had good experiences with ISSI in Bern. I attended workshops on solar astronomy back in the 1990s -2010s. They had lasted two or three days. ISSI paid for the hotel and per diems. This was a very good arrangement for young researchers. Perhaps best of all, ISSI did not interfere with the content of the workshops at all; the organizers had total control.

I would encourage ISSI-BJ to continue to operate in the spirit of the home office in Bern. And at the same time, look for scientific opportunities unique to the Asia-Pacific region. Everyone knows that space science is important to the future of Asia; and I like to think that Asia is important to the future of space science.

7. I saw a comment in your article (Open Access Government, Issue 32, page 274, October 2021), that twenty-first century astronomy is founded on collaboration across political boundaries and traditional boundaries between research fields. This can almost be taken up as the motto for ISSI-BJ. We hope very much that with the participation of scientists in Japan, ISSI-BJ can fulfill its promise as an advanced institute for outstanding space science on the basis of international cooperation and neutrality. Thank you in advance.
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