Hayabusa2, an asteroid probe launched by the Japan Aerospace Exploration Agency (JAXA) in December 2014 as the successor to Hayabusa, the probe that miraculously completed its mission after recovering from a malfunction. In April 2019, Hayabusa2 succeeded in the world’s first crash experiment that created an artificial crater on Ryugu, a near-earth asteroid. The probe is still in space, searching for clues to understanding the origins of life. We interviewed Takafumi Onishi, the leader of the team responsible for the orbit determination system that is vital to this monumental mission.
(Interviewer: Haruka Mori, freelance announcer)
Manager of the Science Solutions Division
Technical Computing Solutions Unit
A Kid Astronomer Who Loved the Stars and Programming
-- What triggered your interest in space?
I have liked observing stars ever since my childhood. I used to observe the Moon, nebula and star clusters with a telescope. In my junior high and high school days, I joined an astronomy club and photographed the stars. Another hobby of mine is programming, which I started to teach myself when I was a junior high schooler. I made video games on an 8-bit computer. When I went to university, I came to know about space projects such as the International Space Station, which led to my fascination with the idea of expanding human activities into space.
Consequently, I started wanting a job that supports space development in the IT industry.
Another reason for my wanting a space-related job is that, since my generation grew up watching Gundam anime on TV, I yearned for those space colonies (laughs).
-- You’re not wearing a suit today. Your jacket looks like it came from the “Ultraman” TV show (laughs)!
Exactly (laughs)! Our division designed and created this staff jacket.
Support System for the Dramatic Terrestrial Return of Hayabusa
-- Everyone was talking about the episode of Hayabusa overcoming its malfunction.
The strongest impression I have of the Hayabusa mission was the malfunction that caused all the engines of Hayabusa to fail approximately six months before it returned to Earth. On its way to bringing the particles it collected on the asteroid Itokawa back to Earth, the probe was already in a battered state. It had worked very hard during its originally planned operational period of four years and for another three years after that, exceeding its designed lifespan. Honestly, I said to myself, “This is the end… ”
The Hayabusa project team decided to electrically connect the still properly functioning components of two engines to control it. However, we couldn’t test this operation mode in advance on the ground; it was uncertain how much of the planned level of thrust could actually be achieved.
So, our orbit determination system monitored the orbit in order to calculate the level of thrust in space and feed orbit determination information back, thereby helping continue the careful operation.
-- Your system had a crucial role! How did you feel when Hayabusa returned successfully?
I was deeply moved. In the end, the capsule landed in the Woomera desert, Australia, and its contents were retrieved. To do so, we precisely guided the probe to an Earth atmosphere reentry point as we adjusted its orbit gradually. In this situation where a single failure would mean game over, all the teams fought their battles, one after another: our orbit determination team determined the position and speed of the probe, the control planning team created orbit adjustment plans, and the ion engine operation team adjusted the orbit precisely.
To be honest, the confirmation that the probe had entered its orbit to the atmosphere above Australia was a weight off my shoulders (laughs).
Successor to Hayabusa’s Mission
-- And how did you feel when Hayabusa2 successfully touched down on the asteroid Ryugu in February of this year?
I was excited because I really wanted the probe to take a sufficient number of samples from an asteroid, a task that the first probe failed to accomplish.
By monitoring with Fujitsu’s orbit determination system, I knew when the probe automatically descended to the asteroid, took samples, and took off based on the judgment made by its systems. At the moment when the probe succeeded and departed, all the members in the control room burst into cheers and applause in great joy.
Development of Orbit Calculation Started with Missions to Halley’s Comet in the 1980’s
-- What a marvelous moment! Would you elaborate on orbit-related systems with which your team were involved?
We develop systems for orbit calculation, especially orbit determination. A probe attempts to fly precisely along a predetermined route but, since there is no guide rail in space, the actual route inevitably deviates from the intended route. An orbit determination system knows exactly where a probe flying in space currently is and exactly how fast it is moving.
Missions to Halley’s Comet in the 1980’s were the beginning of Japan’s missions to explore the Solar System. Since then, Fujitsu has been developing and improving its orbit calculation systems for decades.
-- Fujitsu plays a vital role in Japan’s space development.
Since Fujitsu is also an active AI developer, I hope the era when AI can be applied will arrive soon.
-- What motivates you?
My effort and ingenuity have resulted in direct contributions to the successful completion of these missions to explore our Solar System. This both fills me with excitement and thrills me. Now, projects are planned at least 10 years before they are launched. We prepare a system by conducting system-related research and development and performing preliminary analysis and evaluation prior to the launch of the satellite. Even so, when a probe is actually launched into the Solar System, sometimes we do not get the results we expect. We evaluate the data we obtain and, if necessary, we improve the system and its operation based on the results of our evaluation, thereby overcoming various problems and difficulties.
World’s First Creation of an Artificial Crater on an Asteroid, Opening Up a New Frontier
-- What are Hayabusa2’s current challenges?
Our top priority challenge is to safely bring back to Earth the samples that we hope Hayabusa2 was able to obtain after it touched down on the asteroid during this February. In April, we successfully completed a mission to create an artificial crater on the asteroid by shooting an impactor at it. The probe will investigate the crater and after confirmation and determination, it will descend near the crater, take a soil sample, and bring back that soil with the asteroid’s substances in it. The probe will leave Ryugu this winter and return to Earth in winter 2020.
-- What do you think about the potential and development of space-related technology?
Other countries around the world including the US, have their eyes on the Moon and Mars. JAXA is launching projects to land an experimental probe on the Moon and send another one to a Martian satellite in order to bring back rock samples. The next stage is humanity moving its sphere of activities further from the Moon to Mars.
Connecting the Present Day to a Future in which Humanity Lives in Space
-- What challenge do you want to tackle in the future?
I have utilized and want to continue utilizing ICT in order to expand humanity’s sphere of activities in the universe.
-- Do you have any dreams you want to realize?
Since I belong to the Gundam generation as I mentioned earlier (laughs), space colonies really impress me. If we set aside the question of their technological feasibility, an era where humanity lives in space without any problems would be fantastic. There are already several space stations today. When we look back someday, those may be regarded as humanity’s first living environments in space. I hope we can face an age where we will say, “Our current space life started in those space stations.”
-- That would be a wonderful, romantic adventure. Thank you very much.
What Is an Orbit Determination System?
Orbit determination is the estimation of where a spacecraft is and what its speed is at a specific time. The position and velocity of a spacecraft are calculated through radio-wave communication with an antenna on Earth. It is extremely difficult to estimate the position and velocity of a spacecraft in deep space using only radiometric observation. As of June 2019, the asteroid Ryugu is approximately 300 million km away from Earth. Fujitsu’s orbit determination technology used in Hayabusa2 enables aiming that is so accurate that a target a half-meter or so wide located in Chicago could be targeted from Tokyo.