Research Director Dr. Hironori Sahara

Dr. Hironori Sahara

Faculty of System Design, Tokyo Metropolitan University
Professor, Division of Aerospace Engineering

What is this common obstacle?
It was a well known fact, tested around the world, that even in a university laboratory setting, it is possible to launch microsatellites. However there was no clear goal on what to do with the launched microsatellites. Back in the day, the satellites came first without any specific purpose unlike the current trend where we make satellites for a specific purpose.
However, this project had a very clear concept and a big potential to make contributions to academic research.
For example, in the Earth's atmosphere, there's a layer called the mesosphere. The mesosphere is said to impact the climate in spans of a few months to few years, but the altitude is too high to make measurements using balloons and too low for satellites. There are options to use observation rockets, natural shooting stars, or auroras, but the options are limited for research experiements. In contrast, data obtained through this artificial shooting star project will be significant in learning about how the mesosphere works.

What was your role in this project?
First, I started working on a discharge device for source particles (those that become the shooting star) along with partner manufacturers, since deciding on the right material of source particles and accurately discharging them are essential for this project.
We started working on the device with Dr. Watanabe at Tokyo Metropolitan University (currently Lecturer at Teikyo University). However as he was transferring to Teikyo University, we split up the responsibity by having him be in charge of directing the discharge device development along with partner manufacturers and developing the feeding device. I became responsible for the development of the source particle and simulation of the discharged particles (calculations including particle speed, temperature change, and atmospheric influence). This was around 2012.
With regards to the source particle, we were using an instrument called the arc-heated wind tunnel, to further our research on material, size, and shape of the source particle. Last year (2014), Dr. Abe from Nihon University joined the project and we started working together on the source particle.
Together with Dr. Watanabe and Dr. Abe, I believe that we have a very strong development team compared to what we started with three years ago.
With this team, we're currently working on the orbital calculation of the shooting star and minimization of the probability of the particle colliding with debris and satellites in orbit.