This is Part 3 of a series highlighting how our products are contributing to Japan's space development efforts!

Previous articles introduced "IR Flock Sheet," used in the darkroom JAXA (Japan Aerospace Exploration Agency) built for star tracker testing, and "Fineshut KIWAMI," used in the visible-light camera of the Milky Way Galaxy Research Center's astronomical observation telescope. Both examples show how these materials are already playing a role in real space research.

A Visit to JAXA's Sagamihara Campus

JAXA's Sagamihara Campus serves as a key research facility dedicated to studying a range of cosmic phenomena, including solar activity, the Moon and planets, black holes, and the formation of galaxies.

Situated in a quiet, green area about a 20-minute walk from Fuchinobe Station, the campus feels like an unexpectedly peaceful home for such pioneering space research. Right at the entrance, visitors are greeted by a 30-meter-long rocket—a fitting reminder of the facility's role at the forefront of Japan's space exploration efforts.

We'll go deeper into how these technologies support Japan's astronomical research in upcoming posts—but first, here's a look at the visit itself.

Photograph from the Special Public Viewing at Sagamihara Campus (2015)

We interviewed Researcher Miyagawa, who recently purchased "Fineshut KIWAMI."

The rooftop observatory at JAXA's Sagamihara Campus was originally built in 1988 as a prototype for Japan's Subaru Telescope, a large optical-infrared telescope located in Hawaii. At the time, Japan had no prior experience manufacturing large equatorial-mounted astronomical telescopes. This observatory was built to help establish a track record before the development of the Subaru Telescope, making it a historically significant instrument in its own right.

When the observatory was first built, the surrounding area was dark, allowing for unobstructed astronomical observations. Over time, though, urban development brought increased artificial lighting, and the resulting stray light became a growing concern for the telescope's observations.

To address this issue, Researcher Miyagawa focused on "Fineshut KIWAMI," a high-performance anti-stray light sheet we developed.

Already familiar with us through television and other media, Researcher Miyagawa turned to our website after noticing that urban lights were introducing noise into the rooftop observatory's telescope. After reviewing the available materials, he chose "Fineshut KIWAMI" as the best solution.

Introduction to Fineshut KIWAMI: Anti-Reflection Material

The Fineshut series was developed for use on the interior surfaces of optical devices, to prevent internal reflections. It consists of an ultra-fine foamed polyurethane sheet that balances exceptional optical properties with a thin profile. "Fineshut KIWAMI" retains these core material properties while adding a complex surface texture to further enhance light absorption.

One of the standout features of this product is its high light absorption in the infrared spectrum. Traditional anti-stray light materials that rely on dye-based coloring—unlike the carbon-based flocked fabrics we produce, such as our own "IR Flock Sheet"—appear black to the human eye but lose absorption efficiency at wavelengths above roughly 700nm, making them ineffective for near-infrared stray light suppression.

The Fineshut series avoids this problem entirely by blending carbon directly into the raw material, ensuring consistent light absorption across both visible and infrared wavelengths. This makes it an ideal anti-stray light solution for industrial cameras sensitive to near-infrared light.

Effectiveness of Fineshut KIWAMI

Researcher Miyagawa's team has installed "Fineshut KIWAMI" inside the telescope's visible-light camera, as well as on the telescope's structure, to minimize stray light interference. Data analysis confirms a significant reduction in light noise, demonstrating the material's effectiveness.

Currently, the observatory's telescope is equipped with a visible-light camera. However, the team plans to install an infrared detector developed for the JASMINE Project within the coming year. This detector will be used for ground-based data collection before being launched aboard a satellite.

The JASMINE Project aims to deploy an infrared observation satellite to conduct high-precision observations of the central region of the Milky Way Galaxy. This initiative has attracted significant attention, and we're proud that materials we've developed are contributing to such an ambitious project.

Visiting the Astronomical Observation Telescope

After the interview, we visited the site to see the telescope where "Fineshut KIWAMI" is in use.

By the time we took the elevator to the rooftop of JAXA's Sagamihara Campus, the earlier rain had stopped, revealing a clear sky.

On the rooftop, a circular observatory houses a 1.3-meter telescope, actively used for astronomical observations. The image below shows the telescope in its current setup.

This was the first time we'd seen an astronomical observation telescope at a public facility, and its size was truly astonishing. Considering that this is just the prototype for the Subaru Telescope, the actual Subaru Telescope in Hawaii must be an incredibly massive structure.

Here is an image captured by the telescope's visible-light camera.

"Fineshut KIWAMI" has been applied to the interior of the telescope to prevent stray light. It has also been used to reduce stray light in the optical path of the visible-light camera, specifically in the area marked by the red dashed circle.

"Fineshut KIWAMI," mounted on a cardboard backing, was also applied to the back of the secondary mirror. Because "Fineshut KIWAMI" is easy to cut and can be applied to a variety of surfaces, it made this kind of trial-and-error prototyping easy—a real advantage during testing. Given how well this worked, the team eventually plans to upgrade the part by replacing the cardboard with a metal or plastic component for a finalized version.

Conclusion

"IR Flock Sheet," previously featured as a key material in the development of special darkrooms for star tracker testing, has been playing a role in Japan's space research. Similarly, "Fineshut KIWAMI" and "Musou Black Paint" are already helping prevent stray light inside astronomical observation telescope cameras. This visit also gave us a preview of what's next: once the JASMINE Project's infrared detector is installed at the same site, "Fineshut KIWAMI" will play a role there too.

We're honored to see these materials contributing to Japan's space development once again. We'll keep pushing our ultra-black materials forward to support this growth.

Thank you for your support, and stay tuned for future developments!