Continuing to explore possibilities for temperature sensors.

Okazaki Manufacturing Company (OMC) is the top firm in the industrial temperature sensor sector, holding over half the market share. For 50 years since becoming the company’s president, Kazuo Okazaki has continued to explore the possibilities for temperature sensors and the mineral insulated (MI) cables inside them. President Okazaki’s policy is not about having a widespread presence in the measuring business: it’s about mastering temperature measurement.

OMC first got into the space sector in 1983. Production of temperature sensors shifted to Japan to develop the Japanese-built rocket, the H-II Launch Vehicle, and OMC applied to the National Space Development Agency of Japan (NASDA) – the predecessor to Japan’s current aerospace agency, JAXA – to make them. OMC was chosen from among the five candidate companies. Since then, all Japanese rockets have been fitted with OMC temperature sensors. In 1990, NASDA certified OMC temperature sensors as standard components for space development, and in 2012 they were certified by the European Space Agency (ESA) and registered on the European Preferred Parts List (EPPL).

OMC moved its Main Plant to Nishi Ward, Kobe in 2012 to consolidate its temperature sensor production. However, aerospace temperature sensors are manufactured at the Kobe Nishi Plant, a factory specializing in these components.

OMC’s Main Plant began operating in 2012. Non-aerospace temperature sensor production is concentrated here.

The Kobe Nishi Plant, which began operating in 2002, produces aerospace temperature sensors. It has its own clean room, testing equipment and other special facilities.

OMC uses microscopes to visually check space temperature sensor soldering.

Assembly of external and internal rocket parts. Sensors are connected by hand.

These photos show the process by which temperature sensor probes are made by connecting MI cables to sensor casings. The process demands delicate work.

Temperature sensor testing equipment. Precise measurements are needed to meet strict demands for reliability.

A temperature sensor undergoing a visual inspection with a magnifying glass.

Temperature calibration laboratory with Japan Calibration Service System (JCSS) certification authorized by the National Institute of Technology and Evaluation (NITE) has equipments of global standard level.


HQ Location Kobe, Hyogo
Established 1954
Main Facilities Main Plant (Kobe, Hyogo Prefecture)
Kobe Nishi Plant (Kobe, Hyogo Prefecture)
Kobe Iwaoka Plant (Kobe, Hyogo Prefecture)
Fukuoka Plant (Kama, Fukuoka Prefecture)
Kyushu Plant (Kama, Fukuoka Prefecture)
Main Products Temperature sensors (sheathed thermocouple, sheathed resistance temperature detecting), sheathed heaters, MI cables, testing equipment, etc.
Main Astronautics Equipment Produced Temperature sensors and liquid-to-gas sensors for the H-II and H-IIA/B Launch Vehicle rockets
temperature sensors for satellites and the KOUNOTORI ISS supply ship
Corporate site



7 types of satellite sensors certified
for the European EPPL.

Kazuo Okazaki

--Your company has mastered temperature measurement, hasn't it?

We've mastered temperature measurement, but we have not gotten into the instrument manufacturing sector. That's our company's policy. Instrument makers are our customers, so we can't compete with them. Instead, we aim to be the uncontested number-one company in temperature measurement.
Fifty or so years ago when I joined the company, it was called Okazaki Trading. That was when I first came across mineral insulated (MI) cables, and I became very interested in them because a cable with two wires inside inorganic matter can instantly tell you the temperature at the end.
There were still restrictions on overseas travel back then, but I flew to the U.S., visited the manufacturer and concluded a contract for us to be their sole distributor in the Far East. I also suggested that they manufacture in Japan to make supplies move more smoothly, but they flat-out refused.
I learned by watching how they worked and then built an MI cable factory. Then I made my proposal to produce in Japan again, and they said yes.

--Tell us how you got into the space sector.

In 1986, the old NASDA (the National Space Development Agency of Japan, now JAXA) said to us, "We're going to develop a Japanese-built rocket. Will you help us develop temperature sensors? " They wanted sensors that were better than the American ones they were using then, and they wanted us to make them within three years.
If we'd let this chance get away, our company would never be anything more than an average maker. The space industry has the toughest product demands. You can get engineering and knowhow with other applications by working in this field and become an outstanding manufacturer. If you can't make these sensors, then you can't be number one in the world. That was how we thought about it when we decided to get into this business.
Astronautics equipment has to be lightweight. And temperature sensors also have strict demands for lightness. There are big, strong vibrations during a launch, so it also has to withstand those.
Furthermore, the required temperature range is very wide. Liquid hydrogen fuel has a temperature of -253℃, which suddenly rises to nearly 1,000℃ when it starts to burn. Plus, the sensors have to respond within 3 milliseconds. On the ground the air pressure is fairly consistent, but outside our atmosphere is a vacuum. The sensors also have to be radiation-proof because they get showered with cosmic rays.
In this environment, the strict conditions just pile up for the durability to make sure measurements that are reliable and highly precise. For this reason, we had to reconsider everything, like the materials and the coating, and develop it from scratch.
We put one-quarter of the employees we had at the time on this project. We invested incredible effort and money, but as a result we completed a temperature sensor that achieved a higher level of engineering. NASDA loved its reliability and they replaced their old static location sensors placed on the surface of the liquid hydrogen/oxygen fuel with our equipment that made use of heaters and temperature sensors with MI cables.

--It seems that getting into the space business was very advantageous for you later on.

With space temperature sensors, you can't just respond to a customer complaint by offering a replacement. First, you reproduce the conditions under which the problem occurred. After replicating the problem, then you determine the cause. Only after that do you try to fix it.
There is a huge difference in the capabilities of companies that do and don't adopt this approach. The degree to which clients trust the company is also completely different. We apply this approach that we've developed working in astronautics to all our temperature sensors in other fields.
Another advantage is that client demands give engineers new things to develop. The results of our past engineering development leaves behind massive amounts of technical data, but it's new customer demands that lead to the creation of new technologies.
Speaking of space, there's still much more room for growth in satellite temperature sensors. Our company's seven types of satellite sensors are certified by the European Space Agency (ESA) for the European Preferred Parts List (EPPL). This means we don't have to append endurance and performance test data when European satellite makers want to use our sensors, so long as there are no special requirements. That makes it easier for European satellite makers to use our sensors. I have very high hopes for the future.

--Okazaki Manufacturing Company(OMC) has been proactively constructing new factories in Japan.

In 2012 we moved our Main Plant to Kobe and consolidated all our non-aerospace temperature sensor production there to further raise efficiency.
Our company places importance on both design and production techniques. The sheathed thermocouple temperature sensor with a 0.08 mm diameter that we developed in 2009 was a result of this. This is how we answered a need for a sensor that can measure the temperature of something with almost no extra space, like a fuel cell.
The main engineering aspect of this sheathed thermocouple sensor depends on how thin the MI cable is. We applied all our production techniques to create this cable: contraction and temperature control during processing, etc. The 0.08 mm diameter is the thinnest in the world. It's even in the Guinness Book of World Records.
We now make more MI cables than anyone else, at 10 million meters a year. We opened a big MI cable factory in Fukuoka Prefecture in 2008 to consolidate production there. This is where OMC's design, production techniques and knowhow come together.