2024

NTN Corporation (hereafter, NTN) has received a letter of appreciation from Japan Aerospace Exploration Agency (JAXA) for contributing to the development and successful launch of “H3 Launch Vehicle (H3TF2: Test Flight No.2)” through supplying all bearings to of the turbo pumps *¹.

The turbo pumps feed fuel of liquid hydrogen and oxidizer of liquid oxygen into the combustion chamber of the engine. As liquid hydrogen is at -253°C (-423.4°F) and liquid oxygen is at -183°C (-297.4°F), which is cryogenic temperature, lubricant freezing is a concern for bearings used in impeller in turbo pumps. In addition, since the impeller rotates at high speed, bearings are required to have excellent high speed rotational performance.

NTN's bearings used in “H3 Launch Vehicle” adopt its proprietary solid lubricant that offers excellent lubricating performance even at cryogenic temperatures. In addition, by using reinforced fiberglass for retainer, we have secured the strength to withstand centrifugal force during high speed rotation. The use of ceramics balls, which is more lightweight than balls made from metal, suppresses the centrifugal force of balls when rotating. As a result, the product achieves high speed rotational performance with dmn value*² of 2.88 million as a bearing for turbo pumps of “H3 Launch Vehicle” at cryogenic temperatures.

NTN will continue to contribute to the development of the aerospace field by developing and providing products with the functions required for the field.

1. Press release on February 19, 2024:
   NTN Supplies Bearings to “H3 Launch Vehicle”
   https://www.ntnglobal.com/en/news/press/news202400016.html
2. An indicator that expresses the rotational performance of bearings and it is multiplied bearing pitch circle diameter (mm) by rotational speed (min^-1)

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