The failure of a key valve in the main engine of Japan’s H2A launcher during a combustion test recently may have been more serious than it first appeared.

The malfunctioning valve in the liquid hydrogen pump of the LE 7A engine may have to be redesigned before further tests can be run on the engine, the Japanese daily newspaper Yomiuri Simbum reported.

Japan’s national Space Development Agency (NASDA) expects to report on the failure, which occurred on July 5, at a meeting of the Space Activities Commission.

When the engine was shut down, which should have immediately closed a valve In the liquid hydrogen pump, the valve remained open, allowing the leftover liquid hydrogen to flow out of the fuel tank and ignite at the edge of the nozzle, the newspaper said.