Japan launches HTV cargo ship to ISS

Japan today successfully launched to ISS the last of its first generation HTV cargo ships.

This was the ninth such cargo ship launched by Japan. The mission was also the last launch of Mitsubishi’s H-2B rocket, Japan’s most powerful. It is being replaced with the H-3 rocket, which they hope to fly for the first time before the end of this year. They also hope that the H3 will be cheaper to operate, and will allow Mitsubishi to garner some commercial business with it, something they failed entirely to do with the H-2B.

This was also Japan’s second launch in 2020, which means they remain outside the leaders in the 2020 launch race:

8 China
6 SpaceX
6 Russia
3 ULA

The U.S. continues to lead China 11 to 8 in the national rankings.

Mitsubishi IDs cause of launchpad fire, reschedules launch

Mitsubishi, the Japanese company that builds the H-2B rocket for Japan’s space agency JAXA, has identified the cause of the dramatic launchpad fire that broke out only about three hours before the launch of their HTV unmanned ISS cargo freighter.

MHI announced Friday that officials believe the fire started near an “exit hole” on the mobile launch platform. Investigators believe the blaze was most likely caused by static electricity, and exacerbated by a flammable oxygen-rich environment inside the mobile launch platform.

Low winds at Tanegashima during the Sept. 10 countdown allowed oxygen vapors to build up at the launch pad in higher concentrations than previous countdowns, officials said. Super-cold oxygen is used as an oxidizer in both stages of the H-2B rocket, and also flows through the first stage’s twin LE-7A main engines during pre-launch “chilldown” conditioning procedures.

“As a result of the investigation, it was confirmed that there was a high possibility that the fire spread due to the static electricity generated by the oxygen dripping from the engine exhaust port during the propellant filling operation, which continued to blow on the heat-resistant material in the exit hole at the movable launch pad,” MHI said in a statement. “We have taken corrective measures and have confirmed normal functioning of the rocket and facility,” MHI said.

They have rescheduled the launch for September 26. Initially they were aiming for September 24, but rescheduled because there might be an orbital conflict between their rocket’s second stage and the launch of a Soyuz to ISS that same day.

Video of the Japanese launchpad fire

I have embedded below the fold the video of the launchpad fire on September 10 that forced Japan to scrub the launch of its H-2B rocket carrying its HTV unmanned cargo freighter to ISS.

I set up the video to start just prior to the appearance of the fire, at 10 minutes in. Its appearance is quite dramatic. The video then continues for about twenty more minutes, showing the fire-fighting effort that brings the fire under control.

Japan’s space agency JAXA has still not released any further information about what caused the fire, the damage, or when they might reschedule the launch.
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Japan scrubs launch due to launchpad fire

Japan today scrubbed the launch of its unmanned HTV cargo freighter to ISS due to a launchpad fire that broke out only three and half hours before liftoff.

There is as yet no word on the cause of the fire, or how much damage it caused. Nor have they said anything about rescheduling the launch.

This would have been Japan’s second launch in 2019, a drop from the average of 4 to 6 in the last five years.