- Joined
- Jan 22, 2026
- Messages
- 101
- Reaction score
- 948
Telemetry showed a drop in pressure, and the camera recorded damage to the satellite.
The Japanese H3 rocket failed in such an unusual way in December that in the first days after launch it was not even completely clear what exactly happened to the payload. Now the Japanese Aerospace Exploration Agency JAXA has revealed the details of the investigation, and they sound almost like a scenario: the navigation satellite died not because of a "normal" engine failure, but because it lost its protective shell too soon.
The seventh launch of H3 took place on December 21, 2025. The rocket, about 63 meters high, launched the Michibiki 5 satellite into orbit, which belongs to the Japanese navigation system. Shortly after launch, an anomaly occurred in the second stage, the engine shut down prematurely, and the mission was disrupted. But during the analysis of telemetry, it turned out that the root cause was much earlier: about four minutes after launch, the head fairing, that is, the cone-shaped protective shell that covers the satellite in dense layers of the atmosphere, suddenly began to collapse.
After that, the satellite actually remained "naked" at a time when the loads were still far from normal for deployment. According to JAXA, it was during this period that the pressure drop in the hydrogen tank of the second stage was noticed on the telemetry, and even during the operation of the first stage engines. Because of this, the shutdown of the first stage occurred 27 seconds later than planned, and the restart of the second stage was delayed by about 15 seconds. Later, the investigation linked the pressure drop to an abnormal fairing separation: shock and vibrations could damage both the satellite itself and the mounting adapter.
This picture was reinforced by video from the camera mounted on the adapter. The footage shows that after the fairing leaves, the satellite's panels and thermal insulation are damaged, fragments of debris are flying around, and the device itself remains "stuck" to the rocket for some time, although there is no protection anymore. When the first stage separated, the next shock tore the satellite from its mount, and it walked away from the rocket, with virtually no chance of escape. According to the agency, the device eventually fell into the Pacific Ocean, approximately in the same area where the first stage collapsed.
The unusual situation is that rockets are more often characterized by engine failures, problematic automation, or errors in stage separation. A chain of events started here due to the destruction of the fairing, and it was she who, according to JAXA, launched the further "domino effect". The agency has not yet explained why the fairing suddenly began to fall apart, this part remains the subject of a separate investigation.
For the H3, this is a painful story also because the rocket took a long time to achieve the status of a workhorse. It was created for about 11 years as the successor to the H 2A, which was finally decommissioned in June 2025. The H3's debut in March 2023 ended with a self-destruct command about 15 minutes after launch, but then the rocket managed to complete five successful missions in a row, and the agency expected to reach at least two launches per year.
Now these plans can move forward. For 2026, H3 had new navigation devices in line, the HTV X cargo ship to supply orbital programs, as well as the MMX mission to the Martian satellites, scheduled for the end of 2026. After such a strange failure, JAXA will probably have to revise the schedule until it becomes clear why the protective fairing behaved as if it had been detached ahead of time.
The Japanese H3 rocket failed in such an unusual way in December that in the first days after launch it was not even completely clear what exactly happened to the payload. Now the Japanese Aerospace Exploration Agency JAXA has revealed the details of the investigation, and they sound almost like a scenario: the navigation satellite died not because of a "normal" engine failure, but because it lost its protective shell too soon.
The seventh launch of H3 took place on December 21, 2025. The rocket, about 63 meters high, launched the Michibiki 5 satellite into orbit, which belongs to the Japanese navigation system. Shortly after launch, an anomaly occurred in the second stage, the engine shut down prematurely, and the mission was disrupted. But during the analysis of telemetry, it turned out that the root cause was much earlier: about four minutes after launch, the head fairing, that is, the cone-shaped protective shell that covers the satellite in dense layers of the atmosphere, suddenly began to collapse.
After that, the satellite actually remained "naked" at a time when the loads were still far from normal for deployment. According to JAXA, it was during this period that the pressure drop in the hydrogen tank of the second stage was noticed on the telemetry, and even during the operation of the first stage engines. Because of this, the shutdown of the first stage occurred 27 seconds later than planned, and the restart of the second stage was delayed by about 15 seconds. Later, the investigation linked the pressure drop to an abnormal fairing separation: shock and vibrations could damage both the satellite itself and the mounting adapter.
This picture was reinforced by video from the camera mounted on the adapter. The footage shows that after the fairing leaves, the satellite's panels and thermal insulation are damaged, fragments of debris are flying around, and the device itself remains "stuck" to the rocket for some time, although there is no protection anymore. When the first stage separated, the next shock tore the satellite from its mount, and it walked away from the rocket, with virtually no chance of escape. According to the agency, the device eventually fell into the Pacific Ocean, approximately in the same area where the first stage collapsed.
The unusual situation is that rockets are more often characterized by engine failures, problematic automation, or errors in stage separation. A chain of events started here due to the destruction of the fairing, and it was she who, according to JAXA, launched the further "domino effect". The agency has not yet explained why the fairing suddenly began to fall apart, this part remains the subject of a separate investigation.
For the H3, this is a painful story also because the rocket took a long time to achieve the status of a workhorse. It was created for about 11 years as the successor to the H 2A, which was finally decommissioned in June 2025. The H3's debut in March 2023 ended with a self-destruct command about 15 minutes after launch, but then the rocket managed to complete five successful missions in a row, and the agency expected to reach at least two launches per year.
Now these plans can move forward. For 2026, H3 had new navigation devices in line, the HTV X cargo ship to supply orbital programs, as well as the MMX mission to the Martian satellites, scheduled for the end of 2026. After such a strange failure, JAXA will probably have to revise the schedule until it becomes clear why the protective fairing behaved as if it had been detached ahead of time.
