H3 launches navigation satellite

WASHINGTON — A Japanese H3 rocket successfully launched a navigation satellite Aug. 10, more than seven months after a similar launch ended in failure.

The H3-22S rocket lifted off from the Tanegashima Space Center at 3:23 p.m. Eastern, after several days of delays caused by a passing typhoon. The rocket’s upper stage successfully deployed the Michibiki 7 satellite into its planned transfer orbit 29 minutes later.

Michibiki 7 is part of Japan’s Quasi-Zenith Satellite System, or QZSS, a regional navigation system designed to augment global services like the Global Positioning System. The 4.9-metric-ton satellite will operate in a slightly inclined geosynchronous orbit.

This launch was intended to complete the expansion of QZSS from four to seven satellites, using a mix of geostationary and inclined geosynchronous orbits. That seven-satellite system would ensure that at least four satellites are visible over Japan at any time, allowing them to be used exclusively for positioning without also using signals from other navigation satellite systems.

However, one of the new satellites, Michibiki 5, was lost in an H3 launch failure last December. An investigation linked the failure to shocks during payload fairing separation that damaged both the satellite and payload adapter, which in turn caused a pressure loss in the upper stage’s liquid hydrogen fuel system. The satellite itself appeared to fall off the adapter when the upper stage separated from the lower stage.

This is the first flight of that version of the H3, with two engines in its lower stage and two solid-fuel boosters, since the December failure. The H3 returned to flight in June on a test flight of a different configuration, the H3-30S, which uses three engines in its lower stage but no solid-fuel boosters. That launch carried several small satellites.

Japanese officials are pushing to increase the H3’s launch rate, and that of the Japanese launch industry in general. At the Spacetide conference in July, government officials said national space policy has a goal of 30 launches a year from Japan by the early 2030s.

That would mark a steep increase over current launch activity. The launch of Michibiki 7 was just the third launch from Japan this year: two by the H3 and a failed launch in March of Kairos, a small launch vehicle operated by Space One.

The H3 alone will not be able to achieve that goal. Initial plans for the H3 called for six launches a year, said Iwao Igarashi, vice president and general manager of the Space Systems Division at Mitsubishi Heavy Industries, or MHI, the prime contractor for the H3.

Igarashi, speaking at a July 28 event where Japanese lunar lander company ispace signed a contract for an H3 launch of its Mission 3 lander in 2028, said his company and the Japanese space agency JAXA are in talks to increase that capacity to eight launches a year. “With government officials, we are discussing if we want to increase that number even more,” he said.

JAXA and MHI did not disclose when the next H3 launch is planned. However, an H3 launch is projected for November for JAXA’s Martian Moons Exploration, or MMX, mission, which will travel to the moons of Mars and collect samples from Phobos for return to Earth.

The second HTV-X cargo spacecraft mission to the International Space Station is also tentatively scheduled to fly this year on an H3, but NASA did not mention it among the other vehicles planned to go to the ISS in the coming months during an Aug. 3 briefing about the Crew-13 mission to the ISS.

Reporting from SpaceNews contributed to this story.