WASHINGTON — Japan launched the first of a new generation of cargo spacecraft to the International Space Station, with potential applications beyond low Earth orbit.
An H3 rocket lifted off from the Tanegashima Space Center at 8 p.m. Eastern Oct. 25 after several days of weather-related delays. It was the first flight of this version of the H3, designated H3-24W, which features two engines in its first stage, four solid-rocket boosters and a wide payload fairing.
The HTV-X1 spacecraft separated from the rocket’s upper stage about 14 minutes after liftoff and deployed its solar arrays less than 10 minutes later.
HTV-X is an upgraded version of the HTV cargo vehicle that the Japan Aerospace Exploration Agency (JAXA) used to transport cargo to the ISS between 2009 and 2020. The new spacecraft, which weighs 16 tons when fully loaded, can carry about six metric tons of cargo, 50% more than the original HTV. That includes four tons of pressurized cargo and two tons of unpressurized cargo.
The HTV-X features several design changes, including a pressurized module with 60% more volume than its predecessor. It has deployable solar arrays, rather than the HTV’s body-mounted panels, that produce 50% more power. Unpressurized cargo is now mounted on the top of the spacecraft, increasing capacity.
HTV-X1 is carrying about 4.5 tons of cargo, including space station hardware, experiments and supplies. That includes six cubesats that will be deployed from the airlock on the station’s Kibo module.
HTV-X1 is scheduled to arrive at the ISS on Oct. 29, where it will be berthed to the station’s Harmony module by the Canadarm2 robotic arm. The spacecraft is designed to remain at the ISS for up to six months, although JAXA officials said at an Oct. 19 briefing that the exact duration of its stay had not been determined.
After departing the station, HTV-X1 will spend about three months in low Earth orbit conducting technology demonstrations. Those will include releasing a cubesat, testing a laser retroreflector mounted on the spacecraft and deploying a structure with a flat-panel antenna and solar cells to test technologies that could be used on future space-based solar power systems.
The HTV-X, which will be loaded with garbage before leaving the ISS, will reenter the atmosphere and burn up over the South Pacific Ocean after completing its mission.
At least three HTV-X missions to the ISS are currently planned. JAXA has also proposed a version of the spacecraft that could deliver cargo to the lunar Gateway.
