A Mitsubishi Heavy Industries H-IIA rocket placed the Michibiki 4 spacecraft into orbit yesterday. This is the latest element of Japan’s indigenous satellite navigation constellation. The Michibiki constellation, which means “guiding the way”, is also called QZS – quasi-zenith satellite – because the complementary orbits of the four spacecraft will ensure that there is always a satellite near the zenith (as long as you’re in the Eastern Hemisphere, anyway, and particularly near a band from Japan to Australia). They are all intended to operate at geosynchronous altitude, much higher than the GPS constellation, but at a significant inclination. Geostationary satellites orbit on the plane of the Earths’ equator, which allows them to appear fixed in the sky. Since these have an inclined orbit, they will trace a figure-8 pattern in the sky over the course of a day. This variation will give GPS receivers something to track. Yes, I did say GPS — Japan says this will be fully compatible with GPS signals. It will be particularly beneficial in the dense urban areas of Japan, where GPS struggles to be accurate due to all the buildings blocking satellite signals. With satellites that stand high in the sky all the time, it will be much easier to get enough signals for a fix.
This was H-IIA’s thirty-sixth launch.
Japan has launched their newest radar spy satellite, the Information Gathering Satellite (IGS) Radar 5, aboard the H-2A rocket from Tanegashima Space Center. It joins an existing constellation of spy satellites which Japan began assembling in 1998 following a North Korean missile launch that flew over Japanese territory. Officially, the IGS program supports civilian needs, such as disaster awareness, but the unspoken main goal is to keep tabs on Japan’s enemies. This launch of course was not in response to last week’s North Korean missile tests; satellites and launch vehicles take years to plan and procure. But I am sure Japan hopes for it to send a message all the same: we are watching.
Japan has begun placement of its first military commsat constellation, which when complete will be a trio of geostationary commsats serving the Japan Self Defense Force and free them from dependency on commercial satellite operators, who currently lease bandwidth to them. DSN-2 is the first because DSN-1, originally slated to fly aboard an Ariane V in 2016, was damaged in shipment and is currently in Japan, undergoing repairs.
Unlike most countries’ military satellites, the DSN constellation will not be owned or operated by the Japanese government. Instead, they belong to a private corporation, DSN Corp, which itself is owned mostly by SKY Perfect JSAT Corp, a commercial commsat operator. So, in a sense, the JSDF will still be procuring bandwidth from a commercial operator, but now the satellites will be entirely dedicated to them. The satellites themselves are built by NEC, on a chassis manufactured by Mitsubishi Electric Company. They will provide Japan’s military with X-band satellite communications for the first time.
Tuesday, the European Sentinel 3A oceanographic satellite was placed into orbit by a Rockot launcher operating out of Plesetsk Cosmodrome in the Russian Arctic.
Then today, Japan’s H-IIA rocket placed the ASTRO-H X-ray observatory into orbit from Tanegashima Space Center.
Japan’s H-IIA rocket, built by Mitsubishi Heavy Industries, primarily serves the Japanese government, lofting spy satellites, weather satellites, and scientific spacecraft, including SELENE/Kaguya, Ikaros, and the Hayabusa 2 asteroid sample return mission, but as of today it is now also a commercial competitor, having launched Telstar 12 Vantage for Telesat of Ottawa, Canada.
The rocket’s core stage and upper stage both use liquid hydrogen and liquid oxygen; note the sparkly pyrotechnics firing under the engines before ignition, just like the Space Shuttle, to burn off excess hydrogen released during the startup process. The four strap-on boosters (H-IIA flies with 2-4, depending on mission requirements) are solid propellant motors manufactured in Japan. (Some H-IIAs fly with Castor 4 motors built by ATK, but not this one. Like the motor count, it depends on mission requirements.)