Due to an apparent issue with the ground system, JAXA has cancelled its planned launch of the Epsilon rocket, which would have carried the RAISE 2 satellite and rideshare payloads.
According to Space.com, an Epsilon rocket was supposed to launch from Japan's Uchinoura Space Center tonight at 8:51 p.m. EDT during a four-minute window.
The Epsilon was meant to put the RAISE 2 (Rapid Innovative Payload Demonstration Satellite 2) and eight additional JAXA tagalong spacecraft to orbit.
RAISE 2 Technology Explained
The RAISE 2 is a technology demonstrator, as its name suggests. It weighs 240 pounds (110 kilograms). According to JAXA officials, the spacecraft, built by Mitsubishi Electric Corp., will test six different space technologies, including a small sensor called MARIN, which will be used to measure the position, altitude, and velocity of orbiting satellites.
The other eight satellites built by a wide range of Japanese companies and universities are even smaller than the RAISE 2, which measures 3.3 feet (1 meter) in diameter. Four of the rideshare spacecraft weigh less than 8.8 pounds (4 kg), while the remaining four weigh between 101 and 137 pounds (46 to 62 kg). (Of course, in orbit, those satellites will lose weight, but they will still have mass.)
DRUMS (Debris Removal Unprecedented Micro-satellite), a Kawasaki Heavy Industries craft, is the heaviest tagalongs. The 2.75-foot-wide (84-centimeter) DRUMS will release and then capture a small object once it reaches orbit, demonstrating technology that could one day help humanity clean up space junk.
Epsilon Rocket Explained
The 78-foot-tall (24-meter) Epsilon, which JAXA began developing in 2007, will be on its fifth mission. According to the JAXA specifications page, the solid-fueled rocket can deliver payloads weighing up to 2,646 pounds (1,200 kg) to low Earth orbit. It's a three-stage solid-fueled rocket that's meant to complement Japan's larger H-IIA rocket, with which it shares some components.
NASASpaceFlight said the H-IIA uses two or four SRB-A3 solid rocket motors as boosters to provide additional thrust at liftoff. Epsilon's second stage, the M35, was derived from the M-V rocket's third stage, and its third stage, the KM-V2c, is based on a kick motor used as a fourth stage on some M-V missions. HTPB, a common solid propellant compound being used in rockets, is burned in all three stages.
Japan's previous small satellite launcher, the M-V, was retired in 2006 and was the final extension of the Mu family of rockets. M-V was expensive for its capabilities, and one of the Epsilon project's main goals was to provide low-cost access to space for small satellite missions.
The basic Epsilon vehicle has three stages, but it usually flies in a four-stage configuration with a post-boost stage (PBS), the hydrazine-fueled Compact Liquid Propulsion System (CLPS). This can be restarted multiple times throughout the mission to infuse a satellite into an accurate orbit or deliver multiple payloads to different orbits. Epsilon 5 will use this configuration, with a brief orbit adjustment expected between the third and fourth payload separations.
Epsilon has successfully completed all four of its previous launches. The January 2019 mission carried a cluster of seven payloads, after the first three flights each launched a single satellite. RAPIS-1, the forerunner of the RAISE-2 satellite, was the primary payload for that launch.
Epsilon launches are carried out from the Uchinoura Space Center in Kagoshima Prefecture, Japan, where the former M-V launchpad once stood. This complex, known as the Mu Center, was built for the Mu-3 series of rockets and has undergone several modifications as Japan's rockets have progressed. Mu rockets were launched by rail. The former launch rail is now used as an umbilical tower for the Epsilon, launched vertically.
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