Japan's 'affordable' Epsilon rocket triumphs on first flight
BY STEPHEN CLARK
Posted: September 14, 2013
A Japanese rocket designed to make launches cheaper and more efficient blasted off from southern Japan on Saturday, achieving success on its first flight with a compact telescope to peer at Mars, Venus and Jupiter and study their response to blasts of solar wind.
Spectacular footage from four on-board "rocketcams" showed remarkable views of the launcher's pulsing roll control jets firing to steer the 100-ton rocket from the launch pad, then recorded sensational imagery of the release of the rocket's nose fairing and deployment of the mission's payload about one hour after liftoff.
The flight appeared to unfold as planned, and data available on a Japan Aerospace Exploration Agency webcast of the launch showed the rocket hit its marks and released the SPRINT-A satellite in an orbit close to the preflight target.
"The launch vehicle flew smoothly, and, at about 61 minutes and 39 seconds after liftoff, the separation of the SPRINT-A was confirmed," JAXA said in a press release. "We would like to express our profound appreciation for the cooperation and support of all related personnel and organizations that helped contribute to the launch of the Epsilon-1."
The Epsilon rocket's hydrazine-fueled upper stage was supposed to position itself in an orbit between 1,150 kilometers, or 714 miles, and 950 kilometers, or 590 miles, in altitude. The rocket was aiming for an orbital inclination of 31 degrees.
SPRINT-A stands for the Spectroscopic Planet Observatory for Recognition of Interaction of Atmosphere. The satellite was manufactured by NEC Corp.
Keeping with the JAXA tradition of renaming satellites after launch, officials christened the 767-pound observatory Hisaki after a cape near the mission's launch site in Kagoshima prefecture.
Hisaki's one-year mission is to observe the atmospheres of Mars and Venus, along with the immense magnetic field of Jupiter, to study how the planets respond to the solar wind, a stream of charged particles coming from the sun.
The craft's 20-centimeter, or 7.9-inch, ultraviolet telescope and will peer at Mars and Venus to help researchers learn how the solar wind can strip a planet's atmosphere, prompting drastic climate changes and eradicating any life that may have existed there.
The product of a Japanese government investment worth more than $200 million, the Epsilon rocket demonstrated new rocket technologies on Saturday's mission, including a computer allowing the booster to complete many of its preflight preparatory tasks autonomously.
The computer was exercised during an aborted countdown Aug. 27, in which the rocket's on-board software detected a fault and automatically aborted the launch seconds before liftoff.
The rocket's computer detected a signal from a sensor indicating the launcher was tilting in the final seconds of the Aug. 27 countdown. Engineers found no evidence the rocket was out of position, but investigators discovered a time lag in the communication between the vehicle computer and the ground control center.
Fabricated from existing rocket motors used on other Japanese launch vehicles, the Epsilon rocket's advancements are not in propulsion but in intelligence and simplicity.
Japan's M-5 rocket, the Epsilon's predecessor in the small satellite launch market, took six weeks to assemble and prepare for launch. Once engineers perfect the Epsilon's prelaunch flow, the rocket will be ready to fly seven days after the booster's first stage is stacked on the launch pad, according to JAXA.
Developed by an industrial team led by IHI Aerospace Co., the Epsilon booster uses the same launch pad as the M-5, which last flew in 2006. Engineers modified the launch pad by adding a 30-foot-tall pedestal and expanding the facility's flame trench.
Designers improved the motor casings on the Epsilon rocket by reducing weight and switching to a tougher carbon fiber material to make the solid-fueled motors more robust, according to Yasuhiro Morita, the Epsilon rocket's project manager at JAXA.
The Epsilon's ground infrastructure also boasts enhancements to drive down launch costs. Launch controllers can plug into the rocket's control network with laptop computers, cutting the size of the team needed on launch day, according to JAXA.
JAXA expects the Epsilon rocket will launch for half the cost of an M-5 rocket mission. Each Epsilon launch is projected to cost about 3.8 billion yen, or approximately $38 million, according to JAXA.
The Epsilon rocket's second mission is scheduled for 2015 with JAXA's Energization and Radiation in Geospace mission to study the effects of solar storms on Earth.
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