Tuesday, October 10, 2017

JAXA Launches Michibiki-4 Satellite

H-IIA 202 (F36) launch with Michibiki-4. Photo Credit: @naritamasahiro / Twitter

The Japan Aerospace Exploration Agency (JAXA) launched the Michibiki-4 satellite aboard an H-IIA rocket at 7:01 a.m. Japan Standard Time on Oct. 10 (6:01 p.m. EDT / 22:01 GMT Oct. 9), 2017, from the Tanegashima Space Center. The satellite is the fourth in the Quasi-Zenith Satellite System (QZSS), which is a satellite-based positioning system similar to the U.S. operated GPS.

The H-IIA’s liquid hydrogen and liquid oxygen-consuming LE-7A main engine ignited a few seconds before the four solid rocket boosters, which quickly pushed the launch vehicle off the pad and out over the Pacific. Some 130 seconds into flight, one pair of boosters dropped off, followed a couple seconds later by the second pair. The first stage continued to burn for another 4.5 minutes before jettisoning.

About seven minutes after leaving Japan, the LE-5B upper stage engine, which also consumes liquid hydrogen and liquid oxygen, ignited and burned for almost six minutes before shutting down. The upper stage and spacecraft remained in this parking orbit until a mission elapsed time of 24 minutes, 34 seconds. Then a second burn occurred, lasting for about three minutes, placing Michibiki-4 into an elliptical geosynchronous transfer orbit.

About 29 minutes after liftoff, the satellite was deployed. Michibiki-4 (QZS-4) will use its onboard propellant to transfer it into its slightly elliptical geosynchronous orbit of 20,267 by 24,202 miles (32,618 by 38,950 kilometers), inclined 41 degrees.

This was the 36th H-IIA vehicle to be launched and represents the fifth launch of an H-IIA rocket in 2017. Manufactured by Mitsubishi Heavy Industries, the vehicle stands 174 feet (53 meters) tall and generates 1.7 million pounds-force (7,628 kilonewtons) of thrust at liftoff. The H-IIA rocket is the primary Japanese large-scale launch vehicle.

Michibiki-4 is the third QZSS satellite to be launched in 2017 and once operational will bring the constellation to its operating capacity of four until a planned expansion to seven satellites occurs around 2023. Once the four-satellite constellation becomes fully operational in 2018, at least 3 QZSS satellites will be visible in the Asia-Oceania regions at any given time.

QZSS can be integrated with GPS satellites to enable a higher level of precision than previously possible with fewer satellites in visible range. The QZSS constellation will trace out a figure-8 pattern over Japan, the Western Pacific, and Australia. It is expected that at least 8 satellites will be available at any given time when combining QZSS and GPS capabilities over Asia-Oceania. It will provide global positioning and timing services across frequencies ranging from 1575.42 MHz to 2 GHz.

Written by: Paul Knightly
Original source: spaceflightinsider.com

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