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JAXA, NASA prepare to launch precipitation-monitoring satellite

There are approximately five hundred operational satellites, and tens of thousands of pieces of orbital debris, in LEO. Image Credit: NASA

The Japanese Aerospace Exploration Agency (JAXA) and NASA are preparing to launch the Global Precipitation Measurement (GPM) Core Observatory satellite from Tanegashima Space Center located on Tanegashima Island, Japan. Liftoff of the Mitsubishi-built H-IIA rocket is currently scheduled for 1:37 p.m. EST (1837 GMT) February 27.

The joint JAXA / NASA GPM mission will measure the amount of rain and snowfall and coordinate research among other GPM spacecraft. The satellite poised for liftoff was constructed by NASA’s Goddard Space Flight Center in Greenbelt, Md.

The Tanegashima launch site in Japan. Photo Credit: NASA

The Tanegashima launch site in Japan. Photo Credit: NASA

On February 25, the flight team, consisting of engineers from JAXA, NASA, and Mitsubishi Heavy Industries, Ltd. reviewed the readiness of the GPM mission to clear it for launch. All aspects of the mission were covered and the mission was given the go-ahead for launch. The team however did institute one change, the official launch time was pushed back from 1:07 until 1:37 p.m. EST. This change was implemented upon review of a collision avoidance analysis of the GPM Core Observatory’s flight profile and that of the International Space Station.

The weather is certainly cooperating with mostly-clear skies and light winds of only 13 miles per hour (launch constraints come into play at 47 miles per hour).

The launch vehicle and its precious cargo are currently slated to roll out to the launch pad at 11 p.m. EST on February 26.

The spacecraft was encapsulated in its protective fairing on Feb. 13, and then underwent final inspections. The fairing will protect the GPM Core Observatory on its journey “uphill” through the Earth’s atmosphere which it will eventually monitor.

As mentioned, the GPM Core Observatory mission is a collaborative affair with NASA and JAXA taking point, but with the French Space Agency (CNES), the U.S. Department of Defense, Defense Meteorological Satellite Program (DMSP); European Organization for the Exploitation of Meteorological Satellites (EUMETSAT); Indian Space Research Organization (ISRO); and the U.S. National Oceanic and Atmospheric Administration (NOAA) also contributing.

An H-IIA lifts off from Tanegashima Space Center in Japan. Photo Credit: Narita Masahiro

An H-IIA lifts off from Tanegashima Space Center in Japan. Photo Credit: Narita Masahiro

The satellite has a planned design life of three years (but will carry enough fuel for five) and will orbit at a distance of approximately 253 miles (407 kilometers) at an inclination of 65 degrees. It should complete an orbit of the Earth once every 93 minutes or 16 times per day.

The GPM Core Observatory has two primary scientific instruments on board to carry out its mission, they are:

GPM Microwave Imager (GMI)

The GMI was manufactured by Ball Aerospace & technology Corp and will be used to detect total precipitation amounts within all cloud layers to include light rain as well as snowfall. To accomplish this, it measures the strength of microwave energy emitted from all parts of the Earth system.

GMI will use 13 channels to measure the intensity of microwave radiation. Those channels in the low end of the spectrum (10 to 89 gigahertz) will be the ones used to detect heavy-to-moderate rainfall.

Dual-frequency Precipitation Radar (DPR)

The DPR will create 3D measurements of rain and snowfall structures and rates over much of the Earth’s surface. The DPR was designed by JAXA and the National Institute of Information and Communications Technology in Japan and was built by NEC Toshiba Space Systems, Ltd.

Besides the DPR’s Ku-band radar which will measure moderate-to-heavy rain at 13.6 gigahertz, it also has a Ka-band radar which will measure frozen precipitation (snow) as well as light rain at 35.5 gigahertz. Combined, these two radars could shed new information about the different size of raindrops that are within storm systems and how they are dispersed throughout storm clouds.

Combined these instruments should give scientists a better understanding regarding precipitation size, shape and distribution. This should allow for better predictions regarding rain and snowfall estimates across the globe.

Tanegashima Space Center was constructed back in the 1960s during the “Space Race” between the United States and the former Soviet Union. Initially, the complex only launched small rockets aimed at research and development. That changed in the mid-1990s when JAXA began conducting flights of the H-II family of launch vehicles. The H-II was upgraded to the H-IIA after two launch failures of the H-II. The H-IIA is the version of the rocket on the pad for tomorrow’s flight. Out of 22 total flights of the H-IIA – 21 have been deemed successful.

The H-IIA’s flight profile will be managed from the Yoshinobu Block House underground control room. The rocket measures in at about 173 feet (53 meters) tall and some 13 feet (4 meters) in diameter and burns a mix of liquid oxygen and liquid hydrogen as fuel. The H-IIA is Japan’s primary launch vehicle and is designed to be capable of handling a wide range of missions including geosynchronous, sun-synchronous, low-Earth-orbit or even planetary missions.


Video courtesy of NASA


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Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology,, The Mars Society and Universe Today.

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