The "Global Change Observation Mission" (GCOM) aims to construct, use, and verify systems that enable continuous
global-scale observations (for 10 to 15 years) of effective geophysical parameters for elucidating global climate change and
water circulation mechanisms.
The GCOM mission is a two series of satellites, GCOM-W for observing water circulation changes and GCOM-C for climate
changes. The GCOM-W with a microwave radiometer onboard will observe precipitation, vapor amounts, wind velocity above the
ocean, sea water temperature, water levels on land areas, and snow depths.
The GCOM-W1 is the first satellite for the GCOM-W series.
World's Largest Revolving Space Antenna AMSR2:
The Advanced Microwave Scanning Radiometer 2 (AMSR2,) which will be loaded onto the GCOM-W1, is a sensor to observe
radiometers, or microwaves emitted naturally from the ground, sea surface and atmosphere, using six different frequency
bands ranging from 7 GHz to 89 GHz. The strength of a natural microwave is determined by its characteristics and moisture,
including the surface condition and temperature of the material. Although it depends on the frequency, the microwave is very
weak. AMSR2 will detect such weak microwaves at an altitude of 700 kilometers and measure the strength of them with a very
high accuracy. For example, by measuring the strength of a microwave emitted from the sea surface with the AMSR2, we can
understand the water temperature of the sea surface to an accuracy of 0.5 degrees Celsius.
The antenna of the AMSR2, which receives microwaves from the ground, arc scans the ground surface at a ratio of one turn
every 1.5 seconds and observes an area approximately 1,450 kilometers wide in one scan. Using this scanning method, the
AMSR2 can observe over 99 percent of the Earth's area in just 2 days. The diameter of the antenna is about 2 meters, making
it the world's largest observation sensor aboard a satellite. The height of the rotating part is about 2.7 meters and the
weight is about 250 kilograms. The AMSR2 can keep rotating such a large and heavy antenna at a speed of one turn per 1.5
seconds for 24 hours a day and more than five years without a minute of rest.
Mission details:
Was planned to launched in Feb 2012, delayed to May.
Japan's JAXA space agency launched H-IIA flight F21 from Tanegashima on May 17, 2012 into a 1:30am local time sun-synchronous
orbit at 670 x 674 km x 98.2 deg. The main payloads are Shizuku, JAXA's first satellite in the Global Change Observation Mission series,
and Arirang-3 (Kompsat-3). JAXA's 50 kg SDS-4 Small Demonstration
Satellite (kogata jissho eisei 4-gata) carries four technology experiments including a space-based AIS (ship tracking) payload.
A small 7 kg satellite Horyu-2, will study spacecraft charging effects and test a camera payload for Surrey Satellite.
In addition to the four payloads and the second stage, the upper payload adapter and two side panels from the lower fairing were
catalogued in orbit, for a total of 8 objects. The second stage will be monitored after payload deployment to study improved propellant insulation.
The Global Change Observation Mission 1st - Water "SHIZUKU", completed its critical operations as it was successfully inserted
into the initial orbit and
finished the AMSR2 run-up and other essential events normally. JAXA will take about 45 days to insert the satellite
into the "A-Train orbit" in order to participate in an Earth observation mission called the "A-Train" in cooperation
with satellites of other countries while performing the initial functional confirmation for about three months.