MTSAT (Multi-functional Transport Satellite) Himawari

The MTSAT series fulfill two functions: that is a meteorological function and an aeronautical function. Multi-functional Transport Satellites (MTSAT) is a series of geostationary weather satellites operated by the Japan Meteorological Agency (JMA). MTSAT carries an aeronautical mission to assist air navigation, plus a meteorological mission to provide imagery over the Asia-Pacific region. The meteorological mission includes an imager giving nominal hourly full Earth disk images in five spectral bands (one visible, four infrared). The satellites also have the capability to relay weather data from remote Automatic Weather Stations.

MTSATs have been placed at an altitude of about 36,000km above the equator, and its satellites have always observed a vast area within a 6,000-km radius of a point just underneath the spacecraft, covering approximately a quater of the earth's surface. The Japan Meteorological Agency (JMA) operated the GMS and MTSAT series of satellites at around 140 degrees east to cover the East Asia and Western Pacific regions since 1977, and makes related contributions to the WMO's World Weather Watch (WWW) Program.

A successor to the GMS series was expected by 1999 under the MTSAT (Multi-functional Transport Satellite) program. Specifications and a contract award were expected to be released in 1995. MTSAT-1 and 1R were built by Space Systems/Loral.

MTSAT is a box-like structure, 2.4m x 2.6m x 2.6m. The overall deployed length is about 33 meters and a launch mass of the spacecraft is about 2900 kg (dry mass is 1250 kg). It has a 2.7 KW Gallium Arsenide (Ga As) solar array with 3 panels, each 2.4m x 2.6m, mounted on the South pointing side. The array rotates to track the Sun and charges the Ni-Cd batteries. The use of a single solar array allows the emager's north-facing passive radiation cooler to view cold space. There is a 3.3m solar sail on a 15.1m boom on the North side. The solar sail counteracts the torque produced by sunlight pressure on the solar array. The trim tab on the solar array makes small adjustments to the torque balance. Two aeronautical L-band antennas (spot and global) are mounted on the East and West sides.

The Image Sensor, the S-band Receive and Transmit antennas, the UHF antenna for the meteorological mission, and the Ku and Ka spot antennas for the aeronautical mission are all mounted on the Earth facing side. Also mounted on this side is the Earth Sensor which is next to the attitude control system which maintains the spacecraft's position in space using 12 small thrusters.

The MTSAT series of satellites are three axis stabilised satellites which use momentum wheels in the two horizontal axes and two reaction wheels in the vertical axis. The motion of the satellite can then be managed by increasing or decreasing the rotational speed of any of the "wheels" to provide corrections to the satellite's orbital path or to correct for roll, pitch and yaw of the satellite.

The imagery from the Earth is collected using the Japanese Advanced Meteorological Imager (JAMI) on board the satellite. The JAMI scans the Earth using a gimballed two axis scan mirror which relays the input scene to an off axis focal telescope. This telescope is focussed onto two focal planes which spatially sample the Earth at 4 km for the infrared channels and 1 km for the visible channel. The image sizes for a full Earth scan are then equivalent to an image of 121 million pixels for the visible image and 7.5 million pixels for the infrared images. The scan function of the imager is completely flexible but to scan the whole Earth from pole to pole takes about 20 minutes.

From its geosynchronous orbital position at 140 degrees East longitude, MTSAT-1 would carry aeronautical services and a meteorological payload on one satellite. Operating in L-band, the satellite would provide communications and navigational services for aircraft, and would gather weather data for users throughout the entire Asia-Pacific region -- as far south as Australia and New Zealand.

Japan's Civil Aviation Bureau would use MTSAT-1R to increase the efficiency of aircraft flight routes, provide flexible flight profile planning, enhance air travel safety, and improve the quality of aeronautical communications. The Japanese Meteorological Agency (JMA) would use MTSAT-1 to deliver observed data to a processing station and provide cloud imagery and continuous weather data from around the region, such as cloud and water vapor distributions, cloud-motion wind vector, sea surface temperature, and information on typhoon, low pressure, and frontal activity.

MTSAT-1 was a version of SS/L's space-proven three-axis, body-stabilized 1300 bus. SS/L's satellites are designed to achieve long useful orbital life through use of bipropellant propulsion and momentum-bias systems for excellent station-keeping and orbital stability. A system of high-efficiency solar arrays and lightweight batteries provide uninterrupted electrical power. SS/L satellites have amassed more than 1000 years of reliable on-orbit service.

MTSAT-1 used many of the same technologies developed for the most recently deployed U.S. Geostationary Operational Environmental Satellite program, called GOES, for which SS/L was the prime contractor. SS/L manufactured five GOES satellites (I-M) under contract to the National Aeronautics and Space Administration (NASA) for delivery to the National Oceanic and Atmospheric Administration (NOAA) for operations.

The launch of MTSAT-1, on a Japanese H-II rocket, failed on November 15, 1999 and the spacecraft was destroyed. GMS-5, the satellite MTSAT-1 was intended to replace, was decommissioned on April 1, 2003 leaving Japan without weather satellite imagery.

Space Systems/Loral (SS/L) announced March 19, 2004 that it had completed integration and testing of the MTSAT-1R satellite and has shipped the spacecraft to Japan's space center in Tanegashima, Japan, where it would await launch on a H-IIA rocket. MTSAT-1R was built for the Japanese Civil Aviation Bureau (JCAB) and Japanese Meteorological Agency, both of the Ministry of Land, Infrastructure and Transport (MLIT).

Mtsat-1R is a Japanese geostationary weather satellite that was launched by a H-2A rocket from Tanegashima Space Center in Kagoshima prefecture at 09:25 UT 2005-02-26. The 1.78 tonne, satellite would make continuous observations of Earth's surface and cloud cover. Another package on-board would relay transmissions from mobile telephones. It was expected to replace HIMAWARI 5 after parking over 140 deg-E longitude.

MTSat 2

MTSat 2 is a Japanese (JAXA) geostationary weather satellite that was launched by an H2-A rocket from Tanegashima Space Center at 06:55 UT on 18 February 2006. The 1,250 kg (dry mass), 2.7 kW, 2.4 m x 2.6 m x 2.6 m box-shaped satellite carries an imaging telescope, backed by detectors for five wavelength channels: (1) Visible band at 0.55-0.80 microns, detected by silicon photovoltaic detectors at a spatial resolution of 1.25 km; (2) 10.3-11.3 micron infrared channel (IR1) with a HgCdTe photoconductive detector. (3) 11.5-12.5 micron channel (IR2) with a HgCdTe detector; (4) 6.5-7.0 micron water vapor channel (IR3) with a HgCdTe detector; and, (5) 3.5-4.0 micron near-infrared channel with an InSb photovoltaic detector. All infrared channels provide a spatial resolution of 5.0 km. The imagery would provide weather data/warnings, after parking over 145 degrees E longitude. The satellite would also relay ground weather data from many stations to the Meteorological Satellite Center (MSC) in Japan.

MTSAT-2, which sits in geostationary orbit at 145° E, has one visible and three infrared channels as well as MTSAT-1R. These channels have ability to detect fog at nighttime, and to observe sea surface temperature. During MTSAT-2 operation, MTSAT-1R is placed in standby mode at 140° E. In the event that MTSAT-2 malfunctions and loses observation capability, MTSAT-1R would take over its role to continue meteorological observation.

JMA planned to launch the world’s first next-generation geostationary meteorological satellite, Himawari-8, in 2014 and to start its operation in 2015 as a replacement for MTSAT-2 (also called Himawari-7). Himawari-9 would also be launched in 2016 as a backup and successor satellite. Both satellites would be located at around 140 degrees east, and would observe the East Asia and Western Pacific regions for a period of 15 years. All imagery derived from Himawari-8/9 would be distributed to NMHSs via an Internet cloud service. JMA also plans to start the HimawariCast service, by which primary sets of imagery would be disseminated to NMHSs via a communication satellite using Digital Video Broadcasting — Satellite — Second Generation (DVB-S2) technology.

The MTSAT would be the central core of the Future Air Navigation Systems for Japan, being a multi-purpose satellite having both the aeronautical mission to support the air traffic control and the meteorological mission for weather observations. Because higher reliability, integrity, and operational continuity are the basic requirements for the aeronautical satellite system to be utilized in the ATC operation, the system in so configured as to have dual satellites as well as dual ground facilities in order to give sufficient redundancy for the maintaining the operational continuity of the ATC operation even in the occasion of any disturbances to the satellite or ground facility disasters such as caused by an earthquake, etc .

With this highly reliable system configuration,the ATC communications can be instantly switched to use the redundant system when a problem is detected within the satellite. The MTSAT-1R satellite has been launched in the fiscal year 2004, and the MTSAT-2 has been launched in the fiscal year 2005; the ground facilities were implemented for the dual satellites operation.

The GPS system is a satellite based system for position determination, rapidly expanding its utilization today in various areas including the car navigation. In order to utilize the GPS system as a navigation means in the field of civil aviation, high reliability and accuracy have to be realized; GPS alone cannot satisfy the requirement for this. Therefore, such augmentation system is required to improve performances. MSAS (MTSAT Satellite-based Augmentation System) is a system to provide the augmentation information to improve the reliability and accuracy of GPS via MTSAT for the aircraft utilizing the GPS position information for their navigation. Unlike the conventional navigational means such as VOR or DME, it can be utilized to cover a wide range of oceanic and ground areas making it possible to set up flexible flight routes.

Himawari 8

Himawari-8/9?–a new generation of Japanese geostationary meteorological satellites–carry state-of-the-art optical sensors with significantly higher radiometric, spectral, and spatial resolution than those previously available in the geostationary orbit. They have 16 observation bands, and their spatial resolution is 0.5 or 1 km for visible and near-infrared bands and 2 km for infrared bands. These advantages, when combined with shortened revisit times (around 10 min for Full Disk and 2.5 min for sectored regions), provide new levels of capacity for the identification and tracking of rapidly changing weather phenomena and for the derivation of quantitative products. For example, fundamental cloud product is retrieved from observation data of Himawari-8 operationally. Based on the fundamental cloud product, Clear Sky Radiance and Atmospheric Motion Vector are processed for numerical weather prediction, and volcanic ash product and Aeolian dust product are created for disaster watching and environmental monitoring. Imageries from the satellites are distributed and disseminated to users via multiple paths, including Internet cloud services and communication satellite services.

Japanese meteorologists are getting more precise readings on weather phenomena thanks to a new tool. The Himawari 8 satellite successfully completed testing and by July 2015 was operating 36,000 kilometers above the Earth. The satellite, launched in October 2014, is the world's first geostationary weather satellite, which means it follows the rotation of the earth and orbits directly over the equator. Its imager can capture observations in great detail - and instead of shooting objects in black-and-white, it records in vivid color. "This allows us to observe details in color, of things including the ocean and the ground," says Takeshi Otomo of the Japan Meteorological Agency.

The satellite offers imagery resolution four times better than its predecessor. The older device could take photos of typhoons and other weather events just once every half hour. But the Himawari 8 can shoot images every two-and-a-half minutes. Meteorologists said the upgrades will help them observe weather events such as typhoons and torrential rain. The satellite will also ensure forecasts can be more precise.

The Himawari 8 helped scientists keep an eye on volcanic activity. It relayed images of a recent eruption on Kuchinoerabu Island in Japan's south with pictures showing light gray smoke drifting southeast. "We'll use information from Himawari 8 for disaster prevention and other essential tasks," says Otomo. Officials said the Himawari 8 would also be useful to people outside Japan as climate change triggers more extreme weather. Meteorologists in Japan will provide data to countries throughout Asia and Oceania to help reduce natural disaster risks.

Himawari 9

The new-generation geostationary meteorological satellite of the Japan Meteorological Agency, Himawari-9, was successfully launched using H-IIA Launch Vehicle No. 31 at 6:20 UTC on 2 November 2016 from the Tanegashima Space Center in Kagoshima, Japan. The satellite successfully separated from the launch vehicle about 28 minutes after lift-off, and will fly unaided for around 10 days before settling into geostationary orbit. The Himawari-9, weighing about 1.3 tons and the same type as the Himawari-8 that was launched in 2014, is equipped with a high-end camera that can shoot color images. It also has high resolution graphics to display the images. It will be tasked with providing observational data with over 30 countries and regions in Asia and the Pacific region. The newly launched satellite is expected to begin full operations in 2022, replacing Himawari-8. Both satellites will be operational for seven years, with Himawari-9’s observation work continuing to 2029.