Advanced Earth Observing Satellite (ADEOS) is a Japanese satellite program developed by Japan Aerospace Exploration Agency (JAXA) to monitor Earth's environment from space. ADEOS was Japan's first major international satellite dedicated to Earth observation. The ADEOS is also known as "MIDORI" which is a Japanese word that means “Green”. MIDORI was launched from Tanegashima Space Center into a Sun-synchronous sub-recurrent orbit at a height of approximately 830 km on August 17, 1996, at 01:53 UT by an H-II launch vehicle.  

ADEOS primary mission was to monitor global environmental changes, such as climate patterns, ozone depletion, and oceanic conditions, to promote sustainable development and environmental protection.  

Objectives of ADEOS 

The ADEOS program had several key objectives: 

• Global Environmental Monitoring: The primary goal was to provide comprehensive, global-scale observations of Earth's environment. This included monitoring changes in the atmosphere, oceans, land, and cryosphere. 
• Climate Change Research: ADEOS aimed to collect data crucial for understanding and predicting global climate change. This included measuring factors like greenhouse gases, ocean temperatures, and polar ice coverage.
• Atmospheric Studies: A major objective was to study the Earth's atmosphere, particularly focusing on ozone levels and their fluctuations. This was critical in the context of ozone depletion concerns in the 1990s and early 2000s. 
• Ocean Color and Temperature Monitoring: ADEOS satellites were designed to provide detailed measurements of ocean color (indicating phytoplankton concentrations) and sea surface temperatures, vital for understanding marine ecosystems and ocean circulation patterns. 
• Land Observation: The program aimed to monitor land use changes, vegetation patterns, and desertification processes on a global scale. 
• Technological Advancement: ADEOS served as a platform to test and demonstrate new Earth observation technologies, paving the way for future satellite missions. 
• International Collaboration: The program sought to foster international cooperation in Earth science by incorporating instruments from various countries and sharing data globally. 
• Natural Disaster Mitigation: By providing data on environmental conditions, ADEOS aimed to contribute to the prediction and understanding of natural disasters. 
• Support for Environmental Treaties: The data from ADEOS was intended to support international environmental agreements by providing objective, global measurements of key environmental parameters. 

Key Components of ADEOS 

The ADEOS satellites were complex systems with many important parts that make missions succeed. These were carefully designed, enabling the satellites to perform their Earth observation tasks with precision and reliability. 

1. Main satellite bus - The main part of  ADEOS satellite was its  Main satellite bus, which held all the essential systems that kept the satellite running. This included a power system equipped with large solar panels to generate electricity, along with batteries to store energy for times when the satellite passed through Earth's shadow. The bus also featured a thermal control system, which played a vital role in ensuring all onboard equipment stayed within the right temperature range, even in the extreme conditions of space. 
2. Attitude and Orbit Control System (AOCS) - This key part of the satellite, which was crucial for keeping the satellite properly oriented and positioned in space. This was vital for gathering accurate data and maintaining reliable communication with ground stations. The AOCS used tools like star trackers, gyroscopes, and reaction wheels to precisely control the satellite’s orientation. 
3. Communication systems - Communication systems formed another vital part of the ADEOS satellites. These included high-gain antennas for transmitting large volumes of collected data back to Earth, as well as systems for receiving commands from ground control. The onboard data handling system manages the flow of information between various instruments and the communication systems. 
4. Inter-orbit Communication System - A unique feature of the ADEOS satellites was the Inter-orbit Communication System, which allowed them to relay data through other satellites in geosynchronous orbit, enabling near-real-time data transmission even when not in direct line of sight with ground stations. 
5. Propulsion system -The satellites also included a sophisticated propulsion system for orbital adjustments and maintenance. This system was crucial for extending the operational life of the satellites and ensuring they maintained their precise orbital paths. 
6. Structural framework - Lastly, but critically important, was the structural framework that held all these components together. The structure was designed to withstand the intense forces of launch and the harsh conditions of space while providing a stable platform for the sensitive instruments. 
7. Earth observation instruments - Perhaps the most important components from a scientific perspective were the various Earth observation instruments. ADEOS-I carried eight primary instruments, including the NASA-provided Total Ozone Mapping Spectrometer (TOMS) for measuring ozone levels, and the Ocean Color and Temperature Scanner (OCTS) for studying ocean properties. ADEOS-II featured an even more advanced suite of instruments, including the Global Imager (GLI) for detailed Earth surface observations and the Advanced Microwave Scanning Radiometer (AMSR) for measuring precipitation and sea surface temperatures. 
8. Major sensors - The following equipment is part of Midori's integrated continuous land, marine, and air measurement system: NASDA developed the AVNIR (Advanced Visible Near Infrared Radiometer) and OCTS (Ocean Color and Temperature Scanner). Moreover, there are six different types of AO sensors: the Ministry of International Trade and Industry's IMG (Interferometric Monitor for Greenhouse Gases) measures the greenhouse effect; NASA's NSCAT (NASA Scatterometer) and TOMS (Total Ozone Mapping Spectrometer) measure geosurface reflection; POLDER (Polarization and Directionality of the Earth's Reflectances) measures geosurface reflection; ILAS (Improved Limb Atmospheric Spectrometer) is an enhanced spectrometer for measuring infrared radiation on the edge of the atmosphere; and RIS (Retroreflector In-Space) is a retroreflector for measuring laser long light-path absorption between the earth and satellites.

These key components worked in concert to make ADEOS a cutting-edge Earth observation platform. Despite the unfortunate early termination of both ADEOS missions due to solar panel issues, the advanced design of these satellites laid important groundwork for future Earth observation missions, influencing satellite design and Earth science research for years to come. 

Technical Specification of Midori 

Phases of ADEOS 

The ADEOS program had two phases: ADEOS-I and ADEOS-II. ADEOS-I, also known as ADEOS, Midori, or Midori-I, provided a wealth of data on land, sea, and atmospheric conditions for about ten months. However, on June 30, 1997, it unexpectedly lost control due to structural damage in its solar array paddle. After this loss, JAXA developed a successor, ADEOS-II, also referred to as Midori-II. Launched on December 14, 2002, ADEOS-II was built to carry on and expand the mission of its predecessor. 

ADEOS -II

Midori II is another name for the Advanced Earth Observing Satellite-II "Midori II" (ADEOS-II), which was launched in 1996 as the replacement for the Advanced Earth Observing Satellite "Midori" (ADEOS). 

On December 14, 2002, the H-IIA launch vehicle launched Midori II. 

In order to comprehend the reasons and reality of environmental changes occurring throughout the world, such as anomalous weather patterns and the widening ozone hole, Midori II has been involved in a number of observation missions. More accurate Earth observation is made possible by the satellite's ability to identify diverse electromagnetic waves that are reflected or emitted from plants, water, and the atmosphere thanks to the combination of many sensor technologies. 

Component of Midori-II

ADEOS-II carried an even more advanced payload, including: 

• Global Imager (GLI) for monitoring ocean color and land vegetation 
• Advanced Microwave Scanning Radiometer (AMSR) for measuring precipitation, water vapor, and sea surface temperatures 
• Improved Limb Atmospheric Spectrometer-II (ILAS-II) for studying ozone and other atmospheric gases 
• SeaWinds Scatterometer: This was like a wind meter for the whole planet. It bounced radar signals off the ocean to see how rough the water was. From this, it could tell how fast and which way the wind was blowing over the oceans. This information helped with weather forecasts and studying climate.
• Polarization and Directionality of the Earth's Reflectances (POLDER): This instrument studied how sunlight bounces off Earth. It looked at tiny particles in the air (called aerosols) and clouds. This helped scientists understand how these particles and clouds affect Earth's temperature.
• Solar Panels: These were large, flat panels that captured sunlight and turned it into electricity. They were like the satellite's power plant, providing energy for all its instruments and systems.
• Batteries: When the satellite was in Earth's shadow and couldn't use its solar panels, it used batteries for power. The stored energy from the solar panels to used when needed.
• Data Handling System: This was like the satellite's brain. It collected all the information from the different instruments and organized it. Then it sent this data back to Earth for scientists to study.
• Communication System: This system sends all the collected data back to Earth. It was like a very powerful radio that could send messages over long distances in space.
• Attitude Control System: This kept the satellite pointed in the right direction. It used small motors and wheels to adjust the satellite's position, making sure all the instruments were always looking at the right part of Earth.
• Thermal Control System: Space can be very hot or very cold. This system kept all parts of the satellite at the right temperature. It used special coatings, heaters, and coolers to do this.
• Main Structure: This was the body of the satellite. It held all the other parts together and protected them. It was built to be strong enough to survive the trip to space and the harsh space environment.

Impact of ADEOS II

Despite their short lifespans, the ADEOS satellites made significant contributions to Earth science: 

They demonstrated the feasibility of complex, multi-instrument Earth observation platforms. The data collected helped improve our understanding of global environmental processes. The technical challenges faced by ADEOS informed the design of future Earth observation missions. 

Like its predecessor, ADEOS-II faced technical difficulties. The satellite ceased operations on October 25, 2003, due to a malfunction in its solar power system, echoing the fate of ADEOS-I. 

Following the discovery of an anomaly in the "Midori-II" satellite on October 25, 2003, JAXA conducted an investigation, analyzed the data, and determined that there was very little chance of the Midori-II being able to resume operations. As a result, as of October 31, 2003, no communication had been established with the satellite.

Technical specification of Midori II

H-II Launch Vehicle 

Japan's main rocket for its space program is the H-II launch vehicle, a two-stage rocket developed entirely with Japanese technology. It can launch satellites weighing around two tons into geostationary orbit and can also place payloads in low- and medium-altitude orbits. For added efficiency, the H-II can launch two geostationary satellites simultaneously, each weighing about one ton. 

The first stage of the rocket is powered by the LE-7 engine, a highly efficient liquid oxygen/liquid hydrogen engine that generates around 110 tons of thrust in a vacuum. The second stage is powered by the LE-5A engine, an upgraded version of the LE-5 engine used in the H-I launch vehicle, offering better performance and reliability. The rocket’s guidance system uses an inertial guidance method, an enhancement from the H-I model. 

The H-II successfully launched for the first time in 1994, with a total of seven launches in its history. However, after the No. 5 vehicle failed to properly inject a satellite in 1998, and the No. 8 vehicle experienced a launch failure in 1999, the planned launch of No. 7 was canceled. Despite these setbacks, the technology behind the H-II has been carried forward in the development of the H-IIA launch vehicle. 

The ADEOS program laid the groundwork for future Japanese Earth observation satellites, including the Global Change Observation Mission (GCOM) series, which continues to provide essential data for climate research and environmental monitoring. Despite the technical difficulties faced by the ADEOS missions, they marked significant progress in the development of Earth observation satellites and contributed valuable insights into our planet’s complex environmental systems.