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ADEOS II (Advanced Earth Observing Satellite 2) was an
Earth observation satellite An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit, including spy satellites and similar ones intended for non-military uses such as environmental monitoring, me ...
(EOS) launched by
NASDA The , or NASDA, was a Japanese national space agency established on October 1, 1969 under the National Space Development Agency Law only for peaceful purposes. Based on the Space Development Program enacted by the Minister of Education, Culture ...
, with contributions from
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
and
CNES CNES () is the French national space agency. Headquartered in central Paris, the agency is overseen by the ministries of the Armed Forces, Economy and Finance and Higher Education, Research and Innovation. It operates from the Toulouse Spac ...
, in December 2002. and it was the successor to the 1996 mission ADEOS I. The mission ended in October 2003 after the satellite's
solar panels A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited electrons when exposed to light. These electrons flow through a circuit and produce direct ...
failed.


Mission overview

The three primary objectives of the mission, as identified by NASDA, were to: * Regularly monitor the
water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
and energy cycle as a part of the global climate system * Quantitatively estimate the biomass and fundamental productivity as a part of the
carbon cycle The carbon cycle is a part of the biogeochemical cycle where carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycl ...
* Detect trends in long term climate change as a result of continuing the observations started by ADEOS I The project had a proposed minimum life of three years, with a five-year goal.


Instruments

The satellite was equipped with five primary instruments: Advanced Microwave Scanning Radiometer (AMSR), Global Imager (GLI), Improved Limb Atmospheric Spectrometer-II (ILAS-II), Polarization and Directionality of the Earth's Reflectances (POLDER), and SeaWinds. These instruments were designed to monitor
Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
's
water cycle The water cycle (or hydrologic cycle or hydrological cycle) is a biogeochemical cycle that involves the continuous movement of water on, above and below the surface of the Earth across different reservoirs. The mass of water on Earth remains fai ...
, study
biomass Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...
in the
carbon cycle The carbon cycle is a part of the biogeochemical cycle where carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycl ...
, and detect trends in long-term
climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
. The mission was established to continue the work undertaken by ADEOS I between 1996 and 1997.


Advanced Microwave Scanning Radiometer (AMSR)

AMSR monitors water vapor, precipitation, sea surface, wind, and ice by means of microwave radiation emanating from Earth's surface and atmosphere. It is a radiometer that operates in eight frequency bands covering 6.9 GHz to 89 GHz, and monitors the horizontal and vertical polarizations separately. With a dish of aperture, the spatial resolution is in the 89 GHz band, degrading to at 6.9 GHz.


Global Imager (GLI)

GLI (GLobal Imager) is an optical sensor to observe
solar radiation Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible light perceptible to the human eye as well as invisible infrared (typically p ...
reflected from
Earth's surface Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
and map vegetation,
cloud In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles, suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may ...
s, etc. The data is acquired in 23 visible/near-infrared, and in 13 far infrared channels. The scanning is done by a rotating mirror covering along track and cross-track, and at a resolution of .


Improved Limb Atmospheric Spectrometer 2 (ILAS-2)

ILAS-2 maps the vertical distribution of O3, NO2, HNO3, H2O, CFC-11, CFC-12, CH4, N2O, and ClONO2, as well as the distribution of temperature and pressure, all in the
stratosphere The stratosphere () is the second-lowest layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is composed of stratified temperature zones, with the warmer layers of air located higher ...
. It observes the absorption spectrum in Earth's atmospheric limb in the 3-13 micron wavelength band, and in the 753-784 nm band of the occulting
Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
. The altitude resolution is .


Polarization and Directionality of Earth's Reflectances (POLDER)

POLDER measures the polarization, and spectral characteristics of the solar light reflected by aerosols, clouds, oceans and land surfaces. Eight narrow band wavelengths (443, 490, 564, 670, 763, 765, 865, and 910 nm) are covered by the instrument which enables identification of the physical and optical properties of the aerosols and their role in radiation budget.


SeaWinds

SeaWinds is a scatterometer that provides wind speed and direction by observing the microwave reflection from ocean surfaces. With its dish, it scans the surface along conical surfaces at 18
RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 def ...
. It provides speed at an accuracy of 2 m/s, wind direction at an accuracy of 20°, both with a spatial resolution of .


Subsystems

In addition to the five main instruments, nine avionic subsystems were allocated to the bus module. These were the Communication and Data-Handling Subsystem (C&DH), Inter-Orbit Communication Subsystem (IOCS), Mission Data Processing Subsystem (MDPS), Optical Data Recorder (ODR), Electrical Power Subsystem (EPS), Paddle Subsystem (PDL), Attitude and Orbit Control Subsystem (AOCS), Reaction Control Subsystem (RCS), and the Direct Transmission Subsystem (DTL). The C&DH subsystem received and decoded the satellite's tracking control command signals and acted as a processing interface between the instruments. It was capable of adjusting settings on the instruments – such as temperature and voltage. The IOCS was used to communicate with data relay satellites (''see
Data transfer Data communication, including data transmission and data reception, is the transfer of data, transmitted and received over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical ...
''). The MDP device formatted mission data to be sent via the IOCS, and would process it into a
data packet In telecommunications and computer networking, a network packet is a formatted unit of data carried by a packet-switched network. A packet consists of control information and user data; the latter is also known as the '' payload''. Control inform ...
. The ODR was a large-volume storage device that used an optical magnetic disk system. The EPS provided power to the satellite's subsystems. The PDL managed the satellite's solar panel, and transferred electrical energy to the EPS. The solar panel was capable of generating 5 kW using 55,680 solar cells on a jointed mast. The AOCS was used to establish the
attitude control Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle or satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, ...
following the satellite's deployment from the launch vehicle. It was subsequently used to adjust the satellite's attitude, orbit, and solar paddle. The AOCS was equipped with a number of attitude sensors, including a control-standard unit (IRC), an Earth sensor (ESA), and a fine
Sun sensor A Sun sensor is a navigational instrument used by spacecraft to detect the position of the Sun. Sun sensors are used for Spacecraft attitude control, attitude control, solar array pointing, gyroscope, gyro updating, and safe mode (spacecraft), fai ...
assembly (FSSA). The RCS was used to generate propulsion power for attitude adjustments after deployment and control orbit using data from the AOCS.


Data transfer

ADEOS II transferred data to and from
Artemis In ancient Greek religion and Greek mythology, mythology, Artemis (; ) is the goddess of the hunting, hunt, the wilderness, wild animals, transitions, nature, vegetation, childbirth, Kourotrophos, care of children, and chastity. In later tim ...
and the Data Relay Test Satellite (DRTS). The Artemis connection transferred information over a 26
GHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in ter ...
Ka-band link (for payload data) and a 2 GHz
S-band The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the convention ...
link (for telemetry, tracking and control data). These signals were then
downlink In a telecommunications network, a link is a communication channel that connects two or more devices for the purpose of data transmission. The link may be a dedicated physical link or a virtual circuit that uses one or more physical links or shar ...
ed to the Earth Observation Center (EOC) via feeder link stations and the Redu Station. ADEOS II also sent mission data directly to NASA stations, which routed information to bodies such as the EOC and sensor-providing organisations.


Launch

The mission was originally scheduled to launch aboard a
H-II The H-II (H2) rocket was a Japanese satellite launch system, which flew seven times between 1994 and 1999, with five successes. It was developed by NASDA in order to give Japan a capability to launch larger satellites in the 1990s. It was the fi ...
launch vehicle in February 2002. This was postponed as the Japanese Space Activities Commission would not launch without having three successful missions aboard the new
H-IIA H-IIA (H-2A) is an active expendable launch system operated by Mitsubishi Heavy Industries (MHI) for the Japan Aerospace Exploration Agency. These liquid fuel rockets have been used to launch satellites into geostationary orbit; lunar orbi ...
launch vehicle. The satellite was successfully launched from
Tanegashima Space Center The (TNSC) is Japan's primary spaceport, covering approximately about . It is located on the southeastern tip of Tanegashima, the easternmost of the Ōsumi Islands, approximately south of the major island of Kyushu. The site was selected on ...
pad YLP-1 on 14 December 2002, aboard H-IIA 202. Other payloads onboard included the Japanese MicroLabsat and WEOS microsatellites, as well as the Australian FedSat.


Failure

On 23 October 2003, the
solar panel A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited electrons when exposed to light. These electrons flow through a circuit and produce direct ...
failed. At 23:49 UTC, the satellite switched to "light load" operation due to an unknown error. This was intended to power down all observation equipment to conserve energy. At 23:55 UTC, communications between the satellite and the
ground station A ground station, Earth station, or Earth terminal is a terrestrial radio station designed for extraplanetary telecommunication with spacecraft (constituting part of the ground segment of the spacecraft system), or reception of radio waves fr ...
s ended, with no further
telemetry Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', 'far off', an ...
received. Further attempts to procure telemetry data on 24 October 2003 (at 00:25 and 02:05 UTC) also failed.


Investigation

After the power failure,
JAXA The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into o ...
formed the Midori II anomaly investigation team. Analysis of data received before transmissions ceased showed that the solar panel's power output had decreased from 6 kW to 1 kW. The investigation team began surveying the mission to establish whether the failure was due to a technical malfunction or a
solar flare A solar flare is a relatively intense, localized emission of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and ot ...
. One hypothesis was that debris had impacted the satellite's power harness between the solar array and the
satellite bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are less customized than specially-produced satelli ...
. The harness was a core of wires enclosed in multi-layer insulation. The debris impact was theorised to have caused an
electric arc An electric arc (or arc discharge) is an electrical breakdown of a gas that produces a prolonged electrical discharge. The electric current, current through a normally Electrical conductance, nonconductive medium such as air produces a plasma ( ...
, which is an example of the spacecraft charging effect. The mission officially ended at the end of October 2003, with JAXA conceding that the "possibility of restoring the operations of Midori II asextremely slim". The mission, which had cost approximately 70 billion
Yen The is the official currency of Japan. It is the third-most traded currency in the foreign exchange market, after the United States dollar and the euro. It is also widely used as a third reserve currency after the US dollar and the euro. T ...
(US$570 million) was only able to recoup an estimated 300 million Yen through insurance.


References


External links

* {{Orbital launches in 2002 Earth observation satellites of Japan Spacecraft launched in 2002 Spacecraft launched by H-II rockets Derelict satellites orbiting Earth