FORMOSAT-3 satellites were launched from the launch site of Vandenberg Air Force Base in the United States by the Minotaur rocket on April 15, 2006.

Constellation Observing System for Meteorology, Ionosphere and Climate

FORMOSAT-3 is an international collaboration program between Taiwan and the US with joint efforts of Taiwan's Taiwan Space Agency (TASA) and The University Corporation for Atmospheric Research (UCAR) of the US. 

It is based on the advanced technology development plan for establishing a global atmospheric real-time observation network, also known as "Constellation Observing System for Meteorology, Ionosphere and Climate", referred to as FORMOSAT-3 / COSMIC program.

This program launched six micro-satellites at a time, distributed in different orbits at 700 to 800 kilometers above the earth ground, orbiting the earth separately. All six satellites were forming a global low-earth-orbit micro-satellite constellation to receive signals transmitted by 24 US GPS satellites.  

The satellite observation covers the global atmosphere and ionosphere, providing a global average of 2500 points of input data every day. These data are evenly distributed over the world. The global meteorological data collection and analysis can be completed approximately every three hours, and updated approximately every 90 minutes. This program not only increases the frequency of weather forecast updates, so that weather reports have practical benefits, the system can also be used for long-term climate change research, dynamic monitoring of the ionosphere, global space weather forecast, and provide the earth gravity research and other related scientific research.

Payloads
The primary payload of FORMOSAT-3 is the GPS Occultation Experiment (GOX), which receives the radio wave signals of the existing US GPS satellites. Based on the signal transmission delay caused by the electric density, temperature, pressure, and water content in the ionosphere and atmosphere, information about ionosphere and atmosphere can be derived.

Principle of Observation of FORMOSAT-3 Occultation
 

There are also two other payloads carried by each FORMOSAT-3 satellite including Tiny Ionosphere Photometer (referred to as TIP) and Tri-Band Beacon (referred to as TBB) to observe and study the ionosphere.

Green marks are FORMOSAT-3 daily data distribution

Indigenous Components

To further expand the participation of domestic manufacturers in the space industry and to solidify Taiwan's space industry development, TASA incorporated 10 major items with a total of 14 domestic components from 5 manufacturers in each FORMOSAT-3 satellite as follows:

• Satellite Computer and Mission Interface Unit (Acer, Inc.)

• Solar Senor, Rechargeable Storage Battery, and Current Converter (Shihlin Electric & Engineering/eBright Corp.)

• Satellite Antennae, Receiving Coupler, and Transmitting Filter (Victory Industrial Corp.)

• Satellite Heating Elements (Yung Tien Inudstrial Co.)

• Satellite Structure and Preparation (Aerospace Industrial Development Corp.)
   

Observation data 

The observation data of FORMOSAT-3 are stored at Taiwan Analysis Center for COSMIC (TACC), which was jointly planned and established by the Central Weather Bureau (CWB) and TASA.

TACC performs real-time data receiving, processing, archive, and distribution after FORMOSAT-3 satellites were launched. Atmospheric and ionospheric high resolution retrieved products are generated and then delivered not only to downstream weather centers for corresponding operations but also to worldwide research institutes for scientific applications. 
 

Decommission

TASA officially announced on April 30, 2020 that the mission of FORMOSAT-3 would be ended on May 1, 2020 and decommissioned gloriously.