The FORMOSAT-7/COSMIC-2 (simplified as FORMOSAT-7 in the following descriptions) is a major collaborative space program between Taiwan and the U.S. In this collaborative program, the designated representative for Taiwan is TASA (Taiwan Space Agency) and the designated representative for the U.S. is NOAA (National Oceanic and Atmospheric Administration). The FORMOSAT-7 program is a follow-on program to the successful FORMOSAT-3/COSMIC program with upgraded performance for spacecraft bus and mission payload. The United States is responsible for satellite launches, payloads, and deployment of global ground receiving stations; the US team includes NOAA, the United States Air Force, and UCAR (The University Corporation for Atmospheric Research). Taiwan is responsible for the design and integration of mission systems, development of 6 spacecrafts, and constellation mission operations; the Taiwan team includes TASA, Central Weather Bureau, National Central University, and National Cheng Kung University. Data processing and application technology development are developed by the two parties in cooperation.
The FORMOSAT-7 satellites was launched by SpaceX Falcon Heavy rocket on June 25, 2019, at Kennedy Space Center, Florida, USA.
The mission architecture
All six satellites of FORMOSAT-7 constellation were launched into a 720-km circular orbit. These satellites will be gradually transferred to their 550-km mission orbits and deployed to six different orbital planes through the scheduled orbit transfer by 2021 Q1.
FORMOSAT-7 constellation: one satellite per orbital plane
The data distribution simulation for 24-hr coverage by FORMOSAT-7 constellation
FORMOSAT-7 is equipped with a GNSS-R, which can receive GPS signals from the United States and GLONASS signals from Russia. By measuring radio occultation signals, atmospheric parameters such as humidity and humidity, and the electron concentration of the ionosphere can be derived.
After the deployment of the FORMOSAT-7 constellation with the altitude of 550 kilometers and the inclination angle of 24 degrees, all six satellites orbit the earth for about 97 minutes. They can provide about 4,000 data per day between 50 degrees north and south latitudes. The amount of data in the vicinity of Taiwan is about 3 to 4 times that of FORMOSAT-3, which greatly increases meteorological data in low-latitude regions including Taiwan. Observation data provided by CWB of Ministry of Communications can be incorporated in a numerical forecasting system to improve the accuracy of domestic weather forecasts and the forecast accuracy of severe weather (including typhoon paths and rainfall). FORMOSAT-7 can provide an average of 4,000 points of atmospheric data every day, which is of great help to weather forecast, climate observation, and space weather monitoring.
April - Space Weather Data Release: TGRS high rate scintillation, IVM In-situ measurements, GNSS RFI (Radio Frequency Interference)
February - Agreement to Continue the Application of Terms of the FORMOSAT-7/COSMIC-2 Agreement was signed
January - Tahiti ground station operation, reduce the RO data latency.
April - IVM density data release
February - All six satellite deployment was completed
January - GLONASS absolute Total electron content data release
October - 5 satellites have been maneuvered to mission altitudes
March - Space weather provisional data release
March - Neutral atmosphere data release
December - Neutral atmosphere provisional data release
July - First Radio Occultation profile was successfully observed.
June - Six FORMOSAT-7 satellites under STP-2 mission were launched by Falcon Heavy.
January - Joint Program Pre-Shipment Review was completed.
March - Taiwan Data Processing Center readiness review was completed.
May - Integration and test of six satellites was completed.
February - Joint Program Critical Design Review was completed.
December - Joint Program Preliminary Design Review was completed.
May - FORMOSAT-7/COSMIC-2 TECRO/AIT Implementing Arrangement #1 was signed.
April - Joint Program System Requirement Review was completed.
August - Joint Program Mission Definition Review was completed.
The 6 mission satellite buses of FORMOSAT-7 are built by Surrey Satellite Technology Limited(SSTL). TASA is responsible to integrate the bus and payload instruments. The satellite has the following characteristics :
|shape||cuboid unilateral load solar array|
|size||100 x 125 x 125 cm3|
|mass||300 kg (per satellite)|
|communications capabilities||S band,upload speed 32kbps ,download speed 2 Mbps|
|partners||SSTL (Surrey Satellite Technology Ltd.)|
|payload support||data capacity 2Gbits ,load 39.4 kg,power supply 95W|
|mission orbit||low-inclination angle (24 deg), 520~550 km circular orbit|
|S-band antenna||Pyras Technology Inc|
|Ground Antenna of Taiwan backup station||Pyras Technology Inc|
|Mechanical Ground Support Equipment||Aerospace Industrial Development Corporation|
|Satellite Operations System (XPSOC software)||Taiwan Space Agency|
|Data Processing Validation System (TROPS software)||Taiwan Space Agency, National Central University,|
|National Cheng-Kung University, Central Weather Bureau|
|Insurance Service of Pre-Launch||Taiwan Fire & Marine Insurance Company, Ltd.|
|Insurance Service of Launch||Taiwan Fire & Marine Insurance Company, Ltd.|
Each of the 6 satellites equips with three payloads:
Tri-GNSS Radio occultation System (TGRS)
Ion Velocity Meter (IVM)
Radio Frequency Beacon (RFB)
U.S. AIR FORCE
TASA is responsible for satellite operations control center, launch and early orbit operations, orbit maneuver operations, and mission operations as defined in Implementing TECRO/AIT Arrangement#1. A satellite operation control system (Cross Platform Satellite Operation Control System, XPSOC), developed by TASA and domestic companies, will be applied to FORMOSAT-7 mission operations.
The data latency requirement is 30 minutes (median) so that distribution of the ground stations is as shown below. The U.S. Team is responsible for deployment of stations, include Guam, Darwin, Mauritius, Kuwait, Ghana, Cuiaba, Honduras and Hawaii.
Both Taiwan and the United States have established data processing centers to support system monitoring, data management, and user services for the radio occultation meteorological satellite constellation.
The Taiwan Data Processing Center (TDPC) is located at Central Weather Bureau (CWB). Users can obtain FORMOSAT-3 and FORMOSAT-7 data through TDPC. In order to develop localized occultation data processing technology, a set of data processing verification platform (Taiwan RO Processing System, TROPS) is jointly developed by combining the energy of CWB, National Central University (NCU), and National Cheng Kung University (NCKU) to strengthen the domestic occultation data processing and application.
First Retrieved Profiles from FORMOSAT-7
National Applied Research Laboratories (NARLabs) combines the research and development energy of NCU and CWB to establish a localized occultation data application system to enhance the efficiency of the application of occultation in the meteorological numerical model to improve the forecasting ability of severe weather and reduce the uncertainty of disaster warning. The ionospheric space weather forcast module developed by NCKU was incorporated into the Space Weather Forecast Center of CWB to carry out routine operations of space weather forcast with the same function as general weather forecast, reducing the loss in national defense and people's livelihood.