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FormoSat - Taiwan's Earth Observation Systems

The ROCSAT-2 program was approved by the Executive Yuan of ROC in October 1997. ROCSAT-2 is designed to perform near realtime remote sensing of the ocean and landmass in the vicinity of Taiwan. The data from the ROCSAT-2 mission can be applied towards land use, agriculture and forestry, natural disaster evaluation, environmental monitoring, education, and foster international cooperation in various scientific researches. In addition to the remote sensing mission, the scientific mission of investigating the upper atmospheric lighting phenomena is included in ROCSAT-2. In order to achieve these mission objectives, a small class, low earth-orbit remote sensing satellite will be developed. The existing ROCSAT ground system will be upgraded to support this mission.

Taiwan is an island prone to natural disasters brought on by typhoons during the summer months. Timely availability of remote sensing data is critical for Taiwan in the aftermath of these disasters. The ROCSAT-2, as the satellite for ROC, will focus mainly on satisfying local user needs. Therefore, frequent revisit of Taiwan and timely availability of the data for Taiwan are unique characteristics that distinguish ROCSAT-2 from other commercial satellites. The applications of such remote sensing include governing the use of land, agriculture, natural disaster assessment, environmental monitoring, scientific research, and educational activities. In addition to its remote sensing mission, ROCSAT-2 also has the scientific mission of investigating various lighting phenomena in the upper atmosphere.

The major characteristics of the satellite are: the mission orbit of 891 km altitude, sun synchronous (revisiting Taiwan for imaging every day); with panchromatic and multi-spectral bands in Visible/NIR/SWIR; panchromatic ground sampling distance (GSD) better than 5 meters [it is widely reported that the resolution is actually 2 meters] and multi-spectral GSD better than 20 m; swath larger than 50 km; field of regard of 45 degree (almost global coverage); real-time imaging and downlink while ground antenna elevation angle above 20 degree. The electron-optical imager can simultaneously capture four panchromatic, multi-spectrum images and then transmit this data to government agencies, private sector companies, and research organizations.

In February 1999 Dornier Satelliten Systeme GmbH, a subsidiary of DaimlerChrysler Aerospace, won a US$83 million contract to build parts for the ROCSAT-2. However the German government refused to issue the required export license to DASA Dornier, in response to Chinese diplomatic pressure. China claimed that Taiwan would use the satellite's high resolution imaging system for military surveillance, rather than its stated civilian purposes. In December 1999 Taiwan awarded French company Matra-Marconi Space the ROCSAT-2 contract, with plans to equip the satellite with 14 main instruments reduced to six. Beijing dropped its objections once the French promised that the satellite would not be converted for military applications. The launch date of ROCSAT-2 is scheduled for May 2002 on an American Athena launch vehicle, with a mission lifetime more than 5 years.

The ROCSAT Ground System (RGS) contract was awarded to the AlliedSignal Technical Services Cooperation (ATSC) of USA. Through a contractual requirement, four Taiwanese subcontractors, i.e., Tatung, SysCom, TTNS and CTCI, have been selected by ATSC as subcontractors to participate in the development of the system. The two Telemetry, Tracking and Command (TT&C) stations provide the links between the RGS and satellites. There are two stations in the mission located at north and south of Taiwan, respectively. In normal operation, TT&C is controlled by Mission Operations Center (MOC) located in Hsinchu. In an emergency, the operation personnel can reside in the stations and TT&C will perform the same functions as the MOC.

The Republic of China's second satellite -- ROCSAT-2 -- left Taiwan 01 December 2003 for the United States. Preparations to transport the 750kg satellite from Hsinchu in northern Taiwan to Vandenberg Air Force Base in California for a planned liftoff 17 January 2004 were completed. The satellite has been placed in a 2,100kg container into which nitrogen has been injected to ensure stable conditions for the long journey to the United States. The container, owned by the NSPO's contractor Astrium Co. of France, will be airlifted to Los Angeles and then delivered by truck to Vandenberg Air Force Base located on the Pacific coast in central California.

The satellite was scheduled to be launched in late February 2004. Electrical circuit problems were discovered in ROCSAT-2's launcher in early December, prompting U.S. Orbital Sciences Corp (OSC), the operator of the satellite's launch vehicle, to suggest that the launch be postponed from January 17 to February 26. After its fourth circle around the globe, a station in Chungli, Taiwan, will start receiving information from it. By early March the the launch could be scheduled between late March and early April 2004.

The launch of the ROCSAT-2 satellite, which carries a price tag of NT$4.7 billion, led Taiwan into a new era of space research. The ROCSAT-2 satellite is different from its predecessor in that it will have practical applications involving remote-sensing technologies to help upgrade Taiwan's capabilities in disaster prevention, land mapping and environmental monitoring.

The ROCSAT-2 satellite can take pictures of objects on the ground as small as two meters across. The satellite is designed to orbit the Earth 14 times a day, including two passes over Taiwan, at 891 km above the Earth. In addition to its remote sensing mission, the ROCSAT-2 has the scientific mission of investigating various lighting phenomena in the upper atmosphere.

The ROC government launched a 15-year space technology development plan in 1991. In its initial stage, the NSPO is concentrating on a satellite project known as ROCSAT, which consists of three different satellite ventures. The first venture involved the ROC's first satellite -- ROCSAT-1 -- which was built by the U.S. firm TRW and successfully launched in 1999 from Cape Canaveral, Florida, while the third satellite, ROCSAT-3, is an ROC-U.S. joint venture, which will be launched in 2005. Some components of these satellites will be manufactured in Taiwan under the auspices of technology transfer from foreign contractors.

A launch of ROCSat-2 took place on May 20, 2004 (UTC) on a Taurus-XL vehicle of OSC (Orbital Sciences Corporation) from VAFB, CA (maiden flight of Taurus-XL configuration which offers greater lift capability compared to previous versions of the Taurus rocket). Orbit: Sun-synchronous circular orbit, mean altitude = 888 km, inclination = 97.7º, period of 102.9 minutes, the LTDN (Local Time of Descending Node) is 10:00 hours (14 orbits/day). The agility of the spacecraft provides a daily revisit capability for event/disaster monitoring.

A public naming competition took place in Taiwan in 2004 with regard to the ROCSat satellite program. At the end of this contest, the ROCSat program was given the new name of FormoSat in December 2004. Hence, ROCSat-2 became FormoSat-2.

In 2010, FormoSat-2 joined the Sentinel Asia Constellation Initiative as an action to align with its commitments and frameworks in the endeavors to build and strengthen a disaster resilient community in the Asia-Pacific region. The Sentinel Asia Initiative has been operation since 2006 as an international cooperation platform under the APRSAF.

Over the past 12 years, the FormoSat-2 satellite has acquired 2.55 million photos and is best known for documenting images of Taiwan before and after Typhoon Morakot hit the island, which proved helpful to the government's land valuation efforts. Now, according to Taiwan's China Post online infosite July 19, 2016, experts announced plans to decommission FormoSat-2. The satellite will be temporarily replaced with Japan's satellite services until the new FormoSat-5 is launched sometime before the end of 2016. According to a Taipei Times news report August 22, 2016, the FormoSat-2 satellite has been decommissioned after 12 years in operation. The satellite had remained operational eight years past its expected lifespan of five years, but a series of equipment failures finally forced the NSPO (National Space Organization) to pull the plug. NSPO made its last contact with FormoSat-2 during a decommissioning ceremony on August 19 at its headquarters in Hsinchu, bringing an end to the nation's most successful surveillance satellite program.

Satellite Orbital Characteristics:

  1. sun-synchronous orbit with satellite altitude = 891 km
  2. inclination 98.99
  3. orbit adjustment: after drifting 400 km from assigned orbit (about every 6 months)
  4. revisit Taiwan twice daily (one at daytime and the other at night-time)
  5. life span 5 years (over 70% reliability)
  6. figure of satellite tracks
  1. Pan Chromatic pushbroom CCD:¡@ 60 km swath with 2m - 5m resolution
  2. MSS at 15 m resolution
  3. stereo capability
Data and coverage:
  1. swath¡@ 60 km,¡@ maximal nadir angle = 30-degrees
  2. downlink with X-band 50 Mbps ~ 100 Mbps, spot beam antenna
  3. on-board recorder¡@ 10 Gb, plus spare

FormoSat-5 (FS-5)

Formosa-5 is a high resolution, Earth remoteoptical sensing satellite that uses a remote sensingimager (RSI) to provide two-metre panachronic and four-meter multi-spectral resolution images. The main payload was developed domestically by a team including NSPO institutions and commercial partners: ITRC (Instrument Technology Research Center), CIC (National Chip Implementation Center), CSIST (Chung-Shan Institute of Science and Technology), AIDC (Aerospace Industrial Development Corporation), CIS (CMOS Sensor Inc), and CAMELS Vision Technologies.

It replaced the older Formosat-2 which was launched in May 2004 and was at the end of its lifetime. It is unique in being the first satellite to be completely designed by Taiwanese industry through NSPO.

The FormoSat-5 (FS-5) program represents the first indigenous development of remote sensing capabilities at NSPO (National SPace Organization) of Taiwan. After successfully conducting three satellite missions during in the timeframe 1991-2006, NSPO started a new space initiative in 2004 which emphasizes on building up the capabilities for independent development of spacecraft and payload instruments. The strategy for the program is to acquire key technology and setup a heritage bus design for NSPO. The key technology to be developed by NSPO includes flight software, EGSE and IPS.

FormoSat-5 is a follow-on mission of FormoSat-2. An important objective for FormoSat-5 is to build up the domestic capability for the high-resolution optical remote sensing instrument by integrating NSPO with the ITRC (Instrument Technology Research Center) of NARL (National Applied Research Laboratories). Both NSPO and ITRC belong to the NARL, a non-profit organization under the supervision of NSC (National Science Council).

July 17, 2017: FormoSat-5, the first domestically developed satellite operated by Taiwan's NSPO (National Space Organization), was packaged and shipped to the U.S. over the past weekend for the launch by a SpaceX Falcon 9 rocket on August 24 at VAFB, in California.

The launch of FORMOSAT-5 was originally scheduled for 2016 but was delayed due to an explosion of a Falcon 9 rocket in September, which disrupted the SpaceX launch schedules. Falcon 9 is a two-stage launch vehicle that can transport satellites and spacecraft into Earth orbit and was built by SpaceX, a private aerospace company established by Tesla founder Elon Musk.

: The FormoSat-5 spacecraft of NSPO was launched on August 24, 2017 [18:51 GMT, or at 11:51 a.m. PDT (Pacific Daylight Time), corresponding to 2:51 hours Taiwan Time on August 25] — on a Falcon-9 v1.2 (Full Thrust) vehicle of SpaceX. The launch site was VAFB (Vandenberg Air Force Base), CA, SLC-4E (Space Launch Complex-4E.


FORMOSAT-6 was designed to have a remote sensing mission and, however, terminated after a careful evaluation. The sequence of satellite development has progressed numerically from Formosat-1, an Earth observation satellite. Satellite programs typically takes around five years to develop through to launch. NSPO does not build satellites specifically for military use. There was hope that the Formosat-6 satellite would have a launcher built by the Ministry of Defence but that did not happen. The original plan was to source the sensor from the international community but, due to ITAR restrictions, it meant that internal resources had to be identified and used.

At the Fourth Asian Space Conference in 2008, a paper presented by NSPO officials said the agency’s first choice to launch FORMOSAT-6, a micro-satellite under development to carry out scientific investigation, would be the Taiwan Small Launch Vehicle (TSLV). Based on the lack of progress in developing a TSLV, it appears the US reaction to the plan was negative. The involvement of CSIST, the Ministry of National Defense’s principal research and development institution, in the TSLV project, as well as Taiwan’s decision to proceed with the development of the Hsiung Feng-IIE (HF-2E) land-attack cruise missile, may have ensured US opposition to the plan.


The Formosat-7 is a Taiwan-US collaboration between Taiwan's National Space Organisation and the US National Oceanic and Atmospheric Administration (NOAA) to provide a 12-satellite constellation measuring atmospheric and ionosphere soundings.

The National Space Organization (NSPO) said 15 September 2020 that it had developed the nation’s first cross-platform satellite operation control system, which is used to control the Formosat-7/COSMIC2 constellation and would save nearly NT$500 million (US$17.02 million) on project development. The system was trialed on Formosat-5, a remote sensing satellite launched in 2017, and later used to control the Formosat-7 constellation, National Applied Research Laboratories (NARL) president Wu Kuang-chong told a news conference at the NSPO in Hsinchu.

A Taiwan-US collaboration, the six-satellite Formosat-7, which conducts weather observations, was launched on SpaceX’s Falcon Heavy in June 2019. Four of the Formosat-7 satellites were moved from their 720km deployment orbit to 550km mission orbits on separate planes, while the other two would move to their mission orbits by February 2021, the NSPO said. The system has helped the NSPO contact the Formosat-7 satellites more than 30,000 times, over which it downloaded more than 2 million data packages, Wu said. The system marks another leap in Taiwan’s space tech development, as the nation used to purchase satellite software from foreign suppliers, he said.

The system over the past 14 months has proved it is comparable to similar products from foreign suppliers, NSPO associate research fellow Chen Kun-lin said. Built for NT$60 million after work began in 2009, the system saves on software development and maintenance costs that were previously outsourced, Chen said. Development and maintenance costs for the Formosat-3/COSMIC constellation and the Formosat-5 were NT$150 million and NT$170 million respectively, he said.

As the system can be adapted for other missions, the NSPO would save nearly NT$500 million in development costs for its Triton, Formosat-8, Formosat-9 and Formosat-10 constellations, which are part of the nation’s third space technology development program running through 2028, he said. In developing the system, the NSPO engaged private businesses, such as CTCI Advanced Systems Inc and Syscom Computer Engineering Co, he said. Given that it is indigenously developed, the system allows for greater Taiwan-made flexibility and information security protection, Chen said.

The NSPO hopes that the system would provide commercial services, but it needs to formulate the specifications before making such products, he said. After its satellites are fully deployed, Formosat-7 is expected to deliver 4,000 data packages per day covering the 50° north latitude to the 50° south latitude, the NSPO said. The data would be received by stations in Taoyuan and Tainan; Darwin, Australia; Hawaii and Guam; Honduras; Kuwait; Cuiaba, Brazil; Mauritius; and Ghana, it said.

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