The Star Trackers formed part of the six satellites for the FORMOSAT-7 joint U.S.-Taiwanese weather forecasting constellation.
On board the successful launch on 25 June 2019 of the SpaceX Falcon Heavy rocket from the Kennedy Space Center was 12 Terma Star Trackers. They formed part of the six satellites for the FORMOSAT-7 joint U.S.-Taiwanese weather forecasting constellation.
It is also known as COSMIC-2, a joint constellation meteorological satellite mission between Taiwan and the United States for observing and monitoring the global meteorology, climate, and ionosphere. The six satellites are now placed in temporary circular orbit 720 km above the ground.
In 2013, Terma was contracted by the British manufacturer of small satellites, Surrey Satellite Technology, headquartered near London to supply 13 Star Tracker heads (one engineering- and 12 flight units) plus baffles with an option for another 12 units. Thus, two Star Trackers will be mounted on each satellite.
Surrey specifically requested a very compact Star Tracker due to the space available on the launcher.
A Star Tracker is used to precisely determine the satellite’s orientation in its position. In the computer, a huge number of constellations (patterns) are stored. When there is a match between what the camera sees and a stored pattern, you know exactly how the satellite is oriented, which for example is essential for the reliability and usefulness of Earth observations from satellites like meteorological satellite missions.
The SpaceX launch (STP-2 mission) uses the SpaceX Falcon Heavy launch vehicle to perform 20 commanded deployment actions and place 24 separate spacecraft in three different orbits. In addition to the FORMOSAT-7/COSMIC-2 satellite constellation, the spacecraft included the Air Force Research Laboratory Demonstration and Science Experiments (DSX) satellite, four NASA experiments, and many other missions.