Arcsec

Arcsec is a Dutch space components company founded in 2015 and headquartered in Leiden, Netherlands, developing high-accuracy attitude determination and control system (ADCS) products for CubeSat and small satellite applications — specifically the Sagitta star tracker and the Arcus integrated ADCS module.

The Sagitta star tracker provides attitude determination with arc-second angular accuracy — one arc-second equaling 1/3600 of a degree, the resolution implied by the product name. Star trackers determine a satellite's orientation in space by imaging star fields and matching patterns against an onboard star catalog, providing absolute attitude reference substantially more accurate than magnetometers or sun sensors alone. Arcsec's Sagitta is designed in a miniaturized form factor compatible with CubeSat volume and mass constraints, enabling high-pointing-accuracy Earth observation, communications, and science missions in 1U-12U platforms.

The Arcus system integrates the Sagitta star tracker with reaction wheels (spinning gyroscopic flywheels for precise angular momentum management) and magnetorquers (electromagnetic coils that interact with Earth's magnetic field for attitude control torque) into a single integrated ADCS module. This simplifies integration for CubeSat operators who would otherwise need to procure, electrically interface, and calibrate separate attitude sensing and actuation subsystems from different suppliers.

Arcsec has achieved flight heritage through ESA's In-Orbit Demonstration (IOD) CubeSat program, validating Sagitta performance in the actual space environment. The company competes with CubeSpace (South Africa), Solar MEMS, and Berlin Space Technologies for the growing smallsat ADCS market.