As a leading provider of space and ground system equipment, Airbus has developed a unique product line called STOS (Star Tracker Optical Stimulator). Using a specific cutting-edge technology, the STOS enables precise stimulation of star sensors during on-ground operations. Working like a miniaturized dynamic planetarium, it displays stars as well as various disturbances the sensor may encounter in space: Earth, Moon, satellites crossing the field of view, protons impact during solar flare and dazzling effect.

With over 20 years of continuous improvement, the STOS encompasses mature products that are already worldwide known.

Elevate and validate your attitude control system with Airbus’ STOS and experience unparalleled performance and reliability in optical sensor stimulation.


Download STOS Brochure


STOS use during spacecraft integration
STOS cabinets : 2, 3 or 4 channel configurations

The STOS is a powerful Star Tracker Optical Stimulator working like a mini-planetarium and enabling on-ground operations with a large variety of star sensors during AIT operations.
• When the STOS is locally controlled, it can be used to perform sensor characterization, robustness analysis or simply to check good health of the sensor.
• When it is remotely controlled in a real time closed loop environment, it is very useful to enable operating the complete spacecraft Attitude Control modes with real star sensor in the loop.


Discover our application

CubeStar star sensor

Sensor characterization

• Development and characterization of a new sensor (star sensors or even navigation cameras)

STOS Multi head

Attitude Control System validation

• STR modes and functions checking
• Open and closed loop tests
• Synchronous stimulation of 4 optical heads with various alignment

STOS use during spacecraft integration

Spacecraft integration

• Functional tests with complete hardware in the loop
(open and closed loops)
• Equipment or S/C thermal vacuum (TVAC) tests
• Equipment or S/C EMC tests,
• Final Sign test

A powerful planetarium to stimulate star sensors

STOSPilot Demo View
Orion's belt constellation in demo view
With part of the earth in the field of view
STOSPilot Perfect Image
Perfect image
STOSPilot with the moon a nd sun’s stray light
With the moon and sun's stray light

What is STOSPilot ?


STOSPilot local control

When in standby mode: STOSPilot is a dialog-based Windows application. The natural way to control STOSPilot is to use dialog boxes. With these dialogs one can read and set various parameters and launch a local (STD) simulation.
When in simulation: Even when a simulation is running, it is still possible to control STOSPilot using the keyboard and the mouse.


Key functions of STOSPilot application

User Interfaces
• Local : dialog boxes or command files
• Remote : Ethernet
(or RS232 on-demand)
Image building
• Stars (coordinates and instrumental magnitude)
• Planets, bodies, Moon (specific model), Extended Objects (ISS masking stars)
• Proton effect model (dots and streaks)
• Specific dynamic Sun stray-light model
• Possible use of predefined pictures in background or foreground
• Local recording (command file format allows simulation replay)
• Post-processing function (to determine precise image content at any time)
• Self-alignment function (using dedicated alignment pattern or star constellation)



Download STOS demo SW package


Airbus STOS product is collaborating with the European Space Agency (ESA)

JUICE - 2 STOS were used to stimulate JUICE-mounted startrackers during ground tests as part of the ESA-led mission to explore Jupiter's icy Moons.


Looking for more information?

Get in touch with our Technical Team