“Soyuz-2.1b” Launched Satellites with Unique Star Sensors

On July 25, 2025, at 08:54 Moscow time, a Soyuz-2.1b launch vehicle with two “Ionosphere-M” satellites No. 3 and No. 4, and 18 small spacecraft (cubesats) was launched from the Vostochny Cosmodrome.

“Ionosphere-M” No. 3 and No. 4 are part of the “Ionozond” space system, which collects information on spatial and temporal characteristics of the ionosphere, as well as monitoring changes in the electromagnetic fields and the Earth’s atmosphere, studying the distribution of ozone in the upper atmosphere, monitoring radiation levels, and tracking other significant environmental parameters.

As part of the spacecraft (SC) “Ionosphere-M” № 3 and № 4 as experimental samples, two high-precision star sensors manufactured by JSC Peleng with an error of orientation determination not exceeding one angular second were put into orbit. In the coming months, they will undergo flight tests, after which they will be used for backup of infrared vertical sensors and Sun sensors, which will provide the possibility of programme turnaround of “Ionosphere-M” spacecraft at all stages of the flight, including the eclipse, as well as obtaining accurate information on the SC orientation.

This is not the first experience of JSC Peleng in developing, manufacturing, and supplying star sensors to customers for the team of the “Cosmos” ground control complex (GCC). Now, ultra-high-precision star sensors with an orientation error of no worse than 0.3 arc seconds are operating in orbit as part of Earth remote sensing equipment.