Slovenian Trisat-S satellite's image named ESA Technology image of Week

The Slovenian Trisat-S satellite's image showing the Sun with a black dot at its centre has been named Technology Image of the Week by the European Space Agency (ESA). The image captures the Black Sun effect, the result of pixel over-saturation.

This is the third time a Slovenian image has been recognised in such a way, CE Report quotes The Slovenia Times.

Headlined When the Sun Turns Black, the ESA's latest Technology Image of the Week article reads that the image resembles a "glaring eye in the darkness of space".

The black spot is not a camera failure, but an expected behaviour of imaging sensors under extreme illumination, known as the Black Sun effect, where the over-saturation of pixels causes very bright areas to appear dark.

Taken by a miniature camera flying onboard the Trisat-S nanosatellite, this image is "exactly what the mission team was hoping for", the agency said.

Visual reference for developing autonomous space navigation

The otherwise unwanted imaging artefact can be very useful in space navigation. According to the space company SkyLabs, which developed the satellite together with the Maribor Faculty of Electrical Engineering and Computer Science, they deliberately use the Black Sun effect to determine the position of the Sun and orientate the satellite.

Iztok Kramberger, head of the Trisat project at the University of Maribor and director of innovation at SkyLabs, explained that "together with the observations of Earth and the Moon, the 'Black Sun' serves as a visual reference that can be used by a spacecraft to determine its attitude and orbit".

This is also an important step towards the development of autonomous navigation far beyond Earth, Kramberger said.

Third time Slovenian satellite image is celebrated this way

The selection of the image as the ESA Technology Image of the Week is the agency's third such recognition of Slovenian technological development.

In 2023, the title went to an image of a partly shadowed Earth that was captured by the Trisat-R nanosatellite.

This summer, the same honour went to an image created while testing technology in the radiation environment of the particle accelerator Large Hadron Collider at CERN, dubbed The Art of Hadrons.

Trisat-S satellite capabilities

Launched on 5 September, Trisat-S carries six miniature cameras that cover the satellite's surroundings in all directions.

Researchers compare Trisat-S data with simulations and laboratory tests to improve navigation algorithms, as the nanosatellite allows the technology to be tested in real spaceflight conditions.

Trisat-S is also used to test spacecraft hibernation technology with virtually zero energy consumption, which is important for satellites due to their limited primary energy source, but could also be used for future long-duration space missions.

Combining energy-efficient hibernation and navigation based on observations of natural celestial bodies could address two important requirements for future autonomous deep space missions - efficient management of limited energy and the ability to self-orient and navigate without constant support from Earth, SkyLabs said.

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