Earth Through a 2-mm Lens From a 6,000 km Orbit

In a 6,000-kilometer orbit above our planet, the TRISAT-R CubeSat, equipped with a remarkably small 2-mm camera, has captured a distinctive image of Earth, contributing to the European Space Agency’s (ESA) research in medium-Earth orbit and the effects of digital imaging.

This extraordinary image depicts a distant Earth, partly in shadow, from the vantage point of 6,000 kilometers (3,700 miles) above the surface. The uniqueness of this image lies in the use of an incredibly miniature camera, measuring a mere 2 mm (0.08 inches) in size, which is roughly equivalent to the edge of a 20 euro cent coin (or a US nickel). This tiny camera is part of a technology experiment aboard the TRISAT-R CubeSat, a satellite about the size of a shoebox developed under the management of Iztok Kramberger at the University of Maribor.

Mr. Kramberger, the project manager of the TRISAT-R, elaborates on this achievement, stating, “This minuscule camera, with dimensions of less than two cubic millimeters, has captured an image of an object encompassing approximately one trillion cubic kilometers – our magnificent planet Earth – from a distance of thousands of kilometers.”

The TRISAT-R CubeSat, constructed from three standardized 10-cm (4-inch) cubes, represents Slovenia’s second space mission. It was launched into medium-Earth orbit, situated 6,000 kilometers (3,700 miles) above Earth, during Europe’s inaugural Vega-C mission last year. This orbit takes the satellite through the ionosphere, an electrically active layer of Earth’s atmosphere, as well as the inner Van Allen radiation belt.

The image sensor and photo diode of the TRISAT-R CubeSat can be observed in its 10×10 cm side cover. The camera, a small black dot next to the diode at the top of the image, boasts a 2 by 2 mm lens with a 120-degree field of view. The lens, made from clear borosilicate glass for radiation resistance, is directly attached to the image sensor, providing a resolution of 320×320 pixels.

TRISAT-R’s primary mission involves testing a range of radiation-detection instruments. Additionally, the satellite carries a pair of these miniature cameras for its imaging endeavors. It’s important to note that these highly compact cameras were not originally designed for terrestrial imaging. Moreover, the TRISAT-R satellite employs magnetorquers for its attitude control, which makes precise pointing challenging.

Dr. Kramberger further explains, “The resulting Earth image has relatively low resolution due to the miniature nature of these cameras, which were not optimized for terrestrial imaging. Furthermore, TRISAT-R’s use of magnetorquers for attitude control limits our ability to achieve precision pointing.”

While the primary focus has been on capturing instances of the ‘Black Sun effect,’ a common phenomenon in terrestrial digital imaging where over-saturation of pixels results in very bright areas appearing dark, the mission has serendipitously acquired images like the one presented here.

The European Space Agency (ESA) has been a key supporter in the development, assembly, and testing of TRISAT-R through its General Support Technology Program, specifically the ‘Fly’ element, which has enabled in-orbit demonstration opportunities for European companies.

Located in its distinctive and demanding orbit, the TRISAT-R CubeSat is set to conclude its commissioning phase later this month, following 16 months of successful in-orbit operations.

Frequently Asked Questions (FAQs) about TRISAT-R CubeSat Earth Image

More about TRISAT-R CubeSat Earth Image

• University of Maribor
• European Space Agency (ESA)
• TRISAT-R CubeSat
• Vega-C Launch
• Ionosphere
• Van Allen Radiation Belt
• ‘Black Sun Effect’
• ESA General Support Technology Program