Trisat-R’s 2-mm Camera Took This Picture of the Earth From 6,000 Km Away

Trisat-R’s innovative camera pioneering a new technology in space caught a unique view of our home world.

It isn’t much to look at. To be sure, we’ve seen better views of our home planet. But what if I told you it was taken with a tiny camera… only 2-millimeters across?

The camera is just one of the innovative instruments aboard the TriSat-R cubesat. Launched on the inaugural flight of the European Space Agency’s 4-stage Vega-C rocket, Trisat-R is Slovenia’s second satellite fielded in Earth orbit, after the original Trisat. TriSat-R was one of six smallsat rideshare payloads that hitched a ride with the Laser Relativity Satellite (LARES-2) geodesy and geodynamics mission, built to test General Relativity and refine the measurement of relativistic frame-dragging. The mission was launched on July 13th, 2022 from the Guiana Space Center in French Guiana.

Lift-off of a Vega-C rocket, with the Lares-2 mission plus rideshares. Credit: ESA

The image hearkens back to the early era of the Space Age, when controllers were happy to get anything back at all. TriSat-R is built on three 3U cubesat frames, stacked together about the size of a shoe box.

Trisat-R in the lab. Credit: University of Maribor.

The 2mm-wide aperture is about the width of an ultra-fine marker. The camera works similar to an old school pinhole camera. You can see the same soft focus across the frame, similar to a pinhole view.

A closeup of one of the micro-cameras aboard Trisat-R. Credit: Iztok Kramberger/University of Maribor

But the camera wasn’t meant to take pretty pictures.

“We are researching and developing highly miniaturized solutions for satellite attitude determination using sensor fusion, (a method for merging input from multiple sensors) and the highly miniaturized camera plays an important role in this case.” Trisat-R project manager Iztok Kramberger told Universe Today. “Simply put, the camera is used in a similar way that a modern computer mouse is working to detect its motion. For example, we are detecting the motion of (a) 6 by 6 pixels wide black spot over a fully saturated image, which is a consequence of imaging of the Sun.”

This sort of black dot effect exploited by the tiny camera is is a frequent issue on digital sensors, where a black smudge appears due to over-saturation from a bright target. You even see this effect in the images produced by the 10 billion dollar JWST:

Black dots seen in the view of JWST’s Fine Guidance Sensor camera. Credit: NASA/JWST

The tiny pair of cameras contain sensors just 320 pixels square, housed under clear borosilicate glass lenses. These offer radiation resistance and protection from the harsh environment of space. The technology pioneered in Trisat-R could one day be standard features on small nanosats.

“These findings will be applied to new highly miniaturized and ‘smarter’ attitude determination systems for future missions,” says Kramberger. “On the next mission named Trisat-S (launching in the first half of 2024) we will use this newly developed technology to experiment further with 360 degrees view from a satellite in a very fast VLEO (Very Low Earth Orbit).”

Trisat-R is in a Medium Range Orbit (MEO) just under 6,000 kilometers from the Earth. This puts in within the Earth’s inner Van Allen radiation belt.

An artist’s conception of Trisat-R in Earth orbit. Credit: Skylabs

When it comes to resolution, the camera on your smartphone could easily outclass the ones on Trisat-R. Android smartphone operating systems have been built into small ‘phonesats’ before. Now, nano-cameras like the ones on Trisat-R could really start pushing things to the limit.

“In terms of image quality, the camera used on Trisat-R cannot compare to any camera built into a common smartphone.” Says Kramberger. “Even the first mobile phones having imaging capabilities had probably higher resolution than the camera used on Trisat-R, but at the end for the purpose we are using it, it is not about the image quality or even the resolution, it’s about the size. You probably can’t find any smaller camera than the one we are using. You can’t fool physics.”

Trisat-R is expected to operate for two years before succumbing to the harsh space radiation environment. The legacy for the mission includes Trisat, Trisat-R and next up, TriSat-S.

Another far-off concept will be in need a micro-camera: the Breakthrough Starshot initiative, which wants to send a series small ‘Star-Chip’ gram-scale spacecraft to Proxima Centauri b. The Sprite proto-types sent into low Earth orbit in 2017 weighed in at just 4-grams (think the size and mass of a U.S. Nickel).

For now though, we can enjoy the view from Trisat-R, as it pioneers technology needed for the coming revolution in tiny micro-satellites.