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The team from the University of West Bohemia (UWB) communicated with the VZLUSAT-2 satellite more than eight thousand times, and the very last contact was picked up on Saturday evening, just a few hours before the satellite burned up. “We managed to establish two-way communication at the moment when the satellite was flying at an altitude of roughly 180 kilometers above Earth. In this critical phase, when the remaining atmosphere is already slowing the satellite down and heating its surface, we succeeded in downloading the final batch of telemetry and scientific data,” said Ivo Veřtát from UWB. Together with his colleague Jiří Masopust and a team of university staff, he oversaw the operation of the Pilsen station throughout the four-year mission, ensuring the satellite’s functionality.

VZLUSAT-2 was the first Czech satellite capable of capturing high-resolution images of Earth. During its mission, it sent back numerous photographs, including images of Prague, Slovakia, Hungary, and the Alps. It also monitored space weather — the conditions in the near-Earth environment at 500 kilometers above ground. It tracked radiation levels, particle counts, humidity, and X-ray flashes that are remnants of cosmic catastrophes or collapsing stars.

All these data were received at UWB, from where the research team forwarded them to other scientists. “There’s no room for error. Any longer outage of our ground station would have meant fewer downloaded data. The biggest challenge was to maintain nonstop operation during satellite passes, day and night, using low-cost solutions, because national missions like this operate with budgets that are several orders of magnitude smaller than those of large agencies like NASA or ESA,” added Jiří Masopust.

Reconstructing the satellite’s final moments resembled detective work. Small CubeSat-class satellites on low orbits are not under constant radar surveillance. As a result, they often burn up over the ocean, out of sight, and their point of destruction must be calculated mathematically. During its final contact with Pilsen on Saturday at 21:48, the satellite was flying at about 180 kilometers. “We can reliably confirm that at 23:26 UTC on Saturday, a station in Alaska received and decoded a data packet. At that moment, the satellite was at 177 kilometers. We also know with high certainty that around 1:40 a.m. on Sunday, a station in Antarctica picked up its signal, with the altitude down to 170 kilometers. Due to a large Doppler-shift compensation error, however, those packets could not be decoded automatically,” the UWB scientists explained. After that, no station received any further signal. Mathematical models predict the satellite’s breakup around 4:30 UTC, somewhere between Antarctica and South America.

The VZLUSAT-2 project was led by the Aerospace Research and Test Establishment (VZLU). A key role in communication with the satellite was played by the team from the University of West Bohemia in Pilsen, which operated its own ground station and controlled the satellite throughout the mission. Czech technology companies such as Esc Aerospace, Rigaku Innovative Technologies Europe, TTS, Advacam, Spacemanic, Eltvar, and Needronix contributed to the development and manufacturing. Scientific experiments and data processing were supported by grants from TAČR and GAČR. The satellite was the successful successor to the VZLUSAT-1 mission, which also ended with a natural atmospheric re-entry in June 2023.