Scientists have analyzed the final data sent by Rosetta when it crashed on comet 67P/Churyumov–Gerasimenko and have reconstructed the last image it took. The image was taken as the craft was just about to meet its doom.
The team has already collected a “last image” when the European Space Agency’s probe was between 26 and 23 meters (85-75 feet) high. The new image was part of the telemetric packets sent afterward, but the team didn’t know it was there. It was collected when the probe was 5 meters (16 feet) closer to the comet’s surface.
"The last complete image transmitted from Rosetta was the final one that we saw arriving back on Earth in one piece moments before the touchdown at Sais," Holger Sierks, principal investigator for the Rosetta’s OSIRIS camera at the Max Planck Institute for Solar System Research, said in a statement. "Later, we found a few telemetry packets on our server and thought, wow, that could be another image."
Images were sent by the probe in six packets of data, which totaled 23 kilobytes. However, the team received just above half that in the last transmission, as the communication was interrupted. The automatic software didn’t recognize the data as an image, but the engineering team looked at what they had and worked to get something meaningful out of 53 percent of the usual data.
The final image has a compression ratio of 1:38 rather than 1:20, so it’s a lot blurrier than you might expect. The OSIRIS camera wasn't exactly designed for such close-up views.
Rosetta spent two years orbiting comet 67P, collecting an impressive amount of data on the structure and composition of the object. It was crashed on the comet on September 30, 2016, as the comet was moving away from the Sun and the solar-powered probe would not survive the winter.