Rosetta's historic, 5 billion–mile, comet-landing achievement ends in silence

It's the European Space Agency's crowning achievement, but rather than going out in a blaze of glory, the Rosetta space probe ended it all with silence. Having been instructed to crash-land on the comet it had been tracking for 12 and a half years, Rosetta finally said goodnight by switching off its transmitters and cutting the connection with Earth.

At mission control in Darmstadt, Germany, engineers watched a green line representing Rosetta's radio contact with Earth falter, and finally flatline, indicating that Rosetta had successfully completed its mission and landed on comet 67P/Churyumov-Gerasimenko — the focus of its entire mission.

The flatlining signal was greeted with some low-key cheers and handshakes among the engineers and scientists, with some members of the team having spent the best part of three decades working on the mission.

"This is the culmination of tremendous scientific and technical success for this mission," Patrick Martin, Rosetta's mission manager, said. "It was historic, it was pioneering and it is revolutionizing how we see comets. Farewell, Rosetta. You've done the job. That was space science at its best."

From — ESA Rosetta Mission (@ESA_Rosetta)September 30, 2016

Having successfully reached the comet in August 2014, Rosetta dropped a washing machine–sized probe called Philae onto the comet's surface, which was a first in space exploration.

Rosetta's journey lasted 4,595 days and saw the probe travel almost 5 billion miles across space — that's more than 10,000 return trips to the moon, if you want some perspective.

Most of Rosetta's time in space was spent catching up with the 67P, which is travelling at 21 miles per second. For the last 786 says Rosetta has been in orbit around 67P and as well as marking the first successful landing on a comet with Philae, Rosetta was able to use that time to give scientists unprecedented information about the comet, how it was formed and how it changes as it moves towards and away from the sun.

The probe itself is just a speck compared to the comet it was tracking, measuring 2.8 x 2.1 x 2 meters with its solar wings spanning 32 meters. By contrast, 67P is 3 miles long at its longest point and is estimated to weigh a hefty 11 billion tons.

Rosetta's mission was all about data and its various sensors — together with those on Philae — have collected and transmitted a huge 218 gigabytes of information about space and the makeup of the comet - data which is expected to keep scientists busy for decades.