Rosetta has crashed into comet 67P

The European Space Agency (ESA) ordered the Rosetta spacecraft to crash into comet 67P/Churyumov-Gerasimenko at 13:19 CET today. With that, Rosetta’s 12-year journey has come to an end.

The satellite is very lightly built and cannot withstand great forces and will therefore be crushed by the impact. There’s no way to ever get Rosetta or the Philae lander that started the mission: both probes will remain on the comet forever.

ESA has landed Rosetta on the smaller side of the comet where there are many large deep ‘pits’ over 100 meters in diameter and between 50 and 60 meters in depth. This is where many of the dust clouds that the comet emits form. But the landing itself is not only for destruction, it is also unique: the scenario of a device descending towards the comet from about 20 kilometers away is of great interest to scientists. During the descent, Rosetta will continue to take pictures and take measurements with various instruments. The astronomers hope to extract information from this that will provide additional insights into the earliest times in ‘our’ solar system.

Just before the real end, the space agency hoped that Rosetta lands in a favorable spot. The landing site was chosen near a large 130-meter-diameter pit that the team named Deir el-Medina, after a structure similar in appearance to an ancient Egyptian city of that name, the organization writes. Especially the walls of such a pit are probably very interesting because a lot of geological information can be read from them. ESA will try to send high-resolution photos to Earth right up to the last minute, including photos of the pit walls just before Rosetta crashes. Whether Rosetta ended up in the desired place remains to be seen. The target was set within an elliptical area of ​​700 by 500 meters.

The entire operation remained suspenseful right up to the last moment as conditions become more and more extreme as they approach the comet, making it difficult to navigate. If something had gone wrong, there would have been no time to adjust because it takes a long time for the Rosetta signal to reach Earth and return.

Even if the spacecraft was still on when it landed on the comet’s surface, it will automatically shut itself down because ESA is bound by international agreements and the transmitter must not act as an interplanetary jammer.

Final commands to disable Rosetta

what preceded it

A lot has happened from the time of the belated launch to the final end of the physical mission that covered some 6 billion kilometers. In the past twelve years to reach comet 67P/CG, so much data has been collected that there is still plenty to study. Due to problems with the Ariane rocket that was supposed to shoot the whole thing into space, Rosetta’s destination had to be changed from 46P/Wirtanen, a smaller comet, to 67P/CG.

To get to the comet, Rosetta first had to be put into orbit and then, by making several swingbys around the Earth and Mars, catapulted further and further into a large ellipse around the sun by gravity. After passing Earth, Mars, Earth and Earth again, the probe passed asteroids twice more: Šteins in 2008 and Lutetia in 2010, only to do something again in 2014, namely making maneuver corrections. to get into orbit well around 67P. Comet lander Philae was due to land on the comet’s surface on November 12 that same year. Unfortunately, due to a failing anchor system, the probe bounced into the shadows, significantly reducing the time the device was able to collect information.

Discoveries

That same year, data from mass spectrometer Rosina van Rosetta made it clear that the suspicion that the water on Earth comes from comets is probably incorrect because the ratio of heavy water to normal water is more than three times that on Earth.

Remarkably enough, no magnetic field has been measured from the comet, which means that the nucleus of the comet is not magnetized. Because Rosetta orbited the comet for a long time, it was an excellent opportunity to investigate whether a magnetic field exists around comets. With a short ‘fly by’ it is not possible to investigate such a thing.

Instrumentation

All those measurements are not possible without measuring equipment. Rosetta had several instruments on board, including several cameras, spectrometers, and various sensors. All that equipment together had to provide a large amount of high-resolution images with information about shape, density, temperature, interaction with solar wind and the chemical composition of the comet. The gases and dust contained in the so-called coma, the cloud of gas around a comet or ‘atmosphere’, were also analysed.

The entire device of 2.8×2.1×2 meters and two solar panels with a total surface area of ​​64m2, both 14 meters long, initially carried the Philae lander of 1x1x1 meter. Philae had ten instruments on board and Rosetta 11, each with its own function.

Ultimately, ESA lost the signal with Rosetta at 1:19 PM. A tweet saying ‘Operations complete at 720mn km from Earth’ made the news worldly that the spacecraft has come to an end 720 million kilometers away.

ESA: Loss of signal