Years have passed since Rosetta mission which brought human ingenuity to the comet 67 P / Churyumov-Gerasimenko . But, as often happens when it comes to science, even a completed mission can lead to novelty by analyzing the data a posteriori and discovering important information. This is the case of the announcement of ESA regarding the lander Philae .

ESA news on the Rosetta mission and on Philae

Who followed the mission at the time ( launch in 2004, conclusion in 2016) you will remember that not everything went as planned in the case of Philae . The lander , the size of a washing machine not anchored on the surface of the comet 67 P / Churyumov-Gerasimenko using the system of metal grapples.

After release from the Rosetta probe, the descent towards the cometary nucleus lasted about 7 hours. The lander bounced off the intended landing site ( Agilkia) and moving for two hours to the final landing point (Abydos).

Understanding Philae’s hops is key

As explained by Laurence O’Rourke of ESA , find the lander was essential to better understand the data collected by scientific instruments. Researcher stated “it was important to find the landing site because sensors on Philae indicated that it had dug into the surface, most likely exposing the primitive ice. hidden underneath, which would have given us invaluable access to ice of billions of years “.

To understand the sequence of events both the OSIRIS camera (of the probe) and the ROMAP magnetometer of Philae were used , essential for the discovery. Comparing the magnetometer data of the lander with that of the probe it was possible to establish what happened.

Philae spent two minutes at the second landing site touching the comet’s surface and leaving traces in the ice and dust. The lander also sank for 25 cm (for three seconds) in the ice leaving clear and detectable by cameras.

The skull on the comet and the dust that looks like foam of a cappuccino

This unexpected journey on the surface has left marks that reminded researchers of a skull due to its shape. The right eye was created from the upper surface of the lander due to the compression of the powder. Billion-year-old ice was also exposed in this daring movement that shone when exposed to sunlight. The skull is approximately 30 meters from the final point where the lander stopped .

Thanks to the data analysis it was also possible to discover another curiosity. The surface dust of 67 P / Churyumov-Gerasimenko is soft in texture. Researchers have described it as softer than the foam of a cappuccino or the foam found in a bubble bath or above the waves by the sea.

Furthermore, the idea that the comet is an aggregate of dust and portions of rock with a homogeneous structure. And this conformation has remained the same since it was born, about 4.5 billion years ago. The information will allow the development of new landing systems that take this structure into account.