The Rosetta Space Mission (DNL Science - Seconde)

An engaging visit for the DNL Seconde – Science : the Rosetta Space Mission 
At the end of 2016, the DNL class Seconde welcomed Mr Carreau from the European Space Agency – ESA - into their classroom where he enlightened them on the compelling topic of the Rosetta Space Mission. Here is what they learned.  
The Rosetta Space Mission, named after the Rosetta Stone, was a mission whose prime objective was to help understand the origins and evolution of our Solar System by analyzing the comet 67P/Churyumov-Gerasimenko. Indeed, as far as we know, comets are the oldest and most primitive bodies in the Solar System and they could even help us uncover the properties of the solar nebula from which the Sun, planets and small bodies were formed 4.6 billion years ago.  
Launched in 2004 by ESA, the space probe Rosetta and her lander module Philae crossed the asteroid belt and traveled into deep space about 1 billion kilometers away from the Earth. These two took an impressive amount of time, 10 years, to reach the comet and perform a series of maneuvers, such as gravity assists from 4 planetary flybys (one of Mars and three of the Earth), to enter its orbit. At last in November 2014, Philae successfully touched down on the comet's surface (which surprisingly resembled a duck). 
Source: ESA / image from animation of Philae separating from Rosetta
The event was fraught with excitement and joy for the scientists working on the mission but unfortunately, after a couple of hours, something did not seem right. Philae's harpoons hadn't deployed and its thruster had failed to work, all of which made the lander somehow bounce off and land in the shadow of a cliff, where its solar panels could not be provided with energy. None-the-less, the 98kg probe's non-mechanical instruments were working perfectly with eight out of the ten instruments operational thus sending back data which included the comet's temperature, magnetic field (which is nonexistent) and more.  
Even though the mission didn't go quite as planned a great amount of things were learnt about the comet. First of all, it harbors organic compounds, which are carbon-based molecules which, by the way, was the first time that organic compounds were ever detected on the surface of a comet's nucleus. This was an exciting discovery, as all living things on Earth are made up of organic molecules and scientists wanted to know if these could have been brought here by a comet. Then, it debunked the theory that the Earth’s water was brought over by comets when they smashed into our planet in its early life... wrong. Comet 67P contains a different type of water. Finally, Rosetta was the first spacecraft to witness, at close proximity, how a comet changes as it approaches the increasing intensity of the Sun’s radiation. Sadly, the long, dramatic journey of Rosetta came to an end quite recently.  In September 2016, Rosetta made her last maneuver: crash-landed on the comet's surface and as such was permanently deactivated.

Source: ESA / Rosetta’s final imaging sequence
All in all, this lecture was very informative and Mr Carreau somehow managed to keep the students on a string. We would like to thank him again for coming and, as he said, all good things eventually come to an end. Rest in peace Rosetta. 
Clara and Charlotte