Next Thursday, a rocket carrying a robotic explorer will launch, marking the start of the European Space Agency’s Rosetta mission to land on a comet.
The mission will take 10 years, with the lander making three fly-bys of earth and one of Mars before it reaches its destination, Comet 67P/Churyumov-Gerasimenko, in 2014.
The Ariane 5 rocket will launch from Kourou in French Guiana. For large sections of the journey, the craft will fly in hibernation mode, to save on fuel. But it will still make some observations en route, and will activate its camera on approach to send back images of the comet. This will enable the ESA team to improve calculations about the position, size and orbit of the cosmic snowball.
Once on the surface, the Philae lander will conduct a range of experiments with the 10 instruments on board. The Particle Physics and Astronomy Research Council (PPARC) funded development and construction of two key instruments: the Ptolemy experiment on the Philae lander (Open University and CCLRC-Rutherford Appleton Laboratory) and the Plasma Interface Unit (PIU, Imperial College, London) built for the Rosetta Plasma Consortium instrument package on the orbiter. The PIU will study the nature of the solar wind’s interaction with the comet.
Ptolemy will analyse the nature and distribution of the most important cometary surface materials. Its experiment is based upon a coupled gas chromatograph and mass spectrometer. The plan is that these will determine the abundance and stable isotopic compositions of elements such as hydrogen, carbon, nitrogen and oxygen.
Dr. Ian Wright, principal investigator on the Ptolemy project, said the study of these biologically important elements is "strongly implicated in humankind's quest to understand the origin of life on Earth".
The study of comets is important because they open a window into the earliest days of the solar system. They have remained essentially unchanged, relative to other orbiting bodies. They are also known as the bringers of life, and are credited with bringing the lighter elements to the surface of earth, playing a crucial part in forming our atmosphere and our seas. Some speculate that the earliest seeds of life – organic molecules - may also have arrived by comet. ®