Microwave Journal
www.microwavejournal.com/articles/23384-how-european-companies-contributed-to-rosetta-landing-on-comet-surface

How European companies contributed to Rosetta landing on comet surface

International

November 17, 2014

On 12 November 2014, Rosetta, a space probe from the European Space Agency (ESA), successfully deployed the Philae lander on the comet 67P/Churyumov-Gerasimenko. This is the first time in the history of comet research that a landing has been made on a comet's surface and leading European companies including HUBER+SUHNER, e2v and Terma contributed to the success.

After a 10-year journey, the Rosetta space probe entered the orbit of the 67P/Churyumov-Gerasimenko comet on 6 August 2014, and has accompanied it ever since. Philae is a small autonomous probe that will be active on the comet. During this time, it will collect information about the comet's core and environment. The comet is approaching the sun, which is causing it to lose material, mainly in the form of water ice and dust. The scientists want to examine how exactly the comet is changed by the warmth of the sun.

The 100 kg Philae houses ten devices, including cameras, sensors and antennas. Using these devices, scientists can analyse the chemical composition of the comet and receive pictures from the surface.

For the radio frequency connections in the transmitting and receiving antennas, as well as the antennas in the space probe and the lander, HUBER+SUHNER delivered 50 cable assemblies more than 10 years ago after passing special tests. The lightweight cables, which are used for signal transmission offer excellent mechanical and electrical stability. This is especially important in environments with extreme external conditions, as is the case with the space probe.

Five state-of-the-art image sensors, designed and manufactured by leading imaging solutions provider e2v, are helping scientists to perform a detailed study of the comet. There are three on Rosetta: the high resolution imaging camera, OSIRIS, which has a narrow field and wide field camera; NAVCAM – the navigation camera; and the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS), which maps and studies the nature of the solids and the temperature on the surface of the comet. It also identifies gases, characterises the physical conditions of the comet and has helped to identify the best landing site (e2v’s devices are in the visible element of this instrument).

On Philae e2v contributes: the Comet nucleus Infrared and Visible Analyzer (ÇIVA) – six identical micro-cameras that take panoramic pictures of the surface of the comet. A spectrometer studies the composition, texture and albedo (reflectivity) of samples collected from the surface: and the Rosetta Lander Imaging System (ROLIS) – a CCD camera used to obtain high-resolution images during the descent of the lander and take stereo panoramic images of areas sampled by other instruments.

For this mission, Terma, a leading Danish supplier of advanced space electronics, software, and services to ESA, space industry partners, and national space agencies, developed the central power supply, an 8 kg ‘shoe box size’ Power Conditioning Unit (PCU) to supply all onboard instruments with power. The PCU comprises a unique developed technology named Maximum Power Point Tracking (MPPT). With the three batteries and the 65 m2 solar array, this technology will maintain a constant power supply for the scientific and other instruments on board the satellite.

The MPPT is an electronic function that constantly regulates the solar array loading to the exact point where the optimum level of electric power is achieved, a loading point that depends on the amount of solar radiation to which the solar panels are exposed.

Besides the advanced PCU, Terma has also supplied the checkout system for Rosetta. The system was used for a complete functionality test of the satellite prior to launch. Further, Terma has supplied the so-called software validation facility which was used prior to launch for an independent test of the software in Rosetta’s critical sub-systems.