Tracking Philae’s descent with magnetic data

ROMAP co-principal investigator Hans-Ulrich Auster from the Technische Universität Braunschweig, Germany, explains how the instrument will be used with RPC (on the Rosetta orbiter) to monitor Philae as it descends to the surface of comet 67P/Churyumov-Gerasimenko on 12 November – as well as looking out for any evidence of a ‘fossil’ magnetic field linked to the comet itself. On 12 November, the magnetic field instruments on-board the Rosetta orbiter and lander will be assigned the task of monitoring Philae as it descends to the surface. That’s possible because both the lander and the orbiter generate small magnetic fields of their own, due to the electronic circuits inside the spacecraft. These magnetic fields create perturbations in the data that the scientists normally remove in order to analyse the purely natural magnetic fields from the comet and the solar wind. However, on 12 November, these perturbations can be analysed to tell what is happening to the lander as it slowly drops towards the surface of 67P/C-G. Once the lander has separated, the magnetic perturbation registered near the orbiter will decrease as Philae moves away. Later, when the lander deploys a boom arm for its ROMAP instrument, it will cause a brief variation in the perturbation. A similar variation may also be registered when the three landing legs spring into place. The perturbations may prove too subtle for the RPC instruments, operating on Rosetta at some distance from Philae, but the ROMAP instrument on the lander will register the changes loud and clear. “We will be able tell what is happening on the lander by the changes in its magnetic field,” says ROMAP co-principal investigator Hans-Ulrich Auster. These measurements will add to the overall picture of Philae’s progress to the surface of the comet. Of course, the main focus of these instruments is […]



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