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Plasma properties at 67P/Churyumov-Gerasimenko: a comparison between PP-SESAME/Philae/Rosetta and RPC/MIP/Rosetta

Schmidt, Walter and Henri, P. and Lebreton, J.-P. and Vallières, Xavier and Grard, Rejean and Hamelin, Michel and Le Gall, Alice and Lethuillier, Anthony and Ciarletti, V. and Caujolle-Bert, Sylvain and Seidensticker, Klaus J. and Fischer, Hans-Herbert (2016) Plasma properties at 67P/Churyumov-Gerasimenko: a comparison between PP-SESAME/Philae/Rosetta and RPC/MIP/Rosetta. EGU General Assembly 2016, 17. – 22. April 2016, Wien, Österrreich.

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Abstract

On November 12, 2014, the Rosetta landing module Philae approached the nucleus of 67P/Churyumov- Gerasimenko and eventually settled on the surface in a location named Abydos, though its exact coordinates are still unknown. The Permittivity Probe (PP) as part of the SESAME (Surface Electric Sounding and Acoustic Monitoring Experiment) instrument package [1] was designed to not only measure the electrical properties of the comet’s surface material by actively injecting an alternating current at different frequencies into the material underneath the Lander but also to monitor potential variations between its two receivers and the electrical conductivity of the plasma environment while still in space. By sampling the potential difference at 40 kHz between the soles of two of the feet attached to Philae’s landing gear, plasma waves between 20 and 20 000 Hz should be detectable if their amplitudes are large enough. The injection of low frequency currents into the Plasma environment during Philae’s descent gives indications for changes of the plasma density when approaching the comet. In this paper we present observations from the cross-calibration campaign with the Rosetta plasma package Instrument MIP (Mutual Impedance Probe) [2] during the Pre-Delivery Calibration and Science (PDCS) operations on October 17, 2014, during the descent towards the comet surface on November 12, 2014, and from the First Science Sequence at Abydos on November 13. During the PDCS campaign most PP observation slots coincided with plasma waves dominantly in the 100 to 150 kHz range according to MIP measurements. Accordingly PP did not register any signals. Only in the afternoon of the 17th low frequency waves were recorded by MIP. At the same time the measured PP wave power signal was above the background for frequencies below 500 Hz in several subsequent measurements. During the descent [3] the injected current at 758 Hz dropped suddenly by about 5 % possibly indicating a decrease in the plasma density at an altitude of about 18.5 km above the comet surface. During the First Science Sequence PP was monitoring low frequency wave-like activities starting two hours after local sunset.

Item URL in elib:https://elib.dlr.de/109297/
Document Type:Conference or Workshop Item (Poster)
Title:Plasma properties at 67P/Churyumov-Gerasimenko: a comparison between PP-SESAME/Philae/Rosetta and RPC/MIP/Rosetta
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Schmidt, Walterfmi, helsinki, finnlandUNSPECIFIED
Henri, P.lesia, cnrs-observatoire de paris, meudon, franceUNSPECIFIED
Lebreton, J.-P.laboratoire de physique et chimie de l’environnement et de l’espace, umr 7328 cnrs – université d’orléans, franceUNSPECIFIED
Vallières, Xavierlaboratoire de physique et chimie de l’environnement et de l’espace, umr 7328 cnrs – université d’orléans, franceUNSPECIFIED
Grard, RejeanESA, estecUNSPECIFIED
Hamelin, Michellatmos, paris, frankreichUNSPECIFIED
Le Gall, Alicelatmos, paris, frankreichUNSPECIFIED
Lethuillier, Anthonylatmos, paris, frankreichUNSPECIFIED
Ciarletti, V.latmos, Paris, franceUNSPECIFIED
Caujolle-Bert, Sylvainlatmos, paris, frankreichUNSPECIFIED
Seidensticker, Klaus J.Klaus.Seidensticker (at) dlr.dehttps://orcid.org/0000-0003-3671-3769
Fischer, Hans-HerbertHans-Herbert.Fischer (at) dlr.deUNSPECIFIED
Date:April 2016
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Rosetta Philae SESAME PP MIP
Event Title:EGU General Assembly 2016
Event Location:Wien, Österrreich
Event Type:international Conference
Event Dates:17. – 22. April 2016
Organizer:European Geophysical Union
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Projekt ROSETTA Instrumente
Location: Berlin-Adlershof , Köln-Porz
Institutes and Institutions:Institute of Planetary Research
Space Operations and Astronaut Training > User center for space experiments (MUSC)
Deposited By: Seidensticker, Dr. Klaus J.
Deposited On:15 Dec 2016 08:44
Last Modified:31 Jul 2019 20:06

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