Preliminary science results from Rosetta's third Earth swingby
On 13 November 2009 Rosetta successfully performed its third and final swingby of Earth, with closest approach occurring at 07:45:40 UT at an altitude of 2480 km. Several of Rosetta's instruments were active during this swingby and performed science observations and calibration measurements. These measurements are used to characterise the performance of the various instruments and to prepare for the science observations planned during the encounter with asteroid Lutetia in 2010 and, ultimately, with comet 67P/Churyumov-Gerasimenko in 2014.
Below are some of the early results from these activities. Detailed analysis of the data gathered during the Earth swingby is on-going.
VIRTIS
Visible and InfraRed Thermal Imaging Spectrometer
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These pictures were taken by VIRTIS between 14:00-14:25 UT on 13 November 2009, when Rosetta was at about 230 000 km from Earth's surface. The VIRTIS Mapper channel (VIRTIS-M) is a hyperspectral imager that collects image data simultaneously in 864 narrow, adjacent spectral bands (colours). The spectral information is used in studies of the composition of the observed areas, while the combined information from the image and spectral data provide two-dimensional compositional maps.
This sequence of five images shows the capability of VIRTIS to isolate desired features of the observed object using the spectral data. The first two images of the sequence are colour composites made by choosing two different sets of three spectral bands in the visual waveband range. The middle image is a false-colour image that shows the distribution of chlorophyll. The fourth image is a composite made using three spectral bands in the infrared. The final image shows the Earth as seen in a single narrow infrared band at 5.0 µm.
Credit: INAF-IFSI/INAF-IASF/ASI
SREM
Standard Radiation Environment Monitor
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Rosetta's SREM was also active during the swingby and was used to determine the spatial distribution of the Earth's radiation belts along Rosetta's trajectory as the spacecraft passed the Earth.
These plots show the measurements of the electron and proton count rates, the Earth's magnetic field strength and the derived electron fluxes in different energy ranges.
Credit: ESA/Paul Buehler/PSI
RPC
Rosetta Plasma Consortium
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The RPC is a set of 5 instruments designed to make complementary measurements of the plasma environment around comet 67P/Churyumov-Gerasimenko.
Starting at 20:00 UTC on 9 November 2009, the RPC monitored the Earth's plasma environment and performed magnetospheric studies for a period of one week around closest approach. During this period, on 10 November 2009, the RPC's Langmuir Probe (LAP) picked up clear signals from Rosetta's thrusters being fired.
Credit: ESA/RPC-LAP/IRF Uppsala
Last Update: 1 September 2019