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Principal Investigator: Korablev O.
Project
Manager: Shakun A.
MIR and NIR Technical Manager:
Trokhimovsky A.
TIRVIM Technical Manager: Grigoriev A.
ACS is the set of three spectrometers being built in Space
research Institute (IKI) in Moscow, Russia. Its design capitalizes on the
previous developments of high-technology readiness: two instruments built
for the unsuccessful Phobos-Grunt project 2009-2011 and one instrument flown at
the International Space Station (ISS) in 2009-2012.
Some components/subsystems were contributed by the German
Institut für Planetenforschung (DLR) and LATMOS (CNRS) in France.
ACS includes three separate spectrometers, sharing common
mechanical, thermal, and electrical interfaces. On the TGO spacecraft, the
instrument occupies the slot at the upper deck, previously devoted to
MATMOS. The ACS architecture and its concept design are shown in Fig. 1.
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Fig. 1 The concept design of ACS. Suite consists
of four blocks: the NIR channel, the MIR channel, the TIRVIM
channel, and the electronic block. The yellow blocks
designate the instrument's radiators. The pointing
directions of the ACS channels are shown.
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Near-Infrared Channel (NIR)
The ACS NIR channel employs the scheme of solar occultation
infrared (SOIR), a combination of an echelle spectrometer and an
acousto-optic tunable filter (AOTF) for the selection of diffraction orders.
This scheme was originally proposed and prototyped for the measurements in
the terrestrial atmosphere, and first implemented in space for the case of
Venus.
NOMAD on TGO employs the same principle and actually consists
of two SOIR-type spectrometers, one optimized for solar occultation, and
another for nadir. The closest analog of NIR is the RUSALKA instrument
(Russian acronym for manual spectral analyzer of the atmosphere
constituents), flown on the ISS in 2009-2012.
RUSALKA covered the spectral range of 0.7-1.65 μm with
the resolving power of 20,000, and demonstrated measurements of terrestrial
CO2 and CH4 in nadir. However, cosmonauts operated RUSALKA in the habitable
compartment of the ISS, and the instrument was built according to these
requirements, which are very different from those on a deep space mission.
ACS NIR is the adaptation of the RUSALKA design for autonomous operation in
open space with several amendments aimed to improve the sensitivity and the
optical quality of the instrument.
ACS NIR is able to perform nadir and occultation observations
using two FOVs, which are combined inside the instrument.
Mid-Infrared Channel (MIR)
The MIR channel is a cross dispersion spectrometer working in
the 2.3-4.2 μm spectral range, and simultaneously covering up to 300 nm
per measurement. With a cross dispersion concept, the echelle orders are
dispersed along the x-axis and separated along the y-axis of the focal plane
by a secondary dispersion element, making full use of the two dimensions of
the detector array. Acquisition of the wide wavelength domain at once
provides a strategic advantage for maximizing the number of gaseous species
simultaneously mapped. The concept of the cross dispersion echelle
instrument, which is widely accepted in astronomy, has already been employed
in planetary missions with visible and infraRed thermal imaging
spectrometers, with high resolution (VIRTIS-H) instruments presently in
flight on Rosetta and Venus Express missions. The concept of VIRTIS-H
consists of acquiring a broad spectral range of 2-5 μm instantaneously
at the 2-D detector using the echelle grating and a prism. With number of
diffraction orders of 10, the resolving power of VIRTIS-H is
λ∕Δλ ≈ 2000.
Targeting much a higher resolving power than that of
VIRTIS-H, and a broader instantaneous spectral range than that of SOIR-type
echelle-AOTF instruments, we conceived a new type of optical scheme: a cross
dispersion echelle spectrometer with a movable secondary dispersion element.
This concept allows us to achieve high spectral resolution instantaneously
in a large number of adjacent diffraction orders (from 10 to 30 in our
case), covering only a fraction of the full spectral range. A moving
dispersion element allows the instrument to switch from one group of
diffraction orders to another prior to a series of measurements, or
alternates between two desired positions during one measurement sequence.
Targeting very high spectral resolution, the MIR channel
operates in solar occultation only.
Thermal-Infrared Channel (TIRVIM)
In contrast to NIR and MIR abbreviations, which are
self-explicit, TIRVIM stands for thermal infrared V-shape interferometer
mounting, but also commemorates the initials of Vassilii Ivanovich Moroz,
the IR astronomer and the leader of the planetary school in IKI during
1968-2004, who introduced the Fourier-transform spectrometers and pursued
their development in this institution.
TIRVIM is a 2-inch double pendulum Fourier-transform
spectrometer for the spectral range of 1.7-17 μm. It has three
detectors, allowing operation in four different operation modes.. The
primary scientific goal of TIRVIM is the monitoring of atmospheric
temperatures and aerosol states in nadir. The instrument capitalizes on
previous developments of IKI in Fourier spectrometers. One detector
(longwave, LW) is sensitive at 1.7-17 μm, another (shortwave, SW) at
2.2-3.5 μm. The LW detector is employed both in nadir and in solar
occultation, allowing spectral resolution of 1.6 cm−1 and 0.2
cm−1, respectively. The SW detector optimized for the 3-μm range
targets the mapping of minor gases in nadir with the best spectral
resolution of 0.5 cm−1. An additional pyroelectric detector operates
at ambient temperature in the 1.7-25 μm range.
Publications:
1. Korablev, Oleg; Trokhimovsky, Alexander; Grigoriev, Alexei
V.; Shakun, Alexei; Ivanov, Yuriy S.; Moshkin, Boris; Anufreychik,
Konstantin; Timonin, Denis; Dziuban, Ilia; Kalinnikov, Yurii K.; Montmessin,
Franck, Three infrared spectrometers, an atmospheric chemistry suite for the
ExoMars 2016 trace gas orbiter, Journal of Applied Remote Sensing, Volume 8,
id. 084983 (2014)
2. Korablev, Oleg; Grigoriev, Alexei V.; Trokhimovsky,
Alexander; Ivanov, Yurii S.; Moshkin, Boris; Shakun, Alexei; Dziuban, Ilia;
Kalinnikov, Yurii K.; Montmessin, Franck Atmospheric chemistry suite (ACS):
a set of infrared spectrometers for atmospheric measurements on board
ExoMars trace gas orbiter, Proceedings of the SPIE, Volume 8867, id. 886709
12 pp. (2013).
Conferences:
1. Trokhimovskiy A., Oleg Korablev, Yurii Ivanov, Ivan
Syniavskyi, Franck Montmessin, Anna Fedorova, HIGH RESOLUTION MIDDLE
INFRARED SPECTROMETER, A PART OF ATMOSPHERIC CHEMISTRY SUITE (ACS) FOR
EXOMARS 2016 TRACE GAS ORBITER, International Conference on Space Optics,
7-10 October 2014, Tenerife, Spain.
2. Korablev O., Franck Montmessin, Anna Fedorova, Nikolay
Ignatiev, Alexander Trokhimovskiy, Alexei Grigoriev, Alexey Shakun,
Development of Atmospheric Chemistry Suite (ACS) for ExoMars: Three IR
Spectrometers to Characterize the Atmosphere and Climate 40th COSPAR
Scientific Assembly 2014, B0.2-0020-14, 2014.
3. Trokhimovskiy, A.; Korablev, O.; Grigoriev, A.; Fedorova,
A.; Shakun, A.; Ignatiev, N.; Zasova, L.; Moshkin, B.; Dziuban, I.;
Guslyakova, S.; Anufreychik, K.; Stepanov, A.; Titov, A.; Montmessin, F.;
Ivanov, Y.; Kalinnikov, Y.; ACS Team; Atmospheric Chemistry Suite (ACS): a
set of Infrared Spectrometers for Atmospheric Measurements on Board ExoMars
Trace Gas Orbiter, The Fifth International Workshop on the Mars Atmosphere:
Modelling and Observation, held on January 13-16 2014, in Oxford, U.K.
Edited by F. Forget and M. Millour, id.4402.
4. Трохимовский А. Ю., Кораблев О. И., Григорьев А. В., Шакун
А. В., Федорова А. А., Дзюбан И. А. Создание спектрометрического комплекса
АЦС для российско-европейского проекта «ЭкзоМарс-2016», 11я всероссийская
открытая ежегодная конференция «Современные проблемы дистанционного
зондирования Земли из космоса» (Физические основы, методы и технологии
мониторинга окружающей среды, природных и антропогенных объектов), Москва,
ИКИ РАН, 11-15 ноября 2013 г.
5. Трохимовский А.Ю., Кораблев О.И., Григорьев А.Г., Шакун
А.И., Федорова А.А., Дзюбан И.А., Гуслякова С.А., Разработка комплекса
приборов ACS (Atmospheric Chemistry Suit) для исследования химического
состава атмосферы и климата Марса на борту «Экзомарс» (Trace Gas Orbiter),
Десятая всероссийская открытая ежегодная конференция «Современные проблемы
дистанционного зондирования Земли из космоса» (Физические основы, методы и
технологии мониторинга окружающей среды, природных и антропогенных
объектов)Москва, ИКИ РАН, 12-16 ноября 2012 г.
6. Korablev, Oleg; Bertaux, Jean-Loup; Goutail, Jean Pierre;
Trokhimovskiy, Alexander; Montmessin, Franck; Grigoriev, Alexei; Shakun,
Alexei Atmospheric Chemistry Suite (ACS): an instrument to measure the
atmosphere composition and structure for ExoMars Trace Gas Orbiter (2016)
39th COSPAR Scientific Assembly. Held 14-22 July 2012, in Mysore, India.
Abstract E2.6-22-12, p.969
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