Calibration of MAJIS (Moons and Jupiter Imaging Spectrometer). IV. Radiometric calibration (invited).
The Review of scientific instruments 95:11 (2024) 111301
Abstract:
The MAJIS (Moons and Jupiter Imaging Spectrometer) instrument is an imaging spectrometer on-board the JUICE (JUpiter ICy moons Explorer) spacecraft. MAJIS covers the spectral range from 0.5 to 5.54 μm with two channels [visible-near infrared (VISNIR) and IR]. A comprehensive campaign of on-ground MAJIS calibration was conducted in August and September 2021 in the IAS (Institut d'Astrophysique Spatiale, CNRS/Université Paris-Saclay) facilities. In this article, we present the results relevant for the radiometric calibration of MAJIS. Due to the specific characteristics of the MAJIS detectors (H1RG from Teledyne), an extensive detector characterization campaign was implemented for both the VISNIR and IR detectors before integration so as to validate readout procedures providing precision and accuracy. The characterization also provided critical information on linearity and operability as a function of the integration time and operating temperature. The radiometric calibration of the integrated MAJIS instrument focused on the determination of the instrument transfer function in terms of DN output per unit of radiance for each MAJIS data element as a function of its position in the field of view of MAJIS and its central wavelength. The radiometric calibration of the VISNIR channel required a specific procedure due to stray light at short wavelengths. Observations of an internal calibration source during calibration and after launch (April 14, 2023) showed that there were minor changes in both the VISNIR and IR channels. The instrument transfer functions to be used in flight have been updated on this basis.Sensitivity assessment of MAJIS VIS-NIR for the aerosols properties of Jupiter's atmosphere
(2024)
Abstract:
<jats:p>The study of Jupiter&#8217;s atmosphere, its composition, evolution, distribution, structure, and dynamics around the planet, is of interest to the scientific community. The JUICE (JUpiter ICy moons Explorer) mission from the European Space Agency (ESA) launched in April 2023, will make detailed observations to characterize Jupiter&#8217;s atmosphere that are complementary to those from Juno. In preparation for its arrival in July 2031, we upgraded ASIMUT-ALVL, a line-by-line Radiative Transfer (RT) code developed at BIRA-IASB that has been extensively used to characterize terrestrial atmospheres (1), to also allow the characterization of Jupiter&#8217;s atmosphere. Since VIS-NIR spectrometry has a remarkable potential for characterizing the composition and dynamics of planetary atmospheres, we focused on the wavelength range between 0.5&#956;m and 2.5&#956;m, which will also be covered by the VIS-NIR channel of MAJIS (Moons And Jupiter Imaging Spectrometer), a hyperspectral camera on board JUICE.To define Jupiter and its atmosphere into ASIMUT-ALVL, the reference atmospheric profile was taken from Gonz&#225;lez et al. (2) which was extrapolated with constant values below the pressure level of 1bar, and the temperature profile was taken from Moses et al. (3) supplemented with data from Seiff et al. (4) for pressure levels down to 20bar. Since Jupiter&#8217; upper atmosphere is mainly composed of hydrogen (H2), helium (He), and minor traces of other gases such as methane (CH4), ammonia (NH3) and water (H2O), its VIS-NIR spectrum is dominated by absorption bands due to the CH4 and NH3; Rayleigh scattering due to H2 and He; Mie scattering due to aerosols and haze; and Collision-Induced Absorption (CIA) due to H2-H2 and H2-He molecular systems (5). ASIMUT-ALVL calculates the molecular absorption cross-sections for each molecule by considering line broadening through collisions against H2 and He in Jupiter&#8217;s atmosphere. Although HITRAN is one of the most complete and widely used spectroscopic databases, it is incomplete for wavelengths shorter than 1&#956;m. Therefore, the band models of Karkoschka et al. (6) and Coles et al. (7) were implemented for CH4 and NH3, respectively. The extinction coefficient for Rayleigh scattering is based on the calculation of its cross-section from the refractive indexes of H2 and He, determined from the refractivities measured by Chubb et al. (8) and Coles et al. (9), respectively, and the atmospheric King correction factor, obtained from the depolarization ratio of H2 as measured by Parthasarathy (10). The CIA contribution was implemented directly as a cross-section from Borysow (11) and Abel et al. (12) for H2-H2, and Abel et al. (13) for H2-He.To model aerosols and hazes in Jupiter&#8217;s atmosphere, we implemented the Cr&#232;me Brulee (CB) model of Baines at al.(14) and the aerosols model from L&#243;pez-Puertas et al. (5). The CB model offers a solution for chromophores in Jupiter, consisting of three layers of similar composition but different particle size distributions, with the chromophore layer just above the tropospheric cloud. The composition of the chromophore layer is defined as proposed by Carlson et al. (15), formed by the interaction of NH3 and acetylene (C2H2). The model of L&#243;pez-Puertas et al. (5) consists of a crystalline H2O ice cloud below 0.1mbar with particle sizes of &#8764;10nm and three haze layers based on a refractive index obtained from the combination of Martonchik et al. (16) (NH3 ice) and Zhang et al. (17) (CH4 and H2), with particle sizes between 0.1 and 0.6&#181;m.The updated performances of ASIMUT-ALVL were individually validated against KOPRA, an RT code developed by the Astrophysics Institute of Andalusia (IAA) already used for the study of Jupiter (18). The validation of the RT model finished with the comparison of the resultant spectrum against observational data from VIMS (Visible and Infrared Mapping Spectrometer) (19). Now it is possible to include the performances of other instruments in the VIS-NIR range, such as MAJIS (20), and simulate realistic observational scenarios to assess the impact of its capabilities on the characterization of the aerosols present in the atmosphere in comparison with previous instruments. The study of aerosols is mainly possible in the VIS-NIR range, and ASIMUT-ALVL is a new available tool to retrieve their detailed optical properties and vertical distribution, complementary to other models. Moreover, during this assessment, it is possible to optimize the spectral sampling of MAJIS, and provide valuable information for the data return of the instrument, planned during the science operations.AcknowledgmentsWe acknowledge the support of Manuel L&#243;pez-Puertas and Gianrico Filacchione, who respectively provided data from KOPRA and VIMS/Cassini observations. This project also acknowledges the funding provided by the Scientific Research Fund (FNRS) through the Aspirant Grant: 34828772 MAJIS detectors and impact on science.References1. Vandaele AC, et al. ASC, Frascati, Italy; 2006.2. Gonzalez A, et al. Advances in Geosciences; 2011. p. 209&#8211;183. Moses JI, et al. J Geophys Res. 2005 Aug;110(E8):2005JE002411.4. Seiff A, et al. J Geophys Res. 1998 Sep 25;103(E10):22857&#8211;89.5. L&#243;pez-Puertas M, et al. AJ. 2018 Oct 1;156(4):169.6. Karkoschka E, et al. Icarus. 2010 Feb;205(2):674&#8211;94.7. Coles PA, et al. ApJ. 2019 Jan 1;870(1):24.8. Chubb KL, et al. A&amp;A. 2021 Feb;646:A21.9. Coles PA, et al. MNRS. 2019 Dec 21;490(4):4638&#8211;47.10. Parthasarathy S. Indian Journal of Physics. 1951;25:21&#8211;4.11. Borysow A. A&amp;A. 2002 Aug;390(2):779&#8211;82.12. Abel M, et al. J Phys Chem A. 2011 Jun 30;115(25):6805&#8211;12.13. Abel M, et al. J Chem Phys. 2012 Jan 28;136(4):044319.14. Baines KH, et al. Icarus. 2019 Sep;330:217&#8211;29.15. Carlson RW, et al. Icarus. 2016 Aug;274:106&#8211;15.16. Martonchik JV, et al. Appl Opt. 1984 Feb 15;23(4):541.17. Zhang X, et al. Icarus. 2013 Sep;226(1):159&#8211;71.18. Stiller GP, et al. SPIE; 1998. p. 257&#8211;68.19. Brown RH, et al. Icarus. 2003 Aug;164(2):461&#8211;70.20. Poulet F, et al. Space Sci Rev. 2024 Mar 19;220(3):27&#160;</jats:p>Simulating spectra of Jupiter’s atmosphere based on MAJIS VIS-NIR characteristics
(2024)
Abstract:
<jats:p>From Pioneer 10 to Juno, which is still active, several missions and space observatories have studied Jupiter&#8217;s atmosphere. Complementary, although limited by the telluric bands of water vapor, ground-based observations continue providing information about its vertical structure and its distribution around the planet. The main chemical composition of Jupiter&#8217;s atmosphere has been unraveled but lots of questions still remain open, such as the global abundance of water, the responsible chemistry for the coloration of the clouds, or what drives the aurora [1-2]. Moreover, observations by NIMS/Galileo [3-4] and VIMS/Cassini [5], have demonstrated the remarkable potential of VIS-NIR spectrometry for characterizing the composition and dynamics of planetary atmospheres [6].The Moons And Jupiter Imaging Spectrometer (MAJIS) instrument is part of the science payload of the ESA L-Class mission JUICE (Jupiter ICy Moons Explorer) [7] to be launched in 2022 with an arrival at Jupiter in 2031. MAJIS combines two spectral channels able to cover the 0.5 &#8211; 2.35 &#956;m range (VIS-NIR channel) and the 2.25 &#8211; 5.54 &#956;m range (IR channel) [8]. As part of its scientific objectives, MAJIS will investigate the composition, structure, dynamics and evolution of Jupiter&#8217;s atmosphere at different levels, trace tropospheric cloud features, and characterize major and minor species, aerosols properties, and hot spots [9]. As explained by Langevin et al. [9], the spectral resolving power of MAJIS exceeds by three times that of NIMS or VIMS, with a spatial resolution four times better than NIMS, so it will efficiently track tropospheric processes such as clouds and hazes. Moreover, the close to equatorial orbit of JUICE for most of the mission will provide a comprehensive coverage of Jupiter in local time complementary to JIRAM/Juno [9].We are interested in the scientific analysis of the MAJIS observations regarding the composition of Jupiter&#8217;s atmosphere, specifically on the H2O and CH4 contents, which are the most abundant species in the troposphere as a whole, after H2 and He [1]. Although it is expected that water vapor has a higher global volume mixing ratio than CH4 in the deep troposphere, this has yet to be observed [1]. Additionally, the strong spectral features due to crystalline water ice (1.5 &#181;m and 2.0 &#181;m) require a large abundance of water to be explained [10]. Therefore, we would like to perform simulations of different test cases with respect to the viewing geometries of MAJIS and the technical properties of its Flight Model VIS-NIR detector [11].To proceed, we need to adapt the Radiative Transfer code developed at the Belgian Institute for Space Aeronomy (BIRA-IASB), ASIMUT-ALVL. It has been extensively used to characterize Mars and Venus atmospheres [12-19]. This tool is able to perform forward model simulations and atmospheric spectrum retrievals in nadir and limb geometries. To apply it to Jupiter&#8217;s atmosphere, some changes need to be done, such as implementing Jupiter&#8217;s physical parameters and adding the Rayleigh scattering contribution due to the dominant atmospheric species H2 and He. A more demanding modification to the code concerns the treatment of the Collision-Induced Absorption (CIA) due to H2-H2 and H2-He molecular systems.A typical atmosphere&#8217;s vertical structure of Jupiter has been retrieved from [20-21]. The molecular line-lists and cross-sections have been implemented from the HITRAN online database with line parameters adequate for an H2-dominant atmosphere. Additionally, the microphysical parameters of the clouds and aerosols have been obtained from [22]. The different contributions to the spectra are being identified then simulated and finally validated through comparison with previous works [20-21]. This methodology ensures that each radiative contribution is well-understood and correctly implemented into ASIMUT-ALVL before assessing the performances of the MAJIS VIS-NIR channel to characterize the vertical structure of the Jovian atmosphere.In this presentation, we will describe the different contributions and the challenges we faced for their implementation. A preliminary sensitivity analysis of MAJIS VIS-NIR will be discussed.AcknowledgmentsThis project acknowledges the support of M. L&#243;pez-Puertas and the funding provided by the Scientific Research Fund (FNRS) through the Aspirant Grant: 34828772 MAJIS detectors and impact on science.References[1] Mc Grath, M.A., et al., Ed. 2004, Cambridge University Press, p. 59-77.[2] MAJIS Team, JUICE Definition Study Report, 2014.[3] Irwin, P.G.J., et al. Icarus, 2001. 149(2): p. 397-415.[4] Baines, K.H., et al. Icarus, 2002. 159(1): p. 74-94.[5] Brown, R.H., et al. Icarus, 2003. 164(2): p. 461-470.[6] Langevin, Y., et al., Lunar and Planetary Science Conference, 2014.[7] Grasset, O., et al., Planetary and Space Science, Vol. 78, pp. 1-21, 2013.[8] Guerri, I., et al., International Society for Optics and Photonics, Vol. 10690, 2018.[9] Langevin, Y., et al., EPSC, 2013. P. EPSC2013-548-1.[10] Grassi, D., et al., Journal of Geophysical Research: Planets, 2020. 125.4: e2019JE006206.[11] Cisneros-Gonz&#225;lez, M. E. et al., Space Telescopes and Instrumentation in Proc. SPIE 2020, 11443, 114431L.[12] Montmessin, F., et al. Icarus, 2017. 297: p. 195-216.[13] Vandaele, A.C., et al. Optics Express, 2013. 21(18): p. 21148.[14] Vandaele , A.C., et al. Adv. Space Res., 2016. 57: p. 443-458.[15] Vandaele , A.C., et al. Icarus, 2016. 272: p. 48-59.[16] Vandaele, A.C., et al. Icarus, 2017. 295: p. 1-15.[17] Vandaele, A.C., et al. Planet. Space Sci., 2015. 119: p. 233-249.[18] Neefs, E., et al., Applied Optics, 2015. 54(28): p. 8494-8520.[19] Robert, S., et al., Planet. Space Sci., 2016. 124: p. 94-104.[20] L&#243;pez-Puertas, M., et al., The Astronomical Journal, 2018. 156.4: 169.[21] Guerlet, S., et al. Icarus, 2020. 351: 113935.[22] Monta&#241;&#233;s-Rodr&#237;guez, P., et al., The Astrophysical Journal Letters, 2015, vol. 801, no 1, p. L8.</jats:p>Moons and Jupiter Imaging Spectrometer (MAJIS) on Jupiter Icy Moons Explorer (JUICE)
Space Science Reviews Springer 220:3 (2024) 27
Abstract:
The MAJIS (Moons And Jupiter Imaging Spectrometer) instrument on board the ESA JUICE (JUpiter ICy moon Explorer) mission is an imaging spectrometer operating in the visible and near-infrared spectral range from 0.50 to 5.55 μm in two spectral channels with a boundary at 2.3 μm and spectral samplings for the VISNIR and IR channels better than 4 nm/band and 7 nm/band, respectively. The IFOV is 150 μrad over a total of 400 pixels. As already amply demonstrated by the past and present operative planetary space missions, an imaging spectrometer of this type can span a wide range of scientific objectives, from the surface through the atmosphere and exosphere. MAJIS is then perfectly suitable for a comprehensive study of the icy satellites, with particular emphasis on Ganymede, the Jupiter atmosphere, including its aurorae and the spectral characterization of the whole Jupiter system, including the ring system, small inner moons, and targets of opportunity whenever feasible. The accurate measurement of radiance from the different targets, in some case particularly faint due to strong absorption features, requires a very sensitive cryogenic instrument operating in a severe radiation environment. In this respect MAJIS is the state-of-the-art imaging spectrometer devoted to these objectives in the outer Solar System and its passive cooling system without cryocoolers makes it potentially robust for a long-life mission as JUICE is. In this paper we report the scientific objectives, discuss the design of the instrument including its complex on-board pipeline, highlight the achieved performance, and address the observation plan with the relevant instrument modes.Radiative Transfer model of Jupiter’s atmosphere in ASIMUT-ALVL
(2024)