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Abstract:

Despite being often described as Earth’s sister planet due to a similar distance to the Sun and comparable size, Venus’s internal structure and geodynamic regime, together with its upper atmosphere dynamics and asteroid entry rates, are poorly constrained. Whereas Venus is a prime candidate for being a tectonically active planet and presents a very dynamic atmosphere, future missions will not constrain high frequency phenomena such as seismic waves, meteoroid impacts, and high frequency gravity waves. These short duration events can be used to infer Venus' seismicity, internal structure, upper atmosphere dynamics and the small Solar System bodies population [1].We present a mission concept that targets high rate observations of upper atmosphere airglow emissions on both the day and night side of Venus, as well as thermal imaging in the visible. These observations will allow us to image the propagation of acoustic waves generated by seismic waves, enabling us to investigate quake locations and magnitudes, as well as to determine the structure of the crust and upper mantle. Volcanic events will also be studied through the associated increase in surface and atmosphere temperature. In addition, variations in airglow emissions will constrain the transfer of mechanical energy from the lower atmosphere to the thermosphere, as well as atmosphere dynamics (winds) and composition, and its response to solar forcing. Finally, the observation of fireballs produced by asteroid entries will constrain the asteroid population that crosses Venus’s orbit.The instruments required to perform these high rate observations are presented. They are based on a strong heritage relying on previous implementations in planetary missions.The mission concept and spacecraft demand new capabilities in terms of on-board attitude determination and data processing capabilities. In particular, a dedicated on-board data processing unit capable of autonomously detecting different event types with advanced algorithms, including machine learning methods, has been identified as a key component of the mission. This unit will also be used to average out phenomena over different temporal and spatial scales. To maximise science return, the mission will adopt an operational concept involving the capability to download high rate event data from a first quicklook information, similar to the one implemented on InSight NASA mission.The feasibility of the mission, already partly demonstrated by VAMOS JPL/NASA mission concept study [2,3], is validated through a dedicated mission analysis study.References[1] Christou A.A., Gritsevich M. 2024. Feasibility of meteor surveying from a Venus orbiter, Icarus, 417, 15 July 2024, 116116, DOI 10.1016/j.icarus.2024.116116[2] Sutin, B.M. et al. In Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave, volume 10698. SPIE, 2018. doi:10.1117/12.2309439.[3] Didion, A. et al. In 2018 IEEE aerospace conference. IEEE, 2018.

Abstract:

Introduction: This presentation will describe the Modular Infrared Molecules and Ices Sensor currently in final assembly and test at the University of Oxford, UK and VTT Finland for ESA’s upcoming Comet interceptor mission.The Comet Interceptor mission: The Comet Interceptor mission [1] was selected by ESA as the first of its new “F” class of missions in June 2019 and adopted in June 2022.  Comet Interceptor (CI) aims to be the first mission to visit a long period comet, preferably, a Dynamically New Comet (DNC), a subset of long-period comets that originate in the Oort cloud and may preserve some of the most primitive material from early in our Solar System’s history. CI is scheduled to launch to the Earth-Sun L2 point with ESA’s ARIEL [2] mission in ~2029 where it will wait for a suitable DNC target.The CI mission is comprised of three spacecraft.  Spacecraft A will pass by the target nucleus at ~1000 km to mitigate against hazards caused by dust due to the wide range of possible encounter velocities (e.g. 10 – 70 km/s).  As well as acting as a science platform, Spacecraft A will deploy and provide a communications hub for two smaller spacecrafts, B1 (supplied by the Japanese space agency JAXA) and B2 that will perform closer approaches to the nucleus.  Spacecrafts B1 and B2 will make higher risk/higher return measurements but with the increased probability that they will not survive the whole encounter.The MIRMIS Instrument: The Modular InfraRed Molecules and Ices sensor (MIRMIS, Figure 1) instrument is part of the CI Spacecraft A scientific payload.  The MIRMIS consortium includes hardware contributions from Finland (VTT Finland) and the UK (University of Oxford) with members of the instrument team from the Universities of Helsinki, Lyon, NASA’s Goddard Space Flight Center, and Southwest Research Institute.MIRMIS will map the spatial distribution of temperatures, ices, minerals and gases in the nucleus and coma of the comet using covering a spectral range of 0.9 to 25 microns.  An imaging Fabry-Perot interferometer will provide maps of composition at a scale of ~180 m at closest approach from 0.9 to 1.7 microns.  A Fabry-Perot point spectrometer will make observations of the coma and nucleus at wavelengths from 2.5 to 5 microns and finally a thermal imager will map the temperature and composition of the nucleus at a spatial resolution of 260 m using a series of multi-spectral filters from 6 to 25 microns.  Figure 1: (Top) The MIRMIS instrument for ESA’s Comet Interceptor mission. (Bottom) The MIRMIS Structural Thermal model under test at University of Oxford.The MIRMIS instrument is compact (548.5 x 282.0 x 126.8 mm) and low mass (

Abstract:

Ground test data from the Lunar Thermal Mapper instrument. Described in Bowles et al. 2025 submitted to JGR Planets.