Europlanet Science Congress 2021
Virtual meeting
13 – 24 September 2021
Europlanet Science Congress 2021
Virtual meeting
13 September – 24 September 2021

MITM3

Future instruments and sustainable outposts for deep space, Moon and Mars

This merged session (co-sponsored by space agencies, ILEWG EuroMoonMars & IAF ITACCUS) will cover the preparation for future missions and sustainable outposts in deep space, Moon and Earth . It will be interdisciplinary , open to new stakeholders towards Moon and Mars Villages, and include subsessions:
1) Future instruments for deep space and lunar science NASA, ESA, JAXA, ISRO, KARI and other Agencies have active Lunar science instruments programs and concepts. The Artemis and the Gateway programs have also generated a new drive to develop Lunar surface science instruments and technology demonstrations. Ahead of the human return to the Moon, commercial landers are expected to deliver science packages to the Lunar surface as early as 2021. Teams of Instruments already selected for flight as well as concept being developed are encouraged to submit abstracts and get feedback from the wider community.

2) Sustainable outposts for deep space, Moon and Mars.
We invite contributions on various uses of Moon, Mars and planetary outposts : science, technology, international cooperation, resource utilisation, economic development, human/robotic partnership, innovation, inspiration, education, entertainment, tourism, culture and societal benefits. We invite scientists, engineers, designers, architects, astronauts, research agencies, industries from (new) space and non-space to participate. We shall also discuss habitats projects for analogue simulations such as MDRS, Intl Moonbase Alliance HI-SEAS, LunAres, IgLuna, ESA Luna, MAMBA, EMMIHS, ILEWG EuroMoonMars.

Convener: Bernard Foing | Co-conveners: Marc Heemskerk, Sabrina Kerber, Agata Kolodziejczyk, Tai Sik Lee, Michaela Musilova, Roxana Perrier, Henk Rogers, Carol Stoker

Session assets

Discussion on Slack

Oral and Poster presentations and abstracts

Chairperson: Bernard Foing
EPSC2021-849
James W. Head and David R Scott

A fundamental goal of international human and robotic space exploration is to establish human outposts and bases on the Moon and Mars.  We seek to provide a planetary science perspective on lessons learned from the Apollo Lunar Exploration Program.

1) Why?: What is the legacy, the long-term impact of our efforts? Apollo revealed the Earth as a planet, showed the inextricable links of the Earth-Moon system, and made the Solar System our neighborhood. We now ask: What are our origins and where are we heading?: We seek to understand the origin and evolution of the Moon, the Moon’s links to the earliest Earth history, and its lessons for exploration and understanding of Mars. These perspectives impel us to learn the lessons of off-Earth, long-term, long-distance resupply and self-sustaining presence, in order to prepare for the exploration of Mars.

2) Where?: The combination of Transformative Lunar Science (TLS) questions [1] and exploration operational requirements compel us to explore the South Polar Region (SPR) of the Moon. The scientific goals are clear: 1) What is the origin, nature and abundance of polar volatile deposits and what do they tell us about internal/external sources and volatile history? [2-3] 2) What is the nature/composition/age of the South Pole-Aitken basin, and how does this inform us about lunar interior/chronology/bombardment history, and early Solar System dynamics? [4-5] The scientific objectives are: 1) explore, document/sample volatile deposits in permanently shadowed and stratigraphically related regions. 2) explore/document/sample/date SPA ejecta/pre-SPA crustal materials.  Exploration operational goals/objectives are clear: 1) Define regions that optimize realization of scientific goals/objectives. 2) Define regions of continuous/near-continuous solar illumination to provide power to survive lunar night, establish long-term presence. 3) Explore SPR to establish the nature/abundance/mode of occurrence/“grade” of candidate volatile deposits. 4) Characterize surface physical properties/trafficability in order to optimize scientific/operational activities. 5) Prepare for dedicated human/robotic exploration missions to other parts of the Moon and Mars. 6) Test nascent technologies required for sustained human Moon/Mars presence (habitation/energy storage/radiation protection/ISRU).

3) How?: Necessary is the development of a conceptual/operational framework built on a firm foundation of existing knowledge and data, and inclusion/optimization of new ideas/technologies. This permits us to continue the exploration to the next logical stages following the remarkably successful Apollo Lunar Exploration Program and multiple followon orbital/surface robotic missions. What are foundation pillars? a) Science and Engineering Synergism (SES): Apollo was successful because of the shoulder-to-shoulder engineer-scientist work culture that developed, and enabled longer-duration stay times and EVAs, significant mobility, additional equipment and experiments, and significantly greater sample return. SES requires concentrated/dedicated effort, but the rewards are clear, essential and synergistic.  SES maps out into operations at all levels of mission planning and execution. b) Human-Robotic Partnerships: Exploration is not a technique contest, but a partnership. The US sent 21 robotic missions prior to Apollo 11. The key to continual success lies in developing an architecture that complements and optimizes robotic and human capabilities.  c) Exploration Guidelines: Define human and robotic strengths and weaknesses, and optimize exploration plans. Longer-term stays mean both increased interactions with Earth and exploration independence of the Astronauts. Avoid “creeping determinism” [6], and encourage the Apollo T3 approach (Train ‘em/Trust ‘em/Turn ‘em loose). Science and operational goals and objectives require exploration of broad areas: build in extensive Apollo LRV-like mobility. New remote-sensing technologies will enable more in situ characterization, sample analysis and selection but Earth laboratory technology advances will always outpace in situ analysis. Build in significant sample return mass from the beginning. d) Exploration Architectures: Individual missions are viewed as integrated elements in an operational strategy/architecture that is designed to accomplish the overarching goals. Candidate elements: I) Precursor (What do we need to know before we send humans?). II) Context (What are robotic mission requirements for final landing site selection/regional context for results?). III) Infrastructure/Operations (What specific robotic capabilities are required to optimize human scientific exploration performance?). IV) Interpolation (How do we use robotic missions to interpolate between human traverses?). V) Extrapolation (How do we use robotic missions to extrapolate beyond the human exploration radius?). VI) Progeny (What targeted robotic successor missions might be sent to the region to follow up on discoveries during exploration and from post-campaign analysis?). The NASA Commercial Lunar Payload Services (CLPS) Program complements the Artemis Program in this manner. e) Flexibility and Adaptability: Science is the exploration of the unknown.

Site Selection/Traverse Planning Guidelines: Landing site selection always involves a balance of mission goals and objectives, and landing/operation safety/success. Science and Engineering Synergism (SES) is the key to this success as demonstrated during Apollo, and should be implemented throughout the exploration architecture. The same principles apply to traverse planning. SES ensures that science/engineering data needed for key decisions will be available and optimizes decisions. SES also optimizes the long-term goal of lunar base siting: for example, Mons Malapert, an inviting target for base siting due to favorable illumination/power, is difficult to traverse with Lunokhod and Apollo LRV-type vehicles [7].

Surface Operations: New instrumentation and technologies will significantly enhance exploration planning and accomplishment of goals. A multispectral laser reflectometer on the surface can confirm the presence of water ice and its location and distribution on scales relevant to human operations (cm to m), and be used to direct sampling and ISRU efforts undertaken by Artemis astronauts, a capability [9] highly complementary to orbital approaches. The parallel operations of robotic rovers, CLPS payload deliveries, and human activities will require continuous engineering and science operations/analysis centers on Earth. Lessons from the ISS should be incorporated, while also recognizing the human exploration capabilities of the Astronauts on the Moon [6]. 

References: 1. Pieters et al. (2018)*; 2. Zuber et al (2012) Nature 486, 378; 3. Li et al. (2019) PNAS 115, 8907; 4. Moriarty & Pieters (2018) JGR 123, 729; 5. Ivanov et al. (2018) PSS 162, 190; 6. Krikalev et al. (2010) Acta Astro. 66, 70; 7. Mazarico et al., 2020, LSSW; 8. Baslievsky et al. (2019) SSR 53, 383; 9. Cremons et al. (2020) LSSW. *http://www.planetary.brown.edu/pdfs/5480.pdf

How to cite: Head, J. W. and Scott, D. R.: Future instruments and sustainable outposts for deep space, Moon and Mars: Highlights and lessons from geologists supporting Apollo astronauts, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-849, https://doi.org/10.5194/epsc2021-849, 2021.

EPSC2021-798
Sanjay Vijendran, Juergen Schlutz, Alexander Gerst, Eric Istasse, Stefaan De Mey, and Didier Schmitt

ESA’s Exploration Programme, recently renamed “Terrae Novae”, encompasses all ESA’s human and robotic activities related to the exploration and utilisation of Earth Orbit, Moon and Mars.  Its vision is to expand Europe’s human presence into the solar system using robotic missions as precursors, with the horizon goal of human Mars exploration; and to do this for science, economic benefits, to promote global cooperation and for inspiration[1].  In autumn 2020, ESA initiated a two-year long project to define the Terrae Novae long-term strategy, looking to 2030 and beyond. This abstract provides an introduction to the objectives of the project and summarises the progress and results to date.

 

It is the ultimate goal of the strategy work to provide a lighthouse, to enable a steady orientation and long-term navigation of Europe’s decision makers on their voyage beyond the current horizons. The strategy work does not revisit the fundamental goals of ESA’s exploration programme as stated above;  instead, it is preparing the next decisions in implementation that will have to be taken by ESA Member States at the at the ESA Council meeting at ministerial level in 2022 (CM22). Decisions will be required to maintain long term European capabilities (e.g. in Low Earth Orbit (LEO)) and to prepare the next steps (e.g. for lunar surface exploration and preparations to enable humans to Mars). ESA is already anticipating a significant increase in it's request for Exploration Programme funding at CM22.

 

The Agenda 2025 of the new ESA Director General addresses challenges and objectives for ESA in the next four years, with an outlook to 2035[2]. Being ambitious is the keyword in this Agenda, in order to position a transformed ESA in an ever more world-wide competitive arena, by “making space for Europe”.

In a fast evolving international context, the challenging task of the strategy project is to position Europe to realise its exploration ambition in two dimensions.

The presentation will include a status on the strategy development work including the initial results that show options for an integrated exploration roadmap for Europe to 2040. Stakeholder consultation (Member States, Industry, Science Community etc) will continue throughout 2021 into 2022 with refinements of the strategy expected until finalisation and approval by ESA Member States around mid 2022.


[1]http://esamultimedia.esa.int/multimedia/publications/ESA_Space_Exploration_Strategy/offline/download.pdf

[2]Agenda 2025 of the ESA Director General (https://download.esa.int/docs/ESA_Agenda_2025_final.pdf)

 

 

 

How to cite: Vijendran, S., Schlutz, J., Gerst, A., Istasse, E., De Mey, S., and Schmitt, D.: ESA Terrae Novae Exploration Strategy 2040, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-798, https://doi.org/10.5194/epsc2021-798, 2021.

EPSC2021-785
Vidvuds Beldavs

In this paper I will present scenarios of lunar industrial development to 2050 and corresponding development of markets for lunar resources in Earth orbits, cislunar space, the lunar surface, as well as the likely emergence of industrial development in Mars orbits based on use of lunar resources. I will also examine actions needed in the 2021-2030 timeframe to make this possible.

Given that targets for launch to LEO from Earth in the range of $100 to $200/ kg. can be achieved before 2040 the Moon can emerge as the low-cost source of materials for industrial and commercial development in the Earth-Moon system and beyond.  Key assumptions that I will examined include the following:

  • Structures in Earth orbits and cislunar space will be assembled in orbit from components manufactured in space.
  • Space tourism with large-scale space resorts in low Earth orbits will give way to space settlements housing thousands and more as mortgage financing is developed to finance their development.
  • The Moon will emerge as the low-cost site for materials for space manufacturing. Many important materials are on or near the surface and there is high probability of concentrations of high value materials being discovered in accessible locations including potentially the Aitken Basin anomaly [1}. , and the vacuum and fractional gravity of the Moon promises launch costs from the Moon to Earth orbits that are a fraction of launch from Earth.
  • Lunar materials are likely to emerge as a primary source for industrial and commercial developments in Mars orbits. The delta-v of shipment to Mars orbit from the lunar surface is less than launch from Mars [1]. Industrial development in Mars orbit using lunar materials can lower costs and improve effectiveness of operations on Mars.
  • It will become increasingly urgent to limit launch of spacecraft to LEO from Earth as congestion from satellite mega constellations increases and suborbital intercontinental transportation takes off following the model proposed by Elon Musk.
  • Climate change is a threat to all countries and urgent action is called for to limit or eliminate large scale resource extraction on Earth, as well as to limit launches through the atmosphere. This factor will speed lunar industrial development and potentially open opportunities for some lunar derived materials to compete in terrestrial markets.
  • A rules-based order agreed to by all states involved in outer space development will emerge by 2030. Billionaires can speed up development but international cooperation and agreement on governance policies is necessary to assure self-sustaining lunar industrial development.

Notes

[1] An excellent overview of lunar materials that also includes discussion of processing options is Ian A. Crawford, “Lunar resources: A review”, Progress in Physical Geography, 2015, Vol. 39(2) 137–167, retrieved from http://www.homepages.ucl.ac.uk/~ucfbiac/Lunar_resources_review_published.pdf . Pg. 149 summarizes findings on the Aitken Basin anomaly suggesting that a large metallic asteroid approximately 110 meters across may be buried there. The Psyche 16 metallic asteroid that has drawn media attention is 200 meters - 16 Psyche - Wikipedia

[2]https://space.stackexchange.com/questions/2046/delta-v-chart-mathematics

 

How to cite: Beldavs, V.: Development of the Moon-Earth economy – 2030-2050, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-785, https://doi.org/10.5194/epsc2021-785, 2021.

EPSC2021-527
Michelle Lavagna, Jacopo Prinetto, Andrea Colagrossi, Ivan Troisi, Alice dottori, and Paolo lunghi

Space exploration is going to play a relevant role within the just started decade, with the Moon at its centre. Many activities are on going to enhance science of\on and from the Moon and to develop the fundamental technology to accomplish the challenging objectives the foreseen missions to our satellite need. Among those the capability to detect, extract and manipulate the in situ resources is central for humans back on the surface and more. Politecnico di Milano, thanks to the activities started under the cap of an ESA study, developed in consortium with OHB-I and OHB-S, implemented a laboratory plant and run experiments to assess and tune the carbothermal reduction process on NU-LHT 2M in extracting oxygen from feedstock oxides. The experiments were successful and water has been produced, as expected.
To accurately understand the process and address the technology for a flight test the numerical modelling of the whole process steps has been settled and a comprehensive characterisation of the feedstock simulant was performed as well. Results are presented and critically discussed.

The paper will go through the simulant characterisation approach and results, the process description and modelling, the lab plant description and the experimental test campaign results, obtained with the implemented plant.

How to cite: Lavagna, M., Prinetto, J., Colagrossi, A., Troisi, I., dottori, A., and lunghi, P.: Water production from lunar regolith through carbothermal reduction modelling through ground experiments, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-527, https://doi.org/10.5194/epsc2021-527, 2021.

EPSC2021-535
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ECP
Sejal Budholiya, Vigneshwaran Krishnamoorthy, Aayush Bhat, Thirukumaran Venugobal, Kannan Lalgudi Subramanian, Santhanam Lakshmi Narayan, Saravana Prashanth Murali Babu, Vijayan Sivaprahasam, Anil Bhardwaj, Jaya Krishna Meka, and Bhalamurugan Sivaraman

If we are going to colonize the moon, then we must be in a position to build stable structures on-site and manufacture needed items with the resources that are available on the lunar surface/subsurface. Currently, we are limited by the amounts of lunar soil to research and explore the necessary technologies prior to colonization. Therefore, we need to look at the best analogues available as lunar simulants. Perhaps, such efforts have been made in the past [1] and recently new lunar simulants are also being produced in the laboratory [2]. Indeed, our understanding of building structures by 3D printing using lunar simulants is limited so far, and much more needs to be explored.

 

Sittampundi anorthosite complex in South India is reported to be the most appropriate lunar simulant [3] and has been used in bio-cementation studies [4]. We collected more than 100 kg of the anorthosite rock samples from Sittampundi as raw material. After grinding the sand corresponded to IS383 zone II (medium sand) with Fineness Modulus 3.16 and fine aggregate 5 mm down. For initial studies, the raw material composite was prepared with water, cement, class-F ultra fine fly ash, superplasticizer, viscosity modifier, and polypropylene microfiber were then added to the anorthosite sample in varying proportions.

 

The slurry obtained by mixing the seven ingredients including the lunar simulant was then poured into an empty plastic canister. The slurry was manually pressed to extrude layer by layer to produce a 240 mm dia, 40 mm wide, and 31 mm thick structure from four layers. After 14 days of curing and drying process at nominal atmospheric conditions, the strength of the layered 3D printed structure was found to be 39 N mm-2. In this session, we will present more details of the slurry preparation including the proportions of the ingredients used, the 3D printing technique employed, and its implications for future lunar exploration/colonization.

Figure 1: [a] The anorthosite sample before grinding and [b] and [c] the first layer and after three layers of the 3D printed structure, respectively, and [d] printed structure (240 mm dia, 40 mm wide and 31 mm thick) after 14 days. 

 

References:

[1]Hargraves, R.B. and Buddington, A.F., 1970. “Analogy between anorthosite series on the Earth and Moon”. Icarus, 13(3), pp.371-382.

[2]Jäggi, N., Galli, A., Wurz, P., Biber, H., Szabo, P.S., Brötzner, J., Aumayr, F., Tollan, P.M.E. and Mezger, K., 2021. “Creation of Lunar and Hermean analogue mineral powder samples for solar wind irradiation experiments and mid-infrared spectra analysis”. Icarus, p.114492.

[3] Venugopal, I., Muthukkumaran, K., Sriram, K.V., Anbazhagan, S., Prabu, T., Arivazhagan, S. and Shukla, S.K., 2020. “Invention of Indian Moon Soil (Lunar Highland Soil Simulant) for Chandrayaan Missions”. International Journal of Geosynthetics and Ground Engineering, 6(4), pp.1-9.

[4] Dikshit, R., Dey, A., Gupta, N., Varma, S.C., Venugopal, I., Viswanathan, K. and Kumar, A., 2021. “Space bricks: From LSS to machinable structures via MICP”. Ceramics International, 47(10), pp.14892-14898. 

How to cite: Budholiya, S., Krishnamoorthy, V., Bhat, A., Venugobal, T., Subramanian, K. L., Narayan, S. L., Babu, S. P. M., Sivaprahasam, V., Bhardwaj, A., Meka, J. K., and Sivaraman, B.: 3D printing the Sittampundi anorthosite - Indian lunar soil simulant, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-535, https://doi.org/10.5194/epsc2021-535, 2021.

EPSC2021-136
James Abshire, Scott Guzewich, Daniel Cremons, Michael Smith, Kenji Numata, and Xiaoli Sun

The planetary boundary layer (PBL) is the lowest layer of the atmosphere that interacts directly with the surface. For Mars and Titan, processes within the PBL are very important scientifically because they control the transfer of heat, momentum, dust, water, and other constituents between surface and atmospheric reservoirs. For Mars understanding these processes is critical for understanding the modern climate, including the stability and development of the polar caps how the regolith exchanges with the atmosphere how wind shapes the landscape how dust is lifted and transported and for being able to validate and improve general circulation models (GCMs). The PBL is also critical for operations since it is the environment in which landed missions must operate.

On Mars the PBL depth varies between roughly 1 and 10 km, depending on time of day, with the deepest layer occurring during the day when convective turbulence is greatest. The PBL is difficult to observe from orbit, and so detailed observations of it have been mostly limited to those just at the surface from landers. The lack of PBL observations has led to significant gaps of understanding in several key areas. These include diurnal variations of aerosols, water vapor and direct measurements of wind velocity, the combination of which provides information on the horizontal and vertical transport of water, dust, and other trace species and their exchange with the surface. The Mars atmosphere has complex interactions between its dust, water and CO2 cycles. Because these quantities are interrelated and they partially drive the wind fields, it is important to measure the water vapor, aerosols, and winds simultaneously, ideally using a single instrument.

We are developing and plan to demonstrate a breadboard of small, highly capable atmospheric lidar to address these needs for a future lander on Mars or Titan. The lidar is designed to measure vertically-resolved profiles of water vapor by using a single frequency laser. The laser will be tuned onto and off strong isolated water vapor lines near 1911 nm. The vertical distribution of water vapor will be determined from the on- and off-line backscatter profiles via the differential absorption lidar (DIAL) technique. The same laser is used for measuring aerosol and wind profiles via the Doppler shift in the backscatter. The laser beam is linearly polarized and a cross polarized receiver allows separating the backscatter of water ice from dust.  It emits two beams that are offset 30 deg from zenith and perpendicular to one another in azimuth, allowing directional wind profiles to be resolved. Both lidar measurement channels are otherwise identical and use common lens-type receiver telescopes.

These lidar measurements address important science needs that are traceable to Mars Exploration Program Analysis Group (MEPAG) science goals relating to climate, surface-atmosphere interactions, and preparing for human exploration.  Our lidar will measure vertical profiles of water vapor, and dust and water ice aerosols and winds with km-scale vertical resolution from the surface to > 15 km altitude.  These measurements will directly profile the full planetary boundary layer, which is key for understanding how water, dust, CO2 and trace species exchange between surface and atmosphere.  The lidar will provide observations of all quantities simultaneously. 

Only one atmospheric lidar has been previously flown on a planetary lander. The lidar on the Phoenix Mars lander mission (Komguem et al., 2013) successfully measured aerosol backscatter profiles at 1064 nm and 532 nm as a function of altitude and time (Whiteway, et al., 2008). The lidar also measured cloud and ice scattering profiles and measured falling ice over the Phoenix Lander site (Whiteway, 2009).

Our lidar approach is designed to provide several important new capabilities. It will measure, for the first time, water vapor profiles from 100 m to 15 km, along with wind and aerosol profiles at 1911 nm. Our approach utilizes a highly sensitive HgCdTe avalanche photodiode detector as a key component of the lidar receiver. During the next 2 years of this project, our plan is to develop the remaining lidar components from TRL 2 to 4, and to use the breadboard lidar to demonstrate profile measurements of aerosols, water vapor and wind from the Mauna Kea Hawaii astronomy site

Acknowledgement: This work is supported by an award from the 2019 NASA PICASSO program.

How to cite: Abshire, J., Guzewich, S., Cremons, D., Smith, M., Numata, K., and Sun, X.: Small Lidar for Profiling Water Vapor, Aerosols and Winds from Planetary Landers, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-136, https://doi.org/10.5194/epsc2021-136, 2021.

EPSC2021-657
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ECP
Dora Klindžić, Daphne Stam, Frans Snik, Christoph Keller, Vidhya Pallichadath, Chris van Dijk, Marco Esposito, and Dirk van Dam

LOUPE, the Lunar Observatory for Unresolved Polarimetry of the Earth, is a small, robust spectro-polarimeter for observing the Earth as if it were an exoplanet, designed to accompany any landing, roving or orbiting mission to the Moon. Detecting Earth-like planets in stellar habitable zones is one of the key challenges of modern exoplanetary science. Characterizing such planets and searching for traces of life requires the direct detection of their signals. LOUPE provides unique spectral flux and polarization data of sunlight reflected by Earth, the only planet known to harbour life. These data will be used to test numerical codes to predict signals of Earth-like exoplanets, to test algorithms that retrieve planet properties, and to fine-tune the design and observational strategies of future space observatories.

We present a novel spectropolarimetric instrument design: LOUPE, the Lunar Observatory for Unresolved Polarimetry of the Earth (Klindžić, 2020), which aims to observe the Earth from the Moon as if it were an exoplanet and perform spectropolarimetric measurements spanning the full range of phase angles. Various reasons make observing the Earth from the Moon or from a Lunar orbit, rather than a low Earth orbit, crucial to the experiment:

  • The Moon is sufficiently far away to allow a spatially unresolved view of the whole Earth.
  • For a lander on the Lunar surface, the Earth is always visible in a confined area in the sky.
  • From the Moon, the Earth can be observed at all phase angles during a month.
  • From the Moon, the Earth's daily rotation can be captured.

LOUPE’s science requirements include:

  • Perform near-instantaneous (snapshot) spectropolarimetry of the entire Earth.
  • Detect the presence of liquid water oceans and clouds.
  • Derive and monitor atmospheric properties, e.g. via Rayleigh scattering, for potential climate research applications.
  • Detect the O₂A band in flux and polarization and its variance with cloud cover, altitude and phase angle.
  • Detect the Chlorophyll Green Bump and Vegetation Red Edge, the spectroscopic signature of plant life.
  • Derive a map of continents from the disk-integrated signal and identify notable features, such as rainforests, deserts and ice caps.

LOUPE shall perform its science goals by recording and demodulating the disk-integrated Stokes vector of sunlight reflected from the Earth. The leading instrument design principle adopted for LOUPE is to create a compact, low-mass, low-volume, space-ready hyperspectropolarimeter with no moving parts. These constraints require creative solutions from the cutting edge of hyperspectral and polarimetric instrument design, where polarimeters traditionally used active rotating optics (temporal modulation) or beam-splitting (spatial modulation).

The latest LOUPE concept (Fig. 1.) utilizes Patterned Liquid Crystal (PLC) plates for encoding polarization information as a modulation orthogonal to the spectral flux measurement, enabling the linear-Stokes vector of a target to be recorded in one single “snapshot”, as shown in Fig. 2. Unlike a traditional rotating-retarder polarimeter, polarization is modulated in the cross-spectral direction, meaning polarimetry can be performed at full spectral resolution, which is not possible in the case of channeled spectropolarimetry with spectral modulation. This pioneering use of Patterned Liquid Crystals makes it possible to forgo the use of moving elements, resulting in a compact, space-ready instrument with versatile options of installation on a range of landing, roving and orbiting missions.

Here we discuss our detailed design process and the challenges involved in creating a unique space-qualified spectropolarimeter with no moving parts, whilst maintaining flexibility for different usage scenarios: rovers, landers, orbiters, and more. We present a performance trade-off, optical design informed by ray tracing with polarization effects, and the development of methods for spectral and polarimetric demodulation of simulated Earth observation data.

Figure 1: Tentative design of LOUPE.

 

Figure 2: Simulated LOUPE measurement. Wavelength filtering is applied in the y-direction, and polarization modulation in the x-direction. Each dot represents an unresolved image of the Earth.

How to cite: Klindžić, D., Stam, D., Snik, F., Keller, C., Pallichadath, V., van Dijk, C., Esposito, M., and van Dam, D.: LOUPE: Observing the Earth from the Moon to prepare for detecting life on Earth-like exoplanets, Europlanet Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-657, https://doi.org/10.5194/epsc2021-657, 2021.