Atmospheric composition and the feasibility of in-situ resource utilization on Venus

Abstract

The extreme environmental conditions and unique chemical composition of Venus’s atmosphere make it a key target for planetary science while posing significant challenges and opportunities for in-situ resource utilization (ISRU). This paper proposes an integrated in-situ resource utilization system that combines filtration, enrichment, and spectroscopic detection for key atmospheric gases on Venus, including H₂O, PH₃, NH₃, H₂S, and SO₂. The system employs a multi-stage filtration unit to remove corrosive sulfuric acid aerosols and utilizes selective molecular-sieve adsorption to efficiently concentrate trace gases, thereby enhancing their detection sensitivity to meet the precision requirements of tunable laser spectrometers. These gases are not only potential resources for oxygen production, fuel synthesis, or chemical feedstock generation but also serve as crucial indicators of Venus’s geochemical and atmospheric processes, including volcanic activity and redox balance. The proposed technical framework provides a feasible pathway for coupling scientific investigation with practical ISRU objectives in future Venus exploration missions.

Graphical abstract

Keywords

in-situ resource utilization / Venus / tunable laser spectrometers / trace gases

1 Introduction

Venus, a terrestrial planet similar to Earth in size and composition (Alaerts et al., 1979; Avice et al., 2017), offers crucial insights into planetary atmospheric evolution and potential habitability through its extreme conditions and distinctive chemistry. Despite comparable initial formation environments, Venus now exhibits surface pressures near 90 bar, temperatures up to 462°C, and a planet-wide layer of sulfuric acid clouds, conditions that sharply contrast with Earth’s habitable climate. Its atmosphere consists primarily of 96.5% CO₂ and 3.5% N₂, with trace gases such as SO₂, H₂O, and H₂S. Although minor in abundance, these trace species and their isotopic compositions record essential information on atmospheric chemistry, geological activity, escape processes, and potential biosignatures. Measurements of ³³S/³⁴S in SO₂ and H₂S and ¹⁸O/¹⁶O in H₂O can reveal the chemical mechanisms responsible for deviations of their observed abundance distributions from atmospheric model predictions, elucidating the roles of photochemical reactions and surface–atmosphere exchange (Fedorova et al., 2008). High-precision D/H measurements of H₂O at different altitudes enable reconstruction of Venus’s water escape history (Matsui et al., 2012). Furthermore, accurate determinations of ¹⁵N/¹⁴N in trace species such as NH₃ can test their presence and help discriminate between biogenic and abiotic origins, offering key insights into potential biosignatures in the Venusian atmosphere (Krasnopolsky, 2012). Therefore high-precision detection of these components is vital for constraining Venus’s evolutionary history and provides valuable context for understanding Earth’s early atmosphere and assessing exoplanet habitability.

Beyond its scientific significance, the Venusian atmosphere, which is rich in CO₂, SO₂, H₂S, H₂O, NH₃, PH₃, provides a potential material foundation for future in-situ resource utilization (ISRU). These chemical species serve as key indicators for both energy exploration and resource recycling. Specifically, CO₂, as the dominant atmospheric constituent, can be photochemically or electrochemically decomposed into CO and O₂, providing essential feedstock for oxygen production and carbon-based fuel synthesis. The coexistence of SO₂ and H₂S forms a typical sulfur redox system, in which mutual conversion processes release considerable chemical energy and reflect the redox conditions of the Venusian interior and atmosphere. H₂O, an important component of the volatile cycle, can be electrolyzed to produce hydrogen and oxygen, which are fundamental reactants for planetary-scale energy circulation. NH₃, a reduced nitrogen-bearing compound, may decompose to generate hydrogen, offering insight into both hydrogen energy potential and the nitrogen cycle. PH₃, characterized by high chemical potential, could release substantial energy upon oxidation; if its existence is confirmed, it would indicate a strong reducing environment and a possible source of chemical energy gradients in the Venusian atmosphere. Overall, the occurrence and interconversion of these atmospheric species not only document the dynamic chemical and redox processes governing the evolution of Venus’s atmosphere but also delineate prospective pathways for ISRU strategies, including oxygen generation, fuel synthesis, and closed-loop energy recycling, under the planet’s extreme environmental conditions.

Over the past five decades, extensive studies based on ground-based telescopic observations, orbital missions, and descent probes have provided valuable insights into the spatial distribution and evolution of key trace gases in the Venusian atmosphere (Widemann et al., 2023). SO₂ is recognized as the central component of Venus’s sulfur cycle (Krasnopolsky, 2006; Mills and Allen, 2007), exhibiting a pronounced vertical gradient: concentrations range from approximately 130–190 ppmv below the cloud layer (30–40 km) to only 50–500 ppbv near the cloud tops (70–80 km) (Parkinson et al., 2015; Bains et al., 2021; Petkowski et al., 2024). This variation is primarily governed by the interplay between photochemical decomposition and vertical transport processes (Rimmer et al., 2021). On the other hand, H₂O plays a critical role in maintaining Venus’s radiative balance and in the formation of sulfuric acid clouds. Its D/H ratio, roughly 120 times that of terrestrial ocean water, indicates a substantial history of water loss and hydrogen escape from the planet (de Bergh et al., 1991).

Beyond the major atmospheric constituents, the presence, abundance, and origins of phosphorus, nitrogen, and sulfur-bearing trace species such as PH₃, NH₃, and H₂S remain highly controversial. If confirmed, these compounds would not only provide important insights into Venusian atmospheric chemistry and potential prebiotic or biological processes, but also serve as precursors for the in-situ synthesis of amino compounds, phosphides, and sulfur-based fuels, offering potential value for ISRU. PH₃ is typically associated with anaerobic biological activity on Earth. In 2020, Greaves and colleagues reported the detection of approximately 20 ppbv of PH₃ at an altitude of 55–60 km in Venus’s cloud tops, using the Atacama Large Millimeter/submillimeter Array (ALMA), suggesting a potential biological origin (Greaves et al., 2021b). However, in 2021, Villanueva independently analyzed the data and raised concerns that the signal might originate from SO₂ absorption instead (Lincowski et al., 2021; Villanueva et al., 2021). Furthermore, missions such as Venus Express and the SOFIA Infrared Observatory have not detected PH₃, with an upper detection limit of < 23 ppbv. In 2024, the same team conducted additional observations and proposed that the signal might exhibit diurnal variability (Greaves et al., 2021a; Bains et al., 2024), yet its authenticity and formation mechanism remain uncertain. The detection of NH₃ remains unresolved. Early results from the early Venus 8 probe were heavily questioned due to sensor interference (Surkov et al., 1973). However, recent reanalysis of Pioneer Venus data reaffirms its presence (Mogul et al., 2021). Ground-based observations and Venus Express/SOIR measurements report extremely low upper limits for its abundance, with values only up to 6 ppb above the cloud layer and 28.4 ppt in the middle and lower atmosphere (Krasnopolsky, 2012; Mahieux et al., 2024). Accurate measurements of NH₃ and its ¹⁵N/¹⁴N ratio are crucial for constraining its source and early atmospheric escape history, and they can serve as key indicators for distinguishing between biological or abiotic origins (Bains et al., 2021). In addition, although model predictions suggest the presence of H₂S, it has not yet been reliably detected due to its low abundance and complex spectral interferences. Consequently, its specific role and reaction mechanisms in atmospheric chemistry remain unclear.

At present, the detection of trace gases and their isotopes in the Venusian atmosphere still requires instruments with higher sensitivity. From the perspective of detection techniques, isotopic measurements of planetary atmospheres primarily rely on mass spectrometry and spectroscopic methods. The balloon and atmospheric probe of the Galileo mission were equipped with a mass spectrometer, which conducted the first direct measurements of H₂O, CH₄, NH₃, and their isotopic ratios in the deep atmosphere of Venus (Hoffman et al., 1980). Mass spectrometry possesses the advantage of directly identifying atmospheric and organic compounds in planetary exploration. However, its application in high-precision isotope measurements of trace gases under Venusian conditions is constrained by factors such as instrument mass, volume, and power consumption, as well as its dependence on sample preprocessing and susceptibility to background interferences. In contrast, laser spectroscopy has become a crucial analytical technique in deep space exploration due to its high sensitivity, excellent selectivity, and non-contact measurement capability. For example, the Curiosity rover on Mars is equipped with a Tunable Laser Spectrometer (TLS), which has successfully achieved high-precision measurements of isotopes in CH₄, CO₂, and H₂O on Mar (Webster, 2005). The Russian Luna-27 mission is planned to employ comparable laser spectroscopic techniques to perform in-situ measurements of volatile species and their isotopic abundances in lunar polar water ice (Chumikov et al., 2021). The currently planned Venus exploration missions, such as NASA’s DAVINCI and Russia’s Venera-D, aim to acquire trace gas and isotopic data in the Venusian atmosphere using laser spectrometers mounted on descent probes (Glaze et al., 2017; Zasova et al., 2019). The laser spectrometer onboard NASA’s DAVINCI mission demonstrates limited measurement precision, with an accuracy of less than 2% for gases such as H₂O, SO₂, and H₂S, and the D/H isotope precision lower than 2‰. However, it lacks the capability to detect other trace gases, such as PH₃ and NH₃, which are critical for understanding the atmospheric composition and potential chemical processes of Venus. While the Venera-D mission is designed to measure several key atmospheric components, the detection accuracy of its instruments has yet to be disclosed. Meanwhile these instruments can provide valuable in-situ measurements during a single descent, but they are inherently limited in spatial and temporal coverage, and thus cannot achieve global observations. In contrast, traditional remote sensing techniques are capable of providing global-scale observations of the Venusian atmosphere. Yet, their spectral resolution limitations prevent high-precision retrievals of multiple isotopic systems.

In summary, the extreme environment of Venus, marked by high temperatures, immense surface pressure, and a highly corrosive atmosphere, poses major challenges for the precise detection of trace gases and their isotopic compositions. While remote sensing provides valuable global observations of major species such as CO₂, SO₂, and H₂O, its limited spectral resolution and retrieval accuracy make it difficult to resolve minor constituents. To address these challenges, this paper introduces an integrated ISRU system that unites gas filtration, enrichment, and spectroscopic detection within a single platform. This system is designed to selectively extract and concentrate key gases such as PH₃, SO₂, NH₃, H₂O, and H₂S for high-precision compositional and isotopic analysis, while simultaneously enabling experimental validation of ISRU-relevant processes. The modular design provides broad compatibility with present and future Venus mission platforms, including orbiters, descent probes, thereby supporting in-situ testing of resource utilization strategies. This approach establishes a novel technological pathway and scientific foundation for future long-duration atmospheric missions and autonomous ISRU operations under Venusian conditions.

2 Methods

2.1 Overall concept

This paper presents the design of an ISRU system comprising gas filtration, enrichment, and spectroscopic detection modules. To achieve three-dimensional detection of trace gases and isotopic compositions in the Venusian atmosphere, the spectroscopic detection module is based on tunable laser spectroscopy, which exploits the characteristic absorption ‘fingerprints’ arising from isotopic molecular variations induced by differences in atomic mass, thereby enabling precise identification and quantitative analysis of target species. Combined with the Beer–Lambert law, the system quantitatively determines the concentrations of various isotopic species in the Venus atmosphere, enabling high-precision and high-selectivity measurements of isotopic abundance ratios such as ¹⁵N/¹⁴N, D/H, ¹⁸O/¹⁶O, and ³⁴S/³²S. The entire operational mode comprises remote sensing detection and in-situ detection, as illustrated in the Fig. 1 below. In the remote sensing mode, the orbiter is oriented toward the Sun. Solar radiation passing through the Venusian atmosphere enters the laser spectrometer and is heterodyned with a wavelength-tunable local oscillator laser. This configuration retrieves key information about the major atmospheric components, macroscopic structure, and dynamic evolution of the Venusian atmosphere. The orbiter will conduct four flybys around Venus, enabling observations of the upper atmosphere. The remote sensing mode will be used to identify areas of interest, guiding the orbiter to deploy the instruments to target regions.

In the in-situ detection mode, Atmospheric gas molecules first pass through a series of preprocessing modules, including filtration and enrichment, before entering spectroscopic detection. Below 70 km in the atmosphere, sampling, filtration, enrichment, and spectral analysis will be conducted, with an estimated total duration of 2 h, of which the spectral detection will take approximately 30 min.

2.2 Operating principle

Figure 2 illustrates the schematic principles of the spectroscopic techniques employed under different detection modes. In the remote sensing mode, the heterodyne laser remote detection technique is employed to enhance the sensitivity and spectral resolution of atmospheric measurements. A wavelength-division multiplexer combines the local oscillator beam, processed by an optical fiber combiner, with the incoming solar radiation signal. The optical switch is modulated by electrical signals at distinct frequencies to enable synchronous detection. The photodetector then demodulates the received heterodyne signal using a lock-in amplifier. By measuring and analyzing the heterodyne beat signal, the system achieves high–signal-to-noise ratio and high–spectral-resolution detection of extremely weak optical signals. Owing to the square-law response characteristic of the photodetector, the resulting photocurrent can be expressed as

(1)i=k\left\{\frac{1}{2}{A}_s^2+\frac{1}{2}{A}_{LO}^2+A_s{A}_{LO}\left[\cos (w_{LO}-w_s)t+\varphi \right]\right\},

where A_{LO} and A_s present the amplitudes of the local oscillator laser and the sunlight signal, respectively; w_{LO} and w_s denote the optical angular frequencies of the local oscillator and sunlight, t is the propagation time of the optical signal, \varphi represents the phase difference between the two optical waves, k the quantum efficiency of the photodetector.

In the in-situ detection mode, the off-axis integrated cavity output spectroscopy (OA-ICOS) technique is employed to achieve ultra-sensitive measurement of trace isotopic species. The gas sample is first processed through filtration and enrichment modules and then introduced into the optical absorption cell, where the tunable laser beam undergoes multiple reflections inside the cavity. When the laser wavelength precisely coincides with the absorption line of a specific isotope, the corresponding molecular species selectively absorb light at that wavelength. After passing through the gas sample, the transmitted laser intensity is recorded by a high-sensitivity photodetector. By quantifying the attenuation of the transmitted intensity and applying the Beer–Lambert law, the concentration of the target isotope can be accurately determined. This enables high-precision and high-selectivity measurement of isotopic abundance ratios such as D/H and ¹³C/¹²C. The relationship between optical intensity attenuation, molecular concentration, and optical path length is given as follows:

(2)I=I_0\exp (-PCLS(T)\varphi (v)),

where I_0 is the initial laser intensity, I is the laser intensity detected by the photodetector after absorption and attenuation by the target gas, P represents the gas pressure, and C denotes the gas concentration, L is the effective optical absorption path length, S(T) is the line strength of the gas molecular absorption at temperature T, \varphi (v) is the line-shape function at frequency v.

2.3 Selection of gas absorption spectral lines

Given the multicomponent composition, high temperature, and high pressure of Venus’s atmosphere, the selection of appropriate gas absorption spectral lines is essential to achieving the desired instrument performance. In choosing the absorption lines of NH₃, H₂S, PH₃, SO₂, and H₂O, the following principles were considered.

1) Avoid overlapping interferences among absorption spectra of different gas components.

2) Ensure that mature laser sources are available for the corresponding wavelength bands.

3) Maintain moderate spacing between isotopic spectral lines to prevent excessive separation.

4) Prefer absorption lines of heavy and light isotopes with similar lower-state energy levels.

5) Select absorption lines with strong line intensity to ensure a high signal-to-noise ratio (SNR) in the detected signal.

Based on these principles, absorption line selection and calculation were performed. The simulated environmental conditions were set at 308 K and 20.3 mbar. Since the atmosphere of Venus consists primarily of CO₂ (approximately 96.5%), it is necessary to avoid interference from these gases. The corresponding absorption spectra and data are shown in the following Fig. 3 and Table 1.

2.4 Instrument design

In this paper, a laser spectrometer for stable isotopes in the Venusian atmosphere was designed. The instrument employs a tunable semiconductor laser as the light source and integrates laser heterodyne detection and OA-ICOS techniques within laser spectroscopy. This combination enables multi-mode collaborative detection, achieving both remote sensing and in-situ measurement capabilities. The laser heterodyne technique, with its exceptionally high spectral resolution and sensitivity, can effectively process solar reference signals received from a distance, thereby significantly improving the system’s signal-to-noise ratio. In contrast, OA-ICOS technique utilizes an oblique incidence of the laser beam to achieve a long optical path length within the cavity, offering both high sensitivity and structural stability. Moreover, it does not require cavity mode locking, making it particularly well-suited for the detection of trace gases under complex and dynamically varying pressure environments.

The main structure of the system is a sealed cylindrical titanium alloy chamber with dimensions of 90 cm × 80 cm × 70 cm. Inside the chamber, the system is composed of several functional modules: a gas processing unit, an off-axis integrated cavity detection module, a laser heterodyne detection module, a data acquisition and control module, and a thermal control module. Among these, the gas processing module primarily consists of a filtration module and an enrichment module. The detailed structure of this module is illustrated in the following Fig. 4, the system overcomes the limitations of existing detection methods and satisfies the specifications of the key engineering objectives summarized in Table2.

The filtration module functions to efficiently remove sulfuric acid droplets and solid particulate matter present in Venus’s atmosphere. This module adopts a three-stage gradient filtration design, incorporating two layers of porous ceramic filters followed by a microporous polytetrafluoroethylene (PTFE) membrane, providing multi-level filtration. In addition, the module integrates heating elements to achieve a self-cleaning capability, allowing it to evaporate residual liquid droplets in real time and perform periodic high-temperature baking to remove sulfide deposits. The structural layout of the filtration module is shown in the following Fig. 5.

The enrichment module is designed to achieve efficient concentration of trace gases in Venus’s atmosphere, such as NH₃, H₂S, and PH₃. This module operates using a two-stage adsorption process: first, a molecular sieve is employed to efficiently adsorb the background gas CO₂ (with an adsorption selectivity ratio greater than 100:1); subsequently, the trace target gases are captured by another molecular sieve with high selectivity for these species. The main body of the module adopts an adsorption bed structure, internally packed with molecular sieves. During the adsorption process, a vacuum pump assembly drives the gas flow through the adsorption bed, while the pressure is regulated to optimize adsorption efficiency. This process lasts approximately 5 min, during which the target trace gases are efficiently captured. After enrichment, the concentrated gas sample is directly delivered to the downstream detection module for analysis. The detailed structural configuration of the enrichment module is shown in the following figure (Fig. 6).

The structure of the off-axis integrated cavity module is shown in the following Fig. 7. The cavity adopts an integrated design, with external components such as the laser source and detector connected to the cavity body via flanges. At its core, the optical resonant cavity consists of two high-reflectivity mirrors, with their inner surfaces coated with a high-reflection dielectric film. The reflectivity of these mirrors reaches R ≥ 99.997%, ensuring an extremely long effective optical path within the cavity and thereby significantly enhancing the detection sensitivity of trace gases.

The laser heterodyne detection module adopts an all-fiber configuration, as illustrated in the following Fig. 8. Solar radiation is first collected by a telescope and then coupled into a polarization-maintaining fiber link through a fiber collimator. Each channel is equipped with an independent polarizer to control the polarization state of the incident light. The semiconductor laser output passes through a polarizer and is then divided into five optical paths by a polarization-maintaining beam splitter in a fixed ratio. The first four paths carry local oscillator light of equal power, which is coherently mixed with the received signal light in polarization-maintaining fiber couplers. The mixed outputs are then sent to balanced photodetectors for differential detection, effectively enhancing the signal-to-noise ratio. The fifth optical path is used for real-time monitoring of the laser power. Finally, an optical switch is inserted into the signal channel to produce a synchronous reference signal through time-domain modulation. In combination with phase-locked demodulation technology, this setup achieves effective suppression of background noise, ensuring high stability and sensitivity in signal detection.

The data acquisition and control module integrates four major functions: pipeline pressure monitoring, spectral measurement and mode switching, intelligent data processing, and closed-loop optimization control. These correspond respectively to the sample preprocessing unit, spectral detection unit, intelligent analysis unit, and adaptive control unit. The overall layout of this module is shown in the following figure (Fig. 9). In the sample preprocessing unit, the module controls the opening and closing of solenoid valves and performs pipeline pressure monitoring using vacuum gauges. In the spectral detection unit, it achieves wavelength tuning for gas spectral measurement by adjusting the laser driving current and operating temperature, while also enabling dual-mode switching between in-situ detection and remote sensing. Within the intelligent analysis unit, data collected from the instruments are subjected to deep processing and analysis based on a GPU-accelerated architecture, ensuring high computational efficiency and real-time insight extraction. Finally, the adaptive control unit receives the analytical results and executes three closed-loop control processes, including: 1) adjusting laser parameters, 2) generating real-time calibration signals, 3) issuing physical control commands. Together, these processes form a closed-loop optimization system that seamlessly integrates measurement, analysis, and control, ensuring stable and precise operation of the entire spectroscopic detection system.

The thermal control module employs a combined active–passive thermal management strategy to ensure that all subsystems operate stably within their optimal temperature ranges. During the remote sensing phase, the payload primarily relies on the active thermal control mode, in which electrical heaters perform closed-loop temperature regulation (Fig. 10). This maintains a stable working temperature for the payload even under low-temperature environmental conditions.

In the in-situ detection phase, the system switches to passive thermal control, where the thermal management assembly utilizes a synergistic combination of two phase-change materials (PCMs) (Fig. 11). On the side adjacent to the detector housing, a paraffin-based PCM is used, while on the side farther from the detector, a Sn–Pb alloy PCM is applied. These two materials undergo phase transitions at different temperature ranges, each absorbing substantial heat in the process. Through this staged heat absorption mechanism, the module achieves multi-zone thermal regulation of critical payload components, effectively maintaining temperature stability across varying operational environments on Venus.

3 Results and discussion

The atmospheric pressure at the surface of Venus is approximately 92 bar. Under such extremely high pressure, frequent collisions occur between atoms, shortening the lifetimes of their energy levels and consequently broadening the spectral lines. Moreover, these collisions can alter the energy distribution of atomic excited states, further intensifying spectral line broadening. As a result, it becomes difficult to effectively resolve the absorption spectra of trace gases and their isotopes. Therefore, during in-situ detection within the 40–70 km altitude range of Venus’s atmosphere, it is essential to regulate the gas pressure entering the instrument to maintain stable operation under varying ambient conditions. To prevent blockage of the inlet by sulfuric acid cloud droplets, a heating element is installed at the intake to evaporate and remove condensed particles. The inlet employs a metallic capillary tube as a fixed flow restrictor, whose helical configuration promotes viscous laminar flow of high-pressure CO₂, thereby generating a stable pressure drop along the tube. The capillary’s length and inner diameter are designed to control flow resistance, ensuring that the gas pressure is reduced to below 100 mbar before entering the main chamber. The inlet pressure is continuously regulated and maintained in real time by a vacuum pump assembly, providing stable operating conditions for subsequent compositional and isotopic analyses. Figure 12 below shows simulated spectra of five gas molecules at a temperature of 308 K and pressures ranging from 10 mbar to 100 mbar. The results indicate that when the pressure is below 10 mbar, Doppler broadening dominates—the spectral linewidth remains nearly unchanged with pressure, while the absorption peak increases with pressure. In this case, the absorption peaks are relatively weak, and the signal-to-noise ratio is low, which is unfavorable for detecting variations in gas concentration. When the pressure exceeds 30 mbar, water vapor absorption lines tend to saturate. In addition, the simulation does not account for baseline fitting in the spectral processing stage. When the partial pressure is greater than 30 mbar, the SO₂ absorption spectra exhibit a noticeable baseline rise under high pressure, reducing the accuracy of spectral fitting. Therefore, taking all factors into consideration, the optimal working pressure for detecting the five target gases is approximately 20 mbar, which provides a balance between detection sensitivity and spectral fitting accuracy, meeting the requirements of the target engineering application.

4 Conclusions and future work

This paper focuses on the high-precision detection of key trace gases in the Venusian atmosphere, including NH₃, H₂S, PH₃, SO₂, and H₂O, together with their stable isotopes of H, O, N, and S. We propose a novel ISRU system that integrates gas filtration, enrichment, and spectroscopic detection. The system incorporates a multi-stage filtration assembly to effectively eliminate corrosive sulfuric-acid aerosols, while a selective molecular-sieve adsorption unit enables efficient pre-concentration of trace atmospheric species. By coupling laser heterodyne spectroscopy with OA-ICOS, the system achieves ultra-sensitive and high-resolution measurements of both the concentration and isotopic composition of Venusian atmospheric constituents. Furthermore, the proposed integrated strategy combining remote sensing and in-situ detection enables multi-scale observations and cross-validation of data sets, thereby improving the overall accuracy and reliability of atmospheric characterization.

As part of future work, a series of laboratory validation efforts will concentrate on three key technological directions.

1) High-reliability instrument design: the development of heat-resistant materials, optimized thermal and power-management architectures, and lightweight modular integration to ensure stable and long-duration operation under Venus’s extreme temperature and pressure conditions.

2) Ultra-resolution spectroscopic remote sensing: the advancement of doppler-limited heterodyne spectroscopy through innovations in hollow-core waveguide mixing, ultra-stable local oscillators, low-noise RF filtering, and compact high-resolution laser modules for precise isotopic retrievals.

3) High-sensitivity in-situ isotopic detection: the enhancement of cavity-enhanced infrared absorption systems by improving cavity stability, light–cavity coupling efficiency, mid-IR mirror coatings, and ppb-level detection sensitivity for trace biosignature gases.

These developments will provide essential experimental validation for the proposed Venus observation framework and establish a solid technological foundation for future planetary missions. Looking ahead, this integrated framework also holds substantial promise for applications to Mars, Europa, and Titan, offering a robust basis for deep-space exploration and the sustainable utilization of planetary resources.

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