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. 2025 Mar 4;15(1):7535.
doi: 10.1038/s41598-025-91866-4.

Thermal conductivity of high latitude lunar regolith measured by Chandra's Surface Thermophysical Experiment (ChaSTE) onboard Chandrayaan 3 lander

Nizy Mathew  1 , K Durga Prasad  2 , Fazil Mohammad  3 , V Aasik  3 , Dinakar Prasad Vajja  4 , M Ram Prabhu  3 , M Satheesh Chandran  3 , K P Subhajayan  3 , Kiran John Antony  3 , P P Pramod  4 , Chandan Kumar  2 , Dona Mathew  3 , R Suresh  3 , U A Subramanian  3 , V Sathiyamoorthy  4 , Manu V Unnithan  3 , V Preethakumari  3 , Vinitha Ramdas  3 , Ajay Salas  3 , P S Ajeeshkumar  4 , Neha Naik  3 , Vinu Paul  3 , P Kalyana Reddy  2 , G Ambily  2 , K Kannan  3 , M B Dhanya  4 , Sanjeev Mishra  2 , P T Lali  4 , K Sunitha  3 , Samik Jash  3 , Tanmay Singhal  5 , Janmejay Kumar  2 , Manoj Kumar Mishra  6 , R Renju  4 , C Suresh Raju  4 , Anil Bhardwaj  2
Affiliations

Thermal conductivity of high latitude lunar regolith measured by Chandra's Surface Thermophysical Experiment (ChaSTE) onboard Chandrayaan 3 lander

Nizy Mathew et al. Sci Rep. .

Abstract

The thermal conductivity of the lunar regolith is an essential parameter in studying the thermal behavior of the Moon and in planning future lunar exploration. The Chandra's Surface Thermophysical Experiment (ChaSTE) aboard Vikram lander of the Indian Moon mission Chandrayaan 3 made the first in situ measurement of thermal conductivity of lunar regolith at southern high latitude using a thermal probe with ten temperature sensors at uneven intervals within 10 cm and a foil-type heater wound around the probe close to the nose tip. The ChaSTE thermal probe was inserted into the lunar regolith by a controlled motorized penetration in 29 hours. Through the two active heating experiments at a depth of 80 mm, the thermal conductivity of the lunar regolith at the Vikram landing site is estimated to be 0.0115 ± 0.0008 and 0.0124 ± 0.0009 W m[Formula: see text] K[Formula: see text], respectively. The average packing density of the lunar regolith derived using the penetration motor current is 1940 ± 10 kg m[Formula: see text]. An empirical model incorporating the temperature and the packing density value yielded thermal conductivity consistent with the in situ measurement. The value of the thermal conductivity measured by ChaSTE is also corroborated by a numerical model.

Keywords: ChaSTE; Chandrayaan 3; Lunar regolith; Thermal conductivity.

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Conflict of interest statement

Declarations. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
(Top) The ChaSTE probe. (Bottom) The schematic of the probe. The positions of the RTDs and heater on the probe are marked.
Fig. 2
Fig. 2
A schematic showing the lander structure (left) with ChaSTE probe being deployed (middle) and penetrated (right) conditions.
Fig. 3
Fig. 3
Schematic of the test facility showing different units and ChaSTE probe.
Fig. 4
Fig. 4
The schematic of the container showing the set-up details.
Fig. 5
Fig. 5
Variation of thermal conductivity with slope for different self-heating curves of ChaSTE lab experiments.
Fig. 6
Fig. 6
Image of Chandrayaan 3 Vikram lander at Shiv Shakti landing site taken by Pragyan rover navigation camera. ChaSTE is seen in the penetrated configuration.
Fig. 7
Fig. 7
Temperature measured by RTD 9 placed below the heater during the heating experiments.
Fig. 8
Fig. 8
The temperature variation of the RTD 9 during the heater switch ON at a depth of 80 mm for (a) first and (b) second heating experiments.
Fig. 9
Fig. 9
(a, b) Temperature variation with natural logarithm of time for the curves of Fig. 8 (a, b). The portion within the marked region are used for slope estimation.
Fig. 10
Fig. 10
Thermal conductivity variation of lunar regolith with temperatures estimated using the empirical model. The curves for 1930 and 1950 kg mformula image represent the upper and lower bounds of densities simulated for the location of ChaSTE penetration from the penetration motor current and ground penetration experiments. The temperatures measured are 305 K and 303 K, for the first and second heating experiments, respectively.
Fig. 11
Fig. 11
Comparison of numerical model computed and ChaSTE measured temperature rise during active heating experiment.
See this image and copyright information in PMC

References

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