In News:

India’s Chandrayaan-3 mission, which successfully landed on the Moon’s south polar region on August 23, 2023, achieved a global first with its Chandra’s Surface Thermophysical Experiment (ChaSTE) — the first thermal probe to successfully penetrate the soil of a celestial body and measure subsurface temperatures in situ.

About ChaSTE:

• Full form: Chandra’s Surface Thermophysical Experiment.
• Part of: Vikram lander (Chandrayaan-3).
• Depth achieved: Successfully tunnelled10 cm into the lunar regolith.
• Duration of operation: From August 23 to September 2, 2023.
• Significance: First successful deployment of a thermal probe into extraterrestrial soil.

Key Features:

• Temperature sensors: 10 sensors spaced 1 cm apart near the probe’s tip.
• Deployment mechanism: Unique rotation-based system — unlike previous missions that used hammering mechanisms.
• Measurement technique: Monitored changes in motor resistance and tip temperature to determine soil contact and depth.

Scientific Outcomes:

• Provided direct temperature profiles of lunar subsurface near the south pole.
• Enabled insights suggesting greater-than-expected presence of water ice beneath the surface.

Comparison with Previous Attempts:

Mission                                          Agency       Celestial Body         Instrument                        Outcome

Rosetta – Philae (2014)      ESA              Comet 67P              MUPUS                          Deployment failed due to

                                                                                                                                               landing bounce

InSight (2018)                            NASA           Mars                         HP3 ("The Mole")         Could not collect data;

                                                                                                                                               probe failed to burrow

                                                                                                                                               as intended

Chandrayaan-3 (2023)        ISRO           Moon                       ChaSTE                               Successful soil

                                                                                                                                                                                    penetration and 

                                                                                                                                                                                    temperature measurement

• Innovation Edge: Unlike ESA’s and NASA’s hammer-based devices, ChaSTE used a rotating drill, allowing steady penetration despite lunar soil resistance.

• Developed by the Physical Research Laboratory (PRL), Ahmedabad.