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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Chandrayaan-3 | 4/5 | https://en.wikipedia.org/wiki/Chandrayaan-3 | reference | science, encyclopedia | 2026-05-05T12:59:53.549254+00:00 | kb-cron |
=== Plasma measurement === On 31 August, ISRO released plasma density data from the RAMBHA Instrument aboard the Vikram lander, marking the first in-situ measurements of plasma at the lunar poles. The probe aims to explore the changes in the near-surface plasma environment throughout the duration of the lunar day. Initial assessments reported relatively low plasma densities above the lunar surface varying from 5 to 30 million electrons/m3. This evaluation pertains to early stages of the lunar day. Later data collected over the lunar day measured it to be between 380 and 600 electrons/cm³. This is significantly higher than estimates derived from observations taken from orbit using Radio Occultation techniques by the Chandrayaan 2 orbiter. The electrons also possess remarkably high energy, with kinetic temperatures soaring between 3,000 and 8,000 Kelvin.
=== Seismic measurements === On 31st August 2023, ISRO released data from the ILSA payload on the lander, providing vibration measurements of the rover movement on 25 August, and a presumed natural event on 26 August. Although the cause of the latter event is a subject of investigation, it is suspected to be a moonquake.
=== In-situ temperature measurements === The ChaSTE probe penetrated into the lunar soil to carry out measurements for the entire duration of the mission. ChaSTE in-situ measurements were carried out for a significant fraction of a lunar day (~8 AM – 4 PM Local time at the Moon) i.e. approximately 10 Earth days (i.e. from 24 Aug. – 2 Sept. 2023) at an interval of about a second.
In research published in March 2025, ChaSTE observations during the mission indicated that the lunar surface temperatures show a significant spatial variability at metre scales at high latitudes, unlike at the equatorial regions. These effects become prominent as we move towards poles, an important aspect that should be considered for future exploration. The peak surface temperature at the landing site was measured to be 355 K (± 0.5 K), a temperature relatively higher than ~330 K (±3K), as predicted by earlier observations. This unexpected higher temperature is due to penetration of ChaSTE on the Sun-ward (equator-ward) facing surface with a slope of ~6o. Lunar surface temperature measured from a flat surface using an independent sensor, about a metre away from ChaSTE location, was found to be ~332K (±1K), which is consistent with orbiter based remote sensing observation (~330 K). By understanding how well the surface layer conducts heat and how much heat it can hold, as done by ChaSTE, scientists can figure out how heat moves around, predict temperatures below the surface, and see how sunlight interacts with the Moon. This would also help engineers to find subsurface locations with benign thermal environment and design safe places to plan future trips and live on the Moon.
=== Lunar Mantle === Concentrations of volatile elements found in the Primitive lunar mantle material measured at Shiv Shakti station near the South Polar Region were determined using PRL’s Alpha Particle X-ray Spectrometer (APXS) onboard the Pragyan rover . This new finding makes the Chandrayaan-3 landing site a promising site to access primitive mantle samples, which is otherwise lacking in the existing lunar collections.
=== Lunar Subsoil displacement === Following the 'hop' experiment, when the Vikram lander briefly reigniting it's engines, the lunar lander flew above the surface in a gentle arc, peaking at about 40 cm before touching the ground, displaced from its original landing position by about 50 cm and slightly rotated its position on the Moon. The Exhaust gases from the main engines blew away close to 3 cm's of lunar regolith at Statio Shiv Shakthi. Upon concluding the pilot project, mission engineers redeployed the ChaSTE instrument on the waning hours of the lunar day to record temperature changes during the transition from lunar day to night. The instrument data unveiled the presence of a more firm and compact layer of the lunar subsoil. The new ground showcased a two-level structure of the lunar surface within the top 6.5 cm of the Moon’s surface at the new location. The upper layers, extending to about 3 cm below the surface were found to conduct heat more efficiently, whereas the lower layers showed reduced thermal conductivity, indicating slight differences in composition or packing.
== Reactions ==