Embedded Files
1st December 2023
Greetings Astrophiles!
In today’s blog, we will explore some of the scientific data collected in the Chandrayaan-3 mission.
First observations from ChaSTE payload onboard Vikram lander:
On August 27 2023, ChaSTE (Chandra’s Surface Thermophysical Experiment) measured the temperature profile of the lunar topsoil around the southern pole. The temperature probe on it is equipped with a controlled penetration mechanism capable of reaching 10 cm beneath the surface and is fitted with ten individual temperature sensors.
Scientists noted the temperature variations of the lunar surface at various depths. This is the first such profile for the lunar south pole. ISRO scientist BH Darukesha said that the high range of 70 degrees Celsius temperature was “not expected”.
LIBS confirms the presence of Sulphur on the lunar surface through unambiguous in-situ measurements:
On August 28 2023, the LASER-Induced Breakdown Spectroscopy (LIBS) instrument onboard the Pragyan rover confirmed the presence of Sulphur (S) in the region unambiguously, something that was not feasible by the instruments onboard the orbiters.
LIBS is a scientific technique that analyses the composition of materials by exposing them to intense LASER pulses. High-energy pulses are focused onto the surface generating an extremely hot and localised plasma. The collected plasma light is spectrally resolved and detected by detectors such as Charges Coupled Devices (basically, it is a semiconductor device which has capacitors that convert incoming photons into electron charges, these are the pixels. Then these charges are read out to produce high-quality image data.). Preliminary analyses show the presence of Aluminium (Al), Sulphur (S), Calcium (Ca), Iron (Fe), Chromium (Cr) and Titanium (Ti) on the lunar surface. Further measurements revealed the presence of Manganese (Mn), Silicon (Si) and Oxygen (O). A thorough investigation of the presence of Hydrogen is underway.
For more info: https://www.currentscience.ac.in/Volumes/118/04/0573.pdf
APXS onboard Pragyan rover detects the presence of minor elements:
The instrument is best suited for in-situ analysis of the elemental composition of the soil and rocks present on the lunar surface (planetary bodies with thin atmospheres). It has a radioactive source that emits alpha particles and X-rays on the sample. Then the atoms present in the sample emit characteristic X-ray lines that are used to determine its elemental composition.
On August 30 2023, APXS observations discovered the presence of interesting minor elements, including Sulphur (S), along with major elements like Aluminum, Silicon, Calcium and Iron.
Why is sulphur so important? See: https://www.thestatesman.com/technology/services/chandrayaan-3-what-does-the-presence-of-sulphur-on-moon-surface-suggest-1503217019.html
RAMBHA-LP onboard Vikram lander measures near-surface plasma content:
On August 31 2023, initial assessments indicated that the plasma encompassing the lunar surface is very sparse, with about 5 to 30 million electrons per cubic metre (specifically for the early stages of lunar daytime). The probe operated without interruptions throughout the lunar day to comprehend the process of charging within the lunar near-surface region, particularly in response to the fluctuations in solar space weather conditions.
Langmuir probe is a device used for characterising plasma. It consists of a 5cm metallic spherical probe mounted on a 1m boom attached to the Vikram lander’s upper deck. It detects minute return currents, as low as pico-amperes (order of 10-12 amperes), with a dwell time of 1 millisecond.
ILSA listens to the movements around the landing site:
The primary objective is to measure the ground vibrations generated by natural quakes, impacts and artificial events.
It comprises a cluster of 6 highly sensitive accelerometers (basically measures the acceleration of a body in its instantaneous rest frame )
Shows the movement of the rover on 25 August 2023
Shows a seemingly natural event recorded on 26 August 2023, suspected to be a moonquake.
The Pragyan rover was put into sleep mode after it completed all its assignments on September 3 2023. The rover was not built to withstand the extremely cold conditions of the lunar night (~ -120 degrees Celsius). Both the rover and lander missed their wake-up calls on 22 September and all hope for further observations was diminished by 28 September when neither responded.
On 3 September, the Vikram rover carried out a hop test for potential future sample return missions. It ascended 40cm above the lunar surface and covered a similar lateral distance across the surface.
The propulsion module exited the lunar orbit and entered to an orbit around Earth. This makes it the first ever extraterrestrial spacecraft of ISRO to return back to Earth's orbit and the first to do a flyby operation.
All picture credits to ISRO
Written by Charvi Joshi
Page updated
Report abuse