Halfway into its 14-day expedition on the moon after a “textbook landing” on August 23, scientists at the Indian Space Research Organisation (ISRO) have described the performance of the mission as being on par with expectations with various elements in the mission achieving their milestones in the first seven days. While there had been some concerns over the functioning of a navigation camera located on the 32-kg Rover Pragyan that emerged from the Lander a few hours after the landing on August 23, the concerns have been erased in the last two days with the camera sending back clear images of its navigation path on the moon and a clear image of the Lander on the moon. On August 26, three days after the landing, the ISRO chairman had indicated during a visit to ISRO by PM Narendra Modi, that there were some issues with the data processing and time lag in data transfer from the Rover to the Lander and the Lander to the Earth that were delaying pictures. “Images take a lot of time to be transmitted to Earth due to data rate and processing,” ISRO Chairman S Somnath told the PM. The PM was shown the latest images from the Lander camera but there were no images from the Rover till August 27 – four days after the landing. The PM was told that the Rover “will turn later in the day (August 26) and look at the Lander and take more pictures.” Some scientists expressed concern that the early images from the Rover camera were unclear and more images of enhanced quality were awaited. On August 28, ISRO, however, put out the first image clicked by the Rover’s navigation camera stating that “On August 27, 2023, the Rover came across a 4-meter diameter crater positioned 3 meters ahead of its location. The Rover was commanded to retrace the path. It’s now safely heading on a new path.” On Wednesday, ISRO also put out an image of the Lander that was clicked by the Rover’s camera in keeping with the statement made by the ISRO chairman during the PM’s visit. “Pragyan Rover clicked an image of Vikram Lander this morning. The ‘image of the mission’ was taken by the Navigation Camera onboard the Rover (NavCam). NavCams for the Chandrayaan-3 Mission are developed by the Laboratory for Electro-Optics Systems (LEOS),” ISRO said in a statement on social media Wednesday. Since the picture-perfect landing of the Lander Module on August 23, the different stages of ISRO’s first successful landing mission on the moon have gone as planned. “Of the mission objectives – demonstration of a Safe and Soft Landing on the Lunar Surface is accomplished, demonstration of Rover roving on the moon is accomplished, and conducting in-situ scientific experiments is underway. All payloads are performing normally,” ISRO stated three days after the landing on August 26. “All the key aspects of the mission have happened,” a scientist in the mission said Wednesday. B N Ramakrishna, the director of the ISRO Telemetry, Tracking and Command Network centre, from where the Lander and the Rover are being tracked, described the mission as “going super”. ISRO has over the last week announced the establishment of communications between the Lander and the Chandrayaan-2 orbiter, between the Lander and the Mission Operations Center at ISTRAC, and between the Rover and the Lander. ISRO has also announced the switching on of three instruments on the Lander – Rambha-Langmuir Probe (to measure the near-surface plasma – ions and electrons – density and changes with time), ChaSTE – Chandra’s Surface Thermo Physical Experiment (to measure thermal properties of the moon near the south pole) and ILSA – Instrument for Lunar Seismic Activity. The switching on of the two payloads on the Rover – APXS (Alpha Particle X-ray Spectrometer) to derive the chemical composition of the lunar surface, and LIBS (Laser-Induced Breakdown Spectroscope) to determine the elemental composition of the lunar soil – has also been confirmed by ISRO. The first observations from the ChaSTE instrument on the Lander on the temperature of the surface of the moon were reported on August 27 by ISRO. On August 29, ISRO reported that “the Laser-Induced Breakdown Spectroscope (LIBS) instrument onboard the Rover unambiguously confirms the presence of Sulphur (S) in the lunar surface near the south pole, through first-ever in-situ measurements.” The Chandrayaan-3 mission has a 14-day nominal life span on account of the Lander and the Rover being solar-powered and one day on the moon being equal to 14 days of sunlight on the Earth. The day Chandrayaan-3 landed on the moon on August 23 was the first of 14 Earth days of sunlight on the moon and night will fall over the moon on September 6 when the batteries of the Lander and Rover will not be charged for 14 (Earth) days as temperatures fall to the region of below 100 degree Celsius on the surface of the moon. Although the nominal life of the mission is 14 days, the mission could see an extended lease of life if the batteries of the Rover and Lander revive when the sun rises again on the moon.
