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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Chandrayaan programme | 6/7 | https://en.wikipedia.org/wiki/Chandrayaan_programme | reference | science, encyclopedia | 2026-05-05T12:59:47.013443+00:00 | kb-cron |
The presence of water on the Moon has always been a matter of intense debate since the last century. The first study for the lunar water was conducted in 1961 and it revealed that the polar regions, which have a high density of cold traps, have more probability of lunar water ice than the equatorial regions. The samples returned from the equatorial region during Apollo programme failed to provide definitive evidence, reinforcing the need for research on the lunar poles. Since there hadn't been any missions to the lunar poles and since the poles had been speculated to harbour the water ice, Moon Impact Probe's impact site was chosen in the lunar south pole to search for firm evidence of the same in the lunar atmosphere. The Chandra's Altitudinal Composition (ChACE) was one of the three scientific instruments on board the Chandrayaan-1's Moon Impact Probe (MIP). It was a mass spectrometer that was developed to study the composition of the tenuous lunar exosphere through mass spectroscopy. On 12 November 2008, the MIP separated from the Chandrayaan-1 orbiter and began its descent to the surface, during which it detected the clear presence of molecules with atomic mass unit 18 i.e., water. The ionized water molecules (H2O+) and their fragments (such as H+ and OH+ ions) were detected by ChACE. Three months later, the Moon Mineralogy Mapper (M3) an imaging spectrometer on board the Chandrayaan-1 orbiter also detected the presence of water. While observing the reflectance spectra of the Moon, it observed the absorption features of the water ice which are in the 1.0-2.5 μm wavelength region. The shadowed regions that received the reflected light were chosen for the study with water ice being found near the polar region. The ChACE profile indicates a steady rise in the concentration of water molecules starting from 20 degrees south to the poles, however, it peaks at 60-70 degrees south and then declines. Overlaying the M3 profile which begins at 43.1 degrees south depicts a complementary nature of the recordings, confirming the double evidence of lunar water near the south pole. However, the detection of water in every spectrum of ChACE coupled with the fact that it does not indicate either a steady rise or decline or a constant level in its profile, could possibly be due to contamination of water from Earth. Adding to the concerns was the M3's profile which showed a steady increase towards the south pole, unlike ChACE which saw a decline beyond 70 degrees south. But according to Indian mathematician Ramaiyengar Sridharan, if the water ice acts as a source due to sublimation, which would be a strong function of temperature in the prevailing ultra high vacuum condition, then, in the absence of fresh sources during the measurement phase, the increase/decrease in the concentration measured by ChACE should be at the cost of what M3 has detected in the form of ice; which means, the peak measurement recorded may be due to the presence of many water ice sources and the decline may be due to fewer such sources and while M3 mapped the water ice sources on the surface the MIP detected the vapour generated from these sources, thus complementing each other. Despite the Chandrayaan-1 mission ending a year earlier than the intended duration of two years, the data recorded from the instruments onboard over 310 days were very useful even a decade later. In 2018, the data obtained from the M3 was used by the scientist at University of Hawaiʻi, Dr. Shuai Li and his team to research lunar water in the dark craters of the poles. Since the data was patchy and hard for them to work with the dark craters, they used the traces of sunlight that had bounced off crater walls and analyzed the spectral data to find places where the three specific wavelengths (in the range of 1.0-2.5 μm) of near-infrared light were absorbed that indicated the presence of water ice. They conducted thorough statistical analysis to ensure that their findings were not influenced by random anomalies or errors in the instruments. "I consider this to be the most convincing evidence that you actually do have true water ice at the uppermost surface — what we call the optical surface — of the Moon", Li said on the results.
=== Surface features ===
Mapping and Studying the lunar surface features were the primary scientific objectives of Chandrayaan-1. The first images of the surface were acquired by the Terrain Mapping Camera (TMC) onboard the mission's orbiter. The CMOS camera with 5 m (16 ft) resolution and 40 km (25 mi) swath in the Panchromatic band, was activated on 29 October 2008 (within the earth's orbit) and it had captured over 70,000 images during its 3,000 orbits around the Moon. While the other scientific missions at the time usually had a 100 m (330 ft) resolution, many of TMC's images had a sharp resolution of 5 m (16 ft) thus enabling the production of a detailed map of the Moon. During mapping Rilles and Lava tubes on the lunar surface, the TMC discovered a large lava tube near the equator (specifically in the Oceanus Procellarum, to the north of the rille named Rima Galilaei above the lunar equator). The tube measured about 2 km (1.2 mi) in length and 360 m (1,180 ft) in width. The lunar lava tubes are considered as potential habitation sites for future crewed outposts since they act as natural protectors from cosmic radiation, solar radiation, meteorites, micrometeorites, and ejecta from impacts. They are also insulated from the extreme temperature variations on the lunar surface.
== Summary ==
=== List of missions ===
Landing
Intended hard landing
Successful soft landing
Unsuccessful soft landing
=== Timeline ===
=== Named sites ===
== Future ==
=== On-site sampling and sample return ===