Science from the Chandrayaan series by Ms. Megala.S

Overview of Chandrayaan Missions

Significance of the Moon

• The moon is described as a fascinating object in the night sky, essential for life on Earth due to its gravitational influence and aesthetic beauty.

• Among inner solar system bodies, Earth uniquely has a large moon that stabilizes its orbit and climate, preventing extreme temperature fluctuations.

• The moon's tidal effects have slowed Earth's rotation from 2-5 hours to 24 hours, significantly impacting biological rhythms.

• It is believed that lunar tides facilitated the migration of marine life onto land, contributing to terrestrial evolution.

Origin and Geological History of the Moon

• The giant impact theory posits that a Mars-sized body collided with proto-Earth, leading to the formation of the moon from molten plasma.

• Major geological events include the formation of solar systems 4.5 billion years ago and subsequent heavy bombardment creating craters on the lunar surface.

• The moon serves as a natural laboratory for studying solar system history due to its lack of chemical weathering and absence of a global magnetic field.

Current Trends in Lunar Exploration

Evolving Perspectives on Lunar Utilization

• Recent trends focus on utilizing lunar resources rather than solely understanding them; this includes sustained human exploration efforts.

• International cooperation is deemed essential for high-risk lunar missions due to their complexity and cost implications.

Potential Uses for Moon Resources

• The moon could serve various roles: as a radio observatory, habitat for humans, launch base due to lower gravity, or scientific research station.

Indian Lunar Exploration Roadmap

Development Timeline

• India's lunar exploration began with discussions in 1999 among scientists leading to Chandrayaan-1's launch in 2008 after ISRO demonstrated relevant technologies.

• Chandrayaan-1 included an orbiter and impact probe; it was followed by Chandrayaan-2 in 2019 which had an orbiter, lander, and rover configuration despite landing challenges.

Future Missions

• Plans include Chandrayaan-3 (2023), aimed at demonstrating landing capabilities; future missions will focus on sample return and resource utilization by 2040 with human presence anticipated on the moon by then.

Key Findings from Chandrayaan Missions

Highlights from Chandrayaan-1

• Launched on October 22, 2008, it aimed at high-resolution remote sensing and mineralogical mapping of the moon using five Indian payloads alongside six international ones.

Discovery of Water

• Notably credited with discovering water (H2O) on the moon through various instruments like Moon Mineralogy Mapper showing absorption bands indicative of water presence near polar regions.

• Evidence suggests three potential origins for lunar water: endogenic (from formation), exogenic (from comets/asteroids), or produced via chemical reactions involving solar wind hydrogen.

Additional Scientific Contributions

• Other significant findings include insights into solar wind interactions with lunar surfaces revealing unexpected hydrogen ion behavior.

• Observations indicate ongoing volcanic activity such as lava flows around Tycho crater suggesting geological activity contrary to previous beliefs about a geologically dead moon.

Insights from Chandrayaan-2 Mission

Mission Overview

• Launched July 22, 2019; designed primarily for detailed studies including topography and mineral composition while exceeding expected operational lifespan providing valuable data over seven years instead of one year.

Advanced Payload Capabilities

• Equipped with state-of-the-art instruments including high-resolution cameras capable of capturing features less than five meters across at an altitude of approximately 100 km above the surface.

Chandrayaan Missions: Insights and Discoveries

Overview of Lunar Orbital Platform

• The lunar orbital platform's unique capabilities enhance landing site characterization for both Indian and international missions.

Water Presence on the Moon

• Chandrayaan-1's moon mineralogy mapper had a wavelength range up to 3 microns, crucial for detecting water ice signatures around 3.2 microns, indicating widespread water presence beyond polar regions.

• Total water concentration varies from 0 to 800 ppm across different latitudes, with Shackleton crater showing significant hydration features (700 to 2400 ppm).

Elemental Composition Studies

• The class payload utilizes x-ray fluorescence spectroscopy to map elemental abundances like sodium and potassium, aiding in understanding the moon's origin and evolution history. Minor elements were found at less than 1 weight percentage.

• Ongoing measurements during the solar cycle provide high-resolution global elemental maps, including magnesium aluminum distributions.

Dual Frequency Synthetic Aperture Radar (DF SAR)

• DF SAR operates in S-band and L-band, revealing subsurface details that optical images may miss; it is essential for understanding lunar surface impacts and disturbances.

• Insights from Peary crater suggest potential exploitable depths of water ice in the north polar region through circular polarization ratio mapping.

Advanced Data Products

• The combination of L and S band SAR data produces comprehensive maps detailing surface roughness, density, porosity, and potential water ice presence—key for future lunar exploration planning. This data is publicly available via Pranam website.

Chandrayaan-3 Mission: Achievements

Launch and Landing Details

• Launched on July 14, 2023, Chandrayaan-3 underwent several maneuvers before successfully soft landing on August 23, comprising propulsion, landing modules with an integrated rover.

Payload Objectives

• Landers study ground vibrations and thermophysical properties while rovers analyze regolith composition; SHAPE payload observes Earth as an exoplanet from space. Images show deployment of various instruments like seismometers and thermal probes.

Rover Exploration Results

• The rover traveled approximately 101 meters from the lander; mission objectives were accomplished within one lunar day with excellent quality data collected throughout its operations. Publications based on findings are now open to public access.

Scientific Findings from Chandrayaan-3

Elemental Composition Analysis

• In situ measurements by APXS revealed regolith around Shiv Shakti point consists of ferroan anorthosite and magnesium suit—supporting the lunar magma ocean hypothesis regarding mantle material excavation during impact events in South Polar Aitken Basin region.

Seismic Activity Observations

• ILSA identified over 20 distinct signals related to moonquakes or rover activities; amplitude varied significantly indicating complex interactions between rover navigation patterns and soil dynamics observed over a period of about 190 hours.

Future Lunar Missions: Chandrayaan-4 & LUPEX

Upcoming Chandrayaan Missions

Chandrayaan-4 Mission Goals

• Aimed at returning pristine lunar samples back to Earth by integrating two launches into a single mission profile targeting southern high latitudes for sample collection by ascender module post landing at designated sites like Mons Mouton region by around 2028 timeframe.

LUPEX Mission Collaboration

• Joint ISRO-JAXA mission planned for launch in 2028 focuses on measuring quantity/quality of water in south polar regions using advanced scientific payload such as GPR for subsurface analysis alongside other spectrometers aimed at characterizing volatiles present.