ISRO Assesses Current Situation Around Moon Ahead of Chandrayaan-3 Lander's Soft Landing

As the scheduled soft landing of Chandrayaan-3's lander on the moon's surface approaches on August 23, the Indian Space Research Organisation (ISRO) has conducted an evaluation of the current space dynamics in the lunar vicinity.

In a document released on August 9, the space agency highlighted that the moon and Mars currently stand out as the most extensively explored planetary bodies, displaying a comparably high level of congestion.

ISRO further noted that India's Chandrayaan-3 has newly joined the lunar orbit, and this event has sparked expectations of increased activities around the moon in the coming years. This resurgence of lunar exploration has been spurred by initiatives such as the Artemis missions, aimed at returning to the moon, and preparations for the eventual colonization of Mars.

While earlier missions were primarily geared toward scientific exploration, upcoming ventures are projected to encompass a broader array of interests, including commercial resource utilization. In light of this evolving landscape, ISRO emphasized the importance of gaining a comprehensive understanding of the lunar environment to establish effective strategies for mitigating risks associated with close-approach threats in planetary orbits.

The Current Lunar Environment

According to ISRO's assessment, as of July 2023, six active lunar orbiters are operational.

Within this context, two of NASA's THEMIS mission probes now rebranded as ARTEMIS P1 and ARTEMIS P2, operate in eccentric orbits of low inclination. Additionally, NASA's Lunar Reconnaissance Orbiter (LRO) follows a nearly polar, slightly elliptical orbit around the moon. ISRO's Chandrayaan-2 and Korea Pathfinder Lunar Orbiter (KPLO) also operate in polar orbits at an altitude of 100 km.

Moreover, NASA's Capstone is situated in a 9:2 resonant southern L2 Near Rectilinear Halo Orbit (NRHO), with perilune traversing over the lunar north pole at an altitude of 1500-1600 km, and apolune positioned over the South pole around 70,000 km away.

Defunct spacecraft include Japan's Ouna from the Kaguya/SELENE mission (2009) and India's Chandrayaan-1 (2008). Other orbiters have either shifted away from moon-bound orbits or have touched down on the lunar surface, deliberately or due to landing complications. For example, China's Chang'e 4 mission's data relay satellite Queqiao was initially launched in May 2018 and later relocated to a halo orbit near the Earth-Moon L2 point.

ISRO anticipates that Russia's Luna-25, equipped with a lander and rover, will achieve a lunar orbit of 100 km by August 16, 2023, and subsequently land on the moon's south pole by August 21-23, 2023.

India's Role and Future Endeavors

ISRO highlighted that India has taken proactive steps in collaboration with international organizations such as the Inter-Agency Space Debris Coordination Committee (IADC). These initiatives encompass studies related to the evolving space object environment within the cislunar and lunar regions, to formulate specific guidelines and best practices to ensure sustainable space operations in these domains.