Chandrayaan-4 mission under spotlight as hope fades for Chandrayaan-3's Vikram lander, Pragyan rover

Chandrayaan-3 Status: The Indian Space Research Organisation (ISRO) faces communication challenges with the Vikram lander and Pragyan rover and this may signal end of the Chandrayaan-3 mission. No signals have been received from them after they were put into sleep mode.

With Chandrayaan-3's chances of revival fading fast, resources and findings may be redirected to the Lunar Polar Exploration Mission (LUPEX), also known as Chandrayaan-4, a collaborative effort between ISRO and the Japan Aerospace Exploration Agency (JAXA).

LUPEX aims to send an uncrewed lunar lander and rover to explore the Moon's enigmatic south pole region. The mission is tentatively scheduled for launch in 2026.

LUPEX's origins trace back to December 2017 when ISRO and JAXA signed an Implementation Arrangement to investigate the Moon's polar regions, with a focus on water sources. The feasibility report was completed in March 2018.

Lunar Challenges and Chandrayaan-3: Chandrayaan-3 was planned after the Chandrayaan-2 lander's crash in September 2019. It aimed to demonstrate essential landing capabilities needed for LUPEX.

International Collaboration: Global collaboration in lunar exploration was explored when JAXA and NASA issued a joint statement in September 2019, potentially involving NASA in the LUPEX mission.

JAXA's System Requirement Review in early 2021 marked significant progress. In April 2023, LUPEX Working Group 1 visited India to exchange critical information, including landing site analysis and mission planning.

LUPEX aims to develop pioneering surface exploration technologies for lunar polar terrains, including advanced vehicular transport systems and survival mechanisms for lunar nights.

LUPEX will carry a suite of scientific instruments, including a ground-penetrating radar, neutron spectrometer, and advanced imaging spectrometer, to prospect and analyze water resources on the lunar surface.

Due to international challenges arising from the 2022 Russian invasion of Ukraine, the European Space Agency's Exospheric Mass Spectrometer L-band (EMS-L) became part of LUPEX's payload lineup.