Luna-25: race to the lunar south pole

Aug. 10, 2023, was an important day for cosmonautics: at 23:10 UTC the automatic station Luna-25 was launched from Vostochnij cosmodrome using a Soyuz 2.1b with the Fregat supplementary stage.

Soyuz-2.1b launches Luna 25 to the Moon:

Overview:https://t.co/M50cVOoZKr

Livestream:https://t.co/CUjU8DCLvg pic.twitter.com/CXjrpUFZYs

— Chris Bergin – NSF (@NASASpaceflight) August 10, 2023

This is the return of a Russian-made vehicle to the Moon from the last mission, Luna-24, launched on August 9, 1976, and successfully landed in Mare Crisium on August 18. The station returned 170 grams of lunar soil to Earth using a small vehicle that landed in Western Siberia on August 22, 1976.

The Race to the South Pole

The flight of Luna-25, which will follow a direct trajectory, will lead it to enter a lunar polar orbit after about four days. Once it reaches its destination, it will gradually begin to decrease the radius of its orbit until it goes to the Moon, in an area between 69°545′ and 68°648′ south latitude.

During the final phase of the mission, Luna-25 will engage in a real competition to see who will land first with the Indian probe Chandrayaan-3.  The Indian mission lifted off on July 14 and is expected to land, after a low-consumption trajectory that lasted about forty days, at the latitude of 69°368 south in the same days Luna-25 should reach its target.

Who will arrive first? we will find out around August 20!

The importance of the lunar South Pole

Luna-25 and Chandrayaan-3 will not be the only two automatic stations directed to that region where, moreover, at the latitude of 45°444′ South, the Chinese Chang’e-4 is already operating.

Soon also an automatic JAXA station should attempt a moon landing at those latitudes as it is known that the objective for the Artemis missions is to reach the lunar south pole.

This is one of the regions where the greatest presence of water ice has been detected, essential for implanting a permanent settlement on the lunar surface.

Acquiring and developing moon landing techniques at those latitudes will be a strategic asset for those who want to be the first to exploit the natural resources of the Moon.

Luna-25 and Chandrayaan-3 compared

Externally they are very different: Luna-25 is more than 3 meters high and weighs 1750 kg, while Chandrayaan-3, with almost the same weight (1752 kg) is about 1.70 m high.

The Russian automatic station is, however, designed to last about one Earth year on the ground, while its Indian counterpart has an operational life of one lunar day (14 Earth days).

The onboard instrumentation equipment of the two stations is also different: in addition to instruments for measuring soil thermal conductivity (ChaSTE), seismic activity (ILSA), and a Langmuir probe for plasma measurement (LP); Chandrayaan-3 carries a small rover equipped with an X-ray spectrometer for alpha particles (∫) and a laser spectroscope (LIBS) to determine the composition of the soil surrounding the Moon landing area.

Luna-25 is a real mining analysis laboratory that does not carry a rover inside.

Equipped with a robotic arm remotely controlled from the ground, it can collect and analyze the surrounding terrain on site to determine all its physical characteristics.

All in a long-term mission, one Earth year, which should provide a complete picture of the morphology of the lunar landing area preparatory to the subsequent missions which, on Luna-26 onwards, on an annual basis, will see the return of Russia to the Moon in anticipation of the landing, finally, of the first cosmonauts, probably in a joint mission with the Chinese space agency.

Beethoven on the Moon

Ludwig Van Beethoven composed the famous Piano Sonata n.14 more commonly known as Moonlight Sonata. The inhabitants of the Amur region, where the Vostochnij Cosmodrome stands for the name to be assigned to the mission mascot, were inspired by this work and its suggestions, a nice animated probe created by the designer Ksenia Fetisoba of the Soyuzmultfilm animation studio.

In the competition, organized by the Roscosmos Telegram channel, to choose the name to be assigned to the mascot, many names were proposed, including Luntik, Lunyasha, Lunarik, Prilunia, and Zoya, but Sonata won in the end. It will therefore be Beethoven’s immortal work to accompany the Luna-25 automatic station during its flight to the Moon.