Russia’s Luna 25 enters orbit around the Moon
An onboard image from Luna 25 during its coast toward the Moon. Credit: Roscosmos.
Less than a week after its launch, Russia’s Luna 25 spacecraft has entered orbit around the Moon with the goal of landing as early as next week.
Luna 25 launched atop a Soyuz 2.1b rocket Aug. 11, 2023, from the Vostochny Cosmodrome in Russia’s Far East. Five days later on Aug. 16, the spacecraft braked into lunar orbit. This is the first attempt in the modern history of Russia to conduct scientific research on the Moon. The last robotic Soviet lunar landing mission was in 1976.
The flight profile of Luna 25. Credit: Roscosmos
The Soviet and American landers in the 1960s and 1970s explored the Moon closer to the equator. However, as shown by recent remote lunar studies, the conditions near the lunar poles are distinct from those observed in previously examined areas. The main difference is that the polar regolith (top layer of soil) appears to have a high content of volatile compounds such as water ice.
Additionally, the polar regolith contains many volatile compounds of cosmic origin, from water to complex molecules. This is an extremely interesting place for research, as it holds the potential to study remnants from earlier epochs in the solar system’s evolution.
This is why the primary focus of this second era of lunar exploration is the south polar region. NASA’s Artemis program hopes to send several robotic landers there in the coming years, culminating in human sorties later this decade. China hopes to do the same.
Moreover, India’s Chandrayaan-3 lander, which is currently in lunar orbit, is expected to also touch down in the south polar region as early as Aug. 23.
Luna 25 is scheduled to land as early as Aug. 21 near the Boguslawsky crater at around 70 degrees south. If successful, it would be the first spacecraft to explore this region of the lunar surface.
According to Roscosmos, the Luna 25 mission is to investigate the surface layer of the south polar region of the Moon, analyze the lunar exosphere and advance the technologies for landing and soil analysis. The lander is equipped with a whole complex of scientific instruments, collectively encompassing a diverse range of tasks:
- Laser mass spectrometer LAZMA-LR to study the composition of the upper layer of the lunar soil, including the search for various volatile compounds.
- Neutron and gamma detector ADRON-LR to study the composition of the upper layers of soil and determine the mass fraction of water on the lunar surface. For this, the method of active neutron probing of the upper layer to a depth of up to two meters is used.
- Infrared spectrometer LIS-TV-RPM will study the mineralogical composition of the lunar surface using infrared spectroscopy.
- Dust Monitor PmL is necessary for conducting an experiment to study the dust component of the lunar exosphere, as well as electric fields in the vicinity of a spacecraft.
- Ion energy-mass analyzer ARIES-L will be used to conduct an experiment to study the ions and neutral particles of the lunar exosphere, as well as to study how the upper layers of the Moon interact with the solar wind.
- Service television system STS-L will perform a number of tasks, including surveys during the landing of Luna 25 on the surface of the Moon and cartographic coordinate navigation of the lander. STS-L will also carry out panoramic filming of the lunar horizon, which will be needed to determine the coordinates of the landing point of Luna 25.
- Lunar manipulator complex LMK is needed in order to take samples of lunar regolith and deliver them to the soil receiver container of the LAZMA-LR apparatus. In addition, the manipulator complex will study the physical and mechanical properties of the regolith and will guide the LIS-TV-RPM, which will conduct a series of measurements and surveys. For regolith sampling, the complex is equipped with a manipulator arm. It will take up to 30 samples from a depth of 15-30 centimeters on the surface of the Moon.
- Scientific information control unit BUNI designed to oversee the functionality of all scientific instruments, excluding the STS-L. It facilitates essential functions such as power distribution, operational oversight, data reception, storage and the transmission of information from the equipment.
An illustration of the Luna 25 spacecraft on the surface of the Moon. Credit: Roscosmos
The cumulative mass of the lander’s scientific instruments is about 66 pounds (30 kilograms), contributing to Luna 25’s overall weight of 3,540 pounds (1,605 kilograms). Notably, 2,200 pounds (1,000 kilograms) of this total comprise the fuel component.
On Aug. 13, the Space Research Institute of the Russian Academy of Sciences, the lead organization for the scientific payload, completed an express analysis of telemetry and measurement data of the scientific instruments aboard the Luna 25 spacecraft at a distance of about 193,000 miles (310,000 kilometers) from Earth.
Every instrument demonstrated complete functionality and readiness for lunar exploration. Both the spacecraft’s analog and digital components, as well as nodes and blocks, performed flawlessly during testing. Moreover, the onboard television cameras captured the first images from space, revealing the structural components of the lander set against the backdrop of Earth.
The descent probe’s landing procedure is expected to adhere to the approach of the last Soviet lunar landing missions. The vehicle will move in a low polar orbit around the Moon and then make a deceleration and a vertical descent.
Video courtesy of SciNews
Anastasia Stepanova
A space journalist, researcher and engineer, Anastasia has participated in many experiments and projects helping human exploration of space. A PhD candidate in Space Resources at Colorado School of Mines, crew member of the international space projects "Mars-160" and "SIRIUS-19", and the first female test subject in the experiment "Dry Immersion", Anastasia is also co-author of the book "I wish you a good flight!", which was written under the guidance of cosmonaut Yuriy Baturin.
