Luna 25

Description

Luna 25, also designated the Luna-Glob-Lander, is a Russian lunar lander mission that launched on 10 August 2023. It was targeted to the south polar region of the Moon. There are two primary scientific objectives of the mission: to study composition of the polar regolith, and to study the plasma and dust components of the lunar polar exosphere. Communications were lost on August 19 and the lander reportedly crashed on the surface.

The lander has a four-legged base containing the landing rockets and propellant tanks, an upper compartment holds the solar panels, communication equipment, on-board computers, radiothermal heaters and radiators, and most of the science apparatus. Dry mass is about 800 kg, and it is expected to have roughly 950 kg of propellant at launch. The lander has a 1.6 meter-long Lunar Robotic Arm (LRA, or Lunar Manipulator Complex) to remove and collect the surface regolith to depths of 20 to 30 cm. The LRA is equipped with a scoop (175 cubic cm volume) and a sample acquisition tool, a 4.7 cm long tube with an internal diameter of 1.25 cm. The arm has four degrees of freedom / rotations: azimuthal, shoulder, elbow, and wrist/scoop. Total mass of the LRA is 5.5 kg, it uses 30 W nominal, and 50 W maximum power.

There are eight science instruments. ADRON-LR is a gamma-ray and neutron spectrometer to study the surface regolith. ARIES-L detects charged particles and neutrals in the polar exosphere. LIS-TV-RPM, an infra-red spectrometer, measures surface water and OH and is mounted on the LRA. The LASMA-LR mass spectrometer will measure composition of regolith samples (1 - 2 cubic cm) from the LRA using laser ablation. The PML detector will study dust in the polar exosphere. STS-L is a panoramic and local imaging system. THERMO-L will study the regolith thermal properties, and the lander will also carry a laser retroreflector panel. Data transmission rates back to Earth are planned to be 4 Mbits/sec.

Luna 25 launched on 10 August 2023 at 23:10 UTC (7:10 pm EDT, 2:10 a.m. August 11 Moscow Time) from Vostochny Cosmodrome. Launch was on a Soyuz-2 Fregat into Earth orbit. It then fired the Fregat upper stage again to go into a lunar transfer orbit. On 16 August at 08:57 UT it reached the Moon and fired its engines to enter lunar orbit. On August 19 at 11:10 UT it fired its engines to go into its pre-landing orbit, but at 11:57 UT communications were lost. It reportedly crashed on the lunar surface, a crater believed to be the crash site has been identified at 57.865 degrees south latitude, 61.360 degrees east longitude on the inner rim of Pontécoulant G crater.

The following is the mission plan if it had made a successful landing. Landing would have been in the region of the lunar south pole, the main landing site was at 69.545 S, 43.544 E, north of Boguslavsky crater. The reserve landing site was at 68.773 S and 21.21 E, southwest of Manzini crater. Both coordinate points are centers of 15 x 30 km landing ellipses. The lander was expected to operate on the lunar surface, studying surface regolith and exospheric dust and particles, for one year.

Image credit: N.P.O. Lavochkin (www.laspace.ru), all rights reserved.