Appointment with the moon Chandrayaan-2: The difficult road for a soft landing

For India's second meeting with the Moon, which is expected for the first week of September, Isro scientists have swept left and right in 3,500 images in search of the right place for the rendezvous near the lunar south pole.

Here, they hope to find clues about the origin and early history of not only the Moon, but also Earth and some other members of the solar system. More evidence of water is also expected.

The scientists studied data from NASA and Kaguya Lunar Orbiter in Japan to join mosaics and study craters, boulders and slopes. The images of the lunar surface captured by the instruments on board the Chandrayaan-1, including the terrain mapping camera, the hyperspectral imaging camera, the lunar laser range instrument, the lunar mineralogy mapper and the synthetic aperture radar also They were useful.

Chandrayaan-1 mapped the entire moon when the orbiter worked for nine months, said Mylsamy Annadurai, who was the project manager of Chandrayaan-1. The high resolution orbital camera (OHRC) orbiter on board will return to study the landing site to detect hazards such as rocks up to 32 cm.

In a document presented at the 49th Planetary and Lunar Science Conference in 2018, Isro scientists said that two potential sites were identified: a primary site between the two Manzinus and Simpelius craters, located 350 kilometers north of the southern edge of the Aitken basin and the second nearby site.

China was the first country to land on the other side of the moon, in a crater about 180 kilometers from the south pole of the Aitken basin. As solar energy feeds the system, a place with good visibility and communication area was needed. Also, the place should not have many boulders or craters. The slope for landing must be less than 12 degrees. The south pole has a flat surface proximity, with good visibility and sunlight, said Isro president K Sivan.

The lunar south pole is especially interesting because a larger section of its surface remains in shadow, which means a greater chance of finding water. The region also has craters that are cold traps that contain fossilized records of the early solar system, Isro said in a web publication.

Accuracy is the key We are traveling about 3,84,000 kilometers from Earth. Even if we have a 1 km error in the landing site, all these factors should be maintained, said Annadurai. A study conducted on the topography of the landing ellipse revealed that there are 23,605 craters present, including 12,600 craters with a diameter greater than 10 m and 11 craters with a diameter greater than 500 m. The landing ellipse is generally flat with the primary landing site without craters with significant depth.

Vikram has to land without causing much disturbance. The moon dust can adhere to the instruments, affecting the deployment of the solar panel, sensors and navigation aids. The less time passes, the less discomfort, the PRL scientists said.