Researchers have gained new insights into how spacecraft landing creates craters and pits on the lunar surface by blowing away dust1. The insights will be potentially useful in planning future spacecraft landings more carefully.

When a spacecraft lands on lunar and other planetary surfaces, it blows away dust. Besides forming craters and pits, the blown-out dust falls on the spacecraft's solar panels that harness solar energy to power optical instruments on board. This disrupts the activities of the solar panels, stopping the functions of the optical instruments.

Scientists from the Physical Research Laboratory in Ahmedabad, India, assessed the spacecraft-landing-induced lunar surface damage by numerically evaluating the hovering time and altitude of a spacecraft, and the velocity and mass of the dust particles that it ejects during landing.

They found that the hovering time determines the extent of damage done to the surface. The ejected mass of dust increases by almost three times as the hovering duration increases from 25 seconds to 45 seconds.

To cause minimum damage on the lunar surface, it is necessary to reduce hovering time and altitude. The study reveals that the braking during a spacecraft’s descent should start from high altitudes and should be stopped or minimised as it gets to within 10 metres of the lunar surface.

These findings, the researchers say, will be useful for fine-tuning the technical aspects of enabling a safe descent of a spacecraft during future missions to the Moon.