The concept envisages a Soyuz rocket with a Fregat upper stage for the launch. Following separation of the payload from the upper stage, the two-stage spacecraft (the lander and the lunar module) will enter a transfer orbit before swinging into orbit around the Moon just two kilometres above its surface. At this point, the lander will detach itself from the transfer module and land near the Moon’s south pole. The Moon rover will emerge from the landing module and begin the scientific exploration.
Technological challenges
“There are a number of technological challenges that have to be mastered in order for such a lunar landing manoeuvre to work,” says Peter Kyr, referring to what lies ahead in the second phase of the study. “So far, the Moon has been orbited, but only American astronauts have actually set foot on it. The technologies required for a robotic landing operation, as envisaged in the study, are at present only partially available or still need to be developed.”
The key technologies that make this type of lunar mission so challenging include:
Optical navigation and obstacle avoidance
Even if a suitable landing place can be specified in advance, an autonomous optical navigation system is needed during the landing manoeuvre to ensure that the vehicle does not head for any rocks, slopes or other inaccessible areas. Given that the final phase of the landing approach takes a mere 75 seconds and needs to be executed precisely to within just a few hundred metres, this is a very critical aspect.
Control and propulsion
The idea is for the landing module to use the same types of engines as the ATV automated transfer vehicle: eight 220 N and four 500 N propulsion units. Unlike the ATV, however, the landing module cannot be brought to a standstill in space, so it needs to control and slow down its approach during the entire descent. This is done by pulsed engines that work asynchronously, i.e. that can be switched on and off at alternating times.
