May 15, 2009

Preliminary Landing Site Considerations

The International Atlas for Lunar Exploration by Phil Stooke (also available on our website’s carousel widget) shows the landing sites proposed by the Euromoon 2000 team. These are located at peaks of eternal light near the Moon’s south pole. In the Atlas Stooke also suggests other nearby landing sites with rover routes into the permanently shadowed zones.

We are considering targeting our Google Lunar X PRIZE mission for landing at or near one of those sites since they offer great potential for winning the Water Bonus Prize. Finding a useful deposit of water ice on the Moon would revolutionize space exploration by making a permanently manned lunar base more likely, and we would like to offer our sponsors the chance to be part of such a discovery. Talking about our sponsors, we would also like to offer them exciting video and photography. The Moon’s south pole region is a prime location thanks to its rugged landscape and dramatic shadowing.

There are also interesting scientific benefits of landing in this region including the opportunity of inspecting samples of the South Pole-Aitken impact basin in the ejecta of more recent smaller craters. We intend to reserve a certain amount of mass on our Google Lunar X PRIZE for such customer payloads.

However, landing at a peak of eternal light is quite difficult. Firstly, the polar areas of the moon are typical highland regions which have rough terrain, putting more demands on hazard avoidance and the stability and of the landing craft at touchdown. A mare region would be less demanding in that respect.

An even greater difficulty is the need for a precision landing capability. Missing the landing target at a peak of eternal light by even a few hundred meters could leave the craft in a shadowed area where solar panels cannot generate power, or in a 'communications shadow' where line of sight radio transmissions cannot reach the Earth, leaving relay by a lunar orbiting satellite as the only option for communications.

No robotically guided craft has ever soft-landed on the Moon with the required level of precision to ensure permanent sun illumination at a peak of eternal light, and there are complicated navigation challenges that still need to be solved before that technology becomes available. Remember, there is no satellite navigation system at the Moon with which the lander can determine its position, nor are there any road signs or beacons pointing out the runway!

Considering that landing anywhere on the Moon is already a difficult challenge, we are now focusing our efforts on defining a baseline mission with a landing in a mare region. Mare regions are much flatter than highland ones and this simplifies the landing system design. However, much of the mission architecture and the subsystem designs for a mare landing could also be used for a mission targeting more difficult locations so we will keep open the option to upgrade our Google Lunar X PRIZE mission in the future.

Eventually we will make our landing site selection based upon our assessment of the technical risks, considering also the needs of our potential sponsors and the level of interest in the scientific community for the respective options.

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