The proposed MoonLITE mission would deploy four penetrators from lunar orbit using a modified UK-built ESA GIOVE-A spacecraft as a launch platform. A solid rocket motor would fire to de-orbit the vehicle and cold gas thrusters would control the attitude during its descent. Once the orbital velocity was cancelled, the Penetrator would fall towards the surface of the moon and reorient itself so that it is aligned to within eight degrees of its velocity vector to limit the risk of failure through excessive side-ways stress on the probe. During the descent, an onboard camera would photograph the landing site and, unlike DS2 or Beagle 2, remain in constant contact with the MoonLITE orbiter. Just before impact, the spent rocket motor and delivery system would be jettisoned to allow the Penetrator to enter into the lunar regolith unheeded.
The craft would impact at four locations, widely distributed over the lunar surface. One would be sent to each of the lunar poles, aiming for permanently shadowed craters such as Shackleton, the bottoms of which never see daylight and may act as cold traps for water deposited from comets . Another would be sent to an equatorial region on the near side, perhaps near an Apollo landing site to compare results from the Apollo Lunar Surface Experiments Package (ALSEP). The final penetrator would attempt a landing on the far side of the moon, something never before achieved.
After the probe has come to rest, MoonLITE’s surface science will begin, powered by batteries that will last up to a year. The main objectives of the mission would be the search for lunar water and other volatiles, and to probe the structure of the lunar interior. During this time, the MoonLITE orbiter will act as a communications relay in a 100km polar orbit.
Science & Payload
The proposed mission to the moon would address the following key science which could be incorporated into a kinetic micro-penetrator payload :-
- Lunar Seismology
MoonLITE would deploy the first global lunar seismic network, each penetrator carrying a seismometer and with landing sites roughly equally spaced around the moon. From ALSEP, we know that, like the Earth, the Moon is a differentiated body with a crust and mantle. However, since all of the landings were on the Earth-facing side of the moon, the current model of the Lunar core is not very well constrained. One of the major discoveries made by ALSEP was that the moon is still tectonically active, causing rare, but very energetic “shallow” Moonquakes in the upper mantle which were reminiscent of those detected on Earth. The types of moonquake most commonly detected are the deep moonquakes that occur in two zones, at around 800km and 1000km below the surface. The later can be explained as being at the approximate boundary layer between the solid mid mantle, and the partial melt zone of the lower mantle. It has been theorized that the deep moonquakes that occur at around 800km are the result of the dissipation of tidal energy, but MoonLITE may be able to settle the debate.
- Lunar Water and other Volatiles Sensing
Under its “vision for space exploration”, NASA has set the goal of developing a sustained manned presence on the moon. This has made the question of whether or not there is water on the moon into perhaps one of the most important currently facing the manned exploration of space. Water is arguably the most valuable resource in the solar system and is vitally important for a sustained human presence on the moon.
Apart from the quantity required per astronaut for consumption, it would be needed for the growth of food, vital for a long term self-sustaining lunar colony. Spacecraft and equipment would also need water to keep cool in the searing 100C temperatures of the daytime lunar surface. Because of its weight and the associated expense of transport from earth to our satellite, indigenous lunar water would be extremely valuable for the construction of a Lunar outpost.
Two NASA missions have already hinted at the possibility of water. In 1994, NASA’s Clementine mission beamed radio waves into craters on the South Pole, the bottoms of which never see daylight and are permanently below freezing. The reflections were received on Earth and suggested the presence of ice. However, the results were far from conclusive and a repeat experiment from Earth using the Arecibo radio telescope produced a negative result. In 1998, NASA’s Lunar Prospector scanned the moon with a neutron spectrometer, which looks for the presence of hydrogen-rich substances. It discovered substantial amounts of hydrogen, again, at the Lunar Poles. However, the question remained whether this hydrogen was locked up in water, or simply hydrogen deposited from the solar wind. Clearly, the best way to find out for sure if there is water on the moon would be to send a Lander to make in-situ measurements.
- Far Side Science
As there has not yet been a landing on the far side of the moon, and there is evidence that the near and far sides of the Moon may be quite different internally, this could determine differences in regolith, lunar interior structure and composition.
- Lunar Thermal Gradients
Passive thermometers would be capable of determining heat flow from the Lunar interior and information on inhomogeneity of crustal heat producing elements (U,K,Th). This is relevant to understanding the Moon's early history.
See the website of the penetrator consortium.