Penetrators for MoonLITE

QinetiQ is a member of the ‘UK Penetrator Consortium', led by the Mullard Space Science Laboratory (MSSL). The consortium, comprising industry and academic institutions, is currently designing and developing instrumented penetrators for use in future space science missions.

The general concept is that surface penetrators are carried to a planetary body by a host spacecraft and released once in orbit there. Each penetrator carries a descent motor that is fired causing the penetrator to fall to the surface from orbit. The speed of the surface impact embeds each penetrator several metres into the subsurface geology from where scientific studies into chemistry, seismology and other scientific disciplines can be conducted. The results are radioed back to the orbiting spacecraft for onward transmission back to Earth.

Penetrators offer significant advantages over more traditional approaches to surface science:

• They are less expensive than soft-landers or rovers

• Multiple penetrators can be deployed from a single spacecraft since they are relatively lightweight, allowing a network of sensors to be deployed rather than a single station and thereby enabling distributed studies such as siesmometry

• They directly access the subsurface thanks to their impact speed, without needing drills or scoops as used on soft-landers.

• They can access rugged terrains that would be inaccessible to soft landers or rovers

The challenges compared to other forms of surface landing are to survive impact speeds of 700-1500mph into sand, ice or rock, and to then operate and communicate from several metres under a planetary surface.

QinetiQ brings a variety of skills to this venture including:

• Years of expertise gaining through military-funded programmes into weapons design, modelling impact physics and producing designs for impact-hardened equipment.

• Access to and knowledge of high speed impact test facilities used by the military in the UK.

• Compact communications systems, as developed for the Beagle-II Mars lander.

• Miniaturised sensors for measuring tilt and acceleration.

• Space radiation sensors and radiation dose modelling.

• High energy density primary battery developments.

The first mission that may use penetrators is called MoonLITE; a proposed UK-led mission to the moon planned for launch around 2014. It would carry up to 4 penetrators that would target the north and south poles, the Earth-facing hemisphere and the lunar ‘far side'. For the first time, a widely distributed network of seismometers would be in place to measure moonquakes, allowing new insights into the nature of the lunar interior. Heat flow, volatiles detection and other science would also be conducted on the regolith material adjacent to each penetrator, adding considerable knowledge to that derived from earlier missions to the moon such as the Apollo landings.

Work on the MoonLITE penetrators is already well underway. In May 2008 an initial design concept for a 13kg penetrator was fired into sand at 700mph (almost Mach 1) at the QinetiQ-operated impact facility at Pendine, Wales. Three firings were conducted and each demonstrated the survivability of the design at a speed and into a target which were good first approximations of the real lunar mission. This design and test work was funded by the UK Science and Technology Facilities Council (STFC).

STFC is reviewing the options for taking MoonLITE forward during the summer of 2008 and it is hoped that the mission will proceed into a full Phase A study by the autumn, with full implementation possible from around 2010.

Beyond MoonLITE, future opportunities for penetrators to other planets and moons are gaining popularity within the European Space Agency (ESA) and elsewhere. Possible targets include Mars and the moons of Jupiter and Saturn.