Observing a Lunar Impact (Abstract)

Volume 35 number 1 (2007)

Karen Meech

Abstract

(Abstract only) In view of the highly successful NASA Deep Impact mission (July 4, 2005), the technique of controlled impacts as a remote sensing space experiment is receiving wide interest. The SMART-1 mission is a European Space Agency mission for advanced research in technology. Launched in late September 2003, it headed for the Moon using solar-electric propulsion, arriving in lunar orbit mid-November 2004. In addition to the technology demonstration component of the mission, the SMART-1 is exploring the moon to make a comprehensive chemical inventory of elements on the surface, in part to investigate the theory that the moon formed from a violent collision. After exhausting the xenon fuel onboard the spacecraft, the gravitational perturbations by the Earth and Sun would cause a collision with the lunar surface in mid-August 2006. ESA has approved an extended mission, and beginning June 26 hydrazine thrusters will be fired to extend the mission at low altitude to allow for an impact on the near side of the moon, on the dark part near the lunar terminator under good observing conditions from Earth. The present date and time that the impact will occur are 3 September 2006, 02:00 UT. The impact mass will be 290 kg at 2 km/sec. Cratering predictions suggest that the thermal flash could be as bright as magnitude 7.4 if half of the kinetic energy of the impact were converted into heat, although if less efficient, the flash could be as faint as magnitude 16. The ESA SMART-1 Project Scientist, B. Foing, is soliciting an observing campaign at the time of impact. Because this event may be visible to the public and accessible by small telescopes, this talk will briefly describe the types of observations requested and the possible effects of the impact.