Visual Confirmation of Moon SMARTs
|This contour map of the flash after Smart-1′s impace, so bright that it is saturated, shows that the North and South of the flash are not identical. There is a clear elongation on the South side in the direction of the motion. |
Credit: CFHT 2006
Through infrared observations with its newly installed infra-red mosaic camera WIRCam, the Canada-France-Hawaii Telescope offered a stunning image of the crash of the European spacecraft Smart-1, a very bright flash on the low-contrast landscape lit by earthshine, an image that was made available to the European Space Agency moments after Smart-1 radio-silence had made clear that the mission had ended.
Beyond the media impact of visual "confirmation" of the crash, the image allowed to pinpoint the location of the crash, actually very accurately predicted by the Smart-1 team after the ultimate orbit maneuver a few orbits before the impact.
CFHT observations did not stop once the crash was seen on the Hawaiian evening of September 2. From a preliminary analysis of the long sequence of images acquired every fifteen seconds before and after the crash, the expansion of the dust cloud generated by the high-velocity impact of Smart-1 on the Lunar soil is actually visible over at least the 75 seconds following the crash itself.
|Impact! Credit: CFHT|
This is the first observation of a Lunar impact and the expansion of its subsequent dust cloud ever made from the Earth. The corresponding images, made available on the CFHT web site, should allow observers to survey the area and look for the ejecta through imaging or spectroscopic observations. A careful analysis of the time evolution of the dust cloud, joined to the precise knowledge of the spacecraft dynamics at the time of the crash, should help to better understand the formation of ejecta following a lunar impact.
The Smart-1 team made an amazing work at keeping the astronomical community, both amateurs and professionals, informed in real time of the last moments of the spacecraft. It allowed us to have, from the lunar landscape of Mauna Kea, a last glance at Smart-1 as it ended on the Moon its long journey and a very successful mission.
Images of the CFHT observations of Smart-1 last moments and additional technical information are available on the CFHT web site.