MLA ready to range to Mercury's surface

One week from today, the MESSENGER spacecraft will fly by Mercury for the second time this year.

As part of the final preparations for this encounter, the Mercury Laser Altimeter (MLA) has been powered on after having been off since shortly after the first flyby at the beginning of the year. The entire MESSENGER science payload is now powered and configured to collect data during next week's encounter.

"Right after the January flyby, the MLA completed passive observations of Mercury, without the laser firing, as a calibration," explained MLA Instrument Scientist Olivier Barnouin-Jha of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

"At that point it was switched off, and it has remained off since that time,"

During MESSENGER's first Mercury encounter, the MLA provided the first direct measurements of the topography of Mercury from spacecraft. The results provide evidence for a complex geologic history and indicate that Mercury's craters are shallower than those on the Moon at a given crater diameter, as expected because of the higher surface gravity.

"Unlike the topographic data obtained during the first flyby, which were of terrain for which we have no space-based imaging, some of the area to which MLA will range during this second encounter was imaged by the Mercury Dual Imaging System (MDIS) during the first Mercury flyby," Barnouin-Jha said. Moreover, terrain sampled by MLA during the first flyby will in turn be imaged by MDIS during this visit.

"So this second flyby will allow the first inter-comparison between the topographic observations and high-resolution spacecraft images," he added.

Source: Johns Hopkins University Applied Physics Laboratory
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