As announced by the ESA earlier today, Rosetta will make its controlled impact on an area known as Ma’at, a dusty and pitted region located on the comet’s small lobe.
The circle marks the spot on Ma’at (Image: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)
This region was chosen for its scientific value, and, in the words of the ESA, was a spot that took “into account key operational constraints involved in executing the descent.” In other words, it was one of only a few locations where the spacecraft could actually be maneuvered. The descent will be extremely complicated, requiring several precise navigational adjustments.
Ma’at features active pits, which hint at the comet’s ever-changing and dynamic surface. Scientists theorize that the pits are formed when the ceiling of a subsurface cavity can’t support its own weight, resulting in cometary version of a sinkhole. The resulting pits are exposed to the elements, causing continual erosion over time.
Active pits on Ma’at (image: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)
ESA scientists also want to take a look at Ma’at’s dust-covered surface. Coated on the comet like icing sugar, it exhibits sharp outcrops of materials that appear to be emerging from the ash-like surface. This matches several other regions of the comet, and scientists would like to take a closer look.
As Rosetta makes its descent, it will take hi-resolution images of the region, allowing scientists to peer closer view at the pits and the dusty surface. Unfortunately, the spacecraft will likely be damaged once it hits the comet, effectively ending the mission.
Rosetta is scheduled to crash on the comet in a controlled descent on September 30, 2016.
[ESA]