At first, the images we saw were
fuzzy, but over time they showed
more detail. From the beginning
of the mission, based on all the
data available, scientists thought
comet 67P would be a spherical
world; however, in July we found
out this was not the case. Images
coming in from Rosetta showed
the comet looked more like a rubber ducky, with two distinct lobes.
Scientists began to wonder if this
comet was really a contact binary,
meaning two separate comets
conjoined following a collision.
More observations and analysis is
needed to completely understand
why 67P has this unusual shape.
Approximately a month later, Rosetta officially “arrived” at comet
67P and inserted itself into orbit
around the comet. Over the coming weeks Rosetta would be busy
observing, mapping, and analyzing
the comet’s surface to determine a
suitable landing zone. Most missions,
like the rover missions to Mars, select
the landing zone ahead of time.
Since there was not enough information available about this icy body,
the landing team had to wait until
Rosetta arrived to select the perfect spot for Philae to touchdown.
In order to select the best possible
site, NASA and ESA scientists had to
ask themselves: Will the lander be
able to maintain regular communications with Rosetta? How common
are surface hazards such as large
boulders, deep crevasses or steep
slopes? Is there sufficient illumination
for scientific operations and enough
sunlight to recharge the lander’s
batteries beyond its initial 64-hour lifetime without causing overheating?
The sites were assigned a letter during an initial pre-selection
process, which resulted in 10 potential sites. Further analysis narrowed the field down to five sites.
“The process of selecting a landing site is extremely complex and
dynamic; as we get closer to the
comet, we will see more and more
Summary of properties of Comet 67P/Churyumov–Gerasimenko, as determined by Rosetta’s instruments during the first few months of its comet encounter. Credit: ESA
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