Observation of Cassini’s Entry into Saturn: No Detection, and Lessons Learned
【Abstract】
The mission of the 2000 kg Cassini spacecraft concluded on 2017 September 15, by its deliberate
entry into Saturn’s atmosphere at some 31.1 km s −1 . Observations, using Hubble and groundbased
observatories, to attempt optical detection of this 0.25 kT “artificial meteor” are summarized. No
signatures were identified. A challenge with observing the event is that due to atmospheric drag,
its timing was not completely deterministic months or even days in advance, a particular problem for
space observatories. While imaging observations needed no geometric specification more than
“Saturn,” observations with spectrometers required pointing the instrument aperture or slit at the
specific impact site. Since giant planet longitude systems are not always familiar, distribution of
an unambiguous “finder chart” showing the location of the predicted entry site on the disk is
essential, as is clarity on whether stated times are spacecraft event time, or Earth received time
(light-tr...
【Author】
Ralph D. Lorenz, Frank Crary, Laurent Lamy, Peter Jenniskens, Liang Ge, Xi-Liang Zhang, Jian-Yang Li, Masataka Imai, Tatsuharu Ono, Matthew R. Arnison, and Lee Spitler
【Journal】
Research Notes of the AAS(IF：0) Time：2021-06-19
