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drjmcauliffe / cosmographia

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Cassini crashes in moons of Saturn #13

Closed GoogleCodeExporter closed 8 years ago

GoogleCodeExporter commented 8 years ago 
Due to limited accuracy in the Saturnian satellite ephemerides, Cassini can be 
sometimes observed to crash into a moon instead of performing a close flyby, 
e.g. the Aug. 11, 2008 flyby of Enceladus which had a close approach distance 
of 25km.

To do:
- Compare the TASS 1.7 theory with the latest SPICE kernels and verify that the 
problems aren't due to an implementation error in TASS17.cpp.
- If there's no problem, investigate ways to improve ephemeris accuracy: 
possibly by extracting the Chebyshev coefficients for some of the problem 
satellites from a SPICE kernel and using them instead of the TASS 1.7 theory.

Original issue reported on code.google.com by clau...@gmail.com on 21 Jun 2011 at 6:35

GoogleCodeExporter commented 8 years ago 
Orbits of Dione and Enceladus now use Chebyshev polynomials extracted from 
SPICE kernel sat317.bsp. The Dec 12, 2011 flyby of Dione and the Aug 11, 2008 
flyby of Enceladus are now correct.

Original comment by clau...@gmail.com on 21 Jul 2011 at 12:32