These are chat archives for esa/pykep
PyKEP is a scientific library providing basic tools for research in interplanetary trajectory design.
Hey folks. I'm trying to write a trajopt-type thing. I am trying to use ephemeris data to make a function that calculates net gravitational influence on a spacecraft given position and time. Simple enough, but I am having trouble with something basic: I can't get planet.spice.eph to run, even though util.load_spice_kernel seems to complete with no errors.
In issue #58 @darioizzo shared some code that seemed to work for the OP, but I just get the "spice cannot compute the ephemerides, have you loaded all needed kernel files?" error. I looked in the code, but the error is pretty impenetrable.
from pykep import util, epoch from pykep.planet import spice util.load_spice_kernel('de432s.bsp') x = spice('MARS', 'EARTH') x.eph(epoch(6000, 'mjd2000'))
this gives the aforementioned error.
Now, the reason I'm not just using jpl_lp--which works fine--is that I want to include the sun and moon. If mucking about with SPICE is overkill, I'd appreciate suggestions as to another way I can get that ephemeris data.