Loading Order of Files into Cosmographia

The loading of separate catalog files must be done in order of information dependency. For instance, the SPICE data catalog file for a mission must be loaded prior to any spacecraft, sensor, or observation files since each of the latter require Cosmographia to read SPICE data.

In general, files should be loaded in the following order:

1. SPICE data catalog file (names the SPICE kernels to be used)

2. Spacecraft catalog file(s)

3. Planets, satellites, comets, asteroids catalog files(s) (if using SPICE ephemeris data as opposed to the orbital information built-in to Cosmographia)

4. Sensor catalog file(s)

5. Observation catalog file()

An optional “load” catalog file may be used to load all needed catalog files. If used, the ordering of lines in the “load” catalog file must follow the loading order rules mentioned above. An example of a “load” catalog file is provided earlier in this User’s Guide.

Using Multiple Files of a Given Type

In theory all of the specifications needed to run Cosmographia with SPICE could be provided in a single catalog file, but this would be difficult to construct and to maintain. Using the functional separation shown above – SPICE data, Spacecraft, natural body, Sensor and Observation catalog files – is a better way to organize your inputs. Further, supplying separate files for each sensor-target pair and each observation set is recommended.

Case-Sensitivity

Parameters are case sensitive such as in defining “items: class” and incorrect case usage may cause files to not be loaded properly.

File Placement

Individual SPICE files or meta-kernels must be in the same folder as the corresponding SPICE data catalog file, otherwise a path to the file should be given as an absolute path or a relative to the SPICE data catalog file.