The Apollo dictionary contains classes that describe aspects of the Apollo missions and related instruments. 10/15/21 SHS - Changed definition of Internal_Reference in Metadata_Location, SEED_Equivalent, and ASCII_Equivalent classes, using DD_Association instead of DD_Associate_External_Class. Added rules to validate the reference_type. This is a workaround recommended by Anne Raugh, Small Bodies Node, because LDDTool is currently not correctly handling DD_Associate_External_Class. The original definitions are commented out, and may be restored if LDDTool is revised appropriately. 08/05/2022 GEO/JGW Rebuilt with 1I00 IM Apollo version 1.0.0.0 PDS Build 1.18.0.0 (1I00) LDDTool version 14.0.13 Built with lddtool -plJ PDS4_Apollo_IngestLDD.xml The ASCII_Equivalent class contains attributes that identify and locate the ASCII data product equivalent to a given Apollo PSE SEED data product. The Metadata_Location class contains attributes that identify and locate the metadata associated with a given Apollo PSE data product. The Observation_Information class provides information about a science observation. The SEED_Equivalent class contains attributes that identify and locate the SEED data product equivalent to a given Apollo PSE ASCII data product. Attributes specific to the Apollo Passive Seismic Experiment (PSE) data products. This section contains the simpleTypes that provide more constraints than those at the base data type level. The simpleTypes defined here build on the base data types. This is another component of the common dictionary and therefore falls within the common namespace. Apollo PSE data products are archived in their native SEED format and in a PDS-compatible ASCII format. The ascii_equivalent_file_name attribute gives the name of the file that is the ASCII equivalent of a SEED format file. Apollo PSE channel. Apollo PSE location. Apollo PSE observations are stored with the seismic data from the instrument in one file (mini-SEED or GeoCSV format) and the metadata for the measurements in another file (dataless SEED or StationXML format). The metadata_file_name attribute gives the name of the file containing the metadata associated with a given data file. The product_type identifies a group of data products within a collection that have some property in common, such as processing level, resolution, or instrument-specific setting. Apollo PSE mini-SEED products and their equivalent GeoCSV products contain only seismic data, and therefore have the data_type "waveform". Apollo PSE dataless SEED products and their equivalent StationXML products contain only metadata for the seismic data files, and therefore have the data_type "metadata". Sample_count is the number of samples in a Apollo PSE mini-SEED or GeoCSV product. Sampling_rate represents the number of samples per second. The sampling rate is nominal, and there is a small variation between the nominal sampling rate and the actual sampling rate, which can be estimated using the timing trace ATT. Apollo PSE data products are archived in their native SEED format and in a PDS-compatible ASCII format. The seed_file_name attribute gives the name of the file that is the SEED equivalent of an ASCII data file. Apollo seismic station.