The overall Mission is Mars, the Satellite is Mars_Express, and ASPERA-3 is the Experiment. This page describes the current IDFS hierarchies for the ASPERA-3 Experiment and the Mars Express Ephemeris data. The ASPERA-3 Experiment is comprised of four instruments, a scanning unit, and a data processing unit. Below are the six Instruments (according to the IDFS hierarchy) which make up the ASPERA-3 Experiment:

1. NPI - Neutral Particle Imager
2. NPD - Neutral Particle Detector
3. IMA - Ion Mass Analyzer
4. ELS - Electron Spectrometer
5. SU - Scanning Unit
6. MU - Main Unit (refers to Data Processing Unit)

Each Instrument is further divided into Virtual Instruments where data is logically grouped based on such things as sampling rates, word sizes, types (science vs. engineering), stepping functions, etc. The logical grouping is arbitrary to a degree, since there are many ways to sub-divide the data streams resulting from instrument operations. The idea is to sub-divide the data into Virtual Instruments (IDFS data sets) that are the most efficient and effective for science analysis. Below is the current IDFS Hierarchy for ASPERA-3:

ASPERA-3 Experiment IDFS Hierarchy