MEX PFS Experiment Data Record (EDR)

EDR – Experiment Data Record

Instrument: Planetary Fourier Spectrometer

PDS Data Set ID (Nominal Mission): MEX-M-PFS-2-EDR-NOMINAL-V1.0

PDS Data Set ID (Extended Mission 1): MEX-M-PFS-2-EDR-EXT1-V1.0

PDS Data Set ID (Extended Mission 2): MEX-M-PFS-2-EDR-EXT2-V1.0

PDS Data Set ID (Extended Mission 3): MEX-M-PFS-2-EDR-EXT3-V1.0

PDS Data Set ID (Extended Mission 4): MEX-M-PFS-2-EDR-EXT4-V1.0

DOI: Mars Express DOI Overview Page

For more information about PFS EDR products, see the EDR Product EAICD.

The Planetary Fourier Spectrometer (PFS) Experiment Data Record (EDR) data products contain raw data captured by the double pendulum Fourier Transform interferometer, called interferograms. PFS has two wavelength channels: a Short Wavelength (SW) channel covering 1.2 to 5.7 micrometers and a Long Wavelength (LW) channel covering 5.5 to 45 micrometers. The spectral resolution is the same over the entire spectral range.

The general scientific objective of PFS is to study Mars atmosphere. The specific science measurements to carry out these goals are:

1. Solve the problem of the inversion of the 15 micron CO2 band

2. Obtain the vertical temperature profile without any assumptions about ground pressure and temperature, and retrieve the dust content of the atmosphere

3. Complete global coverage of Mars in each season, to study seasonal variations in the global circulation

4. Study the mixing ratio of trace gases in the Martian atmosphere

5. Study (if possible) the mineralogical composition of the soil, stressing the importance of high spectral resolution to identify hydrated minerals and to resolve polar caps’ ice composition

The system acquires 18,000 points from the Analog Digital Converters (ADCs) of each channel in 4.5 seconds. These are sampled by a laser diode reference signal. The system finds the central part of the interferograms using the Hardware (HW) zero signal read from the sensor, and adds the ZOPD offset (this value is the difference between the interferogram central part and the position of HW zero) taking 8,192 points from the left side and 8,192 points from the right side. The final SW and LW size is 16,384 points and both interferograms are centered to the zero optical. Next, the LW interferogram is smoothed by averaging every four points, resulting in a reduction from 16,384 to 4,096 points. This entire process is detailed in the image below

PFS data acquisition and processing scheme.

PFS EDR Near Earth Verification and Interplanetary Cruise Phase products have the following file names:

PFS_pps_mmm_tt_dd.DAT (with detached PDS label)

where:

pp = phase

IC = Interplanetary Cruise

NEV = Near Earth Verification

s = sub-phase

C = Check Out

D = Dry Earth

E = Observation to Earth and Moon

1 = PS001 (First Switch ON)

2 = PS002 (Calibration)

3 = PS003 (DTM, Pericenter Pass Simulation, Calibration)

4 = PS004 (FOV, Calibration)

5 = PS005 (Calibration, heating of SW detector)

S = Star Calibration

M = Mars Crossing

mmm = instrument mode

CAL = calibration

MEAS = measurement

tt = datatype

HK = housekeeping

RAW = interferogram

RAD = radiance spectra (calibrated data only)

GEO = geometrical data (not found in ODE)

dd = detector

LW = Long Wavelength

SW = Short Wavelength

PFS EDR Orbital Phase products have the following file names:

PFS_nnnn_mmm_tt_dd.DAT (with detached PDS label)

where:

nnnn = mission orbit

mmm = instrument mode

CAL = calibration

MEAS = measurement

tt = datatype

HK = housekeeping

RAW = interferogram

RAD = radiance spectra (calibrated data only)

GEO = geometrical data (not found in ODE)

dd = detector

LW = Long Wavelength

SW = Short Wavelength

In ODE, EDR products have one of the following Product IDs:

PFS_PPS_MMM_TT_DD

PFS_NNNN_MMM_TT_DD