LRO LAMP Experiment Data Record (EDR)

EDR – Experiment Data Record

Instrument: Lyman-Alpha Mapping Project

PDS Data Set ID: LRO-L-LAMP-5-GDR-V1.0DOI: 10.17189/1520244

For more information about LAMP GDR products, see the GDR Product SIS.

For more details on the structure and contents of the LAMP GDR Archive, see the GDR Archive SIS.

The Lyman-Alpha Mapping Project (LAMP) Gridded Data Record (GDR) map products are all derived from “night side” data; that is when the LAMP detector Field of View (FOV) was located on the night side of the Moon or in a Permanently Shaded Region (PSR) and the aperture door was open. The primary sources of data contained in the GDR map products are the LAMP RDR data products.

The LAMP GDR map products are:

  1. Brightness maps: four wavelength ranges are included: Lyman-α (119.57-123.57 nm), full stellar (129.57-189.57 nm), on-band (129.57-155.57 nm), off band (155.57-189.57 nm)

  2. Albedo maps: the same four wavelength ranges are used here as for the brightness maps above

  3. H2O Absorption Feature Depth (“Ratio”) maps: these are computed as the ratio of the off-band to on-band brightness and albedo maps

  4. Count maps

  5. Far Ultraviolet (FUV) Photon maps

  6. Exposure maps

  7. Illumination maps

  8. Statistical Error (Noise) maps

  9. Data Quality maps (a mask including locations of sunlit peaks, noise floor, and other details)

In addition to the cumulative ensemble average maps generated using data taken during the whole nominal Exploration Systems Mission Directorate (ESMD) phase of the Lunar Reconnaissance Orbiter (LRO) mission, monthly maps are provided for all of the above products except for the data quality, statistical error, and H2O absorption feature depth maps.

Map processing generally proceeds as follows. From each LAMP Reduced Data Record (RDR) product a corresponding “exposure record” is generated that records the exposure time of each LAMP spatial pixel in each polar stereographic map cell. Calibrated photon counts (i.e., photons/cm2, where the cm2 is related to the wavelength-dependent instrument effective area) from the RDR products are then paired with these exposure records, one-to-one, to produce integrated photon count and exposure maps, which are in turn used to generate the brightness maps themselves. FUV illumination models are separately used to estimate the time-dependent FUV flux incident on the Moon’s night side and PSRs. These, combined with the brightness maps yield the albedo maps. The ratio of the off-band albedo to the on-band albedo yields the H2O absorption feature depth map.

LAMP GDR products have the following file names:

LAMP_80p_240MPP_www_ttttt_vv.IMG (with detached PDS label)

where:

p = pole

N = north polar

S = south polar

www = variable length map wavelength

long = full stellar

lya = Lyman-α

on = on-band

off = off-band

ttttt = variable length map type

brite = brightness

albed = albedo

count = count

dqual = data quality

error = error

expos = exposure

illum = illumination

photn = photon

vv = 2-digit version number to facilitate unique identification of (possibly reprocessed) GDR map files

LAMP GDR monthly map products have the following file names:

LAMP_80p_240MPP_www_ttttt_yyyymm_vv.IMG (with detached PDS label)

where:

LAMP_80p_240MPP_www_ttttt...vv = product name from above

yyyymm = coverage month

In ODE, GDR products have one of the following product IDs:

LAMP_80P_240MPP_WWW_TTTTT_VV.IMG

LAMP_80P_240MPP_WWW_TTTTT_YYYYMM_VV.IM