RAA-SKYLOAD PERFORMANCE INVESTIGATION AFTER SENSORS FAILURE
Date Issued
2008
Author(s)
Abstract
During RAA FM tests, several doubtful behaviours have been observed, related both to the
Thermal and Radiometric characterization of the SKY LOAD (SKL).
In particular, they can be summarized as follows:
- very large thermal offset between the sensor on the metal plate backing the SKL
(named SKL1 and 2, following the LAMA nomenclature) and the sensor put on a
central pyramid (ECCOSORB) of the SKL.
- strange behaviour of the sensor put on the ECCOSORB panel side: its offset with
respect to the SKL1/2 changes largely from COLD to HOT state, beginning also
negative above a certain soil (TBD).
- Noise temperatures much lower than expected. Values found at RAA level (basing
on sensors put on the ECCOSORB) are very far from RCA results and, for several
channels that are believed to not work properly, should be considered at least
unrealistic.
It was required from the Scientific Team to attempt a first level analysis in order to give an
estimation of uncertainty tied with :
Expected temperatures read from sensors
Expected temperature ‘seen’ from the radiometers.
The output of this work should provide an answer about the possibility of using the sensor
SKL1/2 as input to perform the analysis of RAA radiometric properties, in the case of
effective failure of the ECCOSORB sensors.
An accurate analysis can not be performed in a few days but requires more accurate
investigations: because of that, it will be provided here an estimation of the expected
uncertainty on temperature observed from the feedhorn when the SKL1/2 sensor only are
used.
The global analysis foresees the matching between a Thermal and Radiometric
investigation: the two models will be here presented firstly separately and results will be at
the end related in order to fix a uncertainty in Detectors properties. Models bases either on
computational analysis and experimental results.
The document flow will be:
Design definition
Thermal Model
Radiometric Model
Mix of the two models and impact on Detectors properties.
Conclusions
Volume
PL-LFI-PST-047
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
ESA-38.pdf
Size
1.11 MB
Format
Adobe PDF
Checksum (MD5)
7df73209edc44f3bc14a054ab2c7a25c