In a recent met-jobs job posting (different version here) for a researcher with a background in climatology/meteorology/hydrology or environmental sciences, I saw the phrase breadboard retrieval algorithm (emphasis mine):
Sentinel-4 Retrieval: This Research Fellow Opportunity aims at testing of breadboard retrieval algorithms. It is foreseen that synthetic satellite data, and possibly also real measurements data from airborne and satellite sensors will be used for this purpose. The activity might also cover the exploration of alternative retrieval approaches depending on the expertise and skills of the candidate.
What is a breadboard (retrieval) algorithm? Google Search yields precious few results, mostly from ESA. Another usage I found
Originally, three breadboard algorithms were developed at the Freie Universität Berlin, and the knowledge for their creation was transferred to ESA / Bomem for the creation of the ESA algorithms. In the meantime, the original look-up table approach was replaced for the breadboard algorithms by the use of artificial neural networks, which significantly eases the interpolation of the simulation results onto the actual viewing geometry.
Wikipedia tells me that, in electronics, a breadboard is a construction base for prototyping electronics. The details of the article do not appear relevant for the algorithm usage, but it makes me guess that the meaning of breadboard is related to prototyping. However, from context, it is clear that the job ad or the ENVISAT paper has nothing to do with electronics.
What does breadboard mean in the context of Earth observation retrieval algorithm development (which are the only contexts I could find)? Is it simply a synonym for prototype, or does it have a different meaning?