JAMES CCN3 - Optical test bench for fast and reliable testing of complex payloads


The JAMES CCN3 project goal was the development of a RF test set-up using optical fibres as links between RF test bench and telecommunication payloads in AIT. 

A first challenge was to reach adequate performances, including specifically gain stability, in order for the optical set-up to match and exceed the classical RF set-up performances, including its ability to go through thermal vacuum conditions. 

From there on a second opportunity to improve  the architecture of complex payloads test beds was the introduction of wavelength multiplexing, which allows to consider significant reduction of physical test paths.


Specific attention had to be put on the behavior under TVAC of available optics components, most of them being off-the-shelf commercially available items. 

Calibration of the whole set-up was challenging, and required a great attention and skillful care on data processing.


Major benefit from this activity is the expected simplification of Assembly Integration and Test means to be used for complex programs, as the connectivity of large payloads is actually going into significant growth.

TAS expect that introduction of optics in this area will allow to properly handle huge number of RF paths, increase the quality of our tests while keeping the schedule under control.


The final outcome of the development is a fully defined link characterization approach, involving wavelength multiplexing, and stabilized components allowing to run TVAC sequences with simplified connectivity between test set-up and payloads under test. 

They will expend the James Baseline test bed capabilities, which already included:

  • New techniques for performing fast RF measurements.
  • Methods for telemetry data acquisition to facilitate such measurements.
  • Use of flight-representative payload test signals.
  • Testing over a wide bandwidth (300 MHz).
  • Harmonization of AIT and IOT software.

System Architecture

The target system architecture features multi-beam payloads, either transparent or processed.


A first test-  set-up was elaborated, allowing to make a full optical interconnection of an RF payload featuring numbers of RF paths, through a set of optical devices, thus reducing significantly the number of physical paths to, implement.

This test bed was used to characterize and  stabilize the performances of the links 

Based on this first step, an innovative set-up was built, allowing to evaluate the potential of wavelength multiplexing in order to reduce even more the volume of HW to be included 

Both steps were successfully evaluated through TVAC testing of the full chains

Current status

Project was completed successfully in 2017.

Links mock-up tested under CCN 3 are to be used for further activities on this overall topic of complex and innovative payloads AIT


ESA Contacts

Status date

Thursday, July 12, 2018 - 07:26