LNA-TEC – ESA CSC: Connectivity & Secure Communications

Objectives

The project aims to:

to assess the performance and operation of TEC elements for LNA cooling
to develop TEC implementation concepts on the LNAs considering accommodation constraints with minimum impact on the original LNA design, in particular, without violating the hermetic sealing of the LNA and the components inside it, while minimizing the impact on the overall power, dissipation and mass budgets
to demonstrate the performance of the developed concept by analysis and testing
to develop an Engineering Model to be tested in relevant environment (thermal vacuum and vibration), verified via functional testing for the best configuration selected.
to develop in parallel multiple aspects allowing the final implementation, in particular: repeatability of the attachment method for the TEC element, develop an overall control strategy for the TEC power in order to actively control the temperature on the LNA (both hardware and software)

Challenges

The main challenges within the project are related to the impossibility to perform a direct thermal control on the components to be cooled inside the LNA (as to do so it would compromise the hermetic sealing and though the whole LNA assembly, verification and calibration processes) and the limitations to the design options around the LNA itself. For example, the overall design cannot impact the external interfaces of the LNA and the module on which it is mounted, the only heat sink available is the one of the LNA itself (which can reach relatively high temperatures (ca. 65°C) in operation.

System Architecture

The cooling system presents the following parts impacting on the LNA system architecture:  TEC element/s mounted outside the LNA hermetic sealing: this approach does not cause any impact on the standard LNA assembly and verification process  a gluing process (instead of soldering) is preferred for the EM as it allows more freedom in the system concept definition/modification, although soldering is also possible, increasing performances but also reducing tuning activities for the EM (it can be analysed within a follow-up study)  a temperature sensor is also mounted outside the LNA not to violate the hermetic sealing  the control electronics find allocation below the LNA, inside Interconnection Module, filling the available space. The solution is almost not impacting the standard architecture in terms of volume as the control electronics finds accommodation in the empty space below the interconnection module. The solution presents a total power consumption of the cooling solution of 2.2W (for each LNA) plus 0.39W for the control electronics and ca. 125 grams additional mass.

Plan

The main project tasks are organized as follows:

 definition of project requirements;

 development of the TEC implementation concept on the LNA (starting analysing multiple ones) providing optimum performance and minimum impact on the original LNA design;

 verification of developed concept by analysis (thermal and structural);

 implementation and verification via Structural Thermal Modelling (thermal vacuum and vibrational test);

 finalization of the design and manufacturing of an Engineering Model of the LNA equipped with TEC element;

 testing of the EM in relevant environment (thermal vacuum chamber and shaker);

 post-evaluation of test results and future development plan.