Within the OADT project, SwissOptic (SO) is developing two high performance optical assemblies, which form a substantial part of the reception and calibration path of Laser Communication Terminals (LCT) for the European Data Relay Satellite (EDRS) system. Extremely tight performance specifications require cutting edge technologies; with one of the main challenges of the project being the translation of previous performed feasibility studies into established industrial manufacturing procedures.
The objective of the project is to develop, build and qualify two high performance optical assemblies: a Beam Splitting Telescope (BST) and a Calibration Unit Assembly (CUA). These assemblies are forming important optical elements in the reception and calibration path of Laser Communication Terminals (LCT). The aim of the proposed development activity is to bring the technology readiness level from the existing TRL 2/3 to TRL 6.
Within the LCTs the OADT assemblies provide the following features:
- Beam Splitting Telescope (BST):
- Transmit/receive path diplexer
- Beam diameter reducer
- Integration of acquisition sensor
- Calibration Unit (CU):
- Transmit/receive beam alignment calibration
- Polarization state converter
- Sun filter
In order to achieve TRL 6 a dedicated development project is necessary. The proposed development approach will follow a classical QM and FM model philosophy. Under the proposed ARTES 3-4 activity the qualification models of the BST and CU are developed, build and tested. In the scope of the QM development some of the SwissOptic commercial manufacturing processes for hardware intended for space flight are qualified. The qualification of these processes is achieved within a dedicated material and process program.
The main challenges addressed in the OADT are as follows:
- Very strict wave-front requirements in a broad temperature range,
- Extremely high narrow-band near-infrared (NIR) transmission combined with sun blocking and (optionally) high broadband transmission in the visible range,
- High polarization extinction ratio (PER) of a large quarter-wave plate (QWP) in a wide operating temperature range vs. launch survival,
- Very low false-light and stray-light,
- Part of BST between 2 specified interfaces combining high mechanical stability and heat conductance and an extremely low thermal bending of one interface,
- Extremely small angular deviation of the back-reflected light on the calibration path.
A successful completion of the proposed development activity will qualify SwissOptic as a future supplier for core optical assemblies of Laser Communication Terminals (LCT).
Integration of QM finished and TRR finalized. All environmental tests (random vibration, shock and thermal cycling) passed successfully. Optical performance tests initiated. First results are positive.
CU-Tube: TRR successfully finalized. QM successfully integrated and tested. Optical test results are positive. Athermalization and wavefront budget currently under test.
QM integration finished. TRR successfully finalized. Optical tests initiated. The transmission performance of the sun filter is considered critical.
Last Update: 11 Mar 2013