Space Active Optics and complex instrumentation – OASIX

The development chart is based on the LAM experience in Active Optics:
- Optical design using ZEMAX and definition of spécifications;
- Opto-mechanical design of active mirrors and deformable detectors for the realisation of the optical designs;
- manufacturing assembly integration ans tests of prototypes for the demonstration of the optical design.

Since the start of OASIX, two sets of specifications have been proposed regarding the actual needs. The HARMONI instrument, first light for the future E-ELT, requires a x30 zoom system with thight specifications in terms of optical quality. The HRT CNEs mission (phase 0) could also require a reflective zoom system in the telescope.
Since the start of the project, several optical designs have been conceived and one of them is now in a patent procedure.
In addition, the OASIX project is supported by the FOCUS Labex, who decided to provide a 2-years post-doc and equipment for the demonstration of the deformable detectors in collaboration with CEA/LETI, which was not scheduled in the OASIX proposition.

The arrival of a new researcher in the project will allow to achieve the simulations phase, since the specifications phase is now completed.

Two patents are under study via the south-east SATT:
- deformable detectors (AMU/CNRS/CEA-LETI);
- active zoom x30 (AMU/CNRS).

Preparing the next generation of space telescopes requires technological breakthrough enabling the emergence of smart imaging systems, combining a very high performance and spatial resolution with a minimal size and mass. Innovation, progress and technological breakthrough are mandatory for the development of innovative space technologies that will allow the French space agency and the French space industry to keep the leadership at the fore front of the international scene.

Several theme or applications will be addressed by the next generation of space telescopes either for observing the universe or the solar system. We can cite the detection of extra solar planets and their characterisation, the detection of earth-like exo-worlds, the characterisation of small bodies in the solar system, the study of galaxies morphology. These scientific goals all require high performance imaging systems.

In this context, the high angular resolution from space is a key point that is reached by increasing the size of telescopes, leading to several issues. For instance, the thermo-elastic deformations of large telescopes in space must be controlled using Active Optics techniques

The future space telescopes will not only increase in size, they also must be smart to reach their ambitious objectives. In close collaboration with our partners at CNES, Thales Alenia Space and ONERA, we already identified Active Optics and new optical architectures development as key points to go forward and be able to propose innovative technologies.

While telescopes will increase in diameter, the mass and cost of a mission cannot be scaled by the same factor. To tackle this problem, innovative instrument architecture is required in order to reduce the size, mass and cost of instrumentation while while improving the performances of imaging systems. In particular, innovative optical trains and focal plane architectures must be proposed.

To tackle the above issues, we will perform global system studies to identify which building blocks need to be improved, and which improvement will impact on the global systems by an optimisation of output parameters like the resolution, stability, image quality, field of view, acquisition rate, regarding the size, mass and cost.

Innovation in the space context will also require prototypes at the sub-system level for active correcting systems, smart active mirrors dedicated to specific applications, miniaturised cameras using for instance curved micro bolometer arrays or smart focal planes to reduce the size of the systems.

The OASIX project will be focused on two main activities: 1/ The development of an Off Axis wide field Zoom system (OAZ) (Mersenne type) made of two Variable Off Axis Parabolas (VOAP), 2/ The feasibility study of an Active Focal Plane (AFP) made of a deformable detector and the demonstration of its gain in terms of optical quality over the field and reduction of the optical design complexity, specifically for the zoom system.

These developments will be pursued in close collaboration with CNES and the space industry on space active optics developments. Thanks to this project, they will be prepared for the future call for tenders on large observatories and will be able to propose smarter, lighter optical designs with specific functions.

A specific strategy of valorisation of results is already in place between CNRS and space industry, through patenting, licence transfer, participation to international conferences and finally publications in peer reviewed journals.

The OASIX project will be the first demonstration of the potential of such active instrumentation and its impact at the system level. The implementation of active mirrors and deformable detectors in future large space telescopes will be the major technological breakthrough that will place our partners at the fore front of the space technology.