Smoke as protection against high energy laser effects

Test results of lateral load insensitive FBGs embedded in composites to suppress spectral distortion

Composite constructions are indispensable in current and future society. Fiber Bragg Gratings (FBGs) embedded in composite need to be carefully aligned with the material fibers to reduce inhomogeneous lateral load exerted onto the FBG which occurs due to the inhomogeneous nature of composite materials. Inhomogeneous load causes distortion of the...

Optical feeder link program and first adaptive optics test results

TNO and DLR envision optical free-space communication between ground stations and geostationary telecommunication satellites to replace the traditional RF links for the next generation of Very High Throughput Satellites. To mitigate atmospheric turbulence, an Adaptive Optics (AO) system will be used. TNO and DLR are developing breadboards to...

Optical technologies for terabit/s-throughput feeder link

To overcome data rate limitations of RF communication links with satellites, TNO and DLR envision optical free-space communication feeder links for next generation high throughput satellites. This paper provides a feasibility assessment of such links and the technology needed. The main results of the link budget and the turbulence modeling of...

TNO optical communications space terminals: Current projects and future plans

This paper presents the activities performed by TNO in the field of Space Laser Communication Terminals for high-volume low cost applications, and its plans for the further development of the required technologies for space terminals with particular emphasis on highly reliable, high performance, cost effective terminals.

Radiometric calibration of the gome-2 instrument

The Global Ozone Monitoring Experiment-2(GOME-2) represents one of the European instruments carried on board the MetOp satellite within the ESA’s “Living Planet Program”. Consisting of three flight models (FM’s) it is intended to provide long-term monitoring of atmospheric ozone and other trace gases over a time frame of 15–20 years, thus...

Gaia on-board metrology: Basic angle and best focus

The Gaia payload ensures maximum passive stability using a single material, SiC, for most of its elements. Dedicated metrology instruments are, however, required to carry out two functions: monitoring the basic angle and refocusing the telescope. Two interferometers fed by the same laser are used to measure the basic angle changes at the level...

Gaia in-orbit realignment: overview and data analysis

The ESA Gaia spacecraft has two Shack-Hartmann wavefront sensors (WFS) on its focal plane. They are required to refocus the telescope in-orbit due to launch settings and gravity release. They require bright stars to provide good signal to noise patterns. The centroiding precision achievable poses a limit on the minimum stellar brightness...

Ultra stable iso-static bonded optical mount design for harsh environments

Through the years many stable optical mounts have been designed, analyzed and tested at TNO. This paper gives an overview of the design principles used. Various examples are presented together with verification test results. The use of adhesives in combination with an iso-static mount design allows mounting of optical components in a limited...

Ultra stable iso-static bonded optical mount design for harsh environments

Through the years many stable optical mounts have been designed, analyzed and tested at TNO. This paper gives an overview of the design principles used. Various examples are presented together with verification test results. The use of adhesives in combination with an iso-static mount design allows mounting of optical components in a limited...

The polarization-based collimated beam combiner and the proposed NOVA fringe tracker (NFT) for the VLTI

The Polarization-Based Collimated Beam Combiner efficiently produces pairwise interference between beams from multiple telescopes. An important feature is achieving "Photometric Symmetry" whereby interference measurements have no first-order sensitivity to wavefront perturbations (or photometric variations following spatial filtering) which...

Wavefront sensor for the ESA-GAIA mission

TNO developed a Wave Front Sensor (WFS) instrument for the GAIA mission. This Wave Front Sensor will be used to monitor the wave front errors of the two main telescopes mounted on the GAIA satellite, which may be corrected by a 5- degree of freedom (DOF) mechanism during operation. The GAIA-WFS will operate over a broad wavelength (450 to 900 nm...

A combined nulling and imaging pupil-plane beam-combiner for DARWIN

The primary goal of DARWIN is to detect earth-like extrasolar planets and to search for biomarkers. This is achieved by means of nulling interferometry, using three free-flying telescopes and a Beam-Combiner (BC) hub. DARWIN will be able to perform astrophysical imaging with high spectral and spatial resolution. Should one of Darwin's telescope...

Nulling at TNO TPD: Status update

TNO TPD has an extensive experience in the realisation of highly stable passive and active opto-mechanical systems. Future missions of ESA like DARWIN [1] rely heavily on these systems such as metrology equipment, delay lines, nulling equipment etc.. The nulling equipment will be used in the Nulling mode of DARWIN in which it will detect Earth...