Patrick Queeckers

Digital Holographic Interferometry with CO2 Lasers Applied to Aspheric Space Reflectors Testing

Digital holographic interferometry at long infrared wavelengths allows monitoring large deformations of space reflectors during vacuum-thermal testing. We present different optical schemes and an application to the complex case of elliptic reflector.

Counterdiffusion protein crystallisation in microgravity and its observation with PromISS (Protein Microscope for the International Space Station)

The crystallisation by counterdiffusion is a very efficient technique for obtaining high-quality protein crystals. A prerequisite for the use of counterdiffusion techniques is that mass transport must be controlled by diffusion alone. Sedimentation and convection can be avoided by either working in gelled systems, working in systems of small dimensions, or in the absence of gravity. We present the results from experiments performed on the ISS using the Protein Microscope for the International Space Station (PromISS), using digital holography to visualise crystal growth processes. We extensively characterised three model proteins for these experiments (cablys3*lysozyme, triose phosphate isomerase, and parvalbumin) and used these to assess the ISS as an environment for crystallisation by counterdiffusion. The possibility to visualise growth and movement of crystals in different types of experiments (capillary counterdiffusion and batch-type) is important, as movement of crystals is clearly not negligible.

In-situ holography microscopy of plankton and particles over the continental shelf of Senegal

We present the first results obtained by a newly developed submersible digital holography microscope (DHM), Holoflow@Sea, to enable continuous in-situ monitoring of ocean or fresh water bodies in a less intrusive manner. The microscope features an off-axis configuration with reduced-coherence illumination. The optics is designed to image plankton and particles in the size range 2 μm-200μm within a water volume of 1 mm × 1 mm × 2 mm. The prototype was successfully deployed for the first time over the continental shelf of Senegal during a fisheries survey carried out in March 2013. The objective was to combine several laboratory techniques used for plankton and particle identification (high-performance liquid chromatography, flow cytometry and optical microscopy) on discrete collected samples with DHM images taken in situ at locations with different environmental conditions. Hologram data were acquired inside an upwelling cell, i.e., new water, and along the coast, i.e., old water, as well as off the upwelling cell at the continental shelf border. Preliminary results of holographic reconstruction are encouraging, with the distinctive morphology of some phytoplankton species allowing easy identification to genera level. Challenges are recognised with the identification of small spheroid organisms. Analyses are underway to allow comparison with traditional methods of plankton identification and evaluate the benefit of additional in-situ observations obtained by holography microscopy. The preliminary results already demonstrate the potential of DHM for in-situ studies of plankton and particles.

Experiment on nucleate pool boiling in microgravity by using transparent heating surface ? Analysis of surface heat transfer coefficients

Investigation of mechanisms in nucleate boiling under microgravity conditions is essential for the development of the cooling systems handling a large amount of waste heat. A transparent heating surface with multiple arrays of 88 thin film temperature sensors and mini-heaters was developed for the clarification of boiling heat transfer mechanisms in microgravity. To investigate gravity effects on the microlayer behaviors and corresponding local heat transfer coefficients, images of liquid-vapor behaviors underneath attached bubbles and local heat transfer data were simultaneously obtained in microgravity pool boiling. The present paper reports the analysis of the data measured during the ESA parabolic flight campaign. It was found that the liquid-vapor behaviors were strongly affected by the direction and the level of residual gravity. Various patterns of liquid-vapor behaviours and corresponding enhancement or deterioration of the heat transfer are observed.

Long-wave infrared digital holography for the qualification of large space reflectors

Deformation metrology of complex and large space reflectors is a recurrent problem addressed by ESA. The challenging tasks of on-ground qualification and verification testing are to achieve the required accuracy in the measurement of these reflectors deformation and to verify their performance under simulated space conditions (vacuum, low temperature). A long-wave infrared digital holographic interferometer for the verification and validation of this type of reflector in a space environment is presented. It has been developed to fill the gap between holography/interferometry techniques in the visible wavelengths and methods based on structured light illumination like videogrammetry, stereocorrelation, and fringe/pattern projection. The former provide a good measurement uncertainty but the displacements are often too large to be measured and they require a very stable environment, while the latter provide large measurement range but with higher measurement uncertainty. The new instrument is based on digital holography and uses a CO2 lasers emitting at 10.6μm combined with a commercial thermographic camera. A diffuser is illuminated by the laser beam, producing a speckle wavefront which is observed after reflection on the reflector surface. This reflected speckle wavefront behaves exactly as if the reflector was a diffusive surface, producing its own speckle, allowing the measurement of its deformation. The advantage of this configuration compared to a classical interferometer working at 10.6μm, is that it requires no specific optics such as a null lens (in the case of parabola) or expensive illumination/collection optics (in the case of ellipse). The metrological certification of the system was performed in the laboratory by measuring the tilts of a 1.1 meter diameter parabolic reflector. The displacements are measured in parallel with a Doppler effect interferometer and the measurement uncertainty is estimated. The technique has been certified during a thermal-vacuum test. The deformation of the parabolic reflector is measured for a temperature variation from 288 K down to 113 K. The results are compared to previous results obtained on the same reflector with a high spatial resolution infrared interferometer, also developed at CSL.

Telescience and Space Missions operations at the Belgian User Support and Operation Centre

The International Space Station (ISS) is the largest space programme that has ever been undertaken on the basis of international cooperation (United States, Russia, Japan, Canada and Europe). Within the framework of this programme, Europe is in charge of the Columbus Module. More particularly, the Belgian User Support and Operation Centre will be the Facility Responsible Centre (FRC) for the SOLAR Observatory and the Facility Support Centre (FSC) for the Proteins Crystallization Diagnostic Facility (PCDF), which will be part of the European Drawer Rack (EDR). The past two years, the B-USOC, as part of the European Space Agency (ESA) Decentralized Ground Segment Infrastructure, managed telescience and operational aspects in four space missions: the OdISSea mission to the International Space Station by using a Russian Soyuz Taxi-flight, performed by Belgium (Federal Science Policy Office) with the support of ESA (October-November 2002), the 15 days STS-107 Shuttle mission (January 2003), the CERVANTES mission to the ISS, a Russian Soyuz Taxi-flight performed by Spain (October 2003), and a 30 days ESA-NASA mission onboard the ISS (February-March 2004). In those missions, B-USOC implemented and maintained, in collaboration with ESA and NASA, a dedicated ground segment for operations in order to link together all centres involved via international communication networks, and to manage several types of data interfaces (Telemetry, Command, Video, and Voice). B-USOC also collected all ground segment requirements from the Belgian users community and allowed Belgian User Home Bases to connect to the missions ground infrastructure. The present paper gives details of the ground segment implemented for the above-mentioned missions and emphasizes the specific role of the B-USOC and its interactions with the other partners’ operation centres. In conclusion, the future operational activities of the B-USOC and its involvement in the European Columbus project will be described.

A new concept for a fluid science facility: The liquid structure facility

Abstract The Liquid Structure Facility (L.S.F.) is presently developed under ESA contract. This instrument will allow to perform a wide range of fluid science experiments taking use of the determination of the velocities, temperatures concentrations and also the interface shape deformations. This facility will be activated automatically or by telescience, or manually by the crew. The main drivers for the design of the L.S.F. were the different diagnostic configurations, the accurate control of the boundary conditions and the modularity of the facility. 1. The L.S.F. is composed by four different modules: 2. -the cell module which is exchangeable and dedicated to an experiment or to a group of experiments in order to achieve the accuracy level requested for the boundary conditions, 3. -the thermal stability of the cell module is obtained by a liquid cooling loop, 4. -the diagnostic module 5. -the electronic module.

Fluid physics experiments under microgravity conditions

Abstract The proposals for the detailed investigations of the Marangoni Benard instability problem are described. It will be performed during the Spacelab D2 mission and prepared during Texus sounding rocket flight.