Ms. Ana B. Fernández-Medina Profile

Ana B. Fernández-Medina

Optical Engineer at INTA Instituto Nacional de Tecnica Aerospacial

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Author

Publications (8)

Proceedings Article | 24 August 2024 Poster

Performance of solar orbiter PHI image stabilisation System (ISS) on ground, during commissioning, and science phase

Reiner Volkmer, Eiji Nakai, Pablo Gutierrez-Marques, Dennis Busse, Johann Hirzberger, Achim Gandorfer, Dietmar Germerott, Martin Kolleck, Thorsten Maue, Jose Maria Gomez Cama, David Roma Dollase, Kinga Albert, David Orozco Suárez, Nestor Albelo Jorge, Thierry Appourchaux, Alberto Alvarez Herrero, Julian Blanco Rodriguez, Lucas Guerrero, Fatima Kahil, Sami Solanki, Jose Carlos del Toro Iniesta, Joachim Woch, Bjoern Fiethe, Isabel Perez Grande, Esteban Sanchis Kilders, Maria Balaguer Martinez, Luis Bellot Rubio, Daniele Calchetti, Manuel Carmona Flores, Werner Deutsch, Alex Feller, German Fernandez Rico, Ana Belen Fernandez Medina Maeso, Pilar Garcia Parejo, Jose Luis Gasent Blesa, Laurent Gizon, Bianca Grauf, Klaus Heerlein, Andreas Lagg, Tobias Lange, Antonio Lopez Jimenez, Reinhard Meller, Harald Michalik, Alejandro Moreno Vacas, Reinhard Müller, Wolfgang Schmidt, Jesper Schou, Udo Schühle, Jonas Sinjan, Hanna Strecker, Jan Staub, Ignacio Torralbo, Gherardo Valori, Thomas Berkefeld

Proceedings Volume 13092, 130927F (2024) https://doi.org/10.1117/12.3021726

KEYWORDS: Image stabilization, Cameras, Calibration, Space operations, Space mirrors, Solar processes, Satellites, Polarimetry, Phase measurement, Mirrors

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Proceedings Article | 29 August 2022 Poster + Paper

CFRP sandwich optical bench with embedded optical fiber sensors for monitoring temperature and thermo-elastic deformations

Ana Fernández-Medina, Malte Frövel, Raquel López Heredero, Antonia de la Torre, Carolina Moravec, Ricardo San Julián, Alejandro Gonzalo, María Cebollero, Tomás Belenguer, Alberto Álvarez-Herrero

Proceedings Volume 12188, 121885X (2022) https://doi.org/10.1117/12.2629424

KEYWORDS: Fiber Bragg gratings, Sensors, Optical benches, Temperature sensors, Temperature metrology, Optical fibers, Skin, Optics manufacturing, Tissue optics, Error analysis

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Proceedings Article | 29 August 2022 Poster + Paper

High precision and thermally controlled Filter Wheel

Antonio Sánchez, Alejandro Gonzalo, Daniel Garranzo, Manuel Silva-López, Armonía Núñez, Hugo Laguna, María Cebollero, Ana Belén Fernández-Medina, Alberto Álvarez-Herrero

Proceedings Volume 12188, 121883A (2022) https://doi.org/10.1117/12.2629408

KEYWORDS: Optical components, Optical filters, Fabry–Perot interferometers, Switching, Switches, Tolerancing, Absorption filters, Thermal engineering, Optomechanical design, Solar telescopes

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Proceedings Article | 29 August 2022 Poster + Paper

The on-ground data reduction and calibration pipeline for SO/PHI-HRT

J. Sinjan, D. Calchetti, J. Hirzberger, D. Orozco Suárez, K. Albert, N. Albelo Jorge, T. Appourchaux, A. Alvarez-Herrero, J. Blanco Rodríguez, A. Gandorfer, D. Germerott, L. Guerrero, P. Gutierrez Marquez, F. Kahil, M. Kolleck, S. K. Solanki, J. C. del Toro Iniesta, R. Volkmer, J. Woch, B. Fiethe, J. M. Gómez Cama, I. Pérez-Grande, E. Sanchis Kilders, M. Balaguer Jiménez, L. R. Bellot Rubio, M. Carmona, W. Deutsch, G. Fernandez-Rico, A. Fernández-Medina, P. García Parejo, J. L. Gasent Blesa, L. Gizon, B. Grauf, K. Heerlein, A. Korpi-Lagg, T. Lange, A. López Jiménez, T. Maue, R. Meller, H. Michalik, A. Moreno Vacas, R. Müller, E. Nakai, W. Schmidt, J. Schou, U. Schühle, J. Staub, H. Strecker, I. Torralbo, G. Valori

Proceedings Volume 12189, 121891J (2022) https://doi.org/10.1117/12.2629323

KEYWORDS: Space operations, Modulation, Polarimetry, Magnetism, Sun, Polarization, Demodulation, Calibration, Telescopes, Sensors, Data processing, Image processing

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Proceedings Article | 29 August 2022 Poster + Paper

TuMag for SUNRISE III mission: development of the optical unit of an imaging spectropolarimeter

Alberto Álvarez Herrero, Ana Fernández-Medina, María Cebollero, Daniel Garranzo-García, Armonía Núñez, Alejandro Gonzalo, Antonio Sánchez, Javier Villanueva, Pilar García Parejo, Antonio Campos-Jara, Manuel Silva-López, Ricardo San Julián, Hugo Laguna

Proceedings Volume 12184, 121842G (2022) https://doi.org/10.1117/12.2629391

KEYWORDS: Fabry–Perot interferometers, Polarization, Cameras, Telescopes, Mirrors, Thermography, Sensors, Optical filters, Polarimetry, Optical components

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Proceedings Article | 27 August 2022 Poster + Paper

Image quality of data products of the high resolution telescope of the polarimetric and helioseismic imager

F. Kahil, A. Gandorfer, J. Hirzberger, D. Orozco Suárez, K. Albert, N. Albelo Jorge, T. Appourchaux, A. Álvarez-Herrero, J. Blanco Rodríguez, D. Germerott, L. Guerrero, P. Gutierrez Marquez, J. Sinjan, D. Calchetti, M. Kolleck, S. Solanki, J. del Toro Iniesta, R. Volkmer, J. Woch, B. Fiethe, J. Gómez Cama, I. Pérez-Grande, E. Sanchis Kilders, M. Balaguer Jiménez, L. Bellot Rubio, M. Carmona, W. Deutsch, G. Fernandez-Rico, A. Fernández-Medina, P. García Parejo, J. Gasent Blesa, L. Gizon, B. Grauf, K. Heerlein, A. Korpi-Lagg, T. Lange, A. López Jiménez, T. Maue, R. Meller, H. Michalik, A. Moreno Vacas, R. Müller, E. Nakai, W. Schmidt, J. Schou, U. Schühle, J. Staub, H. Strecker, I. Torralbo, G. Valori

Proceedings Volume 12180, 121803F (2022) https://doi.org/10.1117/12.2628942

KEYWORDS: Wavefronts, Telescopes, Point spread functions, Image quality, Monochromatic aberrations, Image restoration, Calibration, Sun, Remote sensing, Reconstruction algorithms

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Proceedings Article | 17 November 2017 Open Access

Solar orbiter/PHI full disk telescope entrance window mechanical mount

J. Barandiaran, P. Zuluaga, A. Fernandez, I. Vera, D. Garranzo, A. Nuñez, L. Bastide, M. Royo, A. Alvarez

Proceedings Volume 10563, 1056319 (2017) https://doi.org/10.1117/12.2304261

KEYWORDS: Glasses, Space telescopes, Telescopes, Astronomical imaging, Titanium, Molybdenum, Scanning tunneling microscopy, Chemical elements, Safety, Space operations

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PHI is a diffraction limited, wavelength tunable, quasi-monochromatic, and polarization sensitive imager. These capabilities are needed to infer the magnetic field and line-of-sight (LOS) velocity of the region targeted by the spacecraft (spacecraft (S/C)).

PHI will consist of two telescopes: The High Resolution Telescope (HRT)[1] and the Full Disk Telescope (FDT). The HRT and the FDT will view the Sun through entrance windows located in the S/C heat shield. These windows act as heat rejecting filters with a transmission band of about 30 nm width centered on the science wavelength, such that the total transmittance (integral over the filter curve weighted with solar spectrum, including white leakage plus transmission profile of the pass band) does not exceed 4% of the total energy falling onto the window [2][3].

The HREW filter has been designed by SELEX in the framework of an ESA led technology development activity under original ESTEC contract No. 20018/06/NL/CP[4], and extensions thereof. For FDT HREW SLEX will provide the windows and it coatings.

The HREW consists of two parallel-plane substrate plates (window 1 & window 2)[5] made of SUPRASIL 300 with a central thickness of 9 mm and a wedge of 30 arcsec each. These two substrates are each coated on both sides with four different coatings. These coatings and the choice of SUPRASIL help to minimize the optical absorptivity in the substrate and to radiatively decouple the HREW, which is expected to run at high temperatures during perihelion passages, from the PHI instrument cavity.

The temperature distribution of the HREW is driven by two main factors: the mechanical mounting of the substrates to the feedthrough, and the radiative environment within the heat-shield/feedthrough assembly.

The mechanical mount must ensure the correct integration of both suprasil substrates in its correct position and minimize the loads in windows due to thermal induced deformations and launching vibration environment.

All the subsystem must survive to a launching vibration environment and fulfill optical requirements in an environmental conditions according o its position in the external part of the spacecraft with a pressure of 0.0013Pa and a temperature -163°C<T<230°C.

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Proceedings Article | 17 November 2017 Open Access

Optical performance of the SO/PHI full disk telescope due to temperature gradients effect on the heat rejection entrance window

D. Garranzo, A. Núñez, P. Zuluaga-Ramírez, J. Barandiarán, A. Fernández-Medina, T. Belenguer, A. Álvarez-Herrero

Proceedings Volume 10563, 105634T (2017) https://doi.org/10.1117/12.2304067

KEYWORDS: Space telescopes, Telescopes, Coating, Astronomical imaging, Wavefronts, Refractive index, Image quality, Optical filters, Thermal effects, Finite element methods

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The Polarimetric Helioseismic Imager for Solar Orbiter (SO/PHI) is an instrument on board in the Solar Orbiter mission. The Full Disk Telescope (FDT) will have the capability of providing images of the solar disk in all orbital faces with an image quality diffraction-limited. The Heat Rejection Entrance Window (HREW) is the first optical element of the instrument. Its function is to protect the instrument by filtering most of the Solar Spectrum radiation. The HREW consists of two parallel-plane plates made from Suprasil and each surface has a coating with a different function: an UV shield coating, a low pass band filter coating, a high pass band filter coating and an IR shield coating, respectively.

The temperature gradient on the HREW during the mission produces a distortion of the transmitted wave-front due to the dependence of the refractive index with the temperature (thermo-optic effect) mainly. The purpose of this work is to determine the capability of the PHI/FDT refocusing system to compensate this distortion.

A thermal gradient profile has been considered for each surface of the plates and a thermal-elastic analysis has been done by Finite Element Analysis to determine the deformation of the optical elements. The Optical Path Difference (OPD) between the incident and transmitted wavefronts has been calculated as a function of the ray tracing and the thermo-optic effect on the optical properties of Suprasil (at the work wavelength of PHI) by means of mathematical algorithms based on the 3D Snell Law. The resultant wavefronts have been introduced in the optical design of the FDT to evaluate the performance degradation of the image at the scientific focal plane and to estimate the capability of the PHI refocusing system for maintaining the image quality diffraction-limited. The analysis has been carried out considering two different situations: thermal gradients due to on axis attitude of the instrument and thermal gradients due to 1° off pointing attitude. The effect over the boresight at the instrument focal plane has also been analyzed.

The results show that the effect of the FDT HREW thermal gradients on the FDT performance can be optically corrected. The influence of the thermal gradients on the system is also presented.

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