Kayser Automotive (Germany)

The paper gives an overview of the development of a high-performance space structure achieving an optimum combination of mass, stiffness and stability to cope with the very stringent performance requirements of ALADIN instrument, the space-borne LIDAR built for ADM-AEOLUS ESA's Earth Explorer Mission. Kayser-Threde has been contracted in 2003 by EADS Astrium Toulouse, ALADIN instrument Prime Contractor, for the Phase C/D of ALADIN Structure PFM. The contract with ASF comprised the detailed design, development, verification, PMP qualification, and MAIV program including ALADIN Structure qualification using a complete and fully representative STM.

This paper presents the mission profile as well as the optical configuration of the space-borne AsteroidFinder telescope. Its main objective is to retrieve asteroids with orbits interior to Earth’s orbit. The instrument requires high sensitivity to detect asteroids with a limiting magnitude of equal or larger than 18.5mag (V-Band) and astrometric accuracy of 1arcsec (1σ). This requires a telescope aperture greater than 400cm², high image stability, detectors with high quantum efficiency (peak > 90%) and very low noise, which is only limited by zodiacal background. The telescope will observe the sky between 30° and 60° in solar elongation. The telescope optics is based on a Cook type TMA. An effective 2°×2° field of view (FOV) is achieved by a fast F/3.4 telescope with near diffraction-limited performance. The absence of center obscuration or spiders in combination with an accessible intermediate field plane and exit pupil allow for efficient stray light mitigation. Design drivers for the telescope are the required point spread function (PSF) values, an extremely efficient stray light suppression (due to the magnitude requirement mentioned above), the detector performance, and the overall optical and mechanical stability for all orientations of the satellite. To accommodate the passive thermal stabilization scheme and the necessary structural stability, the materials selection for the telescope main structure and the mirrors are of vital importance. A focal plane with four EMCCD detectors is envisaged. The EMCCD technology features shorter integration times, which is in favor regarding the pointing performance of the satellite. The launch of the mission is foreseen for the year 2013 with a subsequent mission lifetime of at least 1 year.

Using fiber optical components and assemblies for space flight applications brings several challenges for the design and the qualification process. Good knowledge of the system and environmental requirements is needed to derive design decisions and select suitable components for the fiber optical subsystem. Furthermore, the manufacturing process and integration limitations are providing additional constraints, which have to be considered at the beginning of the design phase. Besides Commercial off the shelf (COTS) components, custom made parts are often necessary.

Abstract EXPOSE-R flew as the second of the European Space Agency (ESA) EXPOSE multi-user facilities on the International Space Station. During the mission on the external URM-D platform of the Zvezda service module, samples of eight international astrobiology experiments selected by ESA and one Russian guest experiment were exposed to low Earth orbit space parameters from March 10th, 2009 to January 21st, 2011. EXPOSE-R accommodated a total of 1220 samples for exposure to selected space conditions and combinations, including space vacuum, temperature cycles through 273 K, cosmic radiation, solar electromagnetic radiation at >110, >170 or >200 nm at various fluences up to GJ m−2. Samples ranged from chemical compounds via unicellular organisms and multicellular mosquito larvae and seeds to passive radiation dosimeters. Additionally, one active radiation measurement instrument was accommodated on EXPOSE-R and commanded from ground in accordance with the facility itself. Data on ultraviolet radiation, cosmic radiation and temperature were measured every 10 s and downlinked by telemetry and data carrier every few months. The EXPOSE-R trays and samples returned to Earth on March 9th, 2011 with Shuttle flight, Space Transportation System (STS)-133/ULF 5, Discovery, after successful total mission duration of 27 months in space. The samples were analysed in the individual investigators laboratories. A parallel Mission Ground Reference experiment was performed on ground with a parallel set of hardware and samples under simulated space conditions following to the data transmitted from the flight mission.

In this paper the characteristics of a SESAM mode- locked frequency comb with an intra-cavity electro-optic modulator are examined. To our knowledge this is the first time an intra-cavity EOM is used within a SESAM mode-locked erbium fiber frequency comb. Hereby the sensitivity of the combs offset and repetition frequency is determined as a function of pump power setpoints and EOM voltages considering the cavity's temperatures. In addition the impact of the pump laser's relative intensity noise on the offset frequency's linewidth is analyzed, where a standard FBG pump diode and a hybrid external cavity laser are used for comparison. To prove the comb's function as a stable and accurate interface between optical and HF standards, e.g. for atomic clocks, three different locking schemes for the comb's repetition rate are presented and analyzed using phase noise measurements as reference.

Introduced at ISSS 2010, the Solar Sail Materials (SSM) project conducted for ESA came to its end at the beginning of 2013 with interesting and practical results. The project, relying also on past major European solar sails design projects, aimed at developing and testing future sail technologies suitable for large solar sailcrafts featuring low Sail Film Areal Density σFilm. The proposed paper presents the project’s achievements, mainly in the fields of Sail film and coating materials, Sail-to-Structure Interfaces (SSIF) and, Correlation of ground sail tensioning strategies with 3D imaging and Finite Element Model (FEM) simulations.

Silicon Pore Optics (SPO) provide a high angular resolution with a low areal density as required for future X-ray telescopes for high energy astrophysics. We present progress in two areas of ESA’s SPO development activities: Stray light baffling and environmental qualification. Residual stray light originating from off-axis sources or the sky background can be blocked by placing suitable baffles in front of the mirror modules. We developed two different mechanical implementations. The first uses longer, tapered mirror plates which improve the stray light rejection without the need of mounting additional parts to the modules or the telescope. The second method is based on placing a sieve plate in front of the optics. We compare both methods in terms of baffling performance using ray-tracing simulations and present test results of prototype mirror modules. Any optics for space telescopes needs to be compliant with the harsh conditions of the launch and in-orbit operation. We present new work in improving the mechanical and thermal ruggedness of SPO mirror modules and show recent results of qualification level tests, including tests of modules with externally mounted sieve plate baffles.

GETEMME (Gravity, Einstein’s Theory, and Exploration of the Martian Moons’ Environment), a mission which is being proposed in ESA’s Cosmic Vision program, shall be launched for Mars on a Soyuz Fregat in 2020. The spacecraft will initially rendezvous with Phobos and Deimos in order to carry out a comprehensive mapping and characterization of the two satellites and to deploy passive Laser retro-reflectors on their surfaces. In the second stage of the mission, the spacecraft will be transferred into a lower 1500-km Mars orbit, to carry out routine Laser range measurements to the reflectors on Phobos and Deimos. Also, asynchronous two-way Laser ranging measurements between the spacecraft and stations of the ILRS (International Laser Ranging Service) on Earth are foreseen. An onboard accelerometer will ensure a high accuracy for the spacecraft orbit determination. The inversion of all range and accelerometer data will allow us to determine or improve dramatically on a host of dynamic parameters of the Martian satellite system. From the complex motion and rotation of Phobos and Deimos we will obtain clues on internal structures and the origins of the satellites. Also, crucial data on the time-varying gravity field of Mars related to climate variation and internal structure will be obtained. Ranging measurements will also be essential to improve on several parameters in fundamental physics, such as the Post-Newtonian parameter β as well as time-rate changes of the gravitational constant and the Lense-Thirring effect. Measurements by GETEMME will firmly embed Mars and its satellites into the Solar System reference frame.

The sensor end-to-end simulation software EeteS has been developed within the framework of the Environmental Mapping and Analysis Program (EnMAP) mission. EeteS is capable of simulating EnMAP-like raw image scenes (L0) taking into account a variety of instrumental and environmental configurations. Furthermore, EeteS allows simulations of EnMAP reflectance images carrying out the complete L1 and L2 processing chains and necessary sensor calibration steps. The sequential processing chain of the simulator consists of several independent modules that are briefly described in this paper. Analysis of the intermediate and final EeteS simulation products has shown the accurate, reliable and consistent performance of the developed modules enabling the system to support technical decision-making processes required for the development of the EnMAP sensor. Besides the optimization of fundamental instrument parameters, data simulated by EeteS is already used for the development and evaluation of data pre-processing and scientific-exploitation algorithms.

Ludwig-Maximilians-Universit¨at M¨unchen operates an astrophysical observatory on the summit of Mt. Wendelstein 1 which will be equipped with a modern 2m-class, robotic telescope. 2 One Nasmyth port of the new Fraunhofer telescope is designed to sustain the excellent (< 0.8 median) seeing of the site [1, Fig. 1] over a FOV of 0.2 deg 2 utilizing three-element transmissive field corrector optics for optical wavebands. It will be equipped with a camera built around a customized 64 MPixel Mosaic (Spectral Instruments, 4 × (4k) 2 15μm e2v CCDs). TheWendelsteinWide Field Imager has two filter wheels with eight slots each (SDSS3 [ugriz] + eight still free) as well as two off-axis guiding units (two FLI Microline with 2k Fairchild CCDs on differential focus stages). A Bonn Shutter4 ensures high precision photometric exposures. An option to either insert a low dispersion grating (for field spectroscopy) or support a wave front sensor probe allows for further expansion of the camera. EMI-safe housing has to overcome the emission of a close by 0.5MW radio station. Special care has been taken to design a very low ghost budget of the overall system to allow for low-surface brightness applications (e.g. weak lensing surveys).