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The KATRIN (Karlsruhe Tritium Neutrino) experiment investigates the energetic endpoint of the tritium beta-decay spectrum to determine the effective mass of the electron anti-neutrino. The collaboration has reported a first mass measurement result at this TAUP-2019 conference. The TRISTAN project aims at detecting a keV-sterile neutrino signature by measuring the entire tritium beta-decay spectrum with an upgraded KATRIN system. One of the greatest challenges is to handle the high signal rates generated by the strong activity of the KATRIN tritium source while maintaining a good energy resolution. Therefore, a novel multi-pixel silicon drift detector and read-out system are being designed to handle rates of about 100 Mcps with an energy resolution better than 300 eV (FWHM). This report presents succinctly the KATRIN experiment, the TRISTAN project, then the results of the first 7-pixels prototype measurement campaign and finally describes the construction of the first TRISTAN module composed of 166 SDD-pixels as well as its implementation in KATRIN experiment.

Expose is a multi-user instrument for astrobiological and astrochemical experiments in space. Installed at the outer surface of the International Space Station, it enables investigators to study the impact of the open space environment on biological and biochemical test samples. Two Expose missions have been completed so far, designated as Expose-E (Rabbow et al. 2012) and Expose-R (Rabbow et al. this issue). One of the space-unique environmental factors offered by Expose is full-spectrum, ultraviolet (UV)-rich electromagnetic radiation from the Sun. This paper describes and analyses how on Expose-R, access of the test samples to Solar radiation degraded during space exposure in an unpredicted way. Several windows in front of the Sun-exposed test samples acquired a brown shade, resulting in a reduced transparency in visible light, UV and vacuum UV (VUV). Post-flight investigations revealed the discolouration to be caused by a homogenous film of cross-linked organic polymers at the inside of the windows. The chemical signature varied per sample carrier. No such films were found on windows from sealed, pressurized compartments, or on windows that had been kept out of the Sun. This suggests that volatile compounds originating from the interior of the Expose facility were cross-linked and photo-fixed by Solar irradiation at the rear side of the windows. The origin of the volatiles was not fully identified; most probably there was a variety of sources involved including the biological test samples, adhesives, plastics and printed circuit boards. The outer surface of the windows (pointing into space) was chemically impacted as well, with a probable effect on the transparency in VUV. The reported analysis of the window contamination on Expose-R is expected to help the interpretation of the scientific results and offers possibilities to mitigate this problem on future missions-in particular Expose-R2, the direct successor of Expose-R

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Research in microgravity is indispensable to disclose the impact of gravity on biological processes and organisms. However, research in the near-Earth orbit is severely constrained by the limited number of flight opportunities. Ground-based simulators of microgravity are valuable tools for preparing spaceflight experiments, but they also facilitate stand-alone studies and thus provide additional and cost-efficient platforms for gravitational research. The various microgravity simulators that are frequently used by gravitational biologists are based on different physical principles. This comparative study gives an overview of the most frequently used microgravity simulators and demonstrates their individual capacities and limitations. The range of applicability of the various ground-based microgravity simulators for biological specimens was carefully evaluated by using organisms that have been studied extensively under the conditions of real microgravity in space. In addition, current heterogeneous terminology is discussed critically, and recommendations are given for appropriate selection of adequate simulators and consistent use of nomenclature.

Mechanical precompression stress is a yardstick for the strength and compressibility of soils. The default method for the estimation of precompression stress is the graphic method according to Casagrande. It involves a subjective perception by the engineer who not only determines the point of the highest curvature visually, but decides also which points are to be used for generating the virgin compression line. In order to avoid such subjective approaches, mathematical models for the determination of precompression stress have been developed emanating from the Casagrande method. These models estimate the smallest radius of the curvature based on the minimum of the second numerical derivative. The paper has the aim to quantify the variance of subjectivity implied by the person executing the graphic method, the variance of different model approaches and the accuracy of the latter in handling the graphic values. Additionally we wanted to investigate the effect of different parameters on the ordinate of the diagram and the effect of the first load step on the precompression stress. To understand these relationships, stress/bulk density functions and stress/void ratio functions measured on 13 sites were analysed by five experienced but independent engineers and by use of three mathematical models. The mean errors of precompression stress estimations by the different testers were 0.01-0.12 and by the models 0.10-0.87 on a logarithmic scale. Expressed in kPa, increasing mean errors were observed with rising precompression stress, due to delogarithmization. For the graphical determination, they reached approx. 10-20 kPa at precompression stress levels of 60-150 kPa in typical subsoils; this means 15% on average. The handling of graphically obtained values by help of mathematical models disclosed considerable deviations between them. In the logarithmic variant, the mean absolute errors varied from 0.09 (9 kPa) to 0.40 (30 kPa) and the determination coefficients from 0.71 to