Student Education During The REXUS/BEXUS Projects

The new DLR Institute of Space Systems in Bremen has established a project office to support and manage German student activities related to the preparation of the BEXUS and REXUS (Balloon/Rocket Experiments for University Students) flights. This paper primarily describes the student mentoring and the educational activities undertaken by DLR and SSC with the aim of encouraging and promoting student knowledge throughout the first year of the REXUS/BEXUS student programme

CherryPicker: Semantic Skeletonization and Topological Reconstruction of Cherry Trees

In plant phenotyping, accurate trait extraction from 3D point clouds of trees is still an open problem. For automatic modeling and trait extraction of tree organs such as blossoms and fruits, the semantically segmented point cloud of a tree and the tree skeleton are necessary. Therefore, we present CherryPicker, an automatic pipeline that reconstructs photo-metric point clouds of trees, performs semantic segmentation and extracts their topological structure in form of a skeleton. Our system combines several state-of-the-art algorithms to enable automatic processing for further usage in 3D-plant phenotyping applications. Within this pipeline, we present a method to automatically estimate the scale factor of a monocular reconstruction to overcome scale ambiguity and obtain metrically correct point clouds. Furthermore, we propose a semantic skeletonization algorithm build up on Laplacian-based contraction. We also show by weighting different tree organs semantically, our approach can effectively remove artifacts induced by occlusion and structural size variations. CherryPicker obtains high-quality topology reconstructions of cherry trees with precise details.Comment: Accepted by CVPR 2023 Vision for Agriculture Worksho

Age-related efficiency loss of household refrigeration appliances: Development of an approach to measure the degradation of insulation properties

Despite the omnipresence of household refrigeration appliances, there is still a lack of knowledge about their age-related efficiency loss over time. Past studies provide basic evidence for increasing electricity consumption of cooling appliances with ageing but fail to investigate the associated technical wear. Concentrating on the degradation of the thermal insulation, we first determined the ageing process of sealed samples of polyurethane rigid foam by investigating changes in cell gas composition and thermal conductivity over time. Simultaneously, the main challenge was to develop an approach that investigates the age-related efficiency loss of the insulation without its destruction. This testing procedure is referred to as the Bonn method. The non-destructive Bonn method was applied to varying refrigerator models in a series of successive experiments to evaluate the insulation degradation over time. Subsequently, the physical relationship between the test value of the Bonn method and the heat transfer through the multi-layered compartment walls of domestic refrigeration appliances was established, ultimately characterising the degrading insulation in terms of increasing heat transfer. Our results give substantiated evidence that the efficiency loss of cooling appliances is greatly influenced by insulation degradation over time. The ageing of sealed samples of polyurethane rigid foam indicates a large initial increase of thermal conductivity by 15% within the first year, corresponding to a change in cell gas composition. These results are in line with those of the Bonn method, emphasising an increasing heat flow through the multi-layered compartment walls of domestic refrigerators with ageing. Therewith, the present study is of significance to a wide range of stakeholders and forms the basis for future research.BMWi, 03ET1544, ALGE: Alterungsmechanismen von Haushaltskältegeräte

Improving HEVC Encoding of Rendered Video Data Using True Motion Information

This paper shows that motion vectors representing the true motion of an object in a scene can be exploited to improve the encoding process of computer generated video sequences. Therefore, a set of sequences is presented for which the true motion vectors of the corresponding objects were generated on a per-pixel basis during the rendering process. In addition to conventional motion estimation methods, it is proposed to exploit the computer generated motion vectors to enhance the ratedistortion performance. To this end, a motion vector mapping method including disocclusion handling is presented. It is shown that mean rate savings of 3.78% can be achieved.Comment: 4 pages, 4 figure

GOSA – An European Offshore Spaceport for Microlaunchers & Small Satellites

Europe profits from the boom of the New Space industry, a growing number of startups and small and medium-sized companies offering space infrastructure and space-based services. With HyImpulse, ISAR Aerospace, Orbex, PLD, Rocket Factory Augsburg and Skyrora, several promising microlauncher companies are located in Europe. An offshore spaceport with a well-connected on-shore site in Northern Germany enabling launch of small satellites to Polar or Sun Synchronous Low Earth Orbits provides the opportunity for this growing New Space region to develop a cluster in a future market and thereby create an economic eco system, which spans everything from the satellite manufacturer to the complete downstream application. Bremen as the German “City of Space” is the perfect host for the Spaceport: In Bremen’s aerospace sector, more than 140 companies and 20 institutes with around 12,000 employees generate over 4 billion euros per year. In 2020, the companies Tractebel DOC Offshore, MediaMobil, OHB and Harren&Partner joined their forces in the German Offshore Spaceport Alliance on the basis of their unique competencies in their respective fields of activity in maritime offshore and space projects. The concept foresees a preparation area in Bremerhaven, Germany, and a mobile launch and control infrastructure on two vessels. The fully integrated launcher is transported to the launch site in the offshore German exclusive economic zone (EEZ) where the launcher is erected and prepared for a launch. The infrastructure and the operational concept is kept flexible and agile to be able to serve different type of launchers and to offer rapid turnaround between two launches. The project has the ambitious target be ready in 2023 to offer launch possibilities for European and international microlauncher providers to serve the worldwide growing small satellite market. In September 2021, the German Offshore Spaceport Alliance GOSA signed MoUs with Skyrora, Rocket Factory Augsburg, T-Minus and HyImpulse. This paper will give an overview on the infrastructure and the operational concept, it will cover topics like airspace and maritime safety and it will show the recent progress in the implementation of the German Offshore Spaceport with regard to technical aspects

Main Achievements of the Rocket Technology Flight Experiment ROTEX-T

Based on experience gathered during the hypersonic flight experiments SHEFEX-I and SHEFEX-II the German Aerospace Center (DLR) performed the extensively instrumented flight experiment ROTEX-T (ROcket Technology EXperiment-Transition). ROTEX-T was successfully launched on 19th July 2016 at 06:05 am CEST from the Esrange Space Center near Kiruna in northern Sweden. Students of the RWTH Aachen University supported the design of the project with numerical simulations. ROTEX-T was a low cost flight experiment mission without inertial measurement unit, reaction control and parachute system. The payload reached an altitude of 183 kilometers, performed a ballistic re-entry with a total flight time of approximately 446 seconds and was afterwards recovered by helicopter. An unique and modular data acquisition system with sampling rates of 20 Hz, 1 kHz, 10 kHz and 2000 kHz was developed for ROTEX-T to study also instationary aerothermal phenomena

In Vivo Emergence of UL56 C325Y Cytomegalovirus Resistance to Letermovir in a Patient with Acute Myeloid Leukemia after Hematopoietic Cell Transplantation

CMV associated tissue-invasive disease is associated with a considerable risk of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Recently, the terminase inhibitor letermovir (LMV) has been approved for prophylaxis of CMV infection in HSCT. We hereby report a 60-year-old female experiencing CMV reactivation after HSCT in a CMV seronegative donor-constellation. Due to ongoing elevated CMV viral load and drug-associated myelosuppression, which prevented ganciclovir therapy, treatment was replaced by foscarnet. Due to nephrotoxicity, foscarnet was switched to LMV. The patient developed skin GvHD and prednisolone was started. Subsequently, CMV viremia worsened despite LMV therapy. Genotyping revealed the mutation C325Y of the CMV UL56 terminase being associated with high-level resistance against LMV. Prolonged uncontrolled low-level viremia due to prednisolone treatment may have favored the selection of drug-resistant CMV. Despite the excellent toxicity profile of LMV, physicians should be aware of risk factors for the emergence of resistance

Determining the heat flow through the cabinet walls of household refrigerating appliances

The increase of the thermal conductivity of PUR foam in the insulation of the cabinet is an important cause for aging processes of household refrigerating appliances. To determine the influence of the PUR foam aging on energy consumption, the development of a new measurement method is necessary because current methods influence the aging behavior of household refrigerators and are therefore not applicable in general. Based on a latent heat sink, constructed as an ice water bucket, a new measurement method is developed to determine the k · A value over time. With this method, the k · A value of four household refrigerating appliances was determined over an interval of 14 months. The k · A value increased between 3.6 % and 11.5 % during this period.BMWi, 03ET1544A, Verbundvorhaben ALGE: Alterungsmechanismen von Haushaltskältegeräte

Atmospheric Re-Entry Analysis of Sounding Rocket Payloads

The atmospheric re-entry of sounding rocket payloads is an important phase of the ballistic flight, especially when instruments and experiments shall be recovered for future flights or interpretation of experiment data. The understanding of the dynamic behaviour of cylindrical and cone-cylindrical payloads during the reentry is a prerequisite to ensure a successful deployment of the parachute system. This includes not only the knowledge of the payload vehicle attitude and rate data but also the “global view” on deceleration, descent time and terminal recovery velocity. The paper describes the analysis work that has been conducted at the Mobile Rocket base of the German Aerospace Center (DLR) on flight data of several TEXUS and MAXUS payloads that have been reviewed and compared

Re-Entry Analysis Of Research Rockets Payloads

The atmospheric re-entry of sounding rocket payloads is an important phase of ballistic flight, especially if instruments and experiments are to be recovered for future flights or interpretation of experimental data. Understanding the dynamic behaviour of cylindrical and cone-cylindrical payloads during the re-entry is a prerequisite for ensuring successful deployment of the parachute system1 2. This includes not only knowledge of the payload vehicle attitude and rate data but also the “global view" of deceleration, descent time and terminal recovery velocity. The paper describes the analysis work that has been conducted at the German Aerospace Center’s Mobile Rocket Base on the flight data of several TEXUS (Technologische EXperimente Unter Schwerelosigkeit) and MAXUS payloads that have been reviewed and compared. Vehicles, in which the centre of gravity coincides with the longitudinal aerodynamic centre, as is the case with TEXUS, MAXUS and MASER payloads, are usually spunup about the longitudinal axis before entry into the atmosphere to eliminate concentration of surface aerodynamic heating and enhance the condition for a flat-spin. Analyses of flight data have shown that the payload pinning stops when dynamic pressure starts to build and it is stabilised to one lateral position depending on devices like Telecommando- or GPS-Antennae before the payload reaches the flight time with maximum deceleration. The differences in the flow separation, forces the cylindrical payload into a rotational motion about the axis of highest inertial moment when it reaches subsonic velocity. During the analysis work that has been conducted at the Mobile Rocket Base, flight data from several TEXUS and MAXUS payloads have been reviewed and compared. The availability of accurate GPS and sensor data support the analysis of the acceleration of the payload from a altitude of 120 km during descent. With the use of gravitation models the acceleration is reduced to its aerodynamic component only. The density of the atmosphere is taken from atmospheric models to calculate the drag coefficient which is dependent on payload attitude, Reynolds-Number and Mach-Number. Up to now estimations for drag coefficients have been based on theoretical data and measurements of a cylinder in a flow field of a certain Reynolds-Number. Modelling the re-entry has also been performed by simulating the payload motion during its flight through the atmosphere, as well as the change of the drag. This paper describes the similar behaviour of the drag coefficient for sounding rocket payloads regarding the dependence on geometry, Reynolds-Number and Mach-Number