The extreme aerodynamic heating and the exothermic chemical reactions due to the gas-surface inte... more The extreme aerodynamic heating and the exothermic chemical reactions due to the gas-surface interaction at hypersonic free stream velocities make the thermal protection system design and testing a challenging process. The chemically reacting hypersonic flight regime cannot be fully duplicated in ground facilities and the design methodologies, experimental and numerical, have to be validated by real flight data which come with high costs. It is the objective of QARMAN CubeSat, QubeSat for Aerothermodynamic Research and Measurements on AblatioN, to perform an atmospheric entry experiment to Earth and collect real flight data for highly affordable costs. QARMAN is a spacecraft respecting the triple unit CubeSat standards; a rectangular prism with dimensions 34x10x10 cm (Figure 1). It has an ablative TPS in the front unit and a ceramic TPS on the side panels. It also has an aerodynamic de-orbiting system which will allow the vehicle to achieve the desired conditions for atmospheric ent...
To persist in the future of space business low cost satellites, which can be produced in high qua... more To persist in the future of space business low cost satellites, which can be produced in high quantities in less time, are mandatory. In the project IRAS (Integrated Research platform for Affordable Satellites), new technologies are investigated and developed to significantly lower the cost and production time for satellite components. To achieve this, additive manufacturing techniques using polymeric, metallic, and ceramic materials are combined with multifunctional and bionic structures, resulting in lightweight, cost-efficient and integrated structures. Advanced propulsion technologies are also considered within this project as well as the implementation of off-the shelf components from other sectors such as automotive electronics. In addition, a Digital Concurrent Engineering Platform (DCEP) is under development, enabling engineers to jointly develop satellites in a novel way without the need for physical proximity. This paper presents the concepts and current developments in th...
Dieser interne Bericht enthält die Aktivitäten des IRAS II-Projekts aller Partner, die vom Projek... more Dieser interne Bericht enthält die Aktivitäten des IRAS II-Projekts aller Partner, die vom Projektbeginn am 1.12.2018 bis zum Projektende am 31.5.2020 stattfanden
The passive/active oxidation behavior of a CVD-SiC coated C/C-SiC thermal protection material of ... more The passive/active oxidation behavior of a CVD-SiC coated C/C-SiC thermal protection material of the hypersonic SpaceLiner vehicle is investigated experimentally. For the safety of spacecraft and its passengers, it is important to know whether the thermal protection system will experience passive/active oxidation during the vehicle's entry into Earth's atmosphere. Active oxidation can promote material loss whereas passive oxidation forms a protective film. The high enthalpy flight conditions of SpaceLiner vehicle are duplicated in VKI Plasmatron, where the samples are exposed to high enthalpy plasma and the surface temperatures increase up to 2800 K at various total pressure (2-20 kPa) conditions. Surface temperature profiles, visual characteristics, mass changes, emissivity, spectrometer and SEM/EDX data are examined to identify the oxidation transition border of the tested material. A temperature jump is observed in all active oxidation regimes. The experimental results are found to be in good agreement with correlations from the literature.
High conservative safety margins, applied to the design of spacecraft thermal protection systems ... more High conservative safety margins, applied to the design of spacecraft thermal protection systems for planetary entry, need to be reduced for higher efficiency of future space missions. Ground testing of such protection systems is of great importance during the design phase. This study covers a methodology for simulating the complex hypersonic entry aerothermochemistry in a plasma wind tunnel for a given spacecraft geometry without any assumption on axisymmetry or bluntness. A demonstration of this proposed methodology is made on the Qubesat for Aerothermodynamic Research and Measurements on AblatioN, QARMAN mission, which is a rectangular reentry CubeSat with a cork-based ablative thermal protection system in the front unit. The reacting boundary-layer profiles of the hypersonic entry probe compare well with the ones developing at the stagnation region of the plasma test model, defined with the proposed flight-to-ground duplication method.
The challenging physics of spacecraft atmospheric entry require detailed investigation for reduci... more The challenging physics of spacecraft atmospheric entry require detailed investigation for reducing the conservative safety margins taken for thermal protection system design. Very important research is conducted in ground test facilities and in this study, a method for accurate Flight-to-Ground Extrapolation is proposed for subsonic plasma wind tunnels. It is intended to make a full aerothermochemical duplication of the stagnation region in the ground facility of a spacecraft’s hypersonic atmospheric entry. The validation of the proposed methodology will be done by the atmospheric entry flight experiment QARMAN which will carry a number of aerothermodynamic in-flight experiments on board.
Increasing cost pressure on satellite builders and their suppliers push the motivation to open up... more Increasing cost pressure on satellite builders and their suppliers push the motivation to open up for new designs and processes. This paper investigates the applicability of thermoplastic additive manufacturing for mass production of satellites. First, the potential of the cost-effective 3D-printing material Polyamide 12 for space structures is examined. Tests include mechanical and thermal-vacuum properties. In the second step, a multifunctional technology demonstrator is designed and a first qualification test is performed. This demonstrator integrates electronic and thermal management components and shows considerable volume savings. Additionally, the automatable processes used for manufacturing enable further cost reductions in series production.
Spacecraft, returning back to Earth, experience a very harsh environment during the encounter wit... more Spacecraft, returning back to Earth, experience a very harsh environment during the encounter with the particles of the atmosphere. One of the major issues of the atmospheric entry is the extreme aerodynamic heating and the exothermic chemical reactions due to the gas-surface interaction at hypersonic free stream velocities. There is a constant effort by the space agencies to increase the understanding of the re-entry flight dynamics to optimize the spacecraft and especially its thermal protection system design. During the design process, ground tests and numerical tools are extensively used for their low cost and controlled environment abilities. However, real flight tests are indispensable for ground test and numerical tools validation. Due to high costs, such missions are rarely launched and thus there is an increasing interest in small affordable entry probes. Such platforms, once matured enough, may serve as an easily accessible tool to produce experimental data. It is the aim ...
The preliminary design of the QARMAN re-entry CubeSat developed by the von Karman Institute is pr... more The preliminary design of the QARMAN re-entry CubeSat developed by the von Karman Institute is presented in this paper from de-orbiting to payload choices. It represents an ideal cost-efficient platform for re-entry flight test and validation of thermal protection system (TPS) materials with a demonstration flight scheduled for June 2015. The CubeSat comprises a standard double-unit platform with sensors for atmospheric research and a functional unit for essential satellite operations. A third unit accommodating an ablative heat shield is added to protect the vehicle against the extreme aerothermal conditions of the re-entry. The challenging aspect of the project lies on the constraining mass and form factor from the CubeSat standard, 3kg and 34x10x10 cm 3. Finally, the preliminary design of the vehicle results in a payload of 400 g collecting data all along the re-entry trajectory including the maximal heat flux conditions.
Cork P50 thermal protection material was characterized under the Earth atmospheric entry conditio... more Cork P50 thermal protection material was characterized under the Earth atmospheric entry conditions in the framework of the in-flight experiment QARMAN. A total of 25 P50 samples were exposed to air plasma ranging the chamber static pressure values of 1500, 4100, 6180, and 20,000 Pa and heat fluxes between 280 and 3250 kW/m$$^2$$ 2 . The sample radius was also varied between 11 and 25 mm radius to investigate the effects of the stagnation line velocity gradient. The experimental results on heat flux, pressure, surface and in-depth temperatures, surface emissivity, swelling and recession rates, and computed boundary layer profiles as well as the mass blowing rates are presented. A material characterization data suite is also provided including thermogravimetric analysis, specific heat, and thermal conductivity. Overall, a wide range of experimental data of Cork P50 material in Earth atmospheric entry conditions is made available to modelers and engineers for improved material respons...
The extreme aerodynamic heating and the exothermic chemical reactions due to the gas-surface inte... more The extreme aerodynamic heating and the exothermic chemical reactions due to the gas-surface interaction at hypersonic free stream velocities make the thermal protection system design and testing a challenging process. The chemically reacting hypersonic flight regime cannot be fully duplicated in ground facilities and the design methodologies, experimental and numerical, have to be validated by real flight data which come with high costs. It is the objective of QARMAN CubeSat, QubeSat for Aerothermodynamic Research and Measurements on AblatioN, to perform an atmospheric entry experiment to Earth and collect real flight data for highly affordable costs. QARMAN is a spacecraft respecting the triple unit CubeSat standards; a rectangular prism with dimensions 34x10x10 cm (Figure 1). It has an ablative TPS in the front unit and a ceramic TPS on the side panels. It also has an aerodynamic de-orbiting system which will allow the vehicle to achieve the desired conditions for atmospheric ent...
To persist in the future of space business low cost satellites, which can be produced in high qua... more To persist in the future of space business low cost satellites, which can be produced in high quantities in less time, are mandatory. In the project IRAS (Integrated Research platform for Affordable Satellites), new technologies are investigated and developed to significantly lower the cost and production time for satellite components. To achieve this, additive manufacturing techniques using polymeric, metallic, and ceramic materials are combined with multifunctional and bionic structures, resulting in lightweight, cost-efficient and integrated structures. Advanced propulsion technologies are also considered within this project as well as the implementation of off-the shelf components from other sectors such as automotive electronics. In addition, a Digital Concurrent Engineering Platform (DCEP) is under development, enabling engineers to jointly develop satellites in a novel way without the need for physical proximity. This paper presents the concepts and current developments in th...
Dieser interne Bericht enthält die Aktivitäten des IRAS II-Projekts aller Partner, die vom Projek... more Dieser interne Bericht enthält die Aktivitäten des IRAS II-Projekts aller Partner, die vom Projektbeginn am 1.12.2018 bis zum Projektende am 31.5.2020 stattfanden
The passive/active oxidation behavior of a CVD-SiC coated C/C-SiC thermal protection material of ... more The passive/active oxidation behavior of a CVD-SiC coated C/C-SiC thermal protection material of the hypersonic SpaceLiner vehicle is investigated experimentally. For the safety of spacecraft and its passengers, it is important to know whether the thermal protection system will experience passive/active oxidation during the vehicle's entry into Earth's atmosphere. Active oxidation can promote material loss whereas passive oxidation forms a protective film. The high enthalpy flight conditions of SpaceLiner vehicle are duplicated in VKI Plasmatron, where the samples are exposed to high enthalpy plasma and the surface temperatures increase up to 2800 K at various total pressure (2-20 kPa) conditions. Surface temperature profiles, visual characteristics, mass changes, emissivity, spectrometer and SEM/EDX data are examined to identify the oxidation transition border of the tested material. A temperature jump is observed in all active oxidation regimes. The experimental results are found to be in good agreement with correlations from the literature.
High conservative safety margins, applied to the design of spacecraft thermal protection systems ... more High conservative safety margins, applied to the design of spacecraft thermal protection systems for planetary entry, need to be reduced for higher efficiency of future space missions. Ground testing of such protection systems is of great importance during the design phase. This study covers a methodology for simulating the complex hypersonic entry aerothermochemistry in a plasma wind tunnel for a given spacecraft geometry without any assumption on axisymmetry or bluntness. A demonstration of this proposed methodology is made on the Qubesat for Aerothermodynamic Research and Measurements on AblatioN, QARMAN mission, which is a rectangular reentry CubeSat with a cork-based ablative thermal protection system in the front unit. The reacting boundary-layer profiles of the hypersonic entry probe compare well with the ones developing at the stagnation region of the plasma test model, defined with the proposed flight-to-ground duplication method.
The challenging physics of spacecraft atmospheric entry require detailed investigation for reduci... more The challenging physics of spacecraft atmospheric entry require detailed investigation for reducing the conservative safety margins taken for thermal protection system design. Very important research is conducted in ground test facilities and in this study, a method for accurate Flight-to-Ground Extrapolation is proposed for subsonic plasma wind tunnels. It is intended to make a full aerothermochemical duplication of the stagnation region in the ground facility of a spacecraft’s hypersonic atmospheric entry. The validation of the proposed methodology will be done by the atmospheric entry flight experiment QARMAN which will carry a number of aerothermodynamic in-flight experiments on board.
Increasing cost pressure on satellite builders and their suppliers push the motivation to open up... more Increasing cost pressure on satellite builders and their suppliers push the motivation to open up for new designs and processes. This paper investigates the applicability of thermoplastic additive manufacturing for mass production of satellites. First, the potential of the cost-effective 3D-printing material Polyamide 12 for space structures is examined. Tests include mechanical and thermal-vacuum properties. In the second step, a multifunctional technology demonstrator is designed and a first qualification test is performed. This demonstrator integrates electronic and thermal management components and shows considerable volume savings. Additionally, the automatable processes used for manufacturing enable further cost reductions in series production.
Spacecraft, returning back to Earth, experience a very harsh environment during the encounter wit... more Spacecraft, returning back to Earth, experience a very harsh environment during the encounter with the particles of the atmosphere. One of the major issues of the atmospheric entry is the extreme aerodynamic heating and the exothermic chemical reactions due to the gas-surface interaction at hypersonic free stream velocities. There is a constant effort by the space agencies to increase the understanding of the re-entry flight dynamics to optimize the spacecraft and especially its thermal protection system design. During the design process, ground tests and numerical tools are extensively used for their low cost and controlled environment abilities. However, real flight tests are indispensable for ground test and numerical tools validation. Due to high costs, such missions are rarely launched and thus there is an increasing interest in small affordable entry probes. Such platforms, once matured enough, may serve as an easily accessible tool to produce experimental data. It is the aim ...
The preliminary design of the QARMAN re-entry CubeSat developed by the von Karman Institute is pr... more The preliminary design of the QARMAN re-entry CubeSat developed by the von Karman Institute is presented in this paper from de-orbiting to payload choices. It represents an ideal cost-efficient platform for re-entry flight test and validation of thermal protection system (TPS) materials with a demonstration flight scheduled for June 2015. The CubeSat comprises a standard double-unit platform with sensors for atmospheric research and a functional unit for essential satellite operations. A third unit accommodating an ablative heat shield is added to protect the vehicle against the extreme aerothermal conditions of the re-entry. The challenging aspect of the project lies on the constraining mass and form factor from the CubeSat standard, 3kg and 34x10x10 cm 3. Finally, the preliminary design of the vehicle results in a payload of 400 g collecting data all along the re-entry trajectory including the maximal heat flux conditions.
Cork P50 thermal protection material was characterized under the Earth atmospheric entry conditio... more Cork P50 thermal protection material was characterized under the Earth atmospheric entry conditions in the framework of the in-flight experiment QARMAN. A total of 25 P50 samples were exposed to air plasma ranging the chamber static pressure values of 1500, 4100, 6180, and 20,000 Pa and heat fluxes between 280 and 3250 kW/m$$^2$$ 2 . The sample radius was also varied between 11 and 25 mm radius to investigate the effects of the stagnation line velocity gradient. The experimental results on heat flux, pressure, surface and in-depth temperatures, surface emissivity, swelling and recession rates, and computed boundary layer profiles as well as the mass blowing rates are presented. A material characterization data suite is also provided including thermogravimetric analysis, specific heat, and thermal conductivity. Overall, a wide range of experimental data of Cork P50 material in Earth atmospheric entry conditions is made available to modelers and engineers for improved material respons...
Uploads
Papers by Isil Sakraker