Reusable Structures for CALLISTO

In order to make access to space more affordable for both scientific and commercial activities the German Aerospace Center (DLR), the Japanese Aerospace Exploration Agency (JAXA), and the French National Centre for Space Studies (CNES) joined in a trilateral agreement to develop and demonstrate the technologies that will be needed for future reusable launch vehicles. In the joined project CALLISTO (Cooperative Action Leading to Launcher Innovation in Stage Toss back Operations) a demonstrator for a reusable vertical take-off, vertical landing rocket, acting as first stage, is developed and built. As long-term objective this project aims at paving the way to develop a rocket that can be fully reused, and the joint efforts of the three agencies will culminate in a demonstrator that will perform its first flights from the Kourou Space Center, in French Guyana. Having regard to the aspect of reusable structures, the development of design represents a special challenge since the components have to withstand a variety of complex manoeuvres for multiple times. Additionally, this technical complexity leads to limitations in size and mass which must be observed during the design process. The structures have to be studied very individually to meet all the requirements for reaching optimal performance during ascent, return and landing. This paper focuses on the design solutions for CALLISTO’s fairing, the aerodynamic surfaces and the approach & landing system with respect to their specific sizing load case during the mission. The challenging concept of deployable aerodynamic surfaces is especially highlighted as the deployment causes a significant transformation of the vehicles outer shape and consequently has direct impact on the trajectory. This also applies to the stowable landing gear that has been one main design challenge in the frame of CALLISTO

The SHEFEXII Thermal Protection System

The SHEFEXII payload tip is ready for flight. Within a period of three years, the experiment has been designed, laid out, parts have been manufactured, mounted and instrumented for the upcoming flight in autumn 2011. The present paper gives an overview over the thermal protection system (TPS) of the SHEFEXII vehicle including the TPS-material, the overall TPS-setup, and detailed informations on the faceted thermal protection including the gap seal, the sharp leading edge, the transpiration-cooling experiment AKTIV, and the aerodynamic control surfaces, i.e. canards

SCRAMSPACE Fins Definition

Beschreibung der Lasten, Materialauswahl, Konstruktion und Auslegung der für den australischen Hyperschall-Flugkörper SCRAMSPACE zu erstellenden Stabilisierungsfinnen

FinEx – Fin Experiment on HIFiRE-5

A set of four ceramic fins will fly as a passenger experiment onboard the american-australian hypersonic vehicle HIFiRE-5. The paper describes their lay-out and design. They consist of C/C-SiC and are mounted to the rocket by aluminum fin shoes. With a total of eight implanted thermocouples, the fins serve to determine three-dimensional heat flux to the CMC fins on the basis of a non-integer system identification approach. Both, the approach and the calibration procedure are described. It is, moreover, demonstrated that the fins are ready for flight

Thermophysical properties of 2008 TC3-derived meteorites for high-fidelity entry modeling

Asteroid 2008 TC3 was characterized in a unique manner prior to impacting Earth's atmosphere, making its October 7, 2008, impact a suitable field test for or validating the application of high-fidelity re-entry modeling to asteroid entry. The accurate modeling of the behavior of 2008 TC3 during its entry in Earth's atmosphere requires detailed information about the thermophysical properties of the asteroid's meteoritic materials at temperatures ranging from room temperature up to the point of ablation (T ~ 1400 K). Here, we present measurements of the thermophysical properties up to these temperatures (in a 1 atm. pressure of argon) for two samples of the Almahata Sitta meteorites from asteroid 2008 TC3: a thick flat-faced ureilite suitably shaped for emissivity measurements and a thin flat-faced EL6 enstatite chondrite suitable for diffusivity measurements. Heat capacity was determined from the elemental composition and density from a 3-D laser scan of the sample. We find that the thermal conductivity of the enstatite chondrite material decreases more gradually as a function of temperature than expected, while the emissivity of the ureilitic material decreases at a rate of 9.5 × 10−5 K−1 above 770 K. The entry scenario is the result of the actual flight path being the boundary to the load the meteorite will be affected with when entering. An accurate heat load prediction depends on the thermophysical properties. Finally, based on these data, the breakup can be calculated accurately leading to a risk assessment for ground damage

Development of CMC Combustion Chambers for Advanced Propellants in Space Propulsion

In the DLR project "Future Fuels", combustion chamber structures made of lightweight and high temperature stable ceramic matrix composites were in the focus of the development. In a first step, C/C-SiC tubes manufactured via the liquid silicon infiltration process and based on three different carbon fibre types and two different production methods for the CFRP preforms, were characterized. In biaxial pressure tests, all the different tubes could withstand the required inner pressure of 60 bar. Highest fracture strength was obtained with wet filament wound tubes based on ultra-high-modulus fibres, whereas tubes manufactured via prepreg wrapping using high tenacity fibre fabrics, offered a cost-effective alternative

REX-Free Flyer: Re-Entry to Earth Experiment - Machbarkeitsstudie

Ziel der Machbarkeitsstudie war, ein System REX-Free Flyer zu entwerfen, welches dem gegenwärtigen Bedarf an Forschungs-möglichkeiten für Forschung unter Weltraum-bedingungen gerecht wird. Ein möglicher Nutzer braucht heutzutage eine Plattform, die einen schnellen Zugang zu vergleichsweise sehr guten μg-Eigenschaften bei gleichzeitiger Rückführbarkeit erlaubt. Im Rahmen dieser Machbarkeitsstudie wurde ausgehend von einem Anforderungsprofil dazu zunächst eine Geometrie definiert, die die Missionsziele unter aerodynamischen Gesichtspunkten erfüllt. Das resultierende Fahrzeug hat die Dimensionen L= 3,36 m, B= 2,10 m und H= 0,72 m mit einer Schwerpunktlage bei 62% der Fahrzeuglänge und ist in Bild 20 dargestellt. Mit dieser Geometrie wurde anschließend anhand einer Bahnanalyse gekoppelt mit aerothermodynamischen Betrachtungen gezeigt, dass ein Kompromiss zwischen der Reichweite und der thermomechanischen Belastung der Fahrzeugwand geschlossen werden kann. Für eine kritischere Trajektorie werden hierbei für eine strahlungsadiabate Wandtemperatur an der Spitze und den Steuerklappen bis zu 2400 K vorhergesagt. Anhand der thermomechanischen Belastung, die aus dieser Untersuchung hervorgehen, wurde schließlich eine Struktur entworfen. Die berechneten Hitzeschilddicken ergeben eine Trägerstrukturmasse ohne Subsysteme von cirka 500 kg. Die durchgeführte Machbarkeitsstudie zeigt, dass die angeforderten Ziele auf Basis der im SHEFEX-Programm bereits erarbeiteten neuen Technologien erreicht werden können - der REX-Free Flyer also machbar ist