Giuliano Marino

Numerical/Experimental Correlation of a Plasma Wind Tunnel Test on a UHTC-Made Nose Cap of a Reentry Vehicle

The nose cap demonstrator named Nose_2 has been tested for the second time in the plasma wind tunnel (PWT) facility which is part of the sharp hot structure (SHS) technology project, focused on the assessment of the applicability of ultrahigh temperature ceramics (UHTC) to the fabrication of high performance vehicles and SHS for reusable launch vehicles. In this paper the FEM based thermal analyses, carried out for the rebuilding of this PWT test, are presented. Experimental data measured in the PWT have been compared with numerical ones in order to validate the FEM model and to help in interpreting the experimental test itself. The knowledge on the physical phenomenon under investigation has been greatly improved, thanks to the synergy between numerical and experimental activities. In particular, a qualitative study of the modeling of the tip-dome interface has been performed in order to estimate the thermal contact resistance that heat flux encounters in passing through the demonstrator. The correlation...

PRORA-USV SHS: Ultra High Temperature Ceramic Materials for Sharp Hot Structures

The Italian Aerospace Research Centre (CIRA) is running the National Aerospace Research Program (PRO.R.A.) funded by the Italian Ministry of Education and Research. In this frame, the Space Program Office of CIRA is managing System and Technology activities finalized to the development of Flying Test Beds (FTB) aimed at the in flight experimentation to test new advanced technologies useful for the next generation of re-entry vehicles. This paper describes the work performed within the technology project named Sharp Hot Structures (SHS), that was started four years ago in support to the system activities related to the development of the orbital re-entry vehicle FTB-X whose first flight is currently scheduled for the year 2010. In order to provide new aerodynamic design criteria and improved manoeuvre capability to the experimental platform, SHS project was focused on the assessment of the applicability of Ultra High Temperature Ceramics (UHTC) to the fabrication of high performance and slender shaped hot structures for reusable launch vehicles. Fundamental technology advancements, progressively reached during the performed activity, will be summarized and critically analyzed. In particular the results of the design phase of two technology demonstrators (Nose_1 and Nose_2) of the nose cap of FTB-X will be shown and compared. Furthermore the paper describes the manufacturing process of the first concept of multi-material hot structure (Nose_1), that has been already built and is now ready to be tested in the CIRA Arc-Jet facility, SCIROCCO. Moreover, a report will be given concerning the on-ground plasma test of a preliminary scaled demonstrator, dubbed Nose_0, that was fabricated to assess the manufacturing technologies and tested to verify the thermal-oxidative stability of the interface between a C/SiC frame and a ZrB2 coating, under consistent heat flux conditions. Considering the specific typology of different materials investigated, up to date, an extensive tests campaign at laboratory level has been performed and concluded in order to create a complete materials data base. The measured materials properties have been then used, together with the aero-thermal loads associated with a reference re-entry mission, as input for the design phase. Our major preliminary findings indicate that the structure is thermally fully compliant with the environment requirements and shows local mechanical criticalities in specific areas such as the materials interfaces and hot/cold joining parts.

CIRA activities on UHTC's: on-ground and in flight experimentations

CIRA has been working since almost a decade on the possibility to use a new class of ceramic materials, the so called Ultra High Temperature Ceramics (UHTC’s), for space applications, and specifically for some critical parts of thermal protection systems.It is well known that sharp aerodynamic configurations could provide much more efficiency in “flying” during the re-entry phase of spacecrafts, and/or the hypersonic cruise of futuristic aerospace planes.However such innovation in the design criteria, implies a dramatic increase of the localized heat fluxes at the stagnation points of the leading edges of the aerodynamic surfaces that, as matter of fact, might then require dedicated thermal protection systems, able to sustain thermal loads much higher than those typically experienced by conventional materials applied on blunt bodies.In this perspective CIRA started its own investigations on the design methodology, characterization methods, manufacturing procedures, and qualification tests of medium size components based on exotic ceramic materials able to sustain temperatures even exceeding 2000°C.This paper summarizes CIRA experience achieved so far trough the test opportunities conducted on-ground in the SCIROCCO plasma wind tunnel, and in-flight onboard re-entry experimental platforms (SHARK, and EXPERT capsules).Then such conclusions related to the level of maturity (TRL), today reached by such materials and their structural parts, for the foreseen applications, will be critically analyzed and discussed.

EXPERT - The ESA Experimental Re-Entry Vehicle: Overview of the Experiments and Payloads qualified and accepted for the flight

The main objective of the EXPERT project is to collect in-flight data on the most critical ATD phenomena via dedicated classical and advanced flight test measurement assemblies categorized as Scientific Payloads. The scientific data will then to be used to validate state-ofthe-art numerical tools for aerothermodynamic applications and ground-to-flight extrapolation procedures. The EXPERT Payloads are developed to perform the selected aerothermodynamic experiments useful to improve the design capabilities with reference to full scale re-entry capsule, by means of measurement data that will be collected using dedicated devices. In the present paper we present an overview of all experiments and payloads as they have been designed, manufactured and qualified and actually ready for the flight.

SHARK: Flying a self-contained capsule with an UHTC- based experimental nose

SHARK (Sounding Hypersonic Atmospheric Re-entering ‘Kapsule’) is a small capsule designed and realized by CIRA. It was launched on March the 26th 2010 on board the European Space Agency sounding rocket MAXUS 8 flight. During the ascent parabola, the capsule was released and successfully executed its 15 minutes ballistic flight and then reentered in the atmosphere and landed. The aim of the project was to prove the possibility to set up a low cost experimental space platform and execute a re-entry test flight by dropping a capsule from a sounding rocket. Since CIRA is investigating new technologies for the re-entry and in particular new ceramic materials for sharp thermal protection systems (TPS), this flight opportunity has been chosen to test in a real flight an UHTC (Ultra High Temperature Ceramic) component, machined from scraps of previous ground tests executed in the Plasma Wind Tunnel SCIROCCO. The paper describes the mission genesis and development, the design and the subsystems of the capsule and then shows the first results from the preliminary analysis of the recorded data.

CIRA Experiments and Payloads flying on EXPERT - The ESA Experimental Re-Entry Vehicle.

The ESA European Space Agency is currently developing the project EXPERT – Experimental Re-entry Vehicle Test-bed. The EXPERT capsule features a generic simple shape and will perform a sub-orbital ballistic hypersonic flight; with a selection of major shape parameters to avoid any surface active oxidation, degradation and flow contamination. In the frame of Expert Project, CIRA has covered a double role: Payloads Coordinator with the main objectives to supervise all scientific aspects of embarked experiments, to coordinate all main and critical mechanical tests, to harmonize and optimize their integration on the EXPERT vehicle and their interfaces from mechanical, electrical and software point of view: and as Principal Investigator of 3 Payloads corresponding to the following experiments: a) Natural LTT Laminar-To-Turbulent Transition, b) SWBLI Shock Layer – Boundary layer Interaction ahead the ceramic flaps, c) Flying Winglet – UHTC Sharp Hot Structure “SHS”. In this paper a detailed overview of the designed experiment, correlation with the theoretical aspects, results of the on-ground qualification activities and expected results from the data collected in the coming flying mission are reported and discussed.