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Plasma Effect on Radiofrequency Communications for Lifting Reentry Vehicles
No full textThe present work investigates plasma effects around two lifting hypersonic vehicles and their implications on the
radiofrequency communication blackout performances during the Earth atmospheric reentry phase. In particular,
the Intermediate Experimental Vehicle developed by the European Space Agency and a slender, high lift-over-drag
space plane, investigated during previous studies, have been taken into account. Chemical nonequilibrium analyses
have been carried out by means of a numerical code, updated with a customized chemical model comprised of several
reacting species and different reaction mechanisms. Different flight conditions, including the most critical for
communications, have been considered for both vehicles. The main outcomes of the study show that, for very similar
freestream conditions, the slender space plane exhibits better communication capabilities when compared with the
Intermediate Experimental Vehicle. Particularly, the results suggest that the Intermediate Experimental Vehicle
would be able to communicate from the lee side for a limited range of the angle of sight, while no communications from
the wind side would be possible. On the other hand, for the slender space plane, flying at relatively low angles of attack,
communications are possible either from the lee side or the wind side with very wide angles of sight
Aerothermodynamic and feasibility study of a deployable aerobraking re-entry capsule
Full text linkA new small recoverable re-entry capsule with deployable heat shield is analyzed. The possible utilization of the capsule is for safe Earth return of science payloads or data from low Earth orbit at an inexpensive cost, taking advantage of its deployable structure to perform an aerobraking re-entry mission, with relatively low heat and mechanical loads. The system concept for the heat shield is based on umbrella-like frameworks and existing ceramic fabrics. An aerothermodynamic analysis is developed to show that the peak heat flux, for a capsule with a ballistic coefficient lower than 10 kg/m2, is in the range 250-350 kW/m2 and the corresponding surface temperatures are sustainable by off-the-shelf ceramic materials.
The article summarizes the main concept and the numerical predictions concerning the re-entry trajectories, the aero-thermal loads, the possibility to control the re-entry trajectory varying the capsule cross-sectional surface. Attention is focused on the effect of the material surface catalyticity on the surface heat flux, in presence of reacting gas mixtures formed behind the strong shock wave in front of the capsule
Hyplane: Challenges for Space Tourism and Business Transportation
No full textIn the present work a preliminary study on a small hypersonic airplane for a long duration space tourism mission is presented. It is also consistent with a point-to-point medium range (5000 km) hypersonic trip, in the frame of the ???urgent business travel??? market segment. Main idea is to transfer technological solutions developed for aeronautical and space atmospheric re-entry systems to the design of such a hypersonic airplane. A winged vehicle characterized by high aerodynamic efficiency and able to maneuver along the flight path, in all aerodynamic regimes encountered, is taken into consideration. Rocket-Based Combined Cycle and Turbine-Based Combined Cycle engines are investigated to ensure higher performances in terms of flight duration and range. Different flight-paths are also considered, including sub-orbital parabolic trajectories and steady state hypersonic cruise. The former, in particular, takes advance of the high aerodynamic efficiency during the unpowered phase, in combination with a periodic engine actuation, to guarantee a long duration oscillating flight path. These trajectories offer Space tourists the opportunity of extended missions, characterized by repeated periods of low-gravity at altitudes high enough to ensure a wide view of the Earth from Space
Experimental and numerical simulation, by an arc-jet facility, of hypersonic flow in Titan's atmosphere
No full textThis paper summarizes experimental and numerical results on high enthalpy hypersonic flows in nitrogen–methane mixtures. The experimental results have been obtained by the Small Planetary Entry Simulator (SPES), an arc-jet hypersonic wind tunnel in operation at the University of Naples “Federico II”. The facility has been used in the past to simulate entry conditions into Earth’s and Mars’ atmosphere and has recently been upgraded to simulate entry into Titan’s atmosphere. Numerical simulations of the flow field in the facility, for a nitrogen–methane mixture in chemical nonequilibrium have been performed. The chemical species and the heat flux distributions on a calorimeter located in the arc-jet test chamber have been computed.
The ability to perform a numerical rebuilding of the facility, by comparing numerical and experimental results has been investigated. The paper also highlights the importance of the wall catalyticity for the characterization of the thermal response of materials in high enthalpy flow
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