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Results for “Planetary Entry”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

The utilization of Shuttle launched vehicles for technical validation of advanced earth and planetary entry systems

Studies of future space missions have shown that transport vehicles which utilize passage (aeroassisted) through the atmosphere of the earth or an appropriate planet have a substantial payload advantage over earlier concepts which used retro propulsion to effect the transition to local orbit. A description is presented of aeroassisted concepts currently under consideration for application to NASA's advanced space entry missions. Proposed aeroassisted planetary orbit entry vehicles are considered, taking into account the aerobrake concept, the aerocapture concept, proposed aeroassisted earth orbit entry vehicles, the application of Shuttle launched research vehicles to aerobrake and aerocapture technology validation, Shuttle launched vehicle options, flight trajectory options, and trajectory termination options.

Jamison, C. C.↗
NASA NTRS2015

Feasibility of Dynamic Stability Measurements of Planetary Entry Capsules Using MSBS

The feasibility of conducting dynamic stability testing of planetary entry capsules at low supersonic Mach numbers using a Magnetic Suspension and Balance System (MSBS) is reviewed. The proposed approach would employ a spherical magnetic core, exert control in three degrees-of-freedom (i.e. x, y, z translations) and allow the model to freely rotate in pitch, yaw, and roll. A proof-of-concept system using an existing MSBS electromagnet array in a subsonic wind tunnel is described, with future potential for development of a new system for a supersonic wind tunnel.

Britcher, Colin↗
NASA NTRS2019

Plasma Science in Planetary Entry

Spacecraft entering a planetary atmosphere dissipate a great deal of energy into the surrounding gas. In the frame of reference of the vehicle, the atmospheric gas suddenly decelerates from hypersonic (Mach ~5-50) to subsonic velocities. The kinetic energy of the gas is rapidly converted to thermal and chemical energy, forming a bow shock behind which a plasma with energies on the order of one electron volt (eV) is produced. The resulting shock layer relaxes from strong thermal non-equilibrium that is translationally hot but internally cold and un-ionized toward a thermochemically equilibrated plasma over a distance of a few centimeters. Composition is dependent upon the planetary atmosphere – Air for Earth, CO2/N2 for Mars and Venus, N2/CH4 for Titan and H2/He/CH4 for Saturn, Neptune and Jupiter. Typical velocities of entry may range from 3-7 km/s (4-25 MJ/kg) for Titan/Mars, 8-14 km/s (30-100 MJ/kg) for Earth/Venus, and 25-40 km/s (300-800 MJ/kg) for outer planets. The equilibrium plasmas produced from these conditions are highly dissociated (up to and above 99%) and ionized (0.1- 15%), with temperatures from 7,000-15,000K and pressures from 0.1-1.0 bar. Understanding the behavior of these plasmas – the way in which they approach equilibrium, how they radiate, and how they interact with materials – is an active area of research necessitated by requirements to predict and test the performance of thermal protection systems (TPS) that enable spacecraft to deliver scientific instruments, and people, to foreign worlds and back to Earth. The endeavor is a multi-physics problem, with key processes highlighted in Fig. 1. This white paper describes the current state of the art in simulating shock layer plasmas both computationally and in ground test facilities. Gaps requiring further research and development are identified.

Cruden, Brett A.↗
NASA NTRS1975

Shuttle launched flight tests - Supporting technology for planetary entry missions

The feasibility of conducting Space Shuttle-launched earth entry flight tests to enhance the technology base for second generation planetary entry missions is examined. Outer planet entry environments are reviewed, translated into earth entry requirements and used to establish entry test system design and cost characteristics. Entry speeds up to those needed to simulate radiative heating levels of more than 30 kW/sq cm are shown to be possible. A standardized recoverable test bed concept is described that is capable of accommodating a wide range of entry technology experiments. The economic advantage of shared Shuttle launches are shown to be achievable through a test system configured to the volume constraints of a single Spacelab pallet using existing propulsion components.

Vetter, H. C.↗
NASA NTRS1971

Vibration characteristics of Z-ring-stiffened 60 deg conical shell models of a planetary entry spacecraft

An experimental investigation of the vibration characteristics of a 60 deg conical shell model of a planetary entry vehicle is described and the results presented. Model configurations include the shell with or without one or two Z-ring stiffeners and with or without a simulated payload. Tests were conducted with the model clamped at the small diameter and with the model suspended at the simulated payload. Additionally, calculated results obtained from application of several analytical procedures reported in the literature are presented together with comparisons between experimental and calculated frequencies and meridional mode shapes. Generally, very good frequency agreement between experimental and calculated results was obtained for all model configurations. For small values of circumferential mode number, however, the frequency agreement decreased as the number of ring stiffeners increased. Overall agreement between experimental and calculated mode shapes was generally good. The calculated modes usually showed much larger curvatures in the vicinity of the rings than were observed in the experimentally measured mode shapes. Dual resonances associated with modal preference were noted for the shell without Z-ring stiffeners, whereas the addition of stiffeners produced resonances for which the model responded in two or more modes over different sections of the shell length.

Naumann, E. C.↗