Aerobraking automation options
This paper will summarize some recent work to automate most of the commanding intensive activities associated with aerobraking.
aerobraking↗
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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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A configuration for re-entry from mars missions using aerobraking.
Reentry vehicle configuration from manned Mars missions, using aerobraking
REENTRY VEHICLE↗
Aerobraking as a potential planetary capture mode.
Sequential approach to synthesize manned aerobraking spacecraft for missions to Mars and Venus, discussing mission profiles and requirements
Boobar, M. G.↗
Deceleration-control system for aerobraking and skipout to orbit at Mars.
Deceleration control system for aerobraking and skipout to orbit at Mars
Schy, A. A.↗
Deceleration control system for aerobraking and skipout to orbit at Mars.
Deceleration control system for aerobraking and skipout to orbit at Mars
Schy, A. A.↗
Ablative thermal protection for space tug multipass, aerobraking entry
Analytical studies had found the employment of an aerobraking trajectory for return of a reusable Space Tug from geosynchronous missions to be feasible and practical. To establish the minimum-weight ablative dome heat shield, trajectories involving 2 and 30 perigee passes were investigated both analytically and by plasma arc testing. Silicone-base ablators with densities of 15, 30, and 50 lb/cu ft were selected for evaluation. All models withstood the multipass exposures without deleterius surface recession or char erosion. Dome heat shield weights based on optimum ablative compositions indicated that ablators are a highly efficient thermal protection system for these missions.
Strauss, E. L.↗
Aerobraking and aerocapture for planetary missions
The paper examines the utilization of aerodynamic forces to capture a vehicle into a closed orbit and/or to modify an orbit. Attention is given to two techniques: aerobraking which uses drag during successive passes through the upper atmosphere to circularize a highly elliptical orbit, and aerocapture which transfers a vehicle into a closed stable orbit from a hyperbolic flyby trajectory. Sample missions employing both techniques are discussed.
French, J. R.↗
Meteorological accuracy requirements for aerobraking orbital transfer vehicles
Accuracy requirements for the prediction of atmospheric density for a transfer mission from geosynchronous orbit to low earth orbit using an aerobraking orbital transfer vehicle are presented. Uniform density variations such as would occur seasonally and diurnally were considered as well as density 'pockets' similar to what may have been observed on some of the Space Shuttle Orbiter entry flights. Variations in the lift-to-drag ratio from 0.3 to 1.5 were evaluated, with the values of the ratio of the vehicle weight to the product of the aerodynamic lift coefficient and the aerodynamic reference area ranging from 20 to 100 lb/sq ft. The results of the study indicated no problems for the range of lift-to-drag ratio values considered for uniform density variations of at least + or - 50 percent. However, density 'pockets' created problems if variations of + or - 30 percent from nominal occurred over altitude ranges of 1,000 to 10,000 ft.
Skalecki, L. M.↗
Numerical procedure for three-dimensional hypersonic viscous flow over aerobrake configuration
A numerical method, which is simpler and more efficient than others currently in use, is proposed for the computation of the full viscous flow over an aerobrake body in hypersonic stream at high altitude. It treats the shock layer surrounding the blunt forebody and the near wake behind the base simultaneously by formulating the Navier-Stokes equations in conformal and azimuthal-angle coordinates. The computational domain is confined by the body wall, outflow surface and the shock, which is adjusted along the coordinate normal to the wall in the course of iterations. Because of the optimal grid and a well developed alternating direction implicit factorization technique for the governing equations, reasonably accurate results can be obtained with a 28 x 36 x 7 grid and 400 time-marching iterations. Excellent agreement of shock location is found between the present result and the schlieren photograph. Details of the base flow and shear layer impingement on the cylindrical aft body are presented for an adiabatic wall case.
Li, C. P.↗
A lateral guidance algorithm to reduce the post-aerobraking burn requirements for a lift-modulated orbital transfer vehicle
A lateral guidance algorithm which controls the location of the line of intersection between the actual and desired orbital planes (the hinge line) is developed for the aerobraking phase of a lift-modulated orbital transfer vehicle. The on-board targeting algorithm associated with this lateral guidance algorithm is simple and concise which is very desirable since computation time and space are limited on an on-board flight computer. A variational equation which describes the movement of the hinge line is derived. Simple relationships between the plane error, the desired hinge line position, the position out-of-plane error, and the velocity out-of-plane error are found. A computer simulation is developed to test the lateral guidance algorithm for a variety of operating conditions. The algorithm does reduce the total burn magnitude needed to achieve the desired orbit by allowing the plane correction and perigee-raising burn to be combined in a single maneuver. The algorithm performs well under vacuum perigee dispersions, pot-hole density disturbance, and thick atmospheres. The results for many different operating conditions are presented.
Herman, G. C.↗
Computation of three-dimensional flow about aerobrake configurations
Ellipsoid, cone and cylinder aerobrake configurations are analyzed to provide comparison data between experimental and model predictions. An analytical model was devised to account for the shock layer ahead of the body and in the near-wake region in terms of the Navier-Stokes equations expressed in conformal polar and azimuthal-angle coordinates. Using polar coordinates simplified the equations by mapping the body onto a sphere, a procedure which also reduced the magnitude of the discretization errors. The equations are then solved using an alternating direction implicit (ADI) factorization technique. Computations were carried out for Mach 3-10 at various grid resolutions and compared with available wind tunnel data. The model generated pressure distributions, heat transfer coefficients and velocity profile data that agreed relatively well with experimental data at a reduced computational cost. Further work is necessary to identify the location of shocks and to model flows about asymmetric configurations.
Li, C. P.↗
Mars vehicle TCS and aerobrake TPS
General design approach, some problems and technology needs for a Mars vehicle manned module Thermal Control System (TCS) and aerobrake Thermal Protection System (TPS) are discussed. The design approach of the TCS will be similar to that of the space station. Mars atmospheric dust storms are identified as an unknown that will impact the design of the Mars landing vehicle and base facility. New technology may be needed for thermal control surfaces to functionally survive the dust storms. The TPS for the Mars aerocapture vehicle will be subject to marginal stagnation heating rates for conjunction class missions and very high heating rates for opposition class missions. New technology TPS materials or an ablative heat shield will be required for the high stagnation heating rate trajectories. No significantly new technology is needed for the manned modules that do not descent to the Mars surface.
Comer, G.↗
A survey of aerobraking orbital transfer vehicle design concepts
The five existing design concepts of the aerobraking orbital transfer vehicle (namely, the raked sphere-cone designs, conical lifting-brake, raked elliptic-cone, lifting-body, and ballute) are reviewed and critiqued. Historical backgrounds, and the geometrical, aerothermal, and operational features of these designs are reviewed first. Then, the technological requirements for the vehicle (namely, navigation, aerodynamic stability and control, afterbody flow impingement, nonequilibrium radiation, convective heat-transfer rates, mission abort and multiple atmospheric passes, transportation and construction, and the payload-to-vehicle weight requirements) are delineated by summarizing the recent advancements made on these issues. Each of the five designs are critiqued and rated on these issues. The highest and the lowest ratings are given to the raked sphere-cone and the ballute design, respectively.
Park, Chul↗
Chemical nonequilibrium and viscous flow computation for conic aerobrake bodies
Three-dimensional analyses are presented for the viscous, reactive flow over a complete entry-body configuration with a wide-angle conic surface. The predictive method uses a split approach that solves iteratively the Navier-Stokes and the continuity equations of chemical species. The finite-difference formulation and the computational grid are adapted to the bow shock and the conformally mapped body such that the velocity components are in the computational spherical-polar space. Combinations of several conic forebody and afterbody configurations have been studied using wind-tunnel, Space Shuttle, and aerobraking orbital transfer vehicle (AOTV) entry conditions. The effects of the borebody bluntness and of finite-rate chemical reactions on the shock layer, the wall catalycity on the boundary layer, the shear-layer impingement on the afterbody, and the base-flow environment are discussed.
Li, C. P.↗
Mechanistic model for catalytic recombination during aerobraking maneuvers
Several mechanistic models are developed to predict recombination coefficients for use in heat shield design for reusable surface insulation (RSI) on aerobraking vehicles such as space shuttles. The models are applied over a temperature range of 300 to 1800 K and a stagnation pressure range of 0 to 3,000 Pa. A four parameter model in temperature was found to work best; however, several models (including those with atom concentrations at the surface) were also investigated. Mechanistic models developed with atom concentration terms may be applicable when sufficient data becomes available. The requirement is shown for recombination experiments in the 300 to 1000 K and 1500 to 1850 K temperature range, with deliberate concentration variations.
Willey, Ronald J.↗
Heavily loaded joints for assembling aerobrake support trusses
The major emphasis was to develop erectable joints for large aerobrake support trusses. The truss joints must be able to withstand the large forces experienced by the truss during the aero-pass, as well as be easily assembled and disassembled on orbit by astronauts or robots. Other important design considerations include; strength, stiffness, and allowable error in strut length. Six mechanical joint designs, as well as a seventh joint design, where a high strength epoxy is injected to make the connection rigid, are presented.
Bandel, Hannskarl↗
Equilibrium radiative heating tables for aerobraking in the Martian atmosphere
Studies currently underway for Mars missions often envision the use of aerobraking for orbital capture at Mars. These missions generally involve blunt-nosed vehicles to dissipate the excess energy of the interplanetary transfer. Radiative heating may be of importance in these blunt-body flows because of the highly energetic shock layer around the blunt nose. In addition, the Martian atmosphere contains CO2, whose dissociation products are known to include strong radiators. An inviscid, equilibrium, stagnation point, radiation-coupled flow-field code has been developed for investigating blunt-body atmospheric entry. The method has been compared with ground-based and flight data for air, and reasonable agreement has been found. In the present work, the method was applied to a matrix of conditions in the Martian atmosphere. These conditions encompass most trajectories of interest for Mars exploration spacecraft. The predicted equilibrium radiative heating to the stagnation point of the vehicle is presented.
Hartung, Lin C.↗
A preliminary TPS design for MRSR - Aerobraking at Mars and at earth
An investigation was made to determine the feasibility of using an aerobrake system for an unmanned mission to Mars and for a return vehicle to earth. A preliminary thermal protection system (TPS) is examined for two small nose radius, straight biconic vehicles aerocapturing at Mars. The TPS for these vehicles, entering at 6 km/s and 8 km/s, are shown to have an advantage over a propulsive burn velocity reduction for orbit insertion. The TPS for each vehicle consisted of an ablator in the region of high heating, and reusable insulation over the rest of the structure. It was determined that a reusable TPS could be used over 98 percent of the aeroshell structure. Also presented is the preliminary TPS design for an Apollo-shaped vehicle aerocapturing at earth. As with the biconics, this vehicle had an ablator in the region of high heating, and reusable insulation on the aft conic section. In contrast to the vehicles aerocapturing at Mars, the ablator is used on 63 percent of the vehicle's aeroshell structure.
Williams, S. D.↗