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Gamble, J. D.

Publications and source records attributed to Gamble, J. D..

15 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Atmospheric guidance concepts for an aeroassist flight experiment

Three atmospheric guidance concepts proposed for an aeroassist flight experiment are presented. The flight experiment will simulate a return from geosynchronous orbit by an aeroassisted orbital transfer vehicle and is proposed to be flown on board the Space Shuttle in 1992. The three guidance concepts include an analytic predictor/corrector, a numeric predictor/corrector, and an energy controller. The algorithms for the three guidance methods are developed and performance results are presented for the nominal case and for several cases dispersed from the nominal conditions.

Gamble, J. D.↗
NASA NTRS1985

Design study of an integrated aerobraking orbital transfer vehicle

An aerobraking orbital transfer vehicle (AOTV) concept, which has an aerobrake structure that is integrated with the propulsion stage, is discussed. The concept vehicle is to be assembled in space and is space-based. The advantages of aeroassist over an all propulsive vehicle are discussed and it is shown that the vehicle considered is very competitive with inflatable and deployable concepts from mass and performance aspects. The aerobrake geometry is an ellipsoidally blunted, raked-off, elliptical wide-angle cone with a toroidal skirt. Propellant tanks, engines, and subsystems are integrated into a closed, isogrid aerobrake structure which provides rigidity. The vehicle has two side-firing, gimbaled RL-10 type engines and carries 38,000 kg of useable propellant. The trajectory during aerobraking is determined from an adaptive guidance logic, and the heating is determined from engineering correlations as well as 3-D Navier-Stokes solutions. The AOTV is capable of placing 13,500 kg payload into geosynchronous Earth orbit (GEO) or carrying a LEO-GEO-LEO round-trip payload of 7100 kg. A two-stage version considered for lunar missions results in a lunar surface delivery capability of 18,000 kg or a round-trip capability of 6800 kg with 3860 kg delivery-only capability.

Scott, C. D.↗
NASA NTRS1985

The aerodynamic challenges of the design and development of the space shuttle orbiter

The major aerodynamic design challenge at the beginning of the United States Space Transportation System (STS) research and development phase was to design a vehicle that would fly as a spacecraft during early entry and as an aircraft during the final phase of entry. The design was further complicated because the envisioned vehicle was statically unstable during a portion of the aircraft mode of operation. The second challenge was the development of preflight aerodynamic predictions with an accuracy consistent with conducting a manned flight on the initial orbital flight. A brief history of the early contractual studies is presented highlighting the technical results and management decisions influencing the aerodynamic challenges. The configuration evolution and the development of preflight aerodynamic predictions will be reviewed. The results from the first four test flights shows excellent agreement with the preflight aerodynamic predictions over the majority of the flight regimes. The only regimes showing significant disagreement is confined primarily to early entry, where prediction of the basic vehicle trim and the influence of the reaction control system jets on the flow field were found to be deficient. Postflight results are analyzed to explain these prediction deficiencies.

Young, J. C.↗
NASA NTRS1985

The development and application of aerodynamic uncertainties: And flight test verification for the space shuttle orbiter

The approach used in establishing the predicted aerodynamic uncertainties and the process used in applying these uncertainties during the design of the Orbiter flight control system and the entry trajectories are presented. The flight test program that was designed to verify the stability and control derivatives with a minimum of test flights is presented and a comparison of preflight predictions with preliminary flight test results is made. It is concluded that the approach used for the Orbiter is applicable to future programs where testing is limited due to time constraints or funding.

Gamble, J. D.↗
NASA NTRS1985

A simplified guidance algorithm for lifting aeroassist orbital transfer vehicles

The derivation, logic, and performance of a simplified atmospheric guidance algorithm for aeroassist orbital-transfer vehicles (AOTVs) are presented. The algorithm was developed to meet the demands for an aerobraking trajectory guidance technique that was uncomplicated, easily integrated into existing trajectory programs, adaptable to a range of vehicle aerodynamic configurations, capable of performance equivalent to currently available guidance programs in compensating for dispersions in entry conditions, atmospheric conditions, and aerodynamic characteristics. The result was a hybrid lifting guidance algorithm combining the method of reference-profile generation with the method of predictor/corrector schemes. The resulting performance is good (less than 3 n.m. error from desired apogee despite uncertainties of + or - 50 percent atmospheric density, + or - 0.2 deg entry flight-path angle, or + or - 50 percent L/D. Combinations of these same dispersions with lesser magnitudes have also been successful, although performance with density 'pockets' within the atmosphere requires more analysis.

Cerimele, C. J.↗
NASA NTRS1984

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.↗
NASA NTRS1984

Lateral directional requirements for a low L/D aeromaneuvering orbital transfer vehicle

The lateral-directional aerodynamics and control requirements for a low L/D (0.3) aeromaneuvering orbital transfer vehicle are evaluated. A lateral directional RCS control concept that permits a linearized analysis is utilized to evaluate the effect of Dutch Roll frequency and damping on the atmospheric guidance and control performance. The bank rate and acceleration requirements for acceptable performance are defined and the sensitivity to a parameter similar to the lateral control departure parameter but involving the RCS jets is evaluated.

Gamble, J. D.↗
NASA NTRS1983

The application of aerodynamic uncertainties in the design of the entry trajectory and flight control system of the space shuttle orbiter

The process used in the application of aerodynamic uncertainties for the design and verification of the Space Shuttle Orbiter Entry Flight Control System is presented. The uncertainties were used to help set center of gravity, angle of attack and dynamic pressure lateral control divergence parameter as well as C sub n sub beta dynamic were instrumental in setting these placards.

Gamble, J. D.↗
NASA NTRS1983

Aerobraking of a low L/D manned vehicle from Geo return to rendezvous with the Space Shuttle

The results of a study of the airbraking portion of the flight of an Apollo class vehicle designed for a sortie from the Orbiter to Geo and return to Leo for Orbiter retrieval are presented. An ablative heat shield would be used on the vehicle to shed velocity to speeds commensurate with Orbiter rendezvous. A reference design was selected for a spacecraft configuration with an L/D ratio of 0.3 and a weight to lift surface ratio of 236 lb/sq ft. Atmospheric guidance would consist of using the bank angle for altitude and inclination angle control and an equilibrium bank angle was defined. The vehicle would have a maximum temperature, considering a reference sphere, of 4800 F and a peak load of about 2 g. Atmospheric exit parameters were also determined, together with minimum delta-V for rendezvous.

Gamble, J. D.↗
NASA NTRS1982

The development and application of aerodynamic uncertainties in the design of the entry trajectory and flight control system of the Space Shuttle Orbiter

In connection with the decision to conduct with the Shuttle an orbital, manned mission on its first launch, certain problems arose related to mission safety, which had to be provided without the benefit of either a graduated flight test program or an initial unmanned flight concept. In an attempt to overcome these problems, the philosophy was adopted to provide a reasonable estimate of maximum possible errors in the preflight predicted aerodynamics. The flight control system (FCS) was to be certified on the basis of the estimated errors prior to STS-1. A set of 'worst case' aerodynamic uncertainties, defined as variations, was developed. As part of the first flight certification, variations, combined with other system uncertainties, were used to 'stress' the FCS through a multitude of simulations. Attention is given to an Orbiter description, the entry mission, the correlation of aerodynamic uncertainties, the application of aerodynamic variation in FCS and trajectory design, and the flight test results.

Gamble, J. D.↗
NASA NTRS1977

Transonic high Reynolds number stability and control characteristics of a 0.015-scale remotely controlled elevon model (44-0) of the space shuttle orbiter tested in calspan 8-foot TWT (LA70)

Transonic Wind Tunnel tests were run on a .015 scale model of the space shuttle orbiter vehicle in the 8-foot transonic wind tunnel. Purpose of the test program was to obtain basic shuttle aerodynamic data through a full range of elevon and aileron deflections, verification of data obtained at other facilities, and effects of Reynolds number. Tests were performed at Mach numbers from .35 to 1.20 and Reynolds numbers from 3,500,000 to 8,200,000 per foot. The high Reynolds number conditions (nominal 8,000,000/foot) were obtained using the ejector augmentation system. Angle of attack was varied from -2 to +20 degrees at sideslip angles of -2, 0, and +2 degrees. Sideslip was varied from -6 to +8 degrees at constant angles of attack from 0 to +20 degrees. Aileron settings were varied from -5 to +10 degrees at elevon deflections of -10, 0, and +10 degrees. Fixed aileron settings of 0 and 2 degrees in combination with various fixed elevon settings between -20 and +5 degrees were also run at varying angles of attack.

Parrell, H.↗
NASA NTRS1976

High supersonic stability and control characteristics of a 0.015-scale (remotely controlled elevon) model 49-0 of the space shuttle orbiter tested in the NASA/LaRC 4-foot UPWT (LEG 2) (LA63B)

The model tested was a Langley-built 0.015-scale SSV Orbiter model with remote independently operated left and right elevon surfaces. The objective of the test was to generate a detailed aerodynamic data base for the current Shuttle Orbiter Configuration. Special attention was directed to definition of nonlinear aerodynamic characteristics by taking data at small increments, angle of attack, angle of sideslip, and elevon position. Six-component aerodynamic force and moment and elevon position data were recorded over an angle-of-attack range from -4 deg to 45 deg, at angles of sideslip of 0 deg, + or - 2 deg, and + or - 4 deg. Additional tests were made over an angle of sideslip range from -6 deg to 8 deg at selected angles of attack. The test Mach numbers were 2.86, 3.90, and 4.60 with Reynolds number held at a constant two million per foot.

Gamble, J. D.↗
NASA NTRS1975

Transonic stability and control characteristics of a 0.015-scale (remotely controlled elevon) model 44-0 of the space shuttle orbiter tested in the NASA/LaRC 8 foot TPT (LA62)

The objective of the test was to generate a detailed aerodynamic data base which can be used to substantiate the aerodynamic design data book for the current shuttle orbiter configuration. Special attention was directed to definition of nonlinear aerodynamic characteristics by taking data at small increments in Mach number, angle of attack, and elevon position. Six-component aerodynamic force and moment and elevon position data were recorded over an angle-of-attack range from -4 deg to 20 deg, at angles of sideslip of 0 deg and 2 deg. The test Mach numbers were from 0.35 to 1.20. The Reynolds number for most of the test was held at a constant 3.5 million per foot.

Gamble, J. D.↗
NASA NTRS1975

Low supersonic stability and control characteristics of .015-scale (remotely controlled elevon) model 44-0 of space shuttle orbiter tests in NASA/LaRC 4-ft UPWT (leg 1) (LA63A)

A Langley-built 0.015-scale Space Shuttle Orbiter model with remote independently operated left and right elevon surfaces was tested. The objective of the test was to generate a detailed aerodynamic data base for the current shuttle orbiter configuration. Special attention was directed to definition of nonlinear aerodynamic characteristics by taking data at small increments in angle of attack, angle of sideslip, and elevon position. Six-component aerodynamic force and moment and elevon position data were recorded over an angle of attack range from -2 deg to 20 deg at angles of sideslip of 0 deg and plus or minus 2 deg. Additional tests were made over an angle of range from -6 deg to 8 deg at selected angles of attack. The test Mach numbers were 1.5 and 2.0 while the Reynolds number held at a constant two million per foot. Photographs of the test configuration are shown.

Gamble, J. D.↗