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An updated summary is presented of the lightning activity recorded at the John F. Kennedy Space Center and the Cape Kennedy Air Force Station. Data was compiled during the periods 1903 through 1924, 1957 through 1962, and 1964 through 1971.
The United States Air Force has published a document entitled Aircraft Structural Integrity Program. One phase of the program is concerned with the fatigue life certification of all types of military aircraft. The document describes the criteria, analyses, and tests that are necessary in order to satisfy the USAF fatigue life requirement. Some recent and valid criticism has been directed toward the document, particularly the fatigue-life requirements contained in it. Some changes are proposed based on surveys conducted in the United States and abroad as well as some recent systems' experience. The surveys covered both military and civilian organizations. The fatigue certification case histories of selected military and commercial aircraft are presented. The design development element tests, preproduction design verification tests, and full-scale fatigue tests of each are described. A brief status report on the revisions to the MIL-A-008860 series specifications is included.
The purpose of this study was to compare recent incidents involving disorientation in flight reported by 336 Air Force, Army, and Navy pilots with incidents reported by 137 pilots in 1956. The pilots reported their experiences using a check list and a written description of an experience with disorientation in the aircraft they were flying at the time. The latter included 40 incidents which occurred in support of operations in Vietnam. The reports of disorientation showed a striking similarity across types of aircraft flown over 14 years of flying, as well as with the incidents occurring in Vietnam. However, some variation in reports between aircraft types was noted. These reports of disorientation suggest that disorientation is currently experienced in a wide variety of flight operations and that it will continue to be experienced by aircraft pilots.
Based on the signal-to-noise ratio, modulation transfer function (MTF), and light transfer characteristics of the return-beam vidicon (RBV) multispectral three-camera subsystem, developed for use on earth resources technology satellites (ERTS), an analytical prediction of the resolvability of ground targets was made as a function of target size, contrast, spectral distribution, and radiance level. To determine whether the analysis was correct, U.S. Air Force targets with various contrasts were utilized to simulate those contrasts and radiance levels that the RBV cameras would see in the actual ERTS scenes. Although the RBV camera used in this test had a somewhat lower signal-to-noise ratio than the flight cameras, the simulation still proved the validity of the theoretical analysis in predicting resolving power performance for any set of input parameters.
The Delta-90 launch vehicle and the IMP-H spacecraft were successfully launched from Pad B, Complex 17, Cape Kennedy Air Force Station, Florida, at 2120:00.559 EDT on September 22, 1972. The countdown proceeded smoothly to liftoff with no major difficulties or unscheduled holds. The Delta-90/IMP-H were launched on a pad azimuth of 115 degrees, the vehicle ten rolled to 95 degrees from the north placing the spacecraft in a highly elliptical transfer orbit. Firing the spacecraft kickmotor at 1136 EDT, September 25, 1972, injected the spacecraft into its final desirable near-circular orbit approximately half way between the planet earth and its moon. Vehicle performance of all stages appeared nominal with all sequenced events occurring at the expected times. Data acquisition from all range stations was very good. Damage to the launch pad caused by liftoff was nominal.
The results are presented of tests conducted on a series of 13 foot rotors with various blade twists during the time period from 1969 to 1972. The tests were accomplished at AFAPL Wright-Patterson Air Force Base, Ohio and the ONERA 8-meter tunnel at Modane, France. Both static and cruise performance data are presented.
Titan/Centaur is NASA's last new expendable launch vehicle prior to the advent of the space shuttle. Titan/Centaur is an adaptation of the Air Force Titan 3 booster with an improved version of the Centaur stage and a new 4.2 meters payload fairing. Titan/Centaur is initially being used for high performance escape missions (Helios Solar Probe - 340 kilograms' Viking Mars Orbiter and Lander - 3,629 kilograms, and Mariner Jupiter/Saturn Fly-Bys at 771 kilograms, but is also particularly suited for larger spacecraft in synchronous orbits (transfer - 7,031 kilograms and equatorial, with three Centaur burns - 3,175 kilograms). The program which began in 1965 with internal NASA feasibility studies will culminate in a proof flight launch in early 1974. With the new payload fairing, which also encloses Centaur, payloads of nearly 8.5 meters long and 3.8 meters in diameter can be accommodated.
The tilt rotor underwent a hover performance test on the Aero Propulsion Laboratory whirl stand at Wright-Patterson Air Force Base. The maximum thrust over density ratio measured at the design tip speed of 740 feet per second was 10,016 pounds. This occurred when the power over density ratio was 1721 horsepower. At the hover overspeed rpm, the thrust and power, over density ratio, were 11,008 pounds and 1866 horsepower. During the test, the maximum measured thrust coefficient was 0.177, and the rotor figure of merit exceeded 0.81. Measured lifting efficiency was 8.35 pounds per horsepower at the thrust a 13,000-pound aircraft would require for hover at sea level on a standard day. No effect of compressibility on performance is discernible in the test results (the range of tip Mach numbers tested was 0.55 to 0.71).
Extreme atmospheres, pertaining to summer (hot) and winter (cold) conditions for Vandenberg Air Force Base, California, are presented from 0- to 90-km altitudes. Computed values of pressure, e, kinetic temperature, virtual temperature, density, and relative differences (percentages from Vandenberg Reference Atmosphere, 1971 (VRA 71)) of the atmospheric parameters versus altitude are tabulated in increments of 250 m. Hydrostatic and gas law equations were used in conjunction with radiosonde and rocketsonde thermodynamic data in determining the vertical structure of the two atmospheric models. The summer-type density profile deviated from -9.0 percent (of the VRA-71) at the ground to 28.4 percent at 74.5-km altitude. The winter density profile went from 5.2 percent at the surface to -31.4 percent at 72 km.
To investigate the effectiveness of fast-acting flaps as direct-lift-control (DLC) devices on a fighter airplane, the aileron servo systems of an F-100C variable-stability airplane were modified to provide symmetrical actuation of the surfaces. Initial flight tests using DLC indicated that the task of formation flying and, hence, in-flight refueling could be eased by actuating the DLC flaps through the conventional control stick, with the degree of improvement depending on the basic stability of the receiver aircraft. Results of refueling approaches and connections with U.S. Air Force tankers indicated a moderate overall improvement in vertical station-keeping performance (approximately 19 percent) and a sizeable overall decrease in receiver airplane motions and control activity (approximately 40 percent) with DLC.
The author has identified the following significant results. When comparing the ERTS-1 imagery with the United States Air Force Operational Navigation Chart, mapping errors were found in Baja California and in the coastal islands off mainland Mexico. One dramatic error noted was the Isla Tortuga which is located 9 to 9.5 km to the west of its photo location. One ERTS-1 photo shows the size of the four islands, Isla San Juanito, Isla Maria Madre, Isla Maria Magdalena, and Isla Maria Cleofas, to be much smaller than the ONC map depicts them. A prominent zone of structural and physiographic lineaments extending approximately from San Fernando, Los Angeles County towards the Oxnard area in Ventura County in an east-north-east trend were observed. In Ventura County several previously unknown faults within this zone were identified and their traces plotted on large scale maps and 1:60,000 aerial photographs. This important fault zone is significant because it trends parallel to and partly coincides with a recent belt of seismicity related to the San Fernando 1971 earthquake.
At the current state-of-technology there are many joining processes that can be used to make sound welds in TD-NiCr sheet. Some of these that are described in this report are electron beam welding (EBW), gas-tungsten arc welding (GTAW), diffusion welding (DFW), resistance spot welding (RSW), resistance seam welding (RSEW), and brazing. Roll welding (RW) and explosion welding (EXW) have not been developed to the point where they can be used to make sound welds in TD-NiCr. Joining work that has previously been done on TD-NiCr by various organizations, both privately supported and under Air Force and NASA contracts, is described in this summary. Current work is also described that is being done at General Dynamics/Convair (under NASA contract) and at NASA/Lewis to develop and evaluate DFW, RSW, RSEW, and brazing. Preliminary comparisons of joining processes are made for typical applications. A brief description of the manufacture of TD-NiCr sheet by a recently standardized process (under NASA contract) also is given.
Titan/Centaur is NASA's last 'new-expendable' launch vehicle prior to the advent of the Space Shuttle. Titan/Centaur is an adaptation of the Air Force Titan III booster with an improved version of the Centaur stage and a new 4.2-meter payload fairing. Titan/Centaur is initially being used for high performance escape missions (Helios Solar Probe - 340 kilograms, Viking Mars Orbiter and Lander - 3,629 kilograms, and Mariner Jupiter/Saturn Fly-Bys at 771 kilograms), but is also particularly suited for larger spacecraft in synchronous orbits (transfer - 7,031 kilograms and equatorial, with three Centaur burns - 3,175 kilograms). The program which began in 1965 with internal NASA feasibility studies will culminate in a 'proof flight' launch in early 1974. With the new payload fairing, which also encloses Centaur, payloads nearly 8.5 meters long and 3.8 meters in diameter can be accommodated.
The magnitude of physiologic changes which are known to occur in human subjects exposed to varying levels of + G sub Z acceleration following bed rest simulation of weightlessness was studied. Bed rest effects were documented by fluid and electrolyte balance studies, maximal exercise capability, 70 deg passive tilt and lower body negative pressure tests and the ability to endure randomly prescribed acceleration profiles of +2G sub Z, +3G sub Z, and +4G sub Z. Six healthy male volunteers were studied during two weeks of bed rest after adequate control observations, followed by two weeks of recovery, followed by a second two-week period of bed rest at which time an Air Force cutaway anti-G suit was used to determine its effectiveness as a countermeasure for observed cardiovascular changes during acceleration. Results showed uniform and significant changes in all measured parameters as a consequence of bed rest including a reduced ability to tolerate +G sub Z acceleration. The use of anti-G suits significantly improved subject tolerance to all G exposures and returned measured parameters such as heart rate and blood pressure towards or to pre-bed-rest (control) values in four of the six cases.
The computer programs are identified pertaining to planetary quarantine activities within the Project Engineering Division, both at the Air Force Eastern Test Range and on site at the Jet Propulsion Laboratory. A brief description of each program and program inputs are given and typical program outputs are shown.
Markov chain and Monte Carlo analysis techniques are applied to the simulated Space Shuttle Orbiter Ferry flights to obtain statistical distributions of flight time duration between Edwards Air Force Base and Kennedy Space Center. The two methods are compared, and are found to be in excellent agreement. The flights are subjected to certain operational and meteorological requirements, or constraints, which cause eastbound and westbound trips to yield different results. Persistence of events theory is applied to the occurrence of inclement conditions to find their effect upon the statistical flight time distribution. In a sensitivity test, some of the constraints are varied to observe the corresponding changes in the results.
The Nimbus 5 meteorological satellite carried aloft a full complement of radiation sensors, the data from which were analyzed and intercompared during orbits 569-570 on 22 January 1973. The electrically scanning microwave radiometer (ESMR) which sensed passive microwave radiation in the 19.35 GHz region, delineated rain areas over the ocean off the U.S. east coast, in good agreement with WSR-57 and FPS-77 radar imagery and permitted the estimation of rainfall rates in this region. Residual ground water in the lower Mississippi Valley, which resulted from abnormal rainfall in previous months, was indicated under clear sky conditions by soil brightness temperature values in the Nimbus 5 ESMR and U.S. Air Force Data Acquisition and Processing Program (DAPP) IR data. The temperature-humidity infrared radiometer showed the height and spatial configuration of frontal clouds along the east coast and outlined the confluence of a polar jet stream with a broad sub-tropical jet stream along the U.S. Gulf Coast. Temperature profiles from three vertical temperature sounders, the infrared temperature profile radiometer (ITPR), the Nimbus E microwave spectrometer (NEMS) and the selective chopper radiometer (SCR) were found to be in good agreement with related radiosonde ascents along orbit 569 from the sub-tropics to the Arctic Circle.
The application of active control technology to the suppression of flutter was successfully demonstrated during two recent studies in the Langley transonic dynamics tunnel. The first study involved the implementation of an aerodynamic-energy criterion, using both leading- and trailing-edge controls, to suppress flutter of a simplified delta-wing model. Use of this technique resulted in an increase in the flutter dynamic pressure of approximately 12 percent for this model at a Mach number of 0.9. Analytical methods used to predict the open- and closed-loop behavior of the model are also discussed. The second study, which is a joint effort with the Air Force Flight Dynamics Laboratory, was conducted to establish the effect of active flutter suppression on a model of the Boeing B-52 Configured Vehicle (CCV). Some preliminary results of this study indicate significant improvements in the damping associated with the critical flutter mode.