Surface roughness effects on the supersonic aerodynamics of the Rockwell International 089B-139 orbiter

An experimental test program was conducted to determine the effects of vehicle surface roughness on the supersonic aerodynamic characteristics of a 0.01875 scale model of a space shuttle configuration. Surface roughness was simulated by applying a sparse coating of carborundum grit to complete model. Various grit sizes were investigated. The tests were conducted in a wind tunnel at Mach numbers from 1.60 to 4.63. The angle of attack was varied from about -2 deg to as much as 42 deg at 0 deg and + or - 3 deg of sideslip. The angle of sideslip was varied from -8 deg to 8 deg at angles of attack from 0 deg to 40 deg

Low-subsonic aerodynamic characteristics of a shuttle-orbiter configuration designed for reduced length

An investigation has been made in a low-turbulence pressure tunnel to determine the low-subsonic aerodynamic characteristics of a 0.01875-scale model of a potential shuttle orbiter. The design has the rocket engines mounted in fairings on either side of the body on top of the wing. The wing had a leading-edge sweep of 50 and a trailing-edge sweep of minus 4. configurations investigated included engine-mounted twin dorsal tails at various rollout angles, a body-mounted center-line vertical tail, cylindrical and boattailed afterbody, and elevon and rudder at several deflections

Study of several factors affecting crew escape trajectories from the Space Shuttle Orbiter at low-subsonic speeds

Factors affecting the bailout characteristics from the space shuttle orbiter at low-subsonic speeds were investigated. In the 12-foot low-speed tunnel and the 4 by 7-meter tunnel with 0.03-scale models. The effect of crew-model exit velocity, body position, and body weight were studied with egress from the main side hatch with the orbiter upright and from the upper cabin hatch with the orbiter inverted. Crew model drag and flow field measurements around the orbiter were estimated. The high-angle-of-attack trim characteristics of the orbiter was determined by force tests in an attempt to improve bailout conditions. A computer simulation was made to evaluate the maneuver necessary to attain the high-angle-of-attack trim

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

Proximal Air-Fall Deposits of Eruptions Between May 24 and August 7, 1980 -- Stratigraphy and Field Sedimentology. U.S. Department of the Interior, Geological Survey

During each of the magmatic eruptions of Mount St. Helens on May 25, June 12, and August 7, a vertical eruptive column rose intermittently to altitudes of 12-15 km, from which pumice, lithic fragments, and crystals settled downwind in lobes that generally become thinner and finer away from the volcano. Each ejecta lobe is asymmetric according to several criteria, including (1) the axes of maximum thickness and of maximum pumice size are not midway between the two margins of the lobe, (2) the axis of maximum pumice size does not correspond to the axis of thickness, and (3) the median size of particles grades through several grain-size intervals from one lateral margin to the other. The fining in grain size across the lobe is due to the rotation of wind directions with altitude, so material falling from a high-level airborne plume is winnowed as it falls through transverse low-level winds. Wind directions that rotate clockwise with increasing altitude effect an air-fall lobe whose axis of maximum coarseness is clockwise of the axis of maximum thickness; wind directions that rotate counterclockwise with increasing altitude effect an air-fall lobe whose trend of maximum coarseness is counterclockwise of the axis of maximum thickness. The thickness of air-fall deposits from eruptions on May 25 through August 7 range variously from one-third to one-fortieth that of the May 18 air-fall deposit at a given distance from the volcano. The post-May 18 deposits are an order of magnitude thinner than Mount St. Helens pumice layer T (A.D. 1800) and two orders of magnitude thinner than Mount St. Helens pumice layer Yn (3400 yr B.P.), which is similar in thickness to the most voluminous air-fall deposits of other Cascade Range volcanoes. The maximum size of pumice within the May 18 air-fall lobe is 5-10 times that of the post-May 18 lobes. The overlapping air-fall lobes of May 25, June 12, July 22, and August 7 form a stratigraphic layer that in most places is indivisible into deposits of the separate eruptions

Searching for Radio Pulsars in 3EG Sources at Urumqi Observatory

Since mid-2005, a pulsar searching system has been operating at 18 cm on the 25-m radio telescope of Urumqi Observatory. Test observations on known pulsars show that the system can perform the intended task. The prospect of using this system to observe 3EG sources and other target searching tasks is discussed.Comment: a training project about MSc thesi

Areal Distribution, Thickness, Mass, Volume, and Grain Size of Air-Fall Ash from the Six Major Eruptions of 1980

The airborne-ash plume front from the Mount St. Helens eruption of May 18 advanced rapidly to the northeast at an average velocity of about 250 km/hr during the first 13 min after eruption. It then traveled to the east-northeast within a high-velocity wind layer at altitudes of 10-13 km at an average velocity of about 100 km/hr over the first 1,000 km. Beyond about 60 km, the thickest ash fall was east of the volcano in Washington, northern Idaho, and western Montana. A distal thickness maximum near Ritzville, Wash., is due to a combination of factors: (1) crude sorting within the vertical eruptive column, (2) eruption of finer ash above the high-velocity wind layer at altitudes of 10-13 km, and (3) settling of ash through and below that layer. Isopach maps for the May 25, June 12, August 7, and October 16-18 eruptions show distal thickness maximums similar to that of May 18. A four-unit tephra stratigraphy formed by the May 18 air fall within proximal areas east of the volcano changes to three units, two units, and one unit at progressively greater distances downwind. Much of the deposits beyond 200 km from the volcano has two units. A lower thin dark lithic ash is inferred to represent products that disintegrated from the volcano\u27s summit in the initial part of the eruption and early juvenile pumice and glass. An upper, thicker, light-gray ash rich in pumice and volcanic-glass shards represents the later voluminous eruption of juvenile magma. The axis of the dark-ash lobe in eastern Washington and norther Idaho is south of the axis of the light-gray ash lobe because the high-velocity wind layer shifted northward during the eruption. The areal distribution of ash on the ground is offset to the north relative to the mapped position of the airborne-ash plume, because the winds below the high-velocity wind layer were more northward. Except for the distal thickness near Ritzville, Wash., mass per area, thickness, and bulk density of the May 18 ash decrease downwind, because larger grains and heavier lithic and crystal grains settled out closer to the volcano than did the lighter pumice and glass shards. A minimum volume of 1.1 km3 of uncompacted tephra is estimated for the May 18 eruption; this volume is equivalent to about 0.20-0.25 km3 of solid rock, assuming an average density of between 2.0 and 2.6 g/cm3 for magma and summit rocks. The estimated total mass from the May 18 eruption is 4.9 x 1014 g, and the average uncompacted bulk density for downwind ash is 0.45 g/cm3. Masses and volumes for the May 24 and June 12 eruptions are an order of magnitude smaller than those of May 18, but average bulk densities are higher (about 1.00 and 1.25), owing to compaction by rain that fell during or shortly after the two eruptions. Volume and mass of the July 22 eruption are two orders of magnitude smaller than those of May 18, and those of the August 7 and October 16-18 eruptions are three orders of magnitude smaller. The eruption of May 18, however, is smaller than five of the last major eruptions of Mount St. Helens in terms of volume of air-fall tephra produced, but probably is intermediate if the directed-blast deposit is included with the air-fall tephra