Orbiter Entry Heating Lessons Learned from Development Flight Test Program

The Space Shuttle orbiter's thermal protection system (TPS), designed mainly on the basis of wind tunnel test data, has successfully completed its design, development, and flight test program. The flight test data provide an exceptional opportunity to evaluate the use of wind tunnel test data for the design of TPS for reentry vehicles. Comparisons of flight test data against wind tunnel data used to design the orbiter's TPS were developed. These flight data, though still in the preliminary analysis phases, generally support the use of wind tunnel test data in the design of TPS for hypersonic reentry vehicles

Space shuttle wing leading edge heating environment prediction derived from development flight data

An analytical program is in progress at Rockwell International to revise wing leading edge heating predictions in order to improve correlation with STS-1 to -5 flight radiometer data. This paper discusses the methods that have been used to improve agreement between prediction and flight and summarizes the aerodynamic correlations which, when updated, will be used to analyze future orbiter missions

Use of dose-dependent absorption into target tissues to more accurately predict cancer risk at low oral doses of hexavalent chromium

AbstractThe mouse dose at the lowest water concentration used in the National Toxicology Program hexavalent chromium (CrVI) drinking water study (NTP, 2008) is about 74,500 times higher than the approximate human dose corresponding to the 35-city geometric mean reported in EWG (2010) and over 1000 times higher than that based on the highest reported tap water concentration. With experimental and environmental doses differing greatly, it is a regulatory challenge to extrapolate high-dose results to environmental doses orders of magnitude lower in a meaningful and toxicologically predictive manner. This seems particularly true for the low-dose extrapolation of results for oral CrVI-induced carcinogenesis since dose-dependent differences in the dose fraction absorbed by mouse target tissues are apparent (Kirman et al., 2012). These data can be used for a straightforward adjustment of the USEPA (2010) draft oral slope factor (SFo) to be more predictive of risk at environmentally-relevant doses. More specifically, the evaluation of observed and modeled differences in the fraction of dose absorbed by target tissues at the point-of-departure for the draft SFo calculation versus lower doses suggests that the draft SFo be divided by a dose-specific adjustment factor of at least an order of magnitude to be less over-predictive of risk at more environmentally-relevant doses

The Improvement of Efficiency in the Numerical Computation of Orbit Trajectories

An analysis, system design, programming, and evaluation of results are described for numerical computation of orbit trajectories. Evaluation of generalized methods, interaction of different formulations for satellite motion, transformation of equations of motion and integrator loads, and development of efficient integrators are also considered

Ungulate Damage to Safflower in San Juan County, Utah

In Utah, farmers are concerned that ungulates are damaging safflower (Carthamus tinctorius) fields. I examined elk (Cervus elaphus) and mule deer (Odocoileus hemionus) damage to safflower production in San Juan County, Utah during 2009 and 2010. Data on damaged safflower plants were collected within 28 fields, totaling 1,581 ha (13 fields totaling 963 ha during 2009; 15 fields totaling 618 ha during 2010). I compared 3 methods to assess losses: ungulate-proof exclosures, adjacent plant compensation method, and counting the number of damaged plants in 50-m transects (safflower count method). Exclosures were of limited use because they could not be erected until farmers stopped using cultivating their fields. Hence, this method did not account for ungulate damage to young plants. The adjacent plant compensation method assessed yields within 1 m of a randomly-selected damaged plant to account for any compensatory growth of neighboring plants but this method proved inaccurate because ungulate herbivory was concentrated so that a browsed plant was often surrounded by other browsed plants so no compensatory growth by surrounding plants occurred. The most accurate method was the safflower count method which determined the number of damaged plants within a field and then multiplied this number by the decrease in yield from an average damaged plant. I used this method to examine 981,000 plants for damage. Deer and elk damaged or killed 7.2% of safflower plants during 2009 and 1.4% of plants during 2010. Overall yield reduction was 2.9% during 2009 and 0.6% in 2010. The total value of safflower loss within all surveyed fields in 2009 was $9,023 for a loss of$9.42 / ha. The loss of value within surveyed fields in 2010 was $2,330, or$3.77 / ha. The best model for predicting ungulate damage in 2009 included distance to canyon from field edge and the percent of a field bordered by a fallow field, while the best model for 2010 included distance to canyon from field edge and the percent of a field bordered by a wheat field. Safflower farmers were surveyed in the spring of 2010 to compare perceived losses in their fields during 2009 to those measured in this study. Farmers believed that damage by deer and elk reduced their yields by 20% with most damage caused by elk (x¯ =12% by elk, 7% by deer, 1% by other wildlife). On average, perceptions of damage were 5.2 times higher than the actual levels I measured during 2009. This was not surprising because farmers usually surveyed their field from the field’s edge and ungulate damage was concentrated along the edge of the fields

An Evaluation of Methods to Provide Financial Stability as a Person Ages

Interviews with financial planners, investment bankers, trust officers, and retired persons were conducted in order to make an evaluation of methods to provide financial stability as a person ages. Emphasis was made on Medigap and Long-Term Care Insurance Policies and investment of lump sum retirement distributions. The financial planners recommended that retired persons, not eligible for a continuation of employer health insurance, purchase Medigap or HMO coverage to supplement Medicare. The financial planners also recommended purchase of Long-Term Care Insurance. Information provided by investment bankers and trust officers indicated that retirement funds invested in Equity or Fixed Income Investments with minimum withdrawals will provide a lifetime income for retired persons. Interviews with retired persons confirm that they do have financial security because of taking minimum withdrawals from their accumulated assets and with the purchase of Medigap Insurance when there was no continuation of employer health insurance. Retired persons indicated a general lack of interest in L ong-Term Care Insurance except when peace of mind could not be achieved without it. The survey and other information provided prove the hypotheses that lifetime financial security is attainable

Soccer Fields and Submarines in Cuba: The Politics of Problem Definition

While Kissinger\u27s observation that Cubans did not play soccer in 1970 was incorrect, the inference that the Soviets were building some kind of naval facility at Cienfuegos, at least opening the possibility of another Cuban crisis, was on the mark. Yet this incident never grew into a full-blown episode in U.S. foreign policy, and no U.S. force was used. There are no great books about this incident, and there have previously been only a few scholarly articles about it

Seabird affinities for Gulf Stream frontal eddies: Responses of mobile marine consumers to episodic upwelling

This study combined ship-board counts of seabirds with satellite hydrography to determine whether Gulf Stream frontal eddies influenced spatial and seasonal patterns of apex consumers on the southeastern United States continental shelf and slope. Stratified sampling indicated seabird densities at eddies were 7–15 × higher than in resident shelf and Gulf Stream water, ranging from 2.31–10.91 birds km−2 compared to 0.15–1.51 birds km−2 in noneddy regions. At any given time eddies covered 3–17% of the outer shelf and upper slope, yet 28–59% of total seabird numbers in this domain aggregated within areas influenced by eddies.Gulf stream eddies consist of an upwelled, nutrient- and phytoplankton-rich cold-core and an oligotrophic warm filament entrained from the Gulf Stream. Seabird densities within eddy cold-cores were 4–21 × higher, ranging from 2.91–16.35 birds km−2 compared to 0.16–3.70 birds km−2 in the warm filament. Seabird abundances within eddy cold-cores were higher (a) near the frontal boundaries between water masses, and (b) within older upwelled (upstream) cold-core water as opposed to recently upwelled (downstream) cold-core water.Eddy size accounted for 99%, 94%, and 98%, respectively, of the between-eddy variation in seabird abundance, biomass, and minimum daily food requirements per unit area. Between-eddy differences in seabird density, biomass, and food requirements showed no relationship to eddy age.The frequency and the extent of satellite-detected, near-surface upwelling originating from eddies on the outer shelf and upper slope decreased during late summer and early fall. Total seabird density (pooled species\u27 abundances) showed no relationship to this seasonality. However, taxa that are particularly dependent on upwelling (Family Hydrobatidae: Oceanites and Oceanodroma) exhibited declines in abundance that correlated with seasonal decreases in near-surface upwelling. Seabird patchiness within the outer shelf and upper slope was greatest during months of frequent eddy upwelling, indicating that small-scale seabird distribution within domains may be affected by upwelling seasonality.Eddies influence seabird distribution and abundance at space scales of 10–50 and 50–150 km, and at time scales of 2–14 and 30–180 days. Seabird responses to environmental heterogeneity caused by eddies give strong circumstantial evidence for energy transfer beyond primary producers at these episodic upwelling features