A computer simulation of Skylab dynamics and attitude control for performance verification and operational support

A simulation of the Skylab attitude and pointing control system (APCS) is outlined and discussed. Implementation is via a large hybrid computer and includes those factors affecting system momentum management, propellant consumption, and overall vehicle performance. The important features of the flight system are discussed; the mathematical models necessary for this treatment are outlined; and the decisions involved in implementation are discussed. A brief summary of the goals and capabilities of this tool is also included

A model for the cost of doing a cost estimate

A model for estimating the cost required to do a cost estimate for Deep Space Network (DSN) projects that range from $0.1 to$100 million is presented. The cost of the cost estimate in thousands of dollars, C(sub E), is found to be approximately given by C(sub E) = K((C(sub p))(sup 0.35)) where C(sub p) is the cost of the project being estimated in millions of dollars and K is a constant depending on the accuracy of the estimate. For an order-of-magnitude estimate, K = 24; for a budget estimate, K = 60; and for a definitive estimate, K = 115. That is, for a specific project, the cost of doing a budget estimate is about 2.5 times as much as that for an order-of-magnitude estimate, and a definitive estimate costs about twice as much as a budget estimate. Use of this model should help provide the level of resources required for doing cost estimates and, as a result, provide insights towards more accurate estimates with less potential for cost overruns

Space shuttle: Heat transfer investigation of the McDonnell-Douglas delta wing orbiter at a nominal Mach number of 10.5

Heat transfer tests for the delta wing orbiter were conducted in a hypervelocity wind tunnel. A 1.1 percent scale model was tested at a Mach number of approximately 10.5 over an angle of attack range from 10 to 60 degrees over a length Reynolds number range from 5 times 10 to the 6th power to 24 times 10 to the 6th power. Heat transfer results were obtained from model surface heat gage measurements and thermographic phosphor paint. Limited pressure measurements were obtained

Spitzer IRS Spectra of Luminous 8 micron Sources in the Large Magellanic Cloud: Testing color-based classifications

We present archival Spitzer IRS spectra of 19 luminous 8 micron selected sources in the Large Magellanic Cloud (LMC). The object classes derived from these spectra and from an additional 24 spectra in the literature are compared with classifications based on 2MASS/MSX (J, H, K, and 8 micron) colors in order to test the "JHK8" classification scheme (Kastner et al. 2008). The IRS spectra confirm the classifications of 22 of the 31 sources that can be classified under the JHK8 system. The spectroscopic classification of 12 objects that were unclassifiable in the JHK8 scheme allow us to characterize regions of the color-color diagrams that previously lacked spectroscopic verification, enabling refinements to the JHK8 classification system. The results of these new classifications are consistent with previous results concerning the identification of the most infrared-luminous objects in the LMC. In particular, while the IRS spectra reveal several new examples of asymptotic giant branch (AGB) stars with O-rich envelopes, such objects are still far outnumbered by carbon stars (C-rich AGB stars). We show that Spitzer IRAC/MIPS color-color diagrams provide improved discrimination between red supergiants and oxygen-rich and carbon-rich asymptotic giant branch stars relative to those based on 2MASS/MSX colors. These diagrams will enable the most luminous IR sources in Local Group galaxies to be classified with high confidence based on their Spitzer colors. Such characterizations of stellar populations will continue to be possible during Spitzer's warm mission, through the use of IRAC [3.6]-[4.5] and 2MASS colors.Comment: 31 pages, 10 figures, to be published in A

Medicare Meets Mephistopheles: Health Care, Government Spending, and Economic Prosperity

This essay is an edited version of my remarks during the first panel of the Mississippi College Law Review’s symposium on health care reform, which was held on February 26, 2010, in Jackson, Mississippi. The essay integrates my prepared comments with my responses to comments and questions during the discussion period. I have also added some further thoughts on several of the issues that are relevant to the subject matter, especially in light of the subsequent passage of a major federal health reform bill. These remarks are necessarily brief, and they therefore can include only a hint of the issues that arise with respect to a subject as important as health care reform. These remarks do, however, provide an opportunity to describe some of the most important issues at stake in our continuing efforts to improve our health care system: the quality of care available, the number of people to whom care is provided, and the cost of providing that care. In future work, I will expand upon the ideas raised in this essay, focusing in particular on whether the 2010 health care law appears to be succeeding in reducing health care costs

Social Security is Fair to All Generations: Demystifying the Trust Fund, Solvency, and the Promise to Younger Americans

The Social Security system has come under attack for having illegitimately transferred wealth from younger generations to the Baby Boom generation. This claim is incorrect, because it fails to understand how the system was altered in order to force the Baby Boomers to finance their own benefits in retirement. Any challenges that Social Security now faces are not caused by the pay-as-you-go structure of the system but because of Baby Boomers’ other policy errors, especially the emergence of extreme economic inequality since 1980. Attempting to fix the wrong problem all but guarantees a solution that will make matters worse

\u27Generational Theft\u27? Even with Stimulus and Bailout Spending, U.S. Fiscal Policy Does Not Cheat Future Generations

Despite the oft-heard claims that current generations are stealing from future generations by running fiscal deficits, both theory and evidence suggest that this is either not true or not knowable. Intergenerational justice is not an appropriate lens through which to analyze fiscal issues, because there is no obvious starting point from which to build a moral consensus about whether current generations owe anything at all to future generations - and even if we do believe that we owe something to future generations, no one has offered a useful method by which we can determine whether we are doing enough for our progeny. Moreover, if we believe that future generations should be made better off than current generations ( I want my kids to be richer than I am. ), even pessimistic forecasts indicate that future generations will be much wealthier than current generations, meaning that we are already being quite generous to our children and grandchildren. In addition, the recent significant decline in our economic prospects does not argue for a more contractionary fiscal policy in light of concerns about future generations. In fact, when times are bad, there is no conflict between the interests of current and future generations. Spending by the government helps to improve the economy, which encourages businesses to invest in future productivity. This virtuous cycle is even stronger if the government\u27s spending is itself used to invest in future productivity

The Uses of the Concept of Efficiency in Tax Analysis

The flexibility and ubiquity of the term efficiency in tax analysis can be a double-edged sword. While tax scholars are naturally drawn to the notion of efficiency, with its implied virtues of eliminating waste and of guiding policy choices through objective, non-normative analysis, the danger exists that we can lose sight of which type of efficiency we are talking about when we invoke the concept. What one scholar calls efficient might be quite inefficient under the definition or perspective used by another scholar