Relative desirability of leisure activities and work parameters in a simulation of isolated work stations

The kinds of activities that are attractive to man in long duration isolation are delineated considering meaningful work as major activity and a choice of leisure/living provisions. The dependent variables are the relative distribution between various work, leisure, and living activities where external constraints on the subject's freedom of choice are minimized. Results indicate that an average of at least five hours per day of significant meaningful work is required for satisfactory enjoyment of the situation; most other parameters of the situation have less effects on overall performance and satisfactio

Modeling Axisymmetric Optical Precision Piezoelectric Membranes

The US Department of Defense (DOD), as well as the National Aeronautics and Astronautics Administration (NASA) and the Jet Propulsion Laboratory (JPL) are interested in developing and deploying precise, compliant, light-weight, space-based structures. More specifically, the Air Force’s core competencies ‘Aerospace Superiority’ and ‘Information Superiority’ demand ever-increasing depth and breadth of capability. Whether used for energy transmission or optical reconnaissance, current launch restraints limit rigid space-based optical reflector size. To support this requirement, the Air Force Research Laboratory (AFRL) is developing a large space-based optical membrane telescope. Inflatable reflectors can conceptually break this barrier, but controlling such a compliant structure presents significant problems. While inflatable technology is flight proven, the ability to control the shape of a flexible space structure to optical precision has yet to be demonstrated. A laminate of piezoelectric polymer material can deform a membrane optical surface; however, modeling this system must be improved. Analytic solutions to the beam and axisymmetric membrane models are produced providing insight into resulting behavior of these materials. Based on these results a new mathematical methodology rooted in fundamental perturbation techniques was developed: The Method of Integral Multiple Scales (MIMS). MIMS allows selectable precision when applied to a special class of dynamic systems which can be represented through a Lagrangian. This new method was first applied to a relatively simple linear beam problem for the purpose of illustration. The method is able to integrate spatial and temporal multiple scales directly producing boundary layer solutions. This method is fully realized through the finite element approach, where the solution was shown to be over three orders of magnitude more accurate than a standard finite element result. The finite element methodology is applied to nonlinear beam and axisymmetric circular membrane models producing insight for future design decisions. The results illustrate the capability of such an active membrane to modify a reflected wavefront and provide control for an inflatable optical reflector

George to Jim, 26 February 1963

Personal correspondenc

George to Jim and Dutch, 26 December 1961

Personal correspondenc

Subscale, hydrogen-burning, airframe-integrated-scramjet: Experimental and theoretical evaluation of a water cooled strut airframe-integrated-scramjet: Experimental leading edge

A water-cooled leading-edge design for an engine/airframe integrated scramjet model strut leading edge was evaluated. The cooling design employs a copper cooling tube brazed just downstream of the leading edge of a wedge-shaped strut which is constructed of oxygen-free copper. The survival of the strut leading edge during a series of tests at stagnation point heating rates confirms the practicality of the cooling design. A finite difference thermal model of the strut was also proven valid by the reasonable agreement of calculated and measured values of surface temperature and cooling-water heat transfer

Rocketborne Measurement of Mesospheric H2O in the Auroral Zone

Infrared emission spectra of the longwavelengtwhi ngo f the 6.3 • waterb andb etween6 .7 and 7.6 yxa have been measured in the mesosphere using a cryogenic rocketborne spectrometerø The resulting zenith radiance profile has been compared with a high altitude radiance model resulting in a volumem ixingra tioo f 3ø5 -+ 2.2 ppmb etwee4n9 and 70 k

Valuing Rigor in the Risk Management Process

NASA, as an organization, takes risk management (RM) seriously, and for most projects, the risk management process is exemplar. There can be challenges, though, with defining RM processes. For example, many different risk analysis methodologies are available, they can be applied with varying degrees of rigor, and they can have different value depending on how projects use them. In particular, risk analysis methodologies vary considerably in the level of quantitative detail, with more probabilistic techniques encouraged in some situations. We discussed these processes and methodologies with ten project managers (PM) at the NASA Goddard Space Flight Center (GSFC). Our intent was not to prove with some level of statistical significance that some are more helpful than others, but rather to obtain a general understanding of how projects are identifying, and thinking, about risks. This paper describes some of the available risk processes and methodologies, and provides some insights about the benefits that can gained from their use. We provide an in-depth discussion of one quantitative methodology, Probabilistic Risk Assessments (PRAs), and conclude with a few insights from observed best practices