[Studies in the 11 Meter Range of Radio Astronomy Using High Resolution and High Sensitivity Antenna Arrays at Clark Lake]

Interplanetary scintillation observations from solar wind inhomogeneitie

The Johnson Space Center management information systems: User's guide to JSCMIS

The Johnson Space Center Management Information System (JSCMIS) is an interface to computer data bases at the NASA Johnson Space Center which allows an authorized user to browse and retrieve information from a variety of sources with minimum effort. The User's Guide to JSCMIS is the supplement to the JSCMIS Research Report which details the objectives, the architecture, and implementation of the interface. It is a tutorial on how to use the interface and a reference for details about it. The guide is structured like an extended JSCMIS session, describing all of the interface features and how to use them. It also contains an appendix with each of the standard FORMATs currently included in the interface. Users may review them to decide which FORMAT most suits their needs

Observations of an increase in the flux from Tau A during occultation by the solar corona

Flux increase from Tau A during solar corona occultatio

Radio interference in the near-earth environment

Natural and man-made radio frequency interference (RFI) are potentially serious obstacles to the successful operation of an array of spacecraft used for low frequency (1 to 30 MHz) radio interferometry in the near-earth environment. Several satellites and planetary probes have carried radio astronomy experiments, and the moderate data base that they provide are examined to help understand the near-earth RFI environment. The general conclusion is that the region of space within 100 earth-radii of the earth is a hostile environment for any radio astronomy experiment. If a low frequency array in earth orbit is to yield useful astronomical results, severe interference problems must be anticipated and overcome. A number of recommendations are made to further examine the feasibility of such an array

Characteristics or Incentives: Why Do Employment Outcomes for the SSA Beneficiary Clients of VR Agencies Differ, on Average, from Those of Other Clients?

This report uses data from the Longitudinal Study of Vocational Rehabilitation Services Programs to compare employment outcomes of state vocational rehabilitation (VR) agency clients who receive Social Security Disability Insurance (DI) or Supplemental Security Income (SSI) -- “beneficiary clients” -- to those of non-beneficiary clients, before and after controlling for detailed information on disability and other characteristics that are likely to affect outcomes. Differences are substantial. Characteristics do explain a substantial share of the differences, but substantial differences remain. For instance, we estimate that only 23 percent of beneficiaries who received services achieved earnings above $500 per month for at least 9 months out of a 15-month period, compared to 54 percent of non-beneficiaries – a 30 percentage point difference. After controlling for other characteristics, the difference is 17 percentage points. One likely explanation for a substantial portion of the remaining difference is work disincentives faced by beneficiary clients. During this period, SSI recipients lost 50 cents in benefits for every dollar earned above certain disregards, and SSDI beneficiaries lost all benefits if they earned more than$500 per month, again net of certain disregards, for more than nine months

Agricultural Household Hedging With Off-Farm Income

Agricultural Finance, Risk and Uncertainty,

Orbit transfer rocket engine technology program. Phase 2: Advanced engine study

In Phase 2 of the Advanced Engine Study, the Failure Modes and Effects Analysis (FMEA) maintenance-driven engine design, preliminary maintenance plan, and concept for space operable disconnects generated in Phase 1 were further developed. Based on the results of the vehicle contractors Orbit Transfer Vehicle (OTV) Concept Definition and System Analysis Phase A studies, minor revisions to the engine design were made. Additional refinements in the engine design were identified through further engine concept studies. These included an updated engine balance incorporating experimental heat transfer data from the Enhanced Heat Load Thrust Chamber Study and a Rao optimum nozzle contour. The preliminary maintenance plan of Phase 1 was further developed through additional studies. These included a compilation of critical component lives and life limiters and a review of the Space Shuttle Main Engine (SSME) operations and maintenance manual in order to begin outlining the overall maintenance procedures for the Orbit Transfer Vehicle Engine and identifying technology requirements for streamlining space-based operations. Phase 2 efforts also provided further definition to the advanced fluid coupling devices including the selection and preliminary design of a preferred concept and a preliminary test plan for its further development

Long wavelength investigations of solar, planetary, and galaxy emissions Final report, May 1 - Sep. 30, 1964

Feasibility of constructing large antenna array and interferometer for radio astronomy studies and spectral observations of discrete sources, sun, and Galax

Solar emission levels at low radio frequencies

Solar radio emission could seriously interfere with observations made by a low frequency (1 to 10 MHz) array in space. International Sun-Earth Explorer (ISEE-3) radio data were used to determine solar emission level. The results indicate that solar emission should seriously disturb less than ten percent of the data, even during the years of solar maximum. Thus it appears that solar emission should not cause a disastrous loss of data. The information needed to design procedures to excise solar interference from the data produced by any low-frequency array is provided