Mariner Mars 1969 navigation, guidance, and control

Design, mechanization, and flight tests for Mariner Mars 1969 navigation, guidance and control system

Guidance and control of the Mariner planetary spacecraft

Guidance and control of Mariner planetary spacecraf

Uncle Curro : J.R.R. Tolkien\u27s Spanish Connection (2018) by José Manuel Ferrández Bru

Book review, by Wayne G. Hammond and Christina Scull, of Uncle Curro: J.R.R. Tolkien\u27s Spanish Connection (2018) by José Manuel Ferrández Br

Shifting Trends in Special Education

In this Fordham Institute paper, analysts examine public data and find that the national proportion of students with disabilities peaked in 2004-05 and has been declining since. This overall trend masks interesting variations; for example, proportions of students with specific learning disabilities, mental retardation, and emotional disturbances have declined, while the proportions of students with autism, developmental delays, and other health impairments have increased notably. Meanwhile, at the state level, Rhode Island, New York, and Massachusetts have the highest rates of disability identification, while Texas, Idaho, and Colorado have the lowest. The ratio of special-education teachers and paraprofessionals to special-education students also varies widely from state to state -- so much so that our analysts question the accuracy of the data reported by states to the federal government

OMEGA navigation system status and future plans

OMEGA is described as a very low frequency (VLF) radio navigational system operating in the internationally allocated navigation band in the electromagentic spectrum between 10 and 14 kilohertz. Full system implementation with worldwide coverage from eight transmitting stations is planned for the latter 1970's. Experimental stations have operated since 1966 in support of system evaluation and test. These stations provided coverage over most of the North Atlantic, North American Continent, and eastern portions of the North Pacific. This coverage provided the fundamental basis for further development of the system and has been essential to the demonstrated feasibility of the one to two nautical mile root-mean-square system accuracy. OMEGA is available to users in all nations, both on ships and in aircraft