Regan, Curtis R. | Engineering Papers

NASA NTRS2019

Virtual Stationary Satellites over Any Area of the Earth for a Continuous or Set Amount of Time

Various embodiments may provide systems and methods for achieving continuous measurements (e.g., continuous video images) of the same spot on the Earth using Low Earth Orbit (LEO) satellite constellations and/or Middle Earth Orbit (MEO) satellite constellations. Various embodiments may provide a system of Virtual Low Earth Orbit (LEO) Stationary Satellites (VLSSs) over any area of the Earth for a continuous or a periodic amount of time.

Regan, Curtis R.↗

NASA NTRS1998

High Displacement Solid State Ferroelectric Loudspeaker

A piezoelectric loudspeaker suitable for midrange frequencies uses a dome shaped piezoelectric actuator to a speaker membrane directly is discussed. The dome shaped actuator is made from a reduced and internally biased oxygen wafer, and generates excursion of the apex of the dome in the order of 0.02-0.05 inches when a rated drive voltage of 350 V rms is applied between the convex and the concave surface of the dome shaped actuator. The load capacity exceeds 10 lbs. The edge of the rim of the dome shaped actuator must be free to rock when the dome height varies to ensure low distortion in the loudspeaker. This is achieved by mounting the rim of the dome shaped actuator on a support surface by prestress only. An exceptionally simple design uses a planar speaker membrane with the center part of one side pressed against the rim of a dome shaped actuator by prestress from a stretched latex surround member.

Regan, Curtis R.↗