Abstract: A whole-spacecraft passive isolation system consisting of a plurality of titanium flexures that act as soft springs to isolate a satellite from its launch vehicle is improved by the addition of piezoceramic wafers attached to the flexures. A low-pass filter feedforward controller is used to cancel out disturbances by applying out-of-phase signals to the piezoceramic wafers thereby creating a hybrid isolation system that significantly reduces the dynamic loads on the spacecraft.

Abstract: A thin membrane is mounted on an optically flat circular outer ring and stretched over a smaller optically flat circular inner ring. Differential pressure is applied to the annulus formed between the inner and outer rings to prestrain the membrane and separately applied to the inner ring where the mirror figure will be produced. The inner ring has a doubly curved top surface and is optically fiat so that the membrane can freely move across the inner ring as incremental stress is applied via the annulus. A calculated combination of annulus stress and differential pressure on the inner ring produces an optical quality mirror figure in the inner ring area.

Abstract: A magnetically suspended door is described for the protection of spacecraft instrumentation exposed to space. The door is slid between an opened or closed position using electromagnets.

Abstract: Large space-based optical systems are expected to produce optical beams with large wavefront phase aberrations due to their size, weight limitations, optical misaligments and primary mirror imperfections. The present invention combines a phase diversity wavefront sensor with a real-time programmable two-dimensional array of liquid crystal variable retarders for wavefront correction.

Abstract: Spectra corresponding to overlapping grating orders are focused onto a multi-waveband focal plane array in order to create spectral images of a scene simultaneously in multiple wavelength regions. The blaze of the grating is chosen so that all spectral orders are dispersed with high grating efficiency. Such an approach extends the spectral range of disperse spectrometers to several octaves of wavelength, while preserving the compact packaging and cryogenic requirements of conventional (one octave) instruments.

Abstract: A plurality of Helmholtz resonators with varying physical characteristics are mechanically coupled within a structure to drastically reduced acoustic transmission through the structure or along a pipe. These mechanically coupled resonator structures produce much flatter broadband acoustic attenuation than uncoupled resonators.

Abstract: A HAN TEAN mixing gas generator pressurization system is proposed for use on pressure-fed rockets. HAN (hydroxyl ammonium nitrate) and TEAN (triethanol ammonium nitrate) are salts dissolved in water to form a single liquid propellant. Combustion of HAN TEAN results in water, carbon dioxide, and nitrogen at high temperatures and pressures. A cryogenic primary working fluid is mixed the HAN TEAN exhaust products to provide warm high-pressure gas to pressurize the rocket's main propellant tanks.

Abstract: An array of micromirror devices is fabricated using standard surface-micromachining techniques such that the reflective mirror surfaces are anchored by a trapped joint rather than by rigid support flexures. These devices are therefore multi-stable in actuation rather than continuous like typical micromirror devices in which the restoring spring force of the flexures is used to balance the force of electrostatic actuation. As a result, the flexureless micromirror can be actuated to specific stable positions that make it ideal for optical switching. Since no direct mechanical connection is required to support the mirror surfaces, these devices can be switched between stable positions in binary fashion and at higher speeds.

Abstract: A multi-band pupil stop is disclosed for use in multi-band focal plane array imaging systems. The object is to provide similar point spread functions at the focal plane array. The pupil stop is comprised of one or more nested annuli. Each annulus is a pass-band filter with the outermost annulus passing the longest wavelength waveband and each successive inner annulus passing a successively shorter wavelength waveband. The pass-band of each annulus is such that the ratio of the center wavelength of each pass-band to the outer diameter of each annulus is approximately equal.

Abstract: A high-reactance transformer is used in combination with a phase-programmed switch to limit and regulate the surge current loading on an AC power source employed to charge a capacitor energy store. A controller commands the phase-programmed switch, which begins the charging cycle by closing at a predetermined phase relation to the AC source. The same switch is used to interrupt the charging when the desired capacitive energy store voltage is reached.

Abstract: An injection-locked semiconductor laser process that improves the modulation bandwidth and reduces the broadband noise of an injection-locked semiconductor laser. Injection locking of a semiconductor laser can significantly improve its broadband modulation characteristics. By adjusting the frequency offset between the master laser and the slave laser, improved modulation bandwidth of the modulation response can be emphasized. The intrinsic modulation bandwidths can be enhanced above the theoretical limit for the free-running laser. The improved modulation characteristics are accompanied by reduced broadband relative intensity noise.

Abstract: A lens is described that produces a columnar focus comprised of a continuum of focal points at varying distances from the principal plane of the lens aligned along the axis of the lens. The lens refracts an incident wavefront with a focal length that is dependent upon the radial distance from the axis of the lens. The radii of curvature of the primary surface of the lens is dependent upon the desired length of the focal column.

Abstract: A compact source of intense radiation includes: a multi-element, disc-style, explosive magnetic flux compression generator, switching, peaking-stage generator, plasma flow switch, and a dense-plasma-focus type, pulsed neutron source. The main explosive generator receives initial amounts of magnetic flux and energy from a smaller explosive generator. Explosive action drives the conductors of the main generator together, reducing the inductance and thereby increasing both the current and magnetic energy. A switch closes to connect the peaking-stage generator and plasma flow switch in series with the main generator (and in parallel with the ballast inductor). As the current rises in the plasma flow switch, its plasma armature is electromagnetically-accelerated axially along coaxial electrodes, attaining speeds above 60-70 km/s. Meanwhile, explosive action on the peaking-stage generator provides additional magnetic flux compression.