Smooth-Walled Feed Horn

NASA's patch antenna technology exhibits higher operational bandwidth (on the order of 20%) than typical patch antennas (less than 10%) and can operate across integer-multiple frequency bands (e.g. S/X, C/X, S/C). Testing of the antenna design has demonstrated &#62 6dB of gain on both S and X bands (boresight), with an axial ratio of &#60 6dB and voltage standing wave ratio (VSWR) &#60 3:1 throughout the entire near-Earth network (NEN) operating bands (22.4GHz and 88.4GHz) with hemispherical coverage. The patch size is on the order of 10 x 10 cm and with associated electronics, is about 1 cm in height.

NASA's newly developed antenna is lightweight (at or below 2 grams), low volume (at or below 1.2 cm3), and low stowage thickness (approx. 0.7 mm), all while delivering high performance (at or above 10 dBi gain). The antenna includes a novel design-material combination in a helical coil conformation. The design allows the antenna to compress for stowage (e.g., satellite launch), then self-deploy at the desired time in orbit. NASA's lightweight, self-deployable helical antenna can be integrated into a thin-film solar array (or other large deployable structures). Integrating antenna elements into deployable structures such as power generation arrays allows spacecraft designers to maximize the inherently limited resources (e.g., mass, volume, surface area) available in a small spacecraft. When used as a standalone (i.e., single antenna) setup, the the invention offers moderate advantages in terms of stowage thickness, volume, and mass. However, in applications that require antenna arrays, these advantages become multiplicative, resulting in the system offering the same or higher data rate performance while possessing a significantly reduced form factor. Prototypes of NASA's self-deployable, helical antenna have been fabricated in S-band, X-band, and Ka-band, all of which exhibited high performance. The antenna may find application in SmallSat communications (in deep space and LEO), as well as cases where low mass and stowage volume are valued and high antenna gain is required.

The SHEARLESS composite boom has a rollable structure with a large moment of inertia per unit of stored height that does not suffer from shear-derived problems. The boom is fabricated from joining two independent tape-springs front-to-front with the use of a durable seamless polymer sleeve. This sleeve allows the two parts to slide past each other during the coiling/deployment process so as to minimize shear and its derived problems. The innovation enables a lightweight structure that can be stowed on a reel without appreciable shear stresses developing in its constitutive composite parts, allowing for unprecedentedly small coiling diameters for the total thickness of the structure. As demonstrated, through specific laminate design of the two inner composite parts, the SHEARLESS composite boom can also be fabricated with a special inherent feature, bi-stability, which enables designs with minimal mechanisms and aids in deployment controllability and reliability.

Conventional neutron beam experiments demand high fluxes that can only be obtained at research facilities equipped with a reactor source and neutron optics. However, access to these facilities is limited. The NASA technology uses grazing incidence reflective optics to produce focused beams of neutrons (Figure 1) from compact commercially available sources, resulting in higher flux concentrations. Neutrons are doubly reflected off of a parabolic and hyperbolic mirror at a sufficiently small angle, creating neutron beams that are convergent, divergent, or parallel. Neutron flux can be increased by concentrically nesting mirrors with the same focal length and curvature, resulting in a convergence of multiple neutron beams at a single focal point. The improved flux from the compact source may be used for non-destructive testing, imaging, and materials analysis. The grazing incidence neutron optic mirrors are fabricated using an electroformed nickel replication technique developed by NASA and the Harvard-Smithsonian Center for Astrophysics (Figure 2). A machined aluminum mandrel is super-polished to a surface roughness of 3-4 angstroms root mean square and plated with layers of highly reflective nickel-cobalt alloy. Residual stresses that can cause mirror warping are eliminated by periodically reversing the anode and cathode polarity of the electroplating system, resulting in a deformation-free surface. The fabrication process has been used to produce 0.5 meter and 1.0 meter lenses.

The side walls and railing rods of a CubeSat are replaced by RF radiators that double as supporting structures. The RF radiators are hollow railing rods with inner dimensions that function as a waveguide to carry RF energy at a desired frequency. Radiating slots are cut on two of the four sides of hollow tubes tube that are open to outside environment. Different operating frequency antennas may be placed at each of the Cubesats four corners. Thus the railing rods provide RF antenna functionality in addition to structurally supporting the CubeSat structure. While this technology was designed for Cubesats, it may be utilized in any technology that utilizes a structural frame. The advantages of this system are increased reliability due to the elimination of deployment mechanisms and decreased payloads. Higher frequency antennas with increased gain and directivity may be embedded into the rails. These higher frequencies are especially useful for remote sensing.