VT ThickSat: A Scalable Chassis in the ThinSat Program

This paper presents a scalable design of a small satellite chassis for the ThinSat Program. This versatile chassis will fly on Virginia Tech’s ThinSat mission in 2020, VT ThickSat. By incrementing the volume of the satellite chassis, students from Virginia Tech introduce a unique capability that combines the ThinSat’s rapid deployment with upscaled payload sizes. The scalable solution reflects an expansion of the original ThinSat 1T chassis up to nearly that of a1U CubeSat. Enabling the accommodation of larger educational and research payloads using the same proven flight hardware as the 1T option, a family of alternative vehicles for institutions previously constrained to the more expensive CubeSat platform can be realized for low-altitude, short-duration missions. The chassis design offers an attractive alternative to educational CubeSat builds, putting the experiment in primary focus rather than using resources on a build-to-suit vehicle design. With rapid development capabilities and reasonable cost, the capability described here introduces an incremental synergy for nanosatellite space applications as well as building the potential to test and prove out further capabilities for the entire SmallSat community

Electronic filters, signal conversion apparatus, hearing aids and methods

An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits as GOVERNMENT SUPPORT This invention was made with U.S. Government support under Veterans Administration Contract VA KV 674P857 and National Aeronautics and Space Administration (NASA) Research Grant No. NAG10-0040. The U.S. Government has certain rights in this invention

Electronic filters, repeated signal charge conversion apparatus, hearing aids and methods

An electronic filter for filtering an electrical signal. Signal processing circuitry therein includes a logarithmic filter having a series of filter stages with inputs and outputs in cascade and respective circuits associated with the filter stages for storing electrical representations of filter parameters. The filter stages include circuits for respectively adding the electrical representations of the filter parameters to the electrical signal to be filtered thereby producing a set of filter sum signals. At least one of the filter stages includes circuitry for producing a filter signal in substantially logarithmic form at its output by combining a filter sum signal for that filter stage with a signal from an output of another filter stage. The signal processing circuitry produces an intermediate output signal, and a multiplexer connected to the signal processing circuit multiplexes the intermediate output signal with the electrical signal to be filtered so that the logarithmic filter operates as both a logarithmic prefilter and a logarithmic postfilter. Other electronic filters, signal conversion apparatus, electroacoustic systems, hearing aids and methods are also disclosed

VT ThickSat: A Passive Deployer Mechanism for a Carbon Fiber Tape Spring in the ThinSat Program

The passive deployer mechanism will fly on Virginia Tech’s ThinSat mission, VT ThickSat, scheduled to launch along with the resupply mission to the ISS, NG-15. This mission is a proof-of-concept that could lead to similar deployable structures in future missions, e.g., solar sails and solar panel deployments. The mission-critical objective is to demonstrate a passive deployment mechanism in space. The boom is required to release itself from the coiled state using only its stored elastic energy. Furthermore, the mechanism takes advantage of a scalable chassis, built for the same mission, restricting it to fit within the space of a 5 x 1T ThinSat form factor. This poster showcases the design progression of the deployer

Ut ProSat-1: A Repeatable Passive Deployer Mechanism for Testing Carbon Fiber Tape Spring Booms

This paper presents the design, production, and testing of a mechanism to passively deploy a bistable coiled tape spring in a controlled, reliable, and repeatable manner on a SmallSat. The design has the tape spring wrapped around a spool that can be connected and disconnected from a motor to allow passive deployment through its stored elastic energy along with motorized retraction. The design went through several iterations before a workable prototype made of 3D-printed ABS and resin was developed. The prototype utilized a threaded clutch mechanism to transfer rotational motion from a servo to linear motion that allows two gears to move toward and away from each other. These two gears are attached to the spool and motor respectively, and their separation allows the motor to be disconnected from the spool to avoid influencing the deployment. The final prototype was capable of autonomous deployment and retraction with proper supporting software. Repeated tape spring deployments allow for automated reliability testing of a tape spring deployer, and the clutch mechanism to facilitate this can also be used in other applications

Multipoint observations of compressional Pc5 pulsations in the dayside magnetosphere and corresponding particle signatures

We use Van Allen Probes (Radiation Belt Storm Probes A and B, henceforth RBSP-A and RBSP-B) and GOES-13 and GOES-15 (henceforth G-13 and G-15) multipoint magnetic field, electric field, plasma, and energetic particle observations to study the spatial, temporal, and spectral characteristics of compressional Pc5 pulsations observed during the recovery phase of a strong geomagnetic storm on 1 January 2016. From ∼ 19:00 to 23:02 UT, successive magnetospheric compressions enhanced the peak-to-peak amplitudes of Pc5 waves with 4.5\u276.0 mHz frequencies from 0\u27 2 to 10\u2715 nT at both RBSP-A and RBSP-B, particularly in the prenoon magnetosphere. Poloidal Pc4 pulsations with frequencies of ∼ 22\u2729 mHz were present in the radial Bx component. The frequencies of these Pc4 pulsations diminished with increasing radial distance, as expected for resonant Alfv n waves standing along field lines. The GOES spacecraft observed Pc5 pulsations with similar frequencies to those seen by the RBSP but Pc4 pulsations with lower frequencies. Both RBSP-A and RBSP-B observed frequency doubling in the compressional component of the magnetic field during the Pc5 waves, indicating a meridional sloshing of the equatorial node over a combined range in ZSM from 0.25 to-0:08 Re, suggesting that the amplitude of this meridional oscillation was ∼ 0.16 Re about an equatorial node whose mean position was near ZSM D∼ 0:08 Re. RBSP-A and RBSP-B HOPE (Helium Oxygen Proton Electron) and MagEIS (Magnetic Electron Ion Spectrometer) observations provide the first evidence for a corresponding frequency doubling in the plasma density and the flux of energetic electrons, respectively. Energetic electron fluxes oscillated out of phase with the magnetic field strength with no phase shift at any energy. In the absence of any significant solar wind trigger or phase shift with energy, we interpret the compressional Pc5 pulsations in terms of the mirror-mode instability

A statistical investigation of traveling convection vortices observed by the west coast Greenland magnetometer chain

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95409/1/jgra16162.pd