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Matrix converters inherently have problems with commutation which are generally mitigated by using snubbers. Problem of commutation also places a limitation on their voltage transfer ratio. In this paper, a new high frequency linked AC-AC converter topology is proposed which ensures reliable commutation, taking care of parasitic inductances, with minimum snubber on the input side. A simple switching...
Government and commercial customers are increasingly interested in robust, reusable flight software. For many spacecraft, Attitude Determination and Control Subsystem (ADCS) contributes a significant portion of the FSW. Thus refinements to ADCS code pay dividends for code development and reuse. Sierra Nevada Corporation (SNC) has recently developed an ADCS model and code set that follows model based...
There is a growing number of infrared (IR) spectral signature data in the scientific community gathered from a variety of sensors using a variety of collection techniques. As the quantity of collected data grows, automated solutions for searching and matching signatures need to be developed. When searching and matching signatures, reducing computational complexity and increasing matching accuracy...
The Earth's natural environment can impact the Space Vehicle and the operation of the Space Vehicle can impact the natural environment. The Solar Electric Propulsion (SEP) Technology Demonstration Mission (TDM) is an ideal opportunity to assess the impact of the natural environment on the Space Vehicle and assess the impact of SEP TDM Space Vehicle operations on the natural environment using a proper-ly...
In the most common space solar power (SSP) system architectures, solar energy harvested by large satellites in geostationary orbit is transmitted to Earth via microwave radiation. Currently, only limited information about the interactions of microwave beams with energy densities of several tens to hundreds of W/m2 with the different layers of the atmosphere is available. Governmental bodies will likely...
Nanoionic based resistive switching memory cells are nowadays being implemented in novel memory technology known as Conductive Bridging Random Access Memory. These memory cells, known as programmable metallization cells, are a promising memory technology not only due to their scaling potential but also because of characteristics such as non-volatility, low-power operation and speed. Resistance switching...
By jointly considering multiple adjacent matched filter samples, target localization can be more accurate than considering only a single sample. For sub-bin range estimation, a power-weighted centroid is typically the method of choice due to its simplicity. However, centroiding does not consider the correlation between adjacent samples, and is hence sub-optimal. By making assumptions on the structure...
The Gravity Recovery and Interior Laboratory (GRAIL), a NASA Discovery mission, twin spacecraft were launched on 10 September 2012 and were inserted into lunar orbit on 31 December 2011 and 01 January 20121. The objective of the mission was to measure a high-resolution lunar gravity field using inter-spacecraft range measurements in order to investigate the interior structure of the Moon from crust...
Presented here is a comparison of partially coherent adaptive optics (AO) beacons simulated with analytical Gaussian-Schell Model (GSM) sources, and extended incoherent AO beacons simulated with more conventional techniques. An analysis of Mutual Coherence Functions (MCFs) is performed with a variety of simulation conditions generated with a single software package developed under the AO Beacon effort...
The NASA Innovation Ecosystem supports discovery, collaboration, and ideation around NASA current and future technology. Innovate.NASA is the virtual platform for citizen scientists to learn about NASA technology, collaborate to rethink these inventions, and shape the discussion around future innovation. The purpose is to strengthen NASA's technology capabilities through actively exposing NASA developed...
A sample acquisition and caching architecture has been developed for the proposed Mars 2020 mission that acquires samples directly into sample tubes in coring bits. Sample tubes are inserted and removed from the bits, seals are inserted into the tubes, and the tubes are placed in the sample canister. This paper describes initial algorithms, implementation, and test results where sample tube transfer...
Mars Sample Return (MSR) is the highest priority planetary science objective as identified in the Planetary Science Decadal Survey. To return a sample to Earth would require the accomplishment of several critical steps in the collection and transfer of the sample from the surface of Mars to the surface of the Earth. While there are many architectures and approaches to returning a sample of Martian...
Model-based systems engineering (MBSE) is intended to enhance productivity and quality through a paradigm shift from document-centric engineering. However, most MBSE development tools require the manual creation of requirement constructs. This time consuming step is vulnerable to human error, and must be repeated as high-level designs inevitably evolve. This paper describes a capability that uses...
Aerospace avionics and operation need another dimension. The “glass cockpit” came as a response to an impossible perceptive situation, when pilots had to monitor countless gauges (the concept being “one info-one gauge”). The change came with the renegotiation of the info/surface ratio given to data at the pilot level by using CRTs to integrate data in a user-friendly (dedicated) format. Since then...
Monitoring the health and well-being of human beings during any manned spaceflight is a critical aspect of the space mission. To date this has been done almost exclusively with telemetry to ground stations and monitoring of the physiological data by physicians. With lunar and Mars missions the transmission latency become problematic, and in additional to longer latency, Mars missions would also be...
The National Aeronautics and Space Administration is currently considering an Asteroid Redirect Mission (ARM), the goal of which is to bring a near-Earth asteroid into lunar orbit for inspection by a team of human astronauts. In this paper we present the results of a simulation study that focuses on the challenge of capturing a target asteroid using a robotic spacecraft. This simulation study was...
The Relativistic Electron and Proton Telescope Integrated Little Experiment (REPTile) is a loaded-disc collimated solid-state particle telescope designed, built, tested, and operated by a team of students at the University of Colorado. It was launched onboard the Colorado Student Space Weather Experiment (CSSWE), a 3U CubeSat, from Vandenberg Air Force Base on September 13th, 2012, as part of NASA's...
In this paper we discuss the regularity conditions required for the classical Cramér-Rao Lower Bound (CRLB) for real-valued (nonrandom unknown) parameters to hold. It is shown that the commonly assumed requirement that the support of the likelihood function (LF) should be independent of the parameter to be estimated can be replaced by the much weaker requirement that the LF is continuous at the end...
A Command and Data Handling (C&DH) system is being developed as part of a series of CubeSat missions being built at the University of Texas at Austin Texas Spacecraft Laboratory (TSL). With concurrent development of four missions and with more missions planned for the future, the C&DH team is developing a system architecture that can support a variety of mission requirements. The presented...
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