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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 145 records · Page 8

Advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) Small Spacecraft System

This paper describes recent advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) currently being developed at NASA's Marshall Space Flight Center. The LISA-T array comprises a launch stowed, orbit deployed structure on which thin-film photovoltaic (PV) and antenna devices are embedded. The system provides significant electrical power generation at low weights, high stowage efficiency, and without the need for solar tracking. Leveraging high-volume terrestrial-market PVs also gives the potential for lower array costs. LISA-T is addressing the power starvation epidemic currently seen by many small-scale satellites while also enabling the application of deployable antenna arrays. Herein, an overview of the system and its applications are presented alongside sub-system development progress and environmental testing plans.

Lockett, Tiffany Russell↗

Multi-Evaporator Miniature Loop Heat Pipe for Small Spacecraft Thermal Control: New Technologies and Validation Approach - Part 1

Under NASA s New Millennium Program Space Technology 8 (ST 8) Project, four experiments Thermal Loop, Dependable Microprocessor, SAILMAST, and UltraFlex - were conducted to advance the maturity of individual technologies from proof of concept to prototype demonstration in a relevant environment , i.e. from a technology readiness level (TRL) of 3 to a level of 6. This paper presents the new technologies and validation approach of the Thermal Loop experiment. The Thermal Loop is an advanced thermal control system consisting of a miniature loop heat pipe (MLHP) with multiple evaporators and multiple condensers designed for future small system applications requiring low mass, low power, and compactness. The MLHP retains all features of state-of-the-art loop heat pipes (LHPs) and offers additional advantages to enhance the functionality, performance, versatility, and reliability of the system. Details of the thermal loop concept, technical advances, benefits, objectives, level 1 requirements, and performance characteristics are described. Also included in the paper are descriptions of the test articles and mathematical modeling used for the technology validation. An MLHP breadboard was built and tested in the laboratory and thermal vacuum environments for TRL 4 and TRL 5 validations, and an MLHP proto-flight unit was built and tested in a thermal vacuum chamber for the TRL 6 validation. In addition, an analytical model was developed to simulate the steady state and transient behaviors of the MLHP during various validation tests. Capabilities and limitations of the analytical model are also addressed.

Ku, Jentung↗

Miniature Linear Actuator for Small Spacecraft

A report discusses the development of a kit of mechanisms intended for use aboard future spacecraft having masses between 10 and 100 kg. The report focuses mostly on two prototypes of one of the mechanisms: a miniature linear actuator based on a shape-memory-alloy (SMA) wire. In this actuator, as in SMA-wire actuators described previously in NASA Tech Briefs, a spring biases a moving part toward one limit of its stroke and is restrained or pulled toward the other limit of the stroke by an SMA wire, which assumes a slightly lesser or greater "remembered" length, depending on whether or not an electric current is applied to the wire to heat it above a transition temperature. Topics addressed in the report include the need to develop mechanisms like these, the general approach to be taken in designing SMA actuators, tests of the two prototypes of the miniature linear actuators, and improvements in the second prototype over the first prototype resulting in reduced mass and increased stroke. The report also presents recommendations for future development, briefly discusses problems of tolerances and working with small parts, states a need for better understanding of behaviors of SMAs, and presents conclusions.

Willey, Cliff E.↗

Small spacecraft conceptual design for a Fast Pluto Flyby mission

The main objective of the Pluto Fast Flyby mission is to conduct first reconnaissance level science at Pluto before its atmospheric collapse in the next two to three decades. The design approach is driven by the consideration of cost (with the objective to deliver two 164-kg spacecraft to Pluto for less than 400 million dollars development cost). The paper describes the mission-design approach and the Pluto Fast Flyby conceptual flight system 1992 baseline. Attention is also given to the design history of the spacecraft concept and the current and future activity of the Pluto Fast Flyby team.

Salvo, Christopher G.↗

Small Spacecraft Technology Initiative (SSTI)

This is the second in a series of semi-annual reports that describe the technology areas being advanced under this contract and the progress achieved to date. The last technology report concentrated on the spacecraft. This report places greater emphasis on the payloads. White papers by several of the payload providers are attached. These are HSI, UCB, PRKE, and CAFE. This report covers the period from January 1995 through June 1995.

Reppucci, George↗

Infrared Communications for Small Spacecraft: From a Wireless Bus to Cluster Concepts

Nanosatellites operating singly or in clusters are anticipated for future space science missions. To implement this new communications paradigm, we are approaching cluster communications by first developing an infrared (IR) intra-craft wireless bus capability, following initially the MIL-STD-1553B protocol. Benefits of an IR wireless bus are low mass, size, power, and cost, simplicity of implementation, ease of use, minimum EMI, and efficient and reliable data transfer. Our goals are to maximize the reliable link margin in order to afford greater flexibility in receiver placement, which will ease technology insertion. We have developed a concept demonstration using a high-speed visible-band silicon PIN photodiode and a high-efficiency visible LED operating at a data rate up to 4 Mb/sec. In designing an internal IR wireless bus, we have characterized various candidate materials, emitters, and geometries, assuming a single reflection. Thus, we have measured the bidirectional reflectance distribution function (BRDF) for five different materials characteristic of typical spacecraft structures, which range from nearly Lambertian to highly specular. We have fit our data to empirical BRDF functions and modeled the detected irradiance anywhere in the plane of incidence for a divergent (LED) emitter. We have also determined the angular limits on the link geometry to remain within the required bit error rate by determining the received signal-to-noise ratio (SNR) for minimum values of irradiance received at the detector.

Webb, Suzanne C.↗

NASA Headquarters/Kennedy Space Center: Organization and Small Spacecraft Launch Services

The objectives of the Kennedy Space Center's (KSC) Expendable Launch Vehicles (ELV) Program are to provide safe, reliable, cost effective ELV launches, maximize customer satisfaction, and perform advanced payload processing capability development. Details are given on the ELV program organization, products and services, foreign launch vehicle policy, how to get a NASA launch service, and some of the recent NASA payloads.

Sierra, Albert↗

Toward a Dynamically Reconfigurable Computing and Communication System for Small Spacecraft

Future science missions will require the use of multiple spacecraft with multiple sensor nodes autonomously responding and adapting to a dynamically changing space environment. The acquisition of random scientific events will require rapidly changing network topologies, distributed processing power, and a dynamic resource management strategy. Optimum utilization and configuration of spacecraft communications and navigation resources will be critical in meeting the demand of these stringent mission requirements. There are two important trends to follow with respect to NASA's (National Aeronautics and Space Administration) future scientific missions: the use of multiple satellite systems and the development of an integrated space communications network. Reconfigurable computing and communication systems may enable versatile adaptation of a spacecraft system's resources by dynamic allocation of the processor hardware to perform new operations or to maintain functionality due to malfunctions or hardware faults. Advancements in FPGA (Field Programmable Gate Array) technology make it possible to incorporate major communication and network functionalities in FPGA chips and provide the basis for a dynamically reconfigurable communication system. Advantages of higher computation speeds and accuracy are envisioned with tremendous hardware flexibility to ensure maximum survivability of future science mission spacecraft. This paper discusses the requirements, enabling technologies, and challenges associated with dynamically reconfigurable space communications systems.

Kifle, Muli↗

Micro-Inspector Avionics Module (MAM): A Self-Contained Low Power, Reconfigurable Avionics Platform for Small Spacecrafts and Instruments

This paper describes development of a radiation tolerant, low power, reconfigurable avionics module aimed at meeting the avionics needs of the JPL Micro-Inspector spacecraft. This module represents a complete avionics system, consisting of two PowerPC 405 CPUs embedded within a reconfigurable FPGA fabric of over 8 Million logic gates, 64MB of EDAC protected Flash storage and 128MB of EDAC protected DDR SDRAM or SDRAM memories, along with FPGA SEU mitigation logic, and all necessary power conversion. Processor SEU mitigation is achieved by running the two processors in a lock-step and compare configuration. All of these building blocks are integrated into a double sided circuit board that takes as little as 6 square inches of board space. This module can be embedded into a user system as part of a bigger circuit assembly or as a self contained module. This module is being developed as part of a JPL led Micro-Inspector Program, funded by NASA ESMD aimed at producing a 10Kg micro spacecraft.

configurable↗

Multi-Evaporator Miniature Loop Heat Pipe for Small Spacecraft Thermal Control

This paper presents the development of the Thermal Loop experiment under NASA's New Millennium Program Space Technology 8 (ST8) Project. The Thermal Loop experiment was originally planned for validating in space an advanced heat transport system consisting of a miniature loop heat pipe (MLHP) with multiple evaporators and multiple condensers. Details of the thermal loop concept, technical advances and benefits, Level 1 requirements and the technology validation approach are described. An MLHP breadboard has been built and tested in the laboratory and thermal vacuum environments, and has demonstrated excellent performance that met or exceeded the design requirements. The MLHP retains all features of state-of-the-art loop heat pipes and offers additional advantages to enhance the functionality, performance, versatility, and reliability of the system. In addition, an analytical model has been developed to simulate the steady state and transient operation of the MHLP, and the model predictions agreed very well with experimental results. A protoflight MLHP has been built and is being tested in a thermal vacuum chamber to validate its performance and technical readiness for a flight experiment.

Ku, Jentung↗

COTSAT Small Spacecraft Cost Optimization for Government and Commercial Use

Cost Optimized Test of Spacecraft Avionics and Technologies (COTSAT-1) is an ongoing spacecraft research and development project at NASA Ames Research Center (ARC). The prototype spacecraft, also known as CheapSat, is the first of what could potentially be a series of rapidly produced low-cost spacecraft. The COTSAT-1 team is committed to realizing the challenging goal of building a fully functional spacecraft for $500K parts and $2.0M labor. The project's efforts have resulted in significant accomplishments within the scope of a limited budget and schedule. Completion and delivery of the flight hardware to the Engineering Directorate at NASA Ames occurred in February 2009 and a cost effective qualification program is currently under study. The COTSAT-1 spacecraft is now located at NASA Ames Research Center and is awaiting a cost effective launch opportunity. This paper highlights the advancements of the COTSAT-1 spacecraft cost reduction techniques.

Swank, Aaron J.↗

Hydrocarbon-Seeded Ignition System for Small Spacecraft Thrusters Using Ionic Liquid Propellants

"Green" propellants based on Ionic-liquids (ILs) like Ammonium DiNitramide and Hydroxyl Ammonium Nitrate have recently been developed as reduced-hazard replacements for hydrazine. Compared to hydrazine, ILs offer up to a 50% improvement in available density-specific impulse. These materials present minimal vapor hazard at room temperature, and this property makes IL's potentially advantageous for "ride-share" launch opportunities where hazards introduced by hydrazine servicing are cost-prohibitive. Even though ILs present a reduced hazard compared to hydrazine, in crystalline form they are potentially explosive and are mixed in aqueous solutions to buffer against explosion. Unfortunately, the high water content makes IL-propellants difficult to ignite and currently a reliable "coldstart" capability does not exist. For reliable ignition, IL-propellants catalyst beds must be pre-heated to greater than 350 C before firing. The required preheat power source is substantial and presents a significant disadvantage for SmallSats where power budgets are extremely limited. Design and development of a "micro-hybrid" igniter designed to act as a "drop-in" replacement for existing IL catalyst beds is presented. The design requires significantly lower input energy and offers a smaller overall form factor. Unlike single-use "squib" pyrotechnic igniters, the system allows the gas generation cycle to be terminated and reinitiated on demand.

Whitmore, Stephen A.↗

Development and Characterization of a Small Spacecraft Electro-Optic Scanner for Free-Space Laser Communications

Emergent data-intensive missions coupled with dramatic reductions in spacecraft size plus an increasing number of space-based missions necessitates new high performance, compact and low cost communications technology. Free space optical communications offer advantages including orders of magnitude increase for data rate performance, increased security, immunity to jamming and lack of frequency allocation requirements when compared with conventional radio frequency (RF) means. The spatial coherence and low divergence associated with the optical frequencies of laser communications lends themselves to superior performance, but this increased directionality also creates one of the primary technical challenges in establishing a laser communications link by repeatedly and reliably pointing the beam onto the receive aperture. Several solutions have emerged from wide angle (slow) mechanical articulation systems, fine (fast) steering mirrors and rotating prisms, inertial compensation gyros and vibration isolation cancellation systems, but each requires moving components and imparts a measured amount of burden on the host platform. The complexity, cost and size of current mechanically scanned solutions limits their platform applicability, and restricts the feasibility of deploying optical communications payloads on very compact spacecraft employing critical systems. A high speed, wide angle, non-mechanical solution is therefore desirable. The purpose of this work is to share the development, testing, and demonstration of a breadboard prototype electro-optic (EO) scanned laser-communication link (see Figure 1). This demonstration is a step toward realizing ultra-low Size, Weight and Power (SWaP) SmallSat/MicroSat EO non-mechanical laser beam steering modules for high bandwidth ( greater than Gbps) free-space data links operating in the 1550 nm wavelength bands. The elimination of all moving parts will dramatically reduce SWaP and cost, increase component lifetime and reliability, and simplify the system design of laser communication modules. This paper describes the target mission architectures and requirements (few cubic centimeters of volume, 10's of grams of weight with milliwatts of power) and design of the beam steering module. Laboratory metrology is used to determine the component performance including horizontal and vertical resolution (20urad) as a function of control voltage (see Figure 2), transition time (0.1-1ms), pointing repeatability and optic insertion loss. A test bed system demonstration, including a full laser communications link, is conducted. The capabilities of this new EO beam steerer provide an opportunity to dramatically improve space communications through increased utilization of laser technology on smaller platforms than were previously attainable.

Laser Optical Communications↗