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Space Shuttle GN and C Development History and Evolution

Completion of the final Space Shuttle flight marks the end of a significant era in Human Spaceflight. Developed in the 1970 s, first launched in 1981, the Space Shuttle embodies many significant engineering achievements. One of these is the development and operation of the first extensive fly-by-wire human space transportation Guidance, Navigation and Control (GN&C) System. Development of the Space Shuttle GN&C represented first time inclusions of modern techniques for electronics, software, algorithms, systems and management in a complex system. Numerous technical design trades and lessons learned continue to drive current vehicle development. For example, the Space Shuttle GN&C system incorporated redundant systems, complex algorithms and flight software rigorously verified through integrated vehicle simulations and avionics integration testing techniques. Over the past thirty years, the Shuttle GN&C continued to go through a series of upgrades to improve safety, performance and to enable the complex flight operations required for assembly of the international space station. Upgrades to the GN&C ranged from the addition of nose wheel steering to modifications that extend capabilities to control of the large flexible configurations while being docked to the Space Station. This paper provides a history of the development and evolution of the Space Shuttle GN&C system. Emphasis is placed on key architecture decisions, design trades and the lessons learned for future complex space transportation system developments. Finally, some of the interesting flight operations experience is provided to inform future developers of flight experiences.

Zimpfer, Douglas↗

PCB-Based Break-Out Box

Break-out boxes (BOBs) are necessary for all electrical integration/cable checkouts and troubleshooting. Because the price of a BOB is high, and no work can be done without one, often the procedure stops, simply waiting for a BOB. A less expensive BOB would take less time in the integration, testing, and troubleshooting process. The PCB-based BOB works and looks the same as a standard JPL BOB, called Gold Boxes. The only differences between the old BOB and the new PCB-based BOB is that the new one has 80 percent of its circuitry in a printed circuit board. This process reduces the time for fabrication, thus making the BOBs less expensive. Moreover, because of its unique design, the new BOBs can be easily assembled and fixed. About 80 percent of the new PCB-based BOB is in a $22 (at the time of this reporting) custom-designed, yet commercially available PCB. This device has been used successfully to verify that BOB cables were properly made. Also, upon completion, the BOB was beeped out via a multimeter to ensure that all sockets on the connectors were properly connected to the respective banana jack. When compared to the Gold Box BOBs, the new BOB has many advantages. It is much more cost efficient, it delivers equal usability at substantially lower cost of the BOB, and the Gold Box is much heavier when compared to the new BOB. The new BOB is also a bit longer and much more versatile in that connectors are easily changeable and if a banana jack is broken, it can be replaced instead of throwing away an entire BOB.

Lee, Jason H.↗

Integrated Atmosphere Resource Recovery and Environmental Monitoring Technology Demonstration for Deep Space Exploration

Exploring the frontiers of deep space continues to be defined by the technological challenges presented by safely transporting a crew to and from destinations of scientific interest. Living and working on that frontier requires highly reliable and efficient life support systems that employ robust, proven process technologies. The International Space Station (ISS), including its environmental control and life support (ECLS) system, is the platform from which humanity's deep space exploration missions begin. The ISS ECLS system Atmosphere Revitalization (AR) subsystem and environmental monitoring (EM) technical architecture aboard the ISS is evaluated as the starting basis for a developmental effort being conducted by the National Aeronautics and Space Administration (NASA) via the Advanced Exploration Systems (AES) Atmosphere Resource Recovery and Environmental Monitoring (ARREM) Project.. An evolutionary approach is employed by the ARREM project to address the strengths and weaknesses of the ISS AR subsystem and EM equipment, core technologies, and operational approaches to reduce developmental risk, improve functional reliability, and lower lifecycle costs of an ISS-derived subsystem architecture suitable for use for crewed deep space exploration missions. The most promising technical approaches to an ISS-derived subsystem design architecture that incorporates promising core process technology upgrades will be matured through a series of integrated tests and architectural trade studies encompassing expected exploration mission requirements and constraints.

Perry, Jay L.↗

Supercritical Water Mixture (SCWM) Experiment

The subject presentation, entitled, Supercritical Water Mixture (SCWM) Experiment, was presented at the International Space Station (ISS) Increment 33/34 Science Symposium. This presentation provides an overview of an international collaboration between NASA and CNES to study the behavior of a dilute aqueous solution of Na2SO4 (5% w) at near-critical conditions. The Supercritical Water Mixture (SCWM) investigation, serves as important precursor work for subsequent Supercritical Water Oxidation (SCWO) experiments. The SCWM investigation will be performed in DECLICs High Temperature Insert (HTI) for the purpose of studying critical fluid phenomena at high temperatures and pressures. The HTI includes a completely sealed and integrated test cell (i.e., Sample Cell Unit SCU) that will contain approximately 0.3 ml of the aqueous test solution. During the sequence of tests, scheduled to be performed in FY13, temperatures and pressures will be elevated to critical conditions (i.e., Tc = 374C and Pc = 22 MPa) in order to observe salt precipitation, precipitate agglomeration and precipitate transport in the presence of a temperature gradient without the influences of gravitational forces. This presentation provides an overview of the motivation for this work, a description of the DECLIC HTI hardware, the proposed test sequences, and a brief discussion of the scientific research objectives.

Hicks, Michael C.↗

The Direction of Fluid Dynamics for Liquid Propulsion at NASA Marshall Space Flight Center

Marshall Space Flight Center (MSFC) is the National Aeronautics and Space Administration (NASA)-designated center for the development of space launch systems. MSFC is particularly known for propulsion system development. Many engineering skills and technical disciplines are needed to accomplish this mission. This presentation will focus on the work of the Fluid Dynamics Branch (ER42). ER42 resides in the Propulsion Systems Department at MSFC. The branch is responsible for all aspects of the discipline of fluid dynamics applied to propulsion or propulsion-induced loads and environments. This work begins with design trades and parametric studies, and continues through development, risk assessment, anomaly investigation and resolution, and failure investigations. Applications include the propellant delivery system including the main propulsion system (MPS) and turbomachinery; combustion devices for liquid engines and solid rocket motors; coupled systems; and launch environments. An advantage of the branch is that it is neither analysis nor test centric, but discipline centric. Fluid dynamics assessments are made by analysis, from lumped parameter modeling through unsteady computational fluid dynamics (CFD); testing, which can be cold flow or hot fire; or a combination of analysis and testing. Integration of all discipline methods into one branch enables efficient and accurate support to the projects. To accomplish this work, the branch currently employs approximately fifty engineers divided into four teams -- Propellant Delivery CFD, Combustion Driven Flows CFD, Unsteady and Experimental Flows, and Acoustics and Stability. This discussion will highlight some of the work performed in the branch and the direction in which the branch is headed.

Griffin, Lisa W.↗

From Concept-to-Flight: An Active Active Fluid Loop Based Thermal Control System for Mars Science Laboratory Rover

The Mars Science Laboratory (MSL) rover, Curiosity, which was launched on November 26, 2011, incorporates a novel active thermal control system to keep the sensitive electronics and science instruments at safe operating and survival temperatures. While the diurnal temperature variations on the Mars surface range from -120 C to +30 C, the sensitive equipment are kept within -40 C to +50 C. The active thermal control system is based on a single-phase mechanically pumped fluid loop (MPFL) system which removes or recovers excess waste heat and manages it to maintain the sensitive equipment inside the rover at safe temperatures. This paper will describe the entire process of developing this active thermal control system for the MSL rover from concept to flight implementation. The development of the rover thermal control system during its architecture, design, fabrication, integration, testing, and launch is described.

heat rejection systems↗

Launch Pad Coatings for Smart Corrosion Control

Corrosion is the degradation of a material as a result of its interaction with the environment. The environment at the KSC launch pads has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the US. The 70 tons of highly corrosive hydrochloric acid that are generated by the solid rocket boosters during a launch exacerbate the corrosiveness of the environment at the pads. Numerous failures at the pads are caused by the pitting of stainless steels, rebar corrosion, and the degradation of concrete. Corrosion control of launch pad structures relies on the use of coatings selected from the qualified products list (QPL) of the NASA Standard 5008A for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment. This standard was developed to establish uniform engineering practices and methods and to ensure the inclusion of essential criteria in the coating of ground support equipment (GSE) and facilities used by or for NASA. This standard is applicable to GSE and facilities that support space vehicle or payload programs or projects and to critical facilities at all NASA locations worldwide. Environmental regulation changes have dramatically reduced the production, handling, use, and availability of conventional protective coatings for application to KSC launch structures and ground support equipment. Current attrition rate of qualified KSC coatings will drastically limit the number of commercial off the shelf (COTS) products available for the Constellation Program (CxP) ground operations (GO). CxP GO identified corrosion detection and control technologies as a critical, initial capability technology need for ground processing of Ares I and Ares V to meet Constellation Architecture Requirements Document (CARD) CxP 70000 operability requirements for reduced ground processing complexity, streamlined integrated testing, and operations phase affordability. Researchers at NASA's Corrosion Technology Laboratory at KSC are developing a smart, environmentally friendly coating system for early corrosion detection, inhibition, and self healing of mechanical damage without external intervention. This smart coating will detect and respond actively to corrosion and mechanical damage such as abrasion and scratches, in a functional and predictable manner, and will be capable of adapting its properties dynamically. This coating is being developed using corrosion sensitive microcapsules that deliver the contents of their core (corrosion inhibiting compounds, corrosion indicators, and self healing agents) on demand when corrosion or mechanical damage to the coating occurs.

Calle, Luz M.↗

CANSAT: Design of a Small Autonomous Sounding Rocket Payload

CanSat is an international student design-build-launch competition organized by the American Astronautical Society (AAS) and American Institute of Aeronautics and Astronautics (AIAA). The competition is also sponsored by the Naval Research Laboratory (NRL), the National Aeronautics and Space Administration (NASA), AGI, Orbital Sciences Corporation, Praxis Incorporated, and SolidWorks. Specifically, the 2009 Virginia Tech CanSat Team is funded by BAE Systems, Incorporated of Manassas, Virginia. The objective of the 2009 CanSat competition is to complete remote sensing missions by designing a small autonomous sounding rocket payload. The payload designed will follow and perform to a specific set of mission requirements for the 2009 competition. The competition encompasses a complete life-cycle of one year which includes all phases of design, integration, testing, reviews, and launch.

Berman, Joshua↗

Orion Suit Loop Variable Pressure Regulator Development

The Orion Multi Purpose Crew Vehicle (MPCV) integrates the cabin and pressure suits with the core life support systems to provide life support during contingency depressurized cabin operations. To provide the multipule suit pressures between nominal pressurized cabin suited operations, suit leak checks, depressurized cabin suited operations, and elevated suit pressure for denitrification, a variable pressure regulator is needed. This paper documents the development and integrated testing of the suit loop regulator for Orion.

Mosher, Michael↗

Logistics Reduction and Repurposing Technology for Long Duration Space Missions

One of NASA's Advanced Exploration Systems (AES) projects is the Logistics Reduction and Repurposing (LRR) project, which has the goal of reducing logistics resupply items through direct and indirect means. Various technologies under development in the project will reduce the launch mass of consumables and their packaging, enable reuse and repurposing of items and make logistics tracking more efficient. Repurposing also reduces the trash burden onboard spacecraft and indirectly reduces launch mass by replacing some items on the manifest. Examples include reuse of trash as radiation shielding or propellant. This paper provides the status of the LRR technologies in their third year of development under AES. Advanced clothing systems (ACS) are being developed to enable clothing to be worn longer, directly reducing launch mass. ACS has completed a ground exercise clothing study in preparation for an International Space Station (ISS) technology demonstration in 2014. Development of launch packaging containers and other items that can be repurposed on-orbit as part of habitation outfitting has resulted in a logistics-to-living (L2L) concept. L2L has fabricated and evaluated several multi-purpose cargo transfer bags (MCTBs) for potential reuse on orbit. Autonomous logistics management (ALM) is using radio frequency identification (RFID) to track items and thus reduce crew requirements for logistics functions. An RFID dense reader prototype is under construction and plans for integrated testing are being made. Development of a heat melt compactor (HMC) second generation unit for processing trash into compact and stable tiles is nearing completion. The HMC prototype compaction chamber has been completed and system development testing is underway. Research has been conducted on the conversion of trash-to-gas (TtG) for high levels of volume reduction and for use in propulsion systems. A steam reformation system was selected for further system definition of the TtG technology. And benefits analysis of all LRR technologies have been updated with the latest test and analysis results.

Broyan, James L.↗

Logistics Reduction and Repurposing Technology for Long Duration Space Missions

One of NASA's Advanced Exploration Systems (AES) projects is the Logistics Reduction and Repurposing (LRR) project, which has the goal of reducing logistics resupply items through direct and indirect means. Various technologies under development in the project will reduce the launch mass of consumables and their packaging, enable reuse and repurposing of items, and make logistics tracking more efficient. Repurposing also reduces the trash burden onboard spacecraft and indirectly reduces launch mass by one manifest item having two purposes rather than two manifest items each having only one purpose. This paper provides the status of each of the LRR technologies in their third year of development under AES. Advanced clothing systems (ACSs) are being developed to enable clothing to be worn longer, directly reducing launch mass. ACS has completed a ground exercise clothing study in preparation for an International Space Station technology demonstration in 2014. Development of launch packaging containers and other items that can be repurposed on-orbit as part of habitation outfitting has resulted in a logistics-to-living (L2L) concept. L2L has fabricated and evaluated several multi-purpose cargo transfer bags for potential reuse on-orbit. Autonomous logistics management is using radio frequency identification (RFID) to track items and thus reduce crew time for logistics functions. An RFID dense reader prototype is under construction and plans for integrated testing are being made. A heat melt compactor (HMC) second generation unit for processing trash into compact and stable tiles is nearing completion. The HMC prototype compaction chamber has been completed and system development testing is under way. Research has been conducted on the conversion of trash-to-gas (TtG) for high levels of volume reduction and for use in propulsion systems. A steam reformation system was selected for further system definition of the TtG technology.

Broyan, James Lee, Jr.↗

System Testing of Ground Cooling System Components

This internship focused primarily upon software unit testing of Ground Cooling System (GCS) components, one of the three types of tests (unit, integrated, and COTS/regression) utilized in software verification. Unit tests are used to test the software of necessary components before it is implemented into the hardware. A unit test determines that the control data, usage procedures, and operating procedures of a particular component are tested to determine if the program is fit for use. Three different files are used to make and complete an efficient unit test. These files include the following: Model Test file (.mdl), Simulink SystemTest (.test), and autotest (.m). The Model Test file includes the component that is being tested with the appropriate Discrete Physical Interface (DPI) for testing. The Simulink SystemTest is a program used to test all of the requirements of the component. The autotest tests that the component passes Model Advisor and System Testing, and puts the results into proper files. Once unit testing is completed on the GCS components they can then be implemented into the GCS Schematic and the software of the GCS model as a whole can be tested using integrated testing. Unit testing is a critical part of software verification; it allows for the testing of more basic components before a model of higher fidelity is tested, making the process of testing flow in an orderly manner.

Unit Test↗

Next Generation Life Support Project Status

Next Generation Life Support (NGLS) is one of over twenty technology development projects sponsored by NASA's Game Changing Development Program. The NGLS Project develops selected life support technologies needed for humans to live and work productively in space, with focus on technologies for future use in spacecraft cabin and space suit applications. Over the last three years, NGLS had five main project elements: Variable Oxygen Regulator (VOR), Rapid Cycle Amine (RCA) swing bed, High Performance (HP) Extravehicular Activity (EVA) Glove, Alternative Water Processor (AWP) and Series-Bosch Carbon Dioxide Reduction. The RCA swing bed, VOR and HP EVA Glove tasks are directed at key technology needs for the Portable Life Support System (PLSS) and pressure garment for an Advanced Extravehicular Mobility Unit (EMU). Focus is on prototyping and integrated testing in cooperation with the Advanced Exploration Systems (AES) Advanced EVA Project. The HP EVA Glove Element, new this fiscal year, includes the generation of requirements and standards to guide development and evaluation of new glove designs. The AWP and Bosch efforts focus on regenerative technologies to further close spacecraft cabin atmosphere revitalization and water recovery loops and to meet technology maturation milestones defined in NASA's Space Technology Roadmaps. These activities are aimed at increasing affordability, reliability, and vehicle self-sufficiency while decreasing mass and mission cost, supporting a capability-driven architecture for extending human presence beyond low-Earth orbit, along a human path toward Mars. This paper provides a status of current technology development activities with a brief overview of future plans.

Barta, Daniel J.↗

Effect of Background Pressure on the Performance and Plume of the HiVHAc Hall Thruster

During the Single String Integration Test of the NASA HiVHAc Hall thruster, a number of plasma diagnostics were implemented to study the effect of varying facility background pressure on thruster operation. These diagnostics include thrust stand, Faraday probe, ExB probe, and retarding potential analyzer. The test results indicated a rise in thrust and discharge current with background pressure. There was also a decrease in ion energy per charge, an increase in multiply-charged species production, a decrease in plume divergence, and a decrease in ion beam current with increasing background pressure. A simplified ingestion model was applied to determine the maximum acceptable background pressure for thrust measurement. The maximum acceptable ingestion percentage was found to be around 1%. Examination of the diagnostics results suggest the ionization and acceleration zones of the thruster were shifting upstream with increasing background pressure.

Electric propulsion↗

Virtualization - A Key Cost Saver in NASA Multi-Mission Ground System Architecture

With science team budgets being slashed, and a lack of adequate facilities for science payload teams to operate their instruments, there is a strong need for innovative new ground systems that are able to provide necessary levels of capability processing power, system availability and redundancy while maintaining a small footprint in terms of physical space, power utilization and cooling.The ground system architecture being presented is based off of heritage from several other projects currently in development or operations at Goddard, but was designed and built specifically to meet the needs of the Science and Planetary Operations Control Center (SPOCC) as a low-cost payload command, control, planning and analysis operations center. However, this SPOCC architecture was designed to be generic enough to be re-used partially or in whole by other labs and missions (since its inception that has already happened in several cases!)The SPOCC architecture leverages a highly available VMware-based virtualization cluster with shared SAS Direct-Attached Storage (DAS) to provide an extremely high-performing, low-power-utilization and small-footprint compute environment that provides Virtual Machine resources shared among the various tenant missions in the SPOCC. The storage is also expandable, allowing future missions to chain up to 7 additional 2U chassis of storage at an extremely competitive cost if they require additional archive or virtual machine storage space.The software architecture provides a fully-redundant GMSEC-based message bus architecture based on the ActiveMQ middleware to track all health and safety status within the SPOCC ground system. All virtual machines utilize the GMSEC system agents to report system host health over the GMSEC bus, and spacecraft payload health is monitored using the Hammers Integrated Test and Operations System (ITOS) Galaxy Telemetry and Command (TC) system, which performs near-real-time limit checking and data processing on the downlinked data stream and injects messages into the GMSEC bus that are monitored to automatically page the on-call operator or Systems Administrator (SA) when an off-nominal condition is detected. This architecture, like the LTSP thin clients, are shared across all tenant missions.Other required IT security controls are implemented at the ground system level, including physical access controls, logical system-level authentication authorization management, auditing and reporting, network management and a NIST 800-53 FISMA-Moderate IT Security plan Risk Assessment Contingency Plan, helping multiple missions share the cost of compliance with agency-mandated directives.The SPOCC architecture provides science payload control centers and backup mission operations centers with a cost-effective, standardized approach to virtualizing and monitoring resources that were traditionally multiple racks full of physical machines. The increased agility in deploying new virtual systems and thin client workstations can provide significant savings in personnel costs for maintaining the ground system. The cost savings in procurement, power, rack footprint and cooling as well as the shared multi-mission design greatly reduces upfront cost for missions moving into the facility. Overall, the authors hope that this architecture will become a model for how future NASA operations centers are constructed!

Ground System Architecture↗

Correlation of Amine Swingbed On-Orbit CO2 Performance with a Hardware Independent Predictive Model

The Amine Swingbed Payload is an experimental system deployed on the International Space Station (ISS) that includes a two-bed, vacuum regenerated, amine-based carbon dioxide (CO2) removal subsystem as the principal item under investigation. The aminebased subsystem, also described previously in various publications as CAMRAS 3, was originally designed, fabricated and tested by Hamilton Sundstrand Space Systems International, Inc. (HSSSI) and delivered to NASA in November 2008. The CAMRAS 3 unit was subsequently designed into a flight payload experiment in 2010 and 2011, with flight test integration activities accomplished on-orbit between January 2012 and March 2013. Payload activation was accomplished in May 2013 followed by a 1000 hour experimental period. The experimental nature of the Payload and the interaction with the dynamic ISS environment present unique scientific and engineering challenges, in particular to the verification and validation of the expected Payload CO2 removal performance. A modeling and simulation approach that incorporates principles of chemical reaction engineering has been developed for the amine-based system to predict the dynamic cabin CO2 partial pressure with given inputs of sorbent bed size, process air flow, operating temperature, half-cycle time, CO2 generation rate, cabin volume and the magnitude of vacuum available. Simulation runs using the model to predict ambient CO2 concentrations show good correlation to on-orbit performance measurements and ISS dynamic concentrations for the assumed operating conditions. The dynamic predictive modelling could benefit operational planning to help ensure ISS CO2 concentrations are maintained below prescribed limits and for the Orion vehicle to simulate various operating conditions, scenarios and transients.

Papale, William↗

Pressure Analysis for LAVA-OVEN

The Lunar Advanced Volatiles Analysis (LAVA) and the Oxygen Volatiles Extraction Node (OVEN) are subsystems included in the Regolith Environment Science, and Oxygen Lunar Volatiles Extraction (RESOLVE) payload bound for the Moon in 2019. This Resource Prospector Mission (RPM) has the objective of landing on a shadowed region of the Moons South Pole to collect data and determine whether the resources could be effectively used for space exploration systems. The quantification of the resources will help understand if it can adequately minimize materials carried from Earth by: providing life support, propellants, construction materials or energy supply to the payload or crew. This paper outlines the procedures done for the pressure analysis of the LAVA-OVEN (LOVEN) Integration Testing. The pressure analysis quantifies how much gases and water are present in the sample tested during the Engineering Testing Unit (ETU) phase of instrument development. Ultimately the purpose of these tests is to improve the estimate of the amount of water in each Lunar sample and reduce the time necessary for this estimate. The governing principle that was used for the analysis is the Ideal Gas Law, PV=nRT where P stands for pressure, V for volume, n for number of moles, R being the gas constant and T for temperature. We also estimate the errors involved in these measured and derived quantities since a key objective of the mission is to estimate the quantity of volatiles present in the lunar samples introduced into OVEN.

Lunar↗

Practical Considerations for Using Constant Force Springs in Space-Based Mechanisms

Mechanical springs are a common element in mechanism from all walks of life; cars, watches, appliances, and many others. These springs generally exhibit a linear relationship between force and deflection. In small mechanisms, deflections are small so the variation in spring force between one position and another are generally small and do not influence the design or functionality of the device. However, as the spacecraft industry drives towards larger, deployable satellites, the distances a spring or springs must function over can become considerable so much so that the structural integrity of the device may be impacted. As such, an increasingly common mechanism element is the constant force spring- one that provides a constant force regardless of deflection. These elements are commonly in the conceptual design phase to deal with system-level large deflections, but in the detailed design or integration test phase they can pose significant implementation issues. This article addresses some of the detailed issues in order for these constant force springs to be properly designed into space systems.

reliability testing↗