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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Design, Development and Testing of the Miniature Autonomous Extravehicular Robotic Camera (Mini AERCam) Guidance, Navigation and Control System

Engineers at NASA Johnson Space Center have designed, developed, and tested a nanosatellite-class free-flyer intended for future external inspection and remote viewing of human spaceflight activities. The technology demonstration system, known as the Miniature Autonomous Extravehicular Robotic Camera (Mini AERCam), has been integrated into the approximate form and function of a flight system. The primary focus has been to develop a system capable of providing external views of the International Space Station. The Mini AERCam system is spherical-shaped and less than eight inches in diameter. It has a full suite of guidance, navigation, and control hardware and software, and is equipped with two digital video cameras and a high resolution still image camera. The vehicle is designed for either remotely piloted operations or supervised autonomous operations. Tests have been performed in both a six degree-of-freedom closed-loop orbital simulation and on an air-bearing table. The Mini AERCam system can also be used as a test platform for evaluating algorithms and relative navigation for autonomous proximity operations and docking around the Space Shuttle Orbiter or the ISS.

Wagenknecht, J.↗
NASA NTRS2010

Validating Human Performance Models of the Future Orion Crew Exploration Vehicle

NASA's Orion Crew Exploration Vehicle (CEV) will provide transportation for crew and cargo to and from destinations in support of the Constellation Architecture Design Reference Missions. Discrete Event Simulation (DES) is one of the design methods NASA employs for crew performance of the CEV. During the early development of the CEV, NASA and its prime Orion contractor Lockheed Martin (LM) strived to seek an effective low-cost method for developing and validating human performance DES models. This paper focuses on the method developed while creating a DES model for the CEV Rendezvous, Proximity Operations, and Docking (RPOD) task to the International Space Station. Our approach to validation was to attack the problem from several fronts. First, we began the development of the model early in the CEV design stage. Second, we adhered strictly to M&S development standards. Third, we involved the stakeholders, NASA astronauts, subject matter experts, and NASA's modeling and simulation development community throughout. Fourth, we applied standard and easy-to-conduct methods to ensure the model's accuracy. Lastly, we reviewed the data from an earlier human-in-the-loop RPOD simulation that had different objectives, which provided us an additional means to estimate the model's confidence level. The results revealed that a majority of the DES model was a reasonable representation of the current CEV design.

Wong, Douglas T.↗
DOE OSTI2015

Novel insights into the apoptosis mechanism of DNA topoisomerase I inhibitor isoliquiritigenin on HCC tumor cell

The inhibitory effect of DNA topoisomerase (Top I) by isoliquiritigenin(ISO) were investigated and their interaction mechanism was evaluated using methods including UV–vis absorption, fluorescence, coupled with molecular simulation, and using the MTT method of inhibition rate of HCC tumor cell SNU475 proliferation assay, finally, the interaction of ISO with calf thymus DNA was investigated by melting measurements and molecular docking studies. It was found that isoliquiritigenin reversibly inhibited DNA Top I in a competitive manner with the concentrations of ISO resulting in 50% activity lost (IC{sub 50}) were estimated to be 0.178 ± 0.12 mM. Isoliquiritigenin exhibited a strong ability to quench the intrinsic fluorescence of Top I through a static quenching procedure. The positive values of enthalpy change and entropy change suggested that the binding of isoliquiritigenin to Top I was driven mainly by hydrophobic interactions. The molecular docking results revealed isoliquiritigenin actually interacted with the primary amino acid residues on the active site of Top I, and the detection results of fluorescence staining and the inhibitory effect on the growth of HCC SUN475 showed that isoliquiritigenin induced the apoptosis cells increased gradually. The interaction of ISO with DNA can cause the denaturation temperature to be increased, which indicated that the stabilization of the DNA helix was increased in the presence of ISO, which indicated that the results provide strong evidence for intercalative binding of ISO with DNA. - Highlights: • ISO reversibly inhibits TOP I activity in an A dose dependent manner. • Hydrophobic interactions play a major role in ISO–TOP I interaction. • ISO has a high affinity close to the active site pocket of TOP I. • The binding of ISO to DNA induces the stability of the structure of DNA.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1994

Autonomous spacecraft executive and its application to rendezvous and docking

Autonomy is needed for future spacecraft to solve the problems of human operator overload and transmission delay. This paper describes the autonomous spacecraft executive for rendezvous and docking. It is an onboard expert system and has decision making capability for mission planning of nominal and contingency cases. The executive has been developed and verified using a hardware motion based simulator.

Komura, Fuminobu↗
NASA NTRS2010

Integration Assessment of Visiting Vehicle Induced Electrical Charging of the International Space Station Structure

The International Space Station (ISS) undergoes electrical charging in low Earth orbit (LEO) due to positively biased, exposed conductors on solar arrays that collect electrical charges from the space plasma. Exposed solar array conductors predominately collect negatively charged electrons and thus drive the metal ISS structure electrical ground to a negative floating potential (FP) relative to plasma. This FP is variable in location and time as a result of local ionospheric conditions. ISS motion through Earth s magnetic field creates an addition inductive voltage up to 20 positive and negative volts across ISS structure depending on its attitude and location in orbit. ISS Visiting Vehicles (VVs), such as the planned Orion crew exploration vehicle, contribute to the ISS plasma charging processes. Upon physical contact with ISS, the current collection properties of VVs combine with ISS. This is an ISS integration concern as FP must be controlled to minimize arcing of ISS surfaces and ensure proper management of extra vehicular activity crewman shock hazards. This report is an assessment of ISS induced charging from docked Orion vehicles employing negatively grounded, 130 volt class, UltraFlex (ATK Space Systems) solar arrays. To assess plasma electron current collection characteristics, Orion solar cell test coupons were constructed and subjected to plasma chamber current collection measurements. During these tests, coupon solar cells were biased between 0 and 120 V while immersed in a simulated LEO plasma. Tests were performed using several different simulated LEO plasma densities and temperatures. These data and associated theoretical scaling of plasma properties, were combined in a numerical model which was integrated into the Boeing Plasma Interaction Model. It was found that the solar array design for Orion will not affect the ISS FP by more than about 2 V during worst case charging conditions. This assessment also motivated a trade study to determine acceptable plasma electron current levels that can be collected by a single or combined fleet of ISS-docked VVs.

Kramer, Leonard↗
NASA NTRS1991

Autonomous docking ground demonstration (category 3)

The NASA Johnson Space Center (JSC) is involved in the development of an autonomous docking ground demonstration. The demonstration combines the technologies, expertise and facilities of the JSC Tracking and Communications Division (EE), Structures and Mechanics Division (ES), and the Navigation, Guidance and Control Division (EG) and their supporting contractors. The autonomous docking ground demonstration is an evaluation of the capabilities of the laser sensor system to support the docking phase (12ft to contact) when operated in conjunction with the Guidance, Navigation and Control Software. The docking mechanism being used was developed for the Apollo Soyuz Test Program. This demonstration will be conducted using the Six-Degrees of Freedom (6-DOF) Dynamic Test System (DTS). The DTS environment simulates the Space Station Freedom as the stationary or target vehicle and the Orbiter as the active or chase vehicle. For this demonstration the laser sensor will be mounted on the target vehicle and the retroreflectors on the chase vehicle. This arrangement was used to prevent potential damage to the laser. The sensor system. GN&C and 6-DOF DTS will be operated closed-loop. Initial condition to simulate vehicle misalignments, translational and rotational, will be introduced within the constraints of the systems involved. Detailed description of each of the demonstration components (e.g., Sensor System, GN&C, 6-DOF DTS and supporting computer configuration) including their capabilities and limitations will be discussed. A demonstration architecture drawing and photographs of the test configuration will be presented.

Lamkin, Steve L.↗
NASA NTRS2012

EMI from Spacecraft Docking Systems Spacecraft Charging - Plasma Contact Potentials

The plasma contact potential of a visiting vehicle (VV), such as the Orion Service Module (SM), is determined while docking at the Orion Crew Exploration Vehicle (CEV). Due to spacecraft charging effects on-orbit, the potential difference between the CEV and the VV can be large at docking, and an electrostatic discharge (ESD) could occur at capture, which could degrade, disrupt, damage, or destroy sensitive electronic equipment on the CEV and/or VV. Analytical and numerical models of the CEV are simulated to predict the worst-case potential difference between the CEV and the VV when the CEV is unbiased (solar panels unlit: eclipsed in the dark and inactive) or biased (solar panels sunlit: in the light and active).

Norgard, John D.↗
NASA NTRS1991

Results of prototype software development for automation of shuttle proximity operations

A Rendezvous Expert System (REX) was implemented on a Symbolics 3650 processor and integrated with the 6 DOF, high fidelity Systems Engineering Simulator (SES) at the NASA Johnson Space Center in Houston, Texas. The project goals were to automate the terminal phase of a shuttle rendezvous, normally flown manually by the crew, and proceed automatically to docking with the Space Station Freedom (SSF). The project goals were successfully demonstrated to various flight crew members, managers, and engineers in the technical community at JSC. The project was funded by NASA's Office of Space Flight, Advanced Program Development Division. Because of the complexity of the task, the REX development was divided into two distinct efforts. One to handle the guidance and control function using perfect navigation data, and another to provide the required visuals for the system management functions needed to give visibility to the crew members of the progress being made towards docking the shuttle with the LVLH stabilized SSF.

Hiers, Harry K.↗
NASA NTRS1991

An overview of autonomous rendezvous and docking system technology development at General Dynamics

The Centaur avionics suite is undergoing a dramatic modernization for the commercial, DoD Atlas and Titan programs. The system has been upgraded to the current state-of-the-art in ring laser gyro inertial sensors and Mil-Std-1750A processor technology. The Cruise Missile avionic system has similarly been evolving for many years. Integration of GPS into both systems has been underway for over five years with a follow-on cruise missile system currently in flight test. Rendezvous and Docking related studies have been conducted for over five years in support of OMV, CTV, and Advanced Upper Stages, as well as several other internal IR&D's. The avionics system and AR&D simulator demonstrated to the SATWG in November 1990 has been upgraded considerably under two IR&D programs in 1991. The Centaur modern avionics system is being flown in block upgrades which started in July of 1990. The Inertial Navigation Unit will fly in November of 1991. The Cruise Missile avionics systems have been fully tested and operationally validated in combat. The integrated AR&D system for space vehicle applications has been under development and testing since 1990. A Joint NASA / GD ARD&L System Test Program is currently being planned to validate several aspects of system performance in three different NASA test facilities in 1992.

Kuenzel, Fred↗
NASA NTRS2010

Orion Active Thermal Control System Dynamic Modeling Using Simulink/MATLAB

This paper presents dynamic modeling of the crew exploration vehicle (Orion) active thermal control system (ATCS) using Simulink (Simulink, developed by The MathWorks). The model includes major components in ATCS, such as heat exchangers and radiator panels. The mathematical models of the heat exchanger and radiator are described first. Four different orbits were used to validate the radiator model. The current model results were compared with an independent Thermal Desktop (TD) (Thermal Desktop, PC/CAD-based thermal model builder, developed in Cullimore & Ring (C&R) Technologies) model results and showed good agreement for all orbits. In addition, the Orion ATCS performance was presented for three orbits and the current model results were compared with three sets of solutions- FloCAD (FloCAD, PC/CAD-based thermal/fluid model builder, developed in C&R Technologies) model results, SINDA/FLUINT (SINDA/FLUINT, a generalized thermal/fluid network-style solver ) model results, and independent Simulink model results. For each case, the fluid temperatures at every component on both the crew module and service module sides were plotted and compared. The overall agreement is reasonable for all orbits, with similar behavior and trends for the system. Some discrepancies exist because the control algorithm might vary from model to model. Finally, the ATCS performance for a 45-hr nominal mission timeline was simulated to demonstrate the capability of the model. The results show that the ATCS performs as expected and approximately 2.3 lb water was consumed in the sublimator within the 45 hr timeline before Orion docked at the International Space Station.

Wang, Xiao-Yen J.↗
NASA NTRS1987

Space Station/Shuttle Orbiter dynamics during docking

Mathematical models of a reference space station configuration (Power Tower) and a Space Shuttle Orbiter are developed and used to study the dynamic behavior of the Space Station/Orbiter system just prior to and subsequent to an impulsive docking of the two spacecraft. The physical model of the space station is a collection of rigid and flexible bodies. The orbiter is modeled as a rigid body. An algorithm developed for use in digitally simulating the dynamics of the system is described and results of its application are presented.

Fitz-Coy, N. G.↗
NASA NTRS2015

Imaging Flash Lidar for Safe Landing on Solar System Bodies and Spacecraft Rendezvous and Docking

NASA has been pursuing flash lidar technology for autonomous, safe landing on solar system bodies and for automated rendezvous and docking. During the final stages of the landing from about 1 kilometer to 500 meters above the ground, the flash lidar can generate 3-Dimensional images of the terrain to identify hazardous features such as craters, rocks, and steep slopes. The onboard flight computer can then use the 3-D map of terrain to guide the vehicle to a safe location. As an automated rendezvous and docking sensor, the flash lidar can provide relative range, velocity, and bearing from an approaching spacecraft to another spacecraft or a space station. NASA Langley Research Center has developed and demonstrated a flash lidar sensor system capable of generating 16,000 pixels range images with 7 centimeters precision, at 20 Hertz frame rate, from a maximum slant range of 1800 m from the target area. This paper describes the lidar instrument and presents the results of recent flight tests onboard a rocket-propelled free-flyer vehicle (Morpheus) built by NASA Johnson Space Center. The flights were conducted at a simulated lunar terrain site, consisting of realistic hazard features and designated landing areas, built at NASA Kennedy Space Center specifically for this demonstration test. This paper also provides an overview of the plan for continued advancement of the flash lidar technology aimed at enhancing its performance to meet both landing and automated rendezvous and docking applications.

Amzajerdian, Farzin↗
NASA NTRSDate not supplied

Design, Development, and Test of the Advanced Apollo Orbital Assembly System

As spaceflight moves toward commercial solutions for Crew Vehicles and Space Stations, opportunity exists to lower costs with novel designs. Probe and cone docking systems provide a lightweight, low cost, and high-performance docking solution. This work revisits the Apollo probe and cone design and modifies it for the requirements of today’s computer-controlled spacecraft. This new system is called the Advanced Apollo Orbital Assembly (APOA) system, and is intended to support satellite, cargo, and space station assembly missions. A simulation of the APOA was programmed, components were sized, and a design was created by scaling the probe to the size of an EELV Secondary Payload Adapter (ESPA) tunnel. Prototype test hardware was 3D printed using Fused Deposition Modeling (FDM) methods with Polylactic Acid (PLA) material. Testing of the APOA-ESPA was conducted at Marshall Space Flight Center’s (MSFC) Flat Floor, and a test-correlated simulation is used to evaluate a Monte-Carlo of Initial Contact Conditions (ICC’s) to establish baseline performance. The successful development, test, and correlation of the APOA-ESPA proves the design validity and increases Technology Readiness Level (TRL) from 2 to 4. This work opens the door to construction of an APOA-ESPA from flight like materials, and to develop a larger scale prototype APOA. When the full scale APOA is incorporated with the Common Berthing Mechanism (CBM), becomes the Hybrid Berthing System (HBS), which allows for berthing without a robotic arm.

Berthing↗
NASA NTRS1991

Experimental validation of docking and capture using space robotics testbeds

This presentation describes the application of robotic and computer vision systems to validate docking and capture operations for space cargo transfer vehicles. Three applications are discussed: (1) air bearing systems in two dimensions that yield high quality free-flying, flexible, and contact dynamics; (2) validation of docking mechanisms with misalignment and target dynamics; and (3) computer vision technology for target location and real-time tracking. All the testbeds are supported by a network of engineering workstations for dynamic and controls analyses. Dynamic simulation of multibody rigid and elastic systems are performed with the TREETOPS code. MATRIXx/System-Build and PRO-MATLAB/Simulab are the tools for control design and analysis using classical and modern techniques such as H-infinity and LQG/LTR. SANDY is a general design tool to optimize numerically a multivariable robust compensator with a user-defined structure. Mathematica and Macsyma are used to derive symbolically dynamic and kinematic equations.

Spofford, John↗
NASA NTRS1990

Approach to large space structure control system design using traditional tools

This paper illustrates how traditional analysis and design tools can be successfully applied, with insights derived from recent research on control-structure interaction, to preliminary control system design for a large space structure such as the Space Station Freedom. The control system regulates attitude during construction, normal on-orbit operation, reboost, and docking using control-moment gyros and thrusters. The tools include finite-element modeling, model reduction based on modal truncation, single-input/single-output Bode plot design, position and rate feedback, roll-off and phase filter, and simulation. The resulting system is characterized by simple architecture and moderate bandwidth. The large configuration changes during the construction period are handled by gain scheduling.

Chu, P. Y.↗
NASA NTRS1988

CAMELOT 2: Personnel transport between Earth and Mars

A summary of the second phase of a design study fo a cycling spacecraft for regular and frequency personnel transport between Earth and a Mars base is presented. The first-phase study, called project CAMELOT, was a mission analysis and configuration design and was completed by the Space Systems Design class at the University of Michigan in the winter term, 1987. In the second phase, the configuration and component design has been developed by the Space Systems Design class in the winter term, 1988, beyond the initial configuration study. Analysis has led to numerous design modifications and improvements, as well as providing more detailed system definition. Major components of the second phase study include innovative detailed designs such as an interface between the rotating and non-rotating portions of the spacecraft, an elevator system that changes orientation to eliminate Coriolis forces, an electromagnetic radiation shield that significantly reduces the mass of the spacecraft, and a detailed assembly sequence and cost analysis. In addition, modifications to the propulsion and the power generation subsystems, taxi-docking facilities, and internal layout design have led to a more efficient, more reliable, and more comfortable vehicle. Finite-element stress and dynamic analysis has verified much of the system and indicates the validity of the design. Computer simulation of many moving components, including torus rotation, elevator and interface operations, and attitude control mechanisms further validate and support the various systems.

Source record↗
NASA NTRS1989

Simulated performance results of the OMV video compression telemetry system

The control system of NASA's Orbital Maneuvering Vehicle (OMV) will employ range/range-rate radar, a forward command link, and a compressed video return link. The video data is compressed by sampling every sixth frame of data; a rate of 5 frames/sec is adequate for the OMV docking speeds. Further axial compression is obtained, albeit at the expense of spatial resolution, by averaging adjacent pixels. The remaining compression is achieved on the basis of differential pulse-code modulation and Huffman run-length encoding. A concatenated error-correction coding system is used to protect the compressed video data stream from channel errors.

Ingels, Frank↗
NASA NTRS1999

Modified Truncated Cone Target Hyperthermal Atomic Oxygen Test Results

The modified truncated cone target is a docking target planned for use on the International Space Station. The current design consists of aluminum treated with a black dye anodize, then crosshairs are laser etched for a silvery color. Samples of the treated aluminum were exposed to laboratory simulation of atomic oxygen and ultraviolet radiation to determine if significant degradation might occur. Durability was evaluated based on the contrast ratio between the black and silvery white areas of the target. Degradation of optical properties appeared to level off after an initial period of exposure to atomic oxygen. The sample that was not alodined according to MIL-C-5541, type 1A, performed better than alodined samples.

Vaughn, J. A.↗