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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 793 records · Page 44

Space Launch System and Missions to Near Rectilinear Halo Orbits

The first major evolution of NASA’s Space Launch System (SLS) will begin its flights starting in the mid-2020’s. This new configuration, called Block 1B, replaces the Interim Cryogenic Propulsion Stage with a larger Exploration Upper Stage (EUS). The additional capability provided by the new upper stage will allow SLS to send heavier payloads into deep space. One destination of interest to the SLS program is called a Near Rectilinear Halo Orbit (NRHO). This is a type of lunar orbit with multiple advantages for deep space exploration. These benefits include Earth/lunar access, low station-keeping requirements, and high communication potential with Earth. Therefore, it is a leading candidate for the proposed Lunar Orbital Platform-Gateway (LOP-G). This paper will provide a detailed assessment of the SLS Block 1B requirements and capabilities for sending payloads to an NRHO. Analysts at Marshall Space Flight Center are producing a multi-year mission availability scan for the SLS Block 1B configuration to a predefined NRHO orbit. The analysis produces an optimized trajectory for each day of the scan window. A maximized payload and minimized propellant requirement are determined for each day. All maneuvers from launch to the end of the Trans-Lunar-Injection (TLI) are being modeled as finite burns. Injections into an NRHO are being modeled as impulsive maneuvers. The payload element is arbitrary, but includes sufficient mass to represent a large habitat or propulsion module. The resulting parameters of payload capability, delta-v requirements, and launch windows length vary over the course of the scan. Many launch days in the scan are eliminated in post-processing as they violate mission constraints such as payload mass and propellant usage to insert into an NRHO. Based off previous one-year scan results for the SLS Block 1B Design Analysis Cycle 2 (DAC-2), it is expected that there will be one to three days per week where the payload is able to insert into an NRHO within SLS constraints objectives. This scan provides results for longer than one-year, allowing analysts to better understand the launch availability and energy requirements of SLS Block 1B over time. The in-space mission design and scans utilize Copernicus, an n-body trajectory optimization tool originally developed out of the University of Texas at Austin with further development at Johnson Space Center in Houston, TX. To seed the in-space trajectory, Copernicus uses a plugin to call a database of SLS ascent trajectories optimized in the Program to Simulate Optimized Trajectories II (POST2). The ascent trajectories are developed using a framework that parametrizes payload mass and LEO inclination, and targets a 100 nmi (nautical mile) altitude circular parking orbit. Though this analysis is specific to the SLS program, it will provide a summary of mission design benefits and constraints associated with generic NRHO access, and may be applied to other programs or concepts that will utilize this orbit.

Statham, T. L.↗

A Joinable Undercarriage to Maximize Payload (JUMP) Lunar Lander for Cargo Delivery to the Lunar Surface

Currently, NASA has engaged industry to develop a series of small to medium capacity landers with payload capacities of up to 5-9 tons by the mid to late 2020s. This contrasts with the former Constellation program, where the Altair lunar lander was targeting a payload capability of roughly 14-20 tons. Investment in smaller landers may present future challenges in delivering habitat modules larger than lunar lander cabins or small logistics modules to the lunar surface. Additionally, given a projected SLS flight rate of 1-2 launches per year, a lunar surface buildup from small elements seems problematic at best. While commercial launchers provide a supplement to SLS, many of the current and projected launch vehicles deliver less than 20 tons to a Trans-Lunar Injection – even fewer to the lunar surface. However, a possible solution could emerge if the lander itself could be launched in pieces with a buildup in Cislunar space. Thus, launchers with these capacities could contribute to a lunar lander capable of delivering 30 tons or more to the lunar surface. This paper introduces the notional concept of a Joinable Undercarriage to Maximized Payload (JUMP) lander. Key elements of a proposed JUMP lander concept will be discussed, followed by recommendations and forward work.

Human spaceflight↗

Constrained structural dynamic model verification using free vehicle suspension testing methods

Verification of the validity of a spacecraft's structural dynamic math model used in computing ascent (or in the case of the STS, ascent and landing) loads is mandatory. This verification process requires that tests be carried out on both the payload and the math model such that the ensuing correlation may validate the flight loads calculations. To properly achieve this goal, the tests should be performed with the payload in the launch constraint (i.e., held fixed at only the payload-booster interface DOFs). The practical achievement of this set of boundary conditions is quite difficult, especially with larger payloads, such as the 12-ton Hubble Space Telescope. The development of equations in the paper will show that by exciting the payload at its booster interface while it is suspended in the 'free-free' state, a set of transfer functions can be produced that will have minima that are directly related to the fundamental modes of the payload when it is constrained in its launch configuration.

Blair, Mark A.↗

Lessons learned from evaluating launch-site processing problems of Space Shuttle payloads

The authors discuss a trend analysis program that is being conducted on the problem reports written during the processing of Space Shuttle payloads at Kennedy Space Center. The program is aimed at developing lessons learned that can both improve the effectiveness of the current payload processing cycles as well as help to guide the processing strategies for Space Station Freedom. The payload processing reports from STS 26R and STS 41 are used. A two-tier evaluation activity is described, and some typical results from the tier one analyses are presented.

Flores, Carlos A.↗

Slew disturbance compensation for multiple payloads of a flexible spacecrafts

This paper extends an earlier developed mirror motion compensation (MMC) scheme (Chu, 1989, 1990) which calculates, on-board and in real time, the spacecraft motion induced by a slewing payload, to cases where one of the four conditions of the MMC scheme is not met. The analysis, the design methodology, and a case study related to the application of MMC to compensation for flexibility effects are presented. A sensitivity study is carried out to determine the compensation efficiency when uncertainties exist in parameters of the dynamic interaction model.

Mclaren, Mark D.↗

Improving UV Resistance of High Strength Fibers Used In Large Scientific Balloons

For the last three decades, NASA has been involved in the development of giant balloons that are capable of lifting heavy payloads of equipment (such as large telescopes and scientific instruments) to the upper atmosphere. While the use of such balloons has led to scientific discoveries, the demand for competitive science payloads and observational programs continues to rise. The NASA Balloon Program Office has entered a new phase of research to develop an Ultra Long Duration Balloon (ULDB) that will lift payloads of up to 3,600 kg to altitudes of up to 40 km. The flight duration is targeted to ranges between 30 to 100 days. Attaining these target durations requires the development of a super-pressure balloon design. The use of textile structures have already been established in these missions in the form of high strength tendons essential for the super pressure pumpkin design. Unfortunately, high strength fibers lose significant strength upon exposure to Ultra Violet (UV) radiation. Such UV degradation poses a serious challenge for the development of the ULDB. To improve the mission performance of the ULDB, new methods for protecting the tendons from the environmental effects need to be developed. NASA and NC State University College of Textiles are undertaking a research program to address these issues. Four tracks have been identified to prepare finishes that are believed to enhance the resistance of high strength fibers to UV. These tracks are: (a) self-polymerizing, (b) diffusion application, (c) polymer-filled with 30-40% UV absorber, and (d) combination of dyeing plus surface application. Four high performance fibers have been selected for this research investigation. These are Vectran (trademark), Spectra (trademark), Kevlar (trademark) and, PBO (Zylon (trademark)). This work will address the current progress of evaluating the performance of the UV finishes. This will be accomplished by comparing the tensile properties (strength, breaking elongation, modulus, etc) of untreated, unexposed to UV fibers; untreated exposed to UV fibers; and treated exposed to UV fibers.

Said, M.↗

ACTS Propagation Measurements in Maryland and Virginia

Rapid growth in new satellite services incorporating very small aperture terminals (VSAT) and ultra small aperture terminals (USAT) is expected in the coming years. Small size terminals allow for widespread use of satellite services in small business and domestic applications. Due to congestion of lower frequency bands such as C and Ku, most of these services will use Ka-band (2/20 GHz) frequencies. Propagation impairments produced by the troposphere is a limiting factor for the effective use of the 20/30 GHz band and the use of smaller Earth terminals makes it difficult to provide sufficient link margins for propagation related outages. In this context, reliable prediction of propagation impairments for low margin systems becomes important. Due to the complexity of propagation phenomena propagation modeling is mainly attempted on an empirical basis. As such, the availability of reliable measured data that extend to probability levels well in excess of the traditional limit of 1 percent is of great importance in the development, validation, and refinement of propagation models. The beacon payload on the Advanced Communications Technology Satellite (ACTS) together with the propagation measurement terminals developed under the NASA ACTS propagation program provide an excellent opportunity to collect such data on a long-term basis. This paper presents the results of ACTS propagation measurements conducted in the Washington, DC metropolitan area by COMSAT Laboratories.

Dissanayake, Asoka↗

Host computer software specifications for a zero-g payload manhandling simulator

The HP PASCAL source code was developed for the Mission Planning and Analysis Division (MPAD) of NASA/JSC, and takes the place of detailed flow charts defining the host computer software specifications for MANHANDLE, a digital/graphical simulator that can be used to analyze the dynamics of onorbit (zero-g) payload manhandling operations. Input and output data for representative test cases are contained.

Wilson, S. W.↗

Plan of advanced satellite communications experiment using ETS-VI

Communications Research Laboratory (CRL, Ministry of Posts and Telecommunications, Japan) has been engaged in development of three advanced satellite communication payloads aiming at experiments by Japan's 2-ton class Engineering Test Satellite VI (ETS-VI) which is to be launched in H-II rocket by NASDA in August 1992. CRL's three experimental systems are: (1) S-band inter-satellite communications; (2) millimeter-wave inter-satellite and personal-satellite communications; and (3) optical inter-satellite communications. CRL develops experimental optical communication system with telescope of 75 mm diameter which has gimbal mirror beam pointing/tracking mechanism. The onboard system has fundamental optical communication functions with laser diode transmitter of wavelength 0.83 micron, laser beam point-ahead mechanism, receiver of wavelength 0.51 micron, modulation/demodulation subsystem, and so on.

Shiomi, Tadashi↗

Recovery of sounding rocket payloads by center-of-gravity position control.

A computerized procedure has been developed to predict dynamic pressure at parachute deployment altitude. Inputs to the program are payload geometry, center-of-gravity position, velocity, and altitude at start of reentry. Payload is assumed to be trimmed, and potential and cross-flow drag theory is used to compute trim angle-of-attack and trim drag coefficient as a function of free-stream Mach number. The computations involve only simple geometric quantities and closed-form equations. Payload flight path is assumed to be vertical, and equations of motion of the payload are integrated from start of reentry to chute deployment altitude.

Mcgarvey, J. F.↗

Guidelines for structural verification and fracture control of Shuttle payloads

The procedures followed by the NASA Office of the Chief Engineer in developing the guidelines concerning the structures, materials, and fracture control of the Space Shuttle payloads are described. Factors controlling the payload launch safety, such as crew and passenger safety, reusability, and mixes of payloads in a single launch are emphasized. Special consideration is given to the STS design and testing approaches, materials considerations, safety criticality review processes, nondestructive evaluation inspection for STS payload fracture control, fracture mechanics screening procedures, and components of special concern (e.g., pressurized vessels, fasteners, and composite structures).

Lifer, C. E.↗

Space station payload operations scheduling with ESP2

The Mission Analysis Division of the Systems Analysis and Integration Laboratory at the Marshall Space Flight Center is developing a system of programs to handle all aspects of scheduling payload operations for Space Station. The Expert Scheduling Program (ESP2) is the heart of this system. The task of payload operations scheduling can be simply stated as positioning the payload activities in a mission so that they collect their desired data without interfering with other activities or violating mission constraints. ESP2 is an advanced version of the Experiment Scheduling Program (ESP) which was developed by the Mission Integration Branch beginning in 1979 to schedule Spacelab payload activities. The automatic scheduler in ESP2 is an expert system that embodies the rules that expert planners would use to schedule payload operations by hand. This scheduler uses depth-first searching, backtracking, and forward chaining techniques to place an activity so that constraints (such as crew, resources, and orbit opportunities) are not violated. It has an explanation facility to show why an activity was or was not scheduled at a certain time. The ESP2 user can also place the activities in the schedule manually. The program offers graphical assistance to the user and will advise when constraints are being violated. ESP2 also has an option to identify conflict introduced into an existing schedule by changes to payload requirements, mission constraints, and orbit opportunities.

Stacy, Kenneth L.↗

Life sciences experiments in the first Spacelab mission

The development of the Shuttle Transportation System (STS) by the United States and the Spacelab pressurized modules and pallets by the European Space Agency (ESA) presents a unique multi-mission space experimentation capability to scientists and researchers of all disciplines. This capability is especially pertinent to life scientists involved in all areas of biological and behavioral research. This paper explains the solicitation, evaluation, and selection process involved in establishing life sciences experiment payloads. Explanations relative to experiment hardware development, experiment support hardware (CORE) concepts, hardware integration and test, and concepts of direct Principal Investigator involvement in the missions are presented as they are being accomplished for the first Spacelab mission. Additionally, discussions of future plans for life sciences dedicated Spacelab missions are included in an attempt to define projected capabilities for space research in the 1980s utilizing the STS.

Huffstetler, W. J.↗

Advanced science and applications space platform

Requirements for and descriptions of the mission equipment, subsystems, configuration, utilities, and interfaces for an Advanced Science and Applications Space Platform (ASASP) are developed using large space structure technology. Structural requirements and attitude control system concepts are emphasized. To support the development of ASASP requirements, a mission was described that would satisfy the requirements of a representative set of payloads requiring large separation distances selected from the Science and Applications Space Platform data base. Platform subsystems are defined which support the payload requirements and a physical platform concept is developed. Structural system requirements which include utilities accommodation, interface requirements, and platform strength and stiffness requirements are developed. An attitude control system concept is also described. The resultant ASASP is analyzed and technological developments deemed necessary in the area of large space systems are recommended.

White, J.↗

International Launch Vehicle Selection for Interplanetary Travel

In developing a mission strategy for interplanetary travel, the first step is to consider launch capabilities which provide the basis for fundamental parameters of the mission. This investigation focuses on the numerous launch vehicles of various characteristics available and in development internationally with respect to upmass, launch site, payload shroud size, fuel type, cost, and launch frequency. This presentation will describe launch vehicles available and in development worldwide, then carefully detail a selection process for choosing appropriate vehicles for interplanetary missions focusing on international collaboration, risk management, and minimization of cost. The vehicles that fit the established criteria will be discussed in detail with emphasis on the specifications and limitations related to interplanetary travel. The final menu of options will include recommendations for overall mission design and strategy.

Ferrone, Kristine↗

Mission planning for the Lidar in Space Technology Experiment

Developing a mission planning system for a Space Shuttle mission is a complex procedure. Several months of preparation are required to develop a plan that optimizes science return during the short operations time frame. Further complicating the scenario is the necessity to schedule around crew activities and other payloads which share Orbiter resources. SpaceTec, Inc. developed the mission planning system for the Lidar In Space Technology Experiment, or LITE, which flew on Space Shuttle mission STS-64 in September of 1994. SpaceTec used a combination of off-th-shelf and in-house developed software to analyze various mission scenarios both premission and real-time during the flight. From this analysis, SpaceTec developed a comprehensive mission plan that met the mission objectives.

Redifer, Matthew E.↗

Consort 3 flight experiments

The third sounding rocket payload in the Consort program was launched from the White Sands Missile Range on May 16, 1990. It carried 12 experiments designed to investigate materials processes in low gravity. All of the experiments were reflights from the Consort 2 payload that was launched on November 1989 but failed to achieve microgravity because of a malfunction in the launch vehicle. Four national Centers for the Commercial Development of Space participated in the mission. The payload included five experiments and two accelerometer systems that flew on Consort 1 and seven new experiments, designed and developed since Consort 1. Experiments from Consort 1 incorporated hardware modifications and changes in experimental parameters based on mission results. The new experiments covered a variety of polymeric and biological investigations. A new power distribution and control system designed to provide discrete, computer-supervised, experiment power monitoring and control was flight qualified on Consort 3. Consort 3 featured very late access (3-5 h before launch vs 27-30 h for Consort 1) for installation of sensitive biological specimens. The integrated payload and mission sequence of events are described. Changes in the Consort 1 experiments are defined and the objectives, methods, and expectations for new experiments are discussed.

Wessling, Francis C.↗

Invite the Chaos Monkey: Test Effect Payloads for Tuning ICS Incident Response

In 2010, when Netflix moved their operational systems to the cloud, they developed a pseudo-random mechanism to cause deliberate outages and failures of key system elements to ensure that automated systems for detecting and remediating outages were mature and fully functional. This Chaos Monkey spawned an entire Simian Army designed to ensure system resilience and enable failure response before issues became outages. Through the DARPA RADICS program, Provatech, INL, and other researchers have developed a mechanism for creating controllable failures via Test Effect Payloads (TEPs) for Industrial Control Systems in order to enable an asset owner to tune network and process sensor technology, increase the effectiveness of incident response and remediation, and highlight areas where resilient technology could bring benefit to Operational Technology. This talk will explore what a TEP is, how to create a TEP, and suggest what a systematic system resilience plan using TEP’s might look like. We will also discuss how regulated entities might employ TEP’s in a compliant resilience strategy.

42 ENGINEERING↗