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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Ground Contact Model for Mars Science Laboratory Mission Simulations

The Program to Optimize Simulated Trajectories II (POST 2) has been successful in simulating the flight of launch vehicles and entry bodies on earth and other planets. POST 2 has been the primary simulation tool for the Entry Descent, and Landing (EDL) phase of numerous Mars lander missions such as Mars Pathfinder in 1997, the twin Mars Exploration Rovers (MER-A and MER-B) in 2004, Mars Phoenix lander in 2007, and it is now the main trajectory simulation tool for Mars Science Laboratory (MSL) in 2012. In all previous missions, the POST 2 simulation ended before ground impact, and a tool other than POST 2 simulated landing dynamics. It would be ideal for one tool to simulate the entire EDL sequence, thus avoiding errors that could be introduced by handing off position, velocity, or other fight parameters from one simulation to the other. The desire to have one continuous end-to-end simulation was the motivation for developing the ground interaction model in POST 2. Rover landing, including the detection of the postlanding state, is a very critical part of the MSL mission, as the EDL landing sequence continues for a few seconds after landing. The method explained in this paper illustrates how a simple ground force interaction model has been added to POST 2, which allows simulation of the entire EDL from atmospheric entry through touchdown.

Raiszadeh, Behzad↗
NASA NTRSDate not supplied

ISS External Microorganisms: Tools and Techniques for Collecting Planetary Protection Samples During Extravehicular Activity

We have designed, built, and tested a sampling kit (Fig. 1) to aseptically collect microbiological samples from exterior surfaces on the ISS (International Space Station). The kit was flown to ISS as part of the NG-19 commercial cargo mission in August of 2023. Astronauts will use the kit to collect samples from six exterior surfaces on ISS. These samples will be frozen at -80°C after collection and returned to the ground for next generation DNA sequencing. The results of this experiment will help inform planetary protection requirements for crewed missions. We hypothesize that there are detectable microbial communities outside ISS and that these communities originate from inside ISS. Current life support systems do not include any components for reducing microbial leakage. Gases are vented from inside ISS without filtration and there are currently no protocols in place to minimize bioburden on space suit exteriors prior to use. It is important to quantify the bioburden on current vehicles so that achievable limits can be set for crewed missions to astrobiologically relevant locations like Mars.

Planetary Protection↗
NASA NTRS1990

X-ray emission from normal stars

The paper addresses the potential for future X-ray missions to determine the fundamental cause of stellar X-ray emissions based on available results and existing analyses. The determinants of stellar X-ray emission are listed, and the relation of stellar X-ray emissions to the 'universal' activity-rotation connection is discussed. The specific rotation-activity connection for evolved stars is mentioned, and the 'decay' of stellar activity at the low-mass end of the main sequence is related to observational data. The data from Einstein and EXOSAT missions that correspond to these issues are found to be sparse, and more observational work is found to be necessary. Also, it is concluded that some issues need to be addressed, such as the X-ray dividing line in evolved stars and the absence of X-ray emission from dA stars. The related observational requirements and instrumental capabilities are given for each significant research focus.

Rosner, Robert↗
NASA NTRS1994

Increases in efficiency and enhancements to the Mars Observer non-stored commanding process

The Mars Observer team was, until the untimely loss of the spacecraft on August 21, 1993, performing flight operations with greater efficiency and speed than any previous JPL mission of its size. This level of through-put was made possible by a mission operations system which was composed of skilled personnel using sophisticated sequencing and commanding tools. During cruise flight operations, however, it was realized by the project that this commanding level was not going to be sufficient to support the activities planned for mapping operations. The project had committed to providing the science instrument principle investigators with a much higher level of commanding during mapping. Thus, the project began taking steps to enhance the capabilities of the flight team. One mechanism used by project management was a tool available from total quality management (TQM). This tool is known as a process action team (PAT). The Mars Observer PAT was tasked to increase the capacity of the flight team's nonstored commanding process by fifty percent with no increase in staffing and a minimal increase in risk. The outcome of this effort was, in fact, to increase the capacity by a factor of 2.5 rather than the desired fifty percent and actually reduce risk. The majority of these improvements came from the automation of the existing command process. These results required very few changes to the existing mission operations system. Rather, the PAT was able to take advantage of automation capabilities inherent in the existing system and make changes to the existing flight team procedures.

Brooks, Robert N., Jr.↗
NASA NTRS1973

Mariner 9 data storage subsystem flight performance summary

The performance is summarized of the Mariner 9 Data Storage Subsystem (DSS) throughout the primary and extended missions. Information presented is limited to reporting of anomalies which occurred during the playback sequences. Tables and figures describe the anomalies (dropouts, missing and added bits, in the imaging data) as a function of time (accumulated tape passes). The data results indicate that the performance of the DSS was satisfactory and within specification throughout the mission. The data presented is taken from the Spacecraft Team Incident/Surprise Anomaly Log recorded during the mission. Pertinent statistics concerning the tape transport performance are given. Also presented is a brief description of DSS operation, particularly that related to the recorded anomalies. This covers the video data encoding and how it is interpreted/decoded by ground data processing and the functional operation of the DSS in abnormal conditions such as loss of lock to the playback signal.

Thomas, N. E.↗
NASA NTRS1994

(abstract) Pluto Integrated Camera-Spectrometer (PICS): a Low Mass, Low Power Instrument for Planetary Exploration

The concept we describe is an integrated instrument (a Pluto Integrated Camera-Spectrometer -- PICS) that will perform the functions of all three optical instruments required by the Pluto Fast Flyby Mission: the near-IR spectrometer, the camera, and the UV spectrometer. This integrated approach minimizes mass and power use. It also forced us early in the conceptual design to consider integrated observational sequences and integrated power management, thus ensuring compatible duty cycles (i.e., exposure times, readout rates) to meet the composite requirements for data collection, compression, and storage. Based on flight mission experience we believe that this integrated approach will result in substantial cost savings, both in reworking instrument designs during accommodation, as well as in sequence planning and integration. Finally, this integrated payload automatically yields a cohesive mission data set, optimized for correlative analysis. The presentation will provide details of the PICS instrument design and describe the fabrication and testing of the integrated SiC structure and optics at SSG Inc. Final integration and test plans for the prototype will also be described.

Pluto↗
NASA NTRS1993

Analysis of the GOES 6.7 micrometer channel observations during FIRE 2

Clouds form in moist environments. FIRE Phase II Cirrus Implementation Plan (August, 1990) noted the need for mesoscale measurements of upper tropospheric water vapor content. These measurements are needed for initializing and verifying numerical weather prediction models and for describing the environment in which cirrus clouds develop and dissipate. Various instruments where deployed to measure the water vapor amounts of the upper troposphere during FIRE II (e.g. Raman lidar, CLASS sonds and new cryogenic frost hygrometer on-board aircraft). The formation, maintenance and dissipation of cirrus clouds involve the time variation of the water budget of the upper troposphere. The GOES 6.7 mu m radiance observations are sensitive to the upper tropospheric relative humidity, and therefore proved extremely valuable in planning aircraft missions during the field phase of FIRE II. Warm 6.7 mu m equivalent black body temperatures indicate a relatively dry upper troposphere and were associated with regions generally free of cirrus clouds. Regions that were colder, implying more moisture was available may or may not have had cirrus clouds present. Animation of a time sequence of 6.7 mu m images was particularly useful in planning various FIRE missions. The 6.7 mu m observations can also be very valuable in the verification of model simulations and describing the upper tropospheric synoptic conditions. A quantitative analysis of the 6.7 mu m measurement is required to successfully incorporate these satellite observations into describing the upper tropospheric water vapor budget. Recently, Soden and Bretherton (1993) have proposed a method of deriving an upper tropospheric humidity based on observations from the GOES 6.7 mu m observations. The method is summarized in the next section. In their paper they compare their retrieval method to radiance simulations. Observations were also compared to ECMWF model output to assess the model performance. The FIRE experiment provides a unique opportunity to further verify the GOES upper tropospheric relative humidity retrieval scheme by providing (1) aircraft observations to cross-validate the calibration of the GOES 6.7 mu m channel, (2) accurate upper tropospheric water vapor concentrations for verification, and (3) veritical variability of upper tropospheric water vapor.

Soden, B. J.↗
NASA NTRS1984

Alternative gravity-assist sequences for the ISEE-3 escape trajectory

The International Sun-Earth Explorer-3 (ISEE-3) was moved from its mission halo orbit upstream of the earth's magnetosphere on June 10, 1982. Multiple lunar swingby maneuvers were then used to shape the trajectory for extensive exploration of the distant geomagnetic tail and finally to place the spacecraft on a course that will intercept the comet Giacobini-Zinner on September 11, 1985. With this new mission objective, the spacecraft was renamed the International Cometary Explorer (ICE). A double-lunar-swingby control technique involving five passes by the moon was eventually implemented to accomplish this, but in the process of finding this solution several feasible, though less optimal, alternative trajectory sequences implementing the same procedure were discovered. This paper provides a descriptive comparison of these very different orbital profiles and serves to illustrate the utility and great flexibility of this orbital control procedure. Targeting methodology for finding constrained solutions in this space is also presented.

Muhonen, D.↗
NASA NTRS1973

Systems design study of the Pioneer Venus spacecraft. Volume 1. Technical analyses and tradeoffs, sections 1-4 (part 1 of 4)

The results are reported of the Pioneer Venus studies from 2 October 1972 through 30 June 1973. Many missions were considered, involving two launch vehicles (Thor/Delta and Atlas/Centaur), and different launch opportunities and spacecraft configurations to meet varying science requirements, all at minimum cost. The sequence of events is described and the specific studies conducted are summarized. The effects of science payload on mission and spacecraft design are discussed along with the mission analyses.

Source record↗
NASA NTRS2017

A Simulation Based Investigation of High Latency Space Systems Operations

This study was the first in a series of planned tests to use physics-based subsystem simulations to investigate the interactions between a spacecraft's crew and a ground-based mission control center for vehicle subsystem operations across long communication delays. The simulation models the life support system of a deep space habitat. It contains models of an environmental control and life support system, an electrical power system, an active thermal control systems, and crew metabolic functions. The simulation has three interfaces: 1) a real-time crew interface that can be use to monitor and control the subsystems; 2) a mission control center interface with data transport delays up to 15 minute each way; and 3) a real-time simulation test conductor interface used to insert subsystem malfunctions and observe the interactions between the crew, ground, and simulated vehicle. The study was conducted at the 21st NASA Extreme Environment Mission Operations (NEEMO) mission. The NEEMO crew and ground support team performed a number of relevant deep space mission scenarios that included both nominal activities and activities with system malfunctions. While this initial test sequence was focused on test infrastructure and procedures development, the data collected in the study already indicate that long communication delays have notable impacts on the operation of deep space systems. For future human missions beyond cis-lunar, NASA will need to design systems and support tools to meet these challenges. These will be used to train the crew to handle critical malfunctions on their own, to predict malfunctions and assist with vehicle operations. Subsequent more detailed and involved studies will be conducted to continue advancing NASA's understanding of space systems operations across long communications delays.

Li, Zu Qun↗
NASA NTRS2017

A Simulation Based Investigation of High Latency Space Systems Operations

This study was the first in a series of planned tests to use physics-based subsystem simulations to investigate the interactions between a spacecraft's crew and a ground-based mission control center for vehicle subsystem operations across long communication delays. The simulation models the life support system of a deep space habitat. It contains models of an environmental control and life support system, an electrical power system, an active thermal control system, and crew metabolic functions. The simulation has three interfaces: 1) a real-time crew interface that can be use to monitor and control the subsystems; 2) a mission control center interface with data transport delays up to 15 minute each way; and 3) a real-time simulation test conductor interface used to insert subsystem malfunctions and observe the interactions between the crew, ground, and simulated vehicle. The study was conducted at the 21st NASA Extreme Environment Mission Operations (NEEMO) mission. The NEEMO crew and ground support team performed a number of relevant deep space mission scenarios that included both nominal activities and activities with system malfunctions. While this initial test sequence was focused on test infrastructure and procedures development, the data collected in the study already indicate that long communication delays have notable impacts on the operation of deep space systems. For future human missions beyond cis-lunar, NASA will need to design systems and support tools to meet these challenges. These will be used to train the crew to handle critical malfunctions on their own, to predict malfunctions, and to assist with vehicle operations. Subsequent more detailed and involved studies will be conducted to continue advancing NASA's understanding of space systems operations across long communications delays.

Li, Zu Qun↗
NASA NTRS2015

Mars Reconnaissance Orbiter Navigation Strategy for Dual Support of Insight and ExoMars Entry, Descent and Landing Demonstrator Module in 2016

Mars Reconnaissance Orbiter (MRO) will support NASA's InSight Mission and ESA's ExoMars Entry, Descent and Landing Demonstrator Module (EDM) in the fall of 2016 when both landers arrive at Mars. MRO provided relay support during the Entry, Descent and Landing (EDL) sequences of Mars Phoenix Lander in 2008 and the Mars Science Laboratory in 2012. Unlike these missions, MRO will coordinate between two EDL events separated by only three weeks: InSight on September 28, 2016 and EDM on October 19, 2016. This paper describes MRO Navigation's maneuver strategy to move MRO's ascending node to meet the In- Sight EDL phasing requirement and support EDM.

EDM↗
NASA NTRS1993

Mars Observer Lecture: Mars Orbit Insertion

The Mars Observer mission spacecraft was primarily designed for exploring Mars and the Martian environment. The Mars Observer was launched on September 25, 1992. The spacecraft was lost in the vicinity of Mars on August 21, 1993 when the spacecraft began its maneuvering sequence for Martian orbital insertion. This videotape shows a lecture by Suzanne R. Dodd, the Mission Planning Team Chief for the Mars Observer Project. Ms Dodd begins with a brief overview of the mission and the timeline from the launch to orbital insertion. Ms Dodd then reviews slides showing the trajectory of the spacecraft on its trip to Mars. Slides of the spacecraft being constructed are also shown. She then discusses the Mars orbit insertion and the events that will occur to move the spacecraft from the capture orbit into a mapping orbit. During the trip to Mars, scientists at JPL had devised a new strategy, called Power In that would allow for an earlier insertion into the mapping orbit. The talk summarizes this strategy, showing on a slide the planned transition orbits. There are shots of the Martian moon, Phobos, taken from the Viking spacecraft, as Ms Dodd explains that the trajectory will allow the orbiter to make new observations of that moon. She also explains the required steps to prepare for mapping after the spacecraft has achieved the mapping orbit around Mars. The lecture ends with a picture of Mars from the Observer on its approach to the planet.

Dodd, Suzanne R.↗
NASA NTRS2010

Incorporating Vibration Test Results for the Advanced Stirling Convertor into the System Dynamic Model

The U.S. Department of Energy (DOE), Lockheed Martin Corporation (LM), and NASA Glenn Research Center (GRC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. As part of the extended operation testing of this power system, the Advanced Stirling Convertors (ASC) at NASA GRC undergo a vibration test sequence intended to simulate the vibration history that an ASC would experience when used in an ASRG for a space mission. During these tests, a data system collects several performance-related parameters from the convertor under test for health monitoring and analysis. Recently, an additional sensor recorded the slip table position during vibration testing to qualification level. The System Dynamic Model (SDM) integrates Stirling cycle thermodynamics, heat flow, mechanical mass, spring, damper systems, and electrical characteristics of the linear alternator and controller. This Paper presents a comparison of the performance of the ASC when exposed to vibration to that predicted by the SDM when exposed to the same vibration.

Meer, David W.↗
NASA NTRS2011

MPS Editor

Previously, it was time-consuming to hand-edit data and then set up simulation runs to find the effect and impact of the input data on a spacecraft. MPS Editor provides the user the capability to create/edit/update models and sequences, and immediately try them out using what appears to the user as one piece of software. MPS Editor provides an integrated sequencing environment for users. It provides them with software that can be utilized during development as well as actual operations. In addition, it provides them with a single, consistent, user friendly interface. MPS Editor uses the Eclipse Rich Client Platform to provide an environment that can be tailored to specific missions. It provides the capability to create and edit, and includes an Activity Dictionary to build the simulation spacecraft models, build and edit sequences of commands, and model the effects of those commands on the spacecraft. MPS Editor is written in Java using the Eclipse Rich Client Platform. It is currently built with four perspectives: the Activity Dictionary Perspective, the Project Adaptation Perspective, the Sequence Building Perspective, and the Sequence Modeling Perspective. Each perspective performs a given task. If a mission doesn't require that task, the unneeded perspective is not added to that project's delivery. In the Activity Dictionary Perspective, the user builds the project-specific activities, observations, calibrations, etc. Typically, this is used during the development phases of the mission, although it can be used later to make changes and updates to the Project Activity Dictionary. In the Adaptation Perspective, the user creates the spacecraft models such as power, data store, etc. Again, this is typically used during development, but will be used to update or add models of the spacecraft. The Sequence Building Perspective allows the user to create a sequence of activities or commands that go to the spacecraft. It provides a simulation of the activities and commands that have been created.

Mathews, William S.↗
NASA NTRS1975

A timeline algorithm for astronomy missions

An algorithm is presented for generating viewing timelines for orbital astronomy missions of the pointing (nonsurvey/scan) type. The algorithm establishes a target sequence from a list of candidate targets in a way which maximizes total viewing time. Two special cases are treated. One concerns dim targets which, due to lighting constraints, are scheduled only during the antipolar portion of each orbit. They normally require long observation times extending over several revolutions. A minimum slew heuristic is employed to select the sequence of dim targets. The other case deals with bright, or short duration, targets, which have less restrictive lighting constraints and are scheduled during the portion of each orbit when dim targets cannot be viewed. Since this process moves much more rapidly than the dim path, an enumeration algorithm is used to select the sequence that maximizes total viewing time.

Moore, J. E.↗
NASA NTRS1981

Improved NOAA satellite scheduled for launch

A description of the NOAA-C satellite and its Atlas launch vehicle are presented. The satellite instrumentation and data transmission systems are discussed. A flight sequence of events is given along with a listing of the mission management responsibilities.

Brennan, W. J.↗