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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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NASA NTRS2005

The Effects of Thrust Uncertainty and Attitude Knowledge Errors on the MMS Formation Maintenance Maneuver

The Magnetospheric Multiscale (MMS) Mission will use a formation of four spinning spacecraft to study the Earth s magnetosphere. The science objectives of MMS require a near-regular tetrahedron formation to be maintained with side lengths ranging from ten kilometers to several thousand kilometers at orbit apogee. To reduce spacecraft complexity and cost, the current mission concept assumes MMS can achieve its formation goals through open-loop orbit control from the ground, rather than in-flight, closed-loop formation control that has been the subject of recent study. Significant analysis has been performed to provide optimal reference orbit and relative orbit designs. However, the feasibility of achieving these orbits, and maintaining them for an extended period of time in the presence of real world errors and perturbations has not been investigated. In particular, attitude knowledge and control errors, which may have a negligible effect on orbit control for conventional missions with spinning spacecraft, can contribute significant errors to the MMS orbits. In this work, a 6 degree-of-freedom (DOF) simulation is developed and used to analyze the effects of realistic errors on formation maintenance maneuver accuracy. Several realistic considerations including a finite-burn model, attitude perturbations, and thrust uncertainty are studied. The primary objective is to quantify the effects of realistic attitude and orbit control, knowledge, and actuator errors on the formation geometry by observing representative maneuver errors of a single spacecraft.

Tsai, Dean C.↗

NASA NTRS1975

Dual shear plate power processor packaging design

The use of solar electric propulsion (SEP) for spacecraft primary propulsion imposes an extreme range of operational and environmental design requirements associated with the diversity of missions for which solar electric primary propulsion is advantageous. One SEP element which is particularly sensitive to these environmental extremes is the power processor unit (PPU) which powers and controls the electric ion thruster. An improved power processor thermal-mechanical packaging approach, referred to as dual shear plate packaging, has been designed to accommodate these different requirements with minimum change to the power processor design. Details of this packaging design are presented together with test results obtained from thermal-vacuum and structural-vibration tests conducted with prototype hardware.

Franzon, A. O.↗

NASA NTRS1989

Cosmic Background Explorer (COBE) press kit

COBE, the Cosmic Background Explorer spacecraft, and its mission are described. COBE was designed to study the origin and dynamics of the universe including the theory that the universe began with a cataclysmic explosion referred to as the Big Bang. To this end, earth's cosmic background - the infrared radiation that bombards earth from every direction - will be measured by three sophisticated instruments: the Differential Microwave Radiometer (DMR), the Far Infrared Absolute Spectrophotometer (FIRAS), and the Diffuse Infrared Background Experiment (DIRBE).

Source record↗

NASA NTRS2011

Orion Crew Module Aerodynamic Testing

The Apollo-derived Orion Crew Exploration Vehicle (CEV), part of NASA s now-cancelled Constellation Program, has become the reference design for the new Multi-Purpose Crew Vehicle (MPCV). The MPCV will serve as the exploration vehicle for all near-term human space missions. A strategic wind-tunnel test program has been executed at numerous facilities throughout the country to support several phases of aerodynamic database development for the Orion spacecraft. This paper presents a summary of the experimental static aerodynamic data collected to-date for the Orion Crew Module (CM) capsule. The test program described herein involved personnel and resources from NASA Langley Research Center, NASA Ames Research Center, NASA Johnson Space Flight Center, Arnold Engineering and Development Center, Lockheed Martin Space Sciences, and Orbital Sciences. Data has been compiled from eight different wind tunnel tests in the CEV Aerosciences Program. Comparisons are made as appropriate to highlight effects of angle of attack, Mach number, Reynolds number, and model support system effects.

Murphy, Kelly J.↗

NASA NTRS2008

The Apollo Experience Lessons Learned for Constellation Lunar Dust Management

In 2008, NASA was embarking on its Exploration Vision, knowing that many technical challenges would be encountered. For lunar exploration missions, one challenge was to learn to manage lunar dust. References to problems associated with lunar dust during the Apollo Program were found on many of pages of the mission reports and technical debriefs. All engineers designing hardware that would come into contact with lunar dust had to mitigate its effects in the design.

Wagner, Sandra↗

NASA NTRS2017

Venus Global Reference Atmospheric Model

Venus Global Reference Atmospheric Model (Venus-GRAM) is an engineering-level atmospheric model developed by MSFC that is widely used for diverse mission applications including: Systems design; Performance analysis; Operations planning for aerobraking, Entry, Descent and Landing, and aerocapture; Is not a forecast model; Outputs include density, temperature, pressure, wind components, and chemical composition; Provides dispersions of thermodynamic parameters, winds, and density; Optional trajectory and auxiliary profile input files Has been used in multiple studies and proposals including NASA Engineering and Safety Center (NESC) Autonomous Aerobraking and various Discovery proposals; Released in 2005; Available at: https://software.nasa.gov/software/MFS-32314-1.

Justh, Hilary L.↗

NASA NTRSDate not supplied

Applying Formal Methods to Safety-Critical Systems

How do you know a proof is correct? Traditionally, mathematical proofs are socially verified – at least one human, following a set of implicit rules of natural language and logic, determines if the proof is believable. If the proof becomes overly tedious and/or is essential to some safety- or mission-critical application, it becomes necessary to determine the soundness to a higher standard. 'Formal methods' refer to mathematically rigorous techniques and tools that enable specification, design, and verification of hardware and software systems. The specification used in formal methods are statements in a mathematical logic while the formal verifications are deductions in that logic. Formal methods can be difficult or time/resource intensive, but offer a higher level of assurance than standard verification through testing or handwritten proofs. This talk will introduce formal methods, motivated by applications of interest to NASA, including uncrewed aircraft operations in the national airspace, urban air environments, and wildfire areas. The audience will be given a crash course in mechanically verified proofs in the Prototype Verification System (PVS), an interactive theorem prover.

Formal Methods↗

NASA NTRS2012

EUROPA Multiple-Flyby Trajectory Design

As reinforced by the 2011 NRC Decadal Survey, Europa remains one of the most scientifically intriguing targets in planetary science due to its potential suitability for life. However, based on JEO cost estimates and current budgetary constraints, the Decadal Survey recommended-and later directed by NASA Headquarters-a more affordable pathway to Europa exploration be derived. In response, a flyby-only proof-of-concept trajectory has been developed to investigate Europa. The trajectory, enabled by employing a novel combination of new mission design techniques, successfully fulfills a set of Science Definition Team derived scientific objectives carried out by a notional payload including ice penetrating radar, topographic imaging, and short wavelength infrared observations, and ion neutral mass spectrometry in-situ measurements. The current baseline trajectory, referred to as 11-F5, consists of 34 Europa and 9 Ganymede flybys executed over the course of 2.4 years, reached a maximum inclination of 15 degrees, has a deterministic delta v of 157 m/s (post-PJR), and has a total ionizing dose of 2.06 Mrad (Si behind 100 mil Al, spherical shell). The 11-F5 trajectory and more generally speaking, flyby-only trajectories-exhibit a number of potential advantages over an Europa orbiter mission.

Europa↗

NASA NTRS2025

Mission-Maps For Outbound Cislunar Transfer Trajectories

This study quantifies the robustness and sensitivity of an outbound cislunar trajectory for a lunar lander in the form of mission-maps, or topological maps that allows either a computer program or mission designer to intuitively optimize the placement of critical outbound correction burns from the derived sensitivity data. The non-linear multi-body dynamics are applied to generate an outbound cislunar reference profile used by a linear covariance analysis (LinCov) tool to compute the expected Δv and trajectory dispersions due to the initial state uncertainty, sensor errors, maneuver execution errors, and disturbance accelerations along the outbound cislunar profile. The rapid performance analysis capabilities of LinCov are complimented with parallel processing techniques to evaluate hundreds and thousands of different translational burn locations, placements, and targeting constraints to identify the combination that minimizes the total Δv usage (nominal plus 3σ Δv) and trajectory dispersions at lunar orbit insertion. This study utilizes a generalized reference targeting algorithm to quickly assess the integrated closed-loop GN&C system performance due to different targeting configurations and constraints. The resulting mission maps provide an intuitive insight to ascertain each trajectory correction maneuver’s (TCM) sensitivity to different burn times along an outbound cislunar trajectory and quickly identify desirable engineering tradeoffs when performing analysis on the number and placement of these burns that nominally zero. Multiple mission maps are generated for a variety of different performance parameters that allow engineers to visually identify optimal solutions for trajectory correction maneuver placements, the number of correction burns, and the targeting constraints for each burn.

GN&C↗

NASA NTRS2019

In Space Assembled Telescope (ISAT) Study Preliminary Findings

“When is it advantageous to assemble telescopes in space rather than deploying them from launch vehicle fairings”? This question forms the crux of the objectives of a NASA study we have been conducting in collaboration with colleagues from different NASA centers, industry and academia. In this study, we have engaged a broad cross section of experts from the various fields of optics engineering, that is, telescope design and instrument design, structure and thermal engineering, robotics, launch system engineering, orbital mechanics, integration and testing, astrophysics, and NASA programmatics among others. Initial efforts began with a quick review of the current state of art of the component technologies that contribute towards an in-space assembled telescope. Then, leveraging the collective expertise of the diverse group of experts, we formulated a reference telescope design and attempted to develop a baseline approach to modularize the telescope into components amenable for robotic assembly. The group identified different trades associated with modularization and also developed a set of criteria to discern between the different options as revealed by the trades. Based on the modularization of the telescope, we will assess the impact of various launch vehicles, orbits for assembly and operation, robotic systems and operational approaches, and other related variables. From this, a concept to assemble the reference telescope in space from modular components will be developed. Based on this concept, and definition of the modules, we will develop a mission lifecycle plan for an assembled telescope over different phases of preliminary design, detailed design, assembly-test-and-integration, and in space operations. The mission lifecycle plan will be used to evaluate cost and risk implications of in-space assembly toward answering our fundamental question of the advantages, if any, of assembling a telescope in space as compared to self-deployment. In this paper, we summarize the objectives of the study, a review of the status of the underlying component technologies, a description of the methodology, including three different multi-day technical interchange meetings (TIMs), summary of findings from the TIMs and other related activities. In addition, a detailed description of the various factors that impact in-space assembly, their interplay and criteria for discerning among them, a preliminary description of the life cycle plan, including the test and integration plan, and initial observations on cost and risk implications will be included in the paper.

Mukherjee, Rudranarayan↗

NASA NTRSDate not supplied

Impact of Handling Qualities on Motor Sizing for Multirotor Aircraft with Urban Air Mobility Missions

Control models of three NASA Urban Air Mobility (UAM) reference vehicles (the quadrotor, octocopter, and Lift+Cruise (LPC)) were created and compared to determine the effect of rotor number and disk loading on control margin and design. The heave and yaw axes demand more actuator usage than the roll and pitch axes. Between heave and yaw, heave was the more demanding of the two because of the dependence of heave on the engine speed controller (ESC). When the feedback gains for all three vehicles were optimized to Level 1 handling qualities (HQs) specifications using CONDUIT, the ESC for the octocopter was the most stable and had the highest rise time (time for the rotor to respond to an input), while the LPC ESC was the least stable and had the smallest rise time. Rise time corresponds to the time required for rotor response. When actuator usage was translated to current margin, torque margin, and power margin, heave was the most demanding axis, followed by yaw, roll, and then pitch for all three vehicles. The results emphasize the importance of an accurate motor model within the control system architecture.

Impact↗

NASA NTRS1974

External store effects on the stability of fighter and interceptor airplanes

Some criteria for external carriage of missiles for fighter aircraft intended for aerial combat missions and for fighter-interceptor missions are considered. The mission requirements discussed include the short-range fighter-interceptor, the short-range interceptor, the medium-range interceptor, and the long-range interceptor. Missiles types considered to be compatible with the various point mission designs include the short-range missile, the medium-range missile, and the long-range missile. From the study, it appears that point mission design aircraft can be arranged in such a way that the required external-store arrangement will not impair the stability of the aircraft. An extensive reference list of NASA external store research is included.

Spearman, M. L.↗

NASA NTRS1988

Liquid rocket booster study. Volume 2, book 3, appendices 2-5: PPIP, transition plan, AMOS plan, and environmental analysis

This Preliminary Project Implementation Plan (PPIP) was used to examine the feasibility of replacing the current Solid Rocket Boosters on the Space Shuttle with Liquid Rocket Boosters (LRBs). The need has determined the implications of integrating the LRB with the Space Transportation System as the earliest practical date. The purpose was to identify and define all elements required in a full scale development program for the LRB. This will be a reference guide for management of the LRB program, addressing such requirement as design and development, configuration management, performance measurement, manufacturing, product assurance and verification, launch operations, and mission operations support.

Source record↗

NASA NTRS2012

Science Objectives and Rationale for the Radiation Belt Storm Probes Mission

The NASA Radiation Belt Storm Probes (RBSP) mission addresses how populationsof high energy charged particles are created, vary, and evolve in space environments,and specifically within Earths magnetically trapped radiation belts. RBSP, with a nominallaunch date of August 2012, comprises two spacecraft making in situ measurements for atleast 2 years in nearly the same highly elliptical, low inclination orbits (1.1 5.8 RE, 10).The orbits are slightly different so that 1 spacecraft laps the other spacecraft about every2.5 months, allowing separation of spatial from temporal effects over spatial scales rangingfrom 0.1 to 5 RE. The uniquely comprehensive suite of instruments, identical on the twospacecraft, measures all of the particle (electrons, ions, ion composition), fields (E and B),and wave distributions (dE and dB) that are needed to resolve the most critical science questions.Here we summarize the high level science objectives for the RBSP mission, providehistorical background on studies of Earth and planetary radiation belts, present examples ofthe most compelling scientific mysteries of the radiation belts, present the mission design ofthe RBSP mission that targets these mysteries and objectives, present the observation andmeasurement requirements for the mission, and introduce the instrumentation that will deliverthese measurements. This paper references and is followed by a number of companionpapers that describe the details of the RBSP mission, spacecraft, and instruments.

Geomagnetic storms↗

NASA NTRSDate not supplied

The Stratospheric Aerosol and Gas Experiment (SAGE) IV

Atmospheric composition continues to be a key Earth science focus for international space agencies and research organizations. The target constituent varies depending upon the topic area of interest such as monitoring the ozone layer and the efficacy of the Montreal Protocol, assessing the influence of volcanic eruptions and large wildfires on the atmosphere, improving our knowledge of transport processes, or evaluating the impacts of greenhouse gases on climate. Additionally, there is a growing need for measurement continuity of many trace gases both from an inability to properly assess long-term trends without it as well as the reliance of reanalyses and chemistry climate models on observational input. To this end, proper continuity requires continuous and overlapping multi-instrument data records of which spaceborne measurements are a critical component. However, most current satellite systems are well beyond their expected lifetimes, and so we look toward the future to develop the Stratospheric Aerosol and Gas Experiment (SAGE) IV as a future mission concept. Enabled by the NASA Earth Science Technology Office’s (ESTO) Instrument Incubator Program, the SAGE IV Pathfinder project developed and validated a prototype demonstration that paves the way for a future SAGE IV spaceflight mission. Utilizing solar occultation imaging, SAGE IV will be capable of measuring key species in the stratosphere and upper troposphere with the same quality as previous SAGE instruments but with greatly improved pointing knowledge and extensibility to new science targets. The precision and stability of a well-designed occultation instrument can act as a calibration reference standard for other spaceborne instruments, ensuring proper continuity of the desired science targets. Furthermore, current technological advancements allow SAGE IV to fit within a CubeSat framework and make use of commercial hardware, significantly reducing the size and cost when compared with traditional missions and enabling sustainability of future measurements.

Robert Damadeo↗

NASA NTRS1989

Middeck Active Control Experiment (MACE), phase A

A rationale to determine which structural experiments are sufficient to verify the design of structures employing Controlled Structures Technology was derived. A survey of proposed NASA missions was undertaken to identify candidate test articles for use in the Middeck Active Control Experiment (MACE). The survey revealed that potential test articles could be classified into one of three roles: development, demonstration, and qualification, depending on the maturity of the technology and the mission the structure must fulfill. A set of criteria was derived that allowed determination of which role a potential test article must fulfill. A review of the capabilities and limitations of the STS middeck was conducted. A reference design for the MACE test article was presented. Computing requirements for running typical closed-loop controllers was determined, and various computer configurations were studied. The various components required to manufacture the structure were identified. A management plan was established for the remainder of the program experiment development, flight and ground systems development, and integration to the carrier. Procedures for configuration control, fiscal control, and safety, reliabilty, and quality assurance were developed.

Crawley, Edward F.↗

NASA NTRS2001

Plans and Considerations for the Exploration of Space

The Mars Settlement Design Competition is a program for high school students and teachers to experience the process of mission and hardware design. It provides a top level view into how NASA plans to explore space. I will be involved with all three days of this competition. On Friday I plan to give two presentations, one to the employees of White Sands Test Facility and one to students and teachers. On Saturday, I will have a question and answer session with some of the teachers participating in the workshop. Sunday I will serve as one of the judges that will review the students projects created over the weekend. The main emphasis of my talk will focus on exploring the possibilities of the future of space exploration. I will discuss the Mars Reference Mission 3.0, as well as some of the current robotic missions being sent to Mars. Next, I will present a business model perfected by Hum Mandell, showing how the public, private, and commercial sectors all play a major role in sending humans to Mars. I will also discuss the work of the Integrated Design Team at JSC and how that working together approach is key for a successful design. Finally, I will present that the question of how humans can reach out beyond low earth orbit and place permanent settlements on Mars is really a function of the imagination of those who intend on going there.

Derkowski, Brian J.↗

NASA NTRS2005

Autonomous Medical Care for Exploration

The goal of Autonomous Medical Care (AMC) is to ensure a healthy, well-performing crew which is a primary need for exploration. The end result of this effort will be the requirements and design for medical systems for the CEV, lunar operations, and Martian operations as well as a ground-based crew health optimization plan. Without such systems, we increase the risk of medical events occurring during a mission and we risk being unable to deal with contingencies of illness and injury, potentially threatening mission success. AMC has two major components: 1) pre-flight crew health optimization and 2) in-flight medical care. The goal of pre-flight crew health optimization is to reduce the risk of illness occurring during a mission by primary prevention and prophylactic measures. In-flight autonomous medical care is the capability to provide medical care during a mission with little or no real-time support from Earth. Crew medical officers or other crew members provide routine medical care as well as medical care to ill or injured crew members using resources available in their location. Ground support becomes telemedical consultation on-board systems/people collect relevant data for ground support to review. The AMC system provides capabilities to incorporate new procedures and training and advice as required. The on-board resources in an autonomous system should be as intelligent and integrated as is feasible, but autonomous does not mean that no human will be involved. The medical field is changing rapidly, and so a challenge is to determine which items to pursue now, which to leverage other efforts (e.g. military), and which to wait for commercial forces to mature. Given that what is used for the CEV or the Moon will likely be updated before going to Mars, a critical piece of the system design will be an architecture that provides for easy incorporation of new technologies into the system. Another challenge is to determine the level of care to provide for each mission type. The level of care refers to the amount and type of care one will render based on perceived need and ability. This is in contrast to the standard of care which is the benchmark by which that care is provided. There are certainly some devices and procedures that have unique microgravity or partial gravity requirements such that terrestrial methods will not work. For example, performing CPR on Mars cannot be done in exactly the same way as on Earth because the reduced gravity causes too large a reduction in the forces available for effective compression of the chest. Likewise, fluid behavior in microgravity may require a specialized water filtration and mixing system for the creation of intravenous fluids. This paper will outline the drivers for the design of the medical care systems, prioritization and planning techniques, key system components, and long term goals.

Johnson-Throop, Kathy A.↗