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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 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

Electrostatic Solar Sail: A Propellantless Propulsion Concept for an Interstellar Probe Mission

The propulsion of an electrostatic solar sail (E Sail) is obtained by extracting momentum from the solar wind through electrostatic repulsion of the positively charged solar wind ions (see Figure 1). The positively charged solar wind protons are deflected by the electric field created around the tethers.This electric field grows in diameter as the spacecraft moves away from the Sun, therefore the E Sail effective area grows. The growth of the E-Sail effective area allows the propulsive force to decrease as 1/r up to distances of 20 AU as it moves away from the Sun, unlike solar sail propulsion whose thrust decreases as 1/r 2 but only to distances of 5AU. This propulsive force is created without using propellant and, therefore, E-sail avoids both the mass and complexity of chemical rockets (that require large amounts of propellant, propellant storage tanks, plumbing, valves, and insulation).

DeStefano, Anthony M.↗
NASA NTRSDate not supplied

Operational Techniques in Microgravity for Cryogenic Fluid Management

Management of cryogens in microgravity is a critical challenge for exploration missions to the Moon and Mars. Operational strategies to aid in cryogenic fluid management (CFM) are proposed and demonstrated using computational fluid dynamics simulations. Application of axial settling thrust is an essential – but potentially expensive – tool for CFM. Demonstrations show that its utilization and timing are important during certain unsettling events, such as engine cutoff. At other times, substantial savings can be realized by reducing the average acceleration (through pulsing thrusters, for example). If the metric for reaching a settled condition is a particular number of slosh periods, then fewer settling resources are needed with a lower acceleration. Alternatively, if a target wave amplitude is the settling objective, then a lower average acceleration will also allow for a higher allowable amplitude for the same heat transfer. Savings can also be obtained by rolling the vehicle, which can mitigate lateral slosh. Advantages and disadvantages of anti-slosh baffles are also discussed along with practical examples of their impact on CFM and ullage collapse. Ullage collapse examples are presented along with recommendations for slewing a vehicle with angular and translational acceleration to mitigate mixing between liquid and ullage.

Cryogenic Fluid Management↗
NASA NTRS2021

Pre-Flight Assessment of Xenon Propellant Usage and Usage Uncertainty for the Psyche Mission

NASA’s Psyche mission will launch in 2022 and begin a 3.6-year cruise to the metallic asteroid Psyche, the largest metal asteroid in the solar system. All primary propulsion will be done with the flight-proven SPT-140 electric propulsion subsystem. The Psyche mission will feature the first use of Hall thrusters for a NASA mission, and the first use of Hall thrusters beyond cis-lunar space, which has presented some unique challenges. In this paper we describe the Psyche propellant feed system architecture, expected propellant usage for the mission, propellant gauging requirements, and challenges associated with propellant gauging. Data from two recent Maxar electric orbit-raising missions with SPT-140 thrusters are reviewed and used to assess in-flight performance. We develop a pressure-volume-temperature gauging method that incorporates the propellant temperature distributions observed in the flight data, and use this method to provide an improved quantitative understanding of in-flight propellant consumption rates and their uncertainties. The results are in excellent agreement with the results of standard Maxar gauging methods and we determine a propellant usage uncertainty of ± 7.1% 3σ based on flight telemetry. Additionally, we demonstrate that the bookkeeping method of propellant gauging accurately predicts the tank pressure flight data. This work has led to design changes in the Psyche spacecraft avionics that will further improve propellant gauging uncertainties, which is particularly important for later phases of the mission. Finally, we statistically combine the predicted propellant mass uncertainties from the two gauging methods and demonstrate that the system will meet the mission requirements for propellant uncertainty. Together, all of this work provides confidence that the Psyche mission can be successfully completed within the existing propellant budget and propellant tank capacity.

Baldwin, Jeff↗
NASA NTRS1972

Radiation analysis of various vehicle and payload configurations for the reusable nuclear shuttle

Radiation analyses were performed and shielding weight requirements were estimated for various candidate vehicle and payload configurations for use with the reusable nuclear shuttle. The analyses included both point kernel and Monte Carlo approaches. The effects on reduced shield weight were determined for propellant ranks with pointed conical tank bottoms and for one case of a cluster of small tanks. This later case, however, had an arrangement which had no center tank in the upper tier of tanks. This effect negated most of the gain of going to the smaller tanks. A range of shield weights is presented for various light and heavy manned payload configurations when used in conjunction with a single liquid hydrogen propellant tank, 33 ft in diameter with a 15 deg conical tank bottom.

Preeg, W. E.↗
NASA NTRS1973

Analysis of axisymmetrical vibration of a partially liquid-filled elastic sphere by the method of Green's function

The longitudinal dynamic behavior of launch vehicles is largely determined by their huge liquid propellant masses which are spring supported by the elastic tank walls. Throughout much of the powered flight time, these masses constitute a high percentage of the entire vehicle mass and, therefore, may dominate the fundamental modes of the vehicle. In this report, a spherical container is considered. The analysis is based on a Galerkin approach, in the course of which a second-order differential equation must be solved. The solution has been obtained by the method of Green's function. This method is favorable because it displays the manner in which the analysis can be extended to partially liquid-filled general shells of revolution. The computer programs currently available for partially liquid-filled propellant tanks are based on the finite element methods and result in analytical models having as many as several hundred degrees of freedom. The method applied in this report results in a model having less than 10 degrees of freedom as can be shown by numerical evaluation. Therefore, it will be possible to analyze propellant tanks using much less computer time with comparable accuracy.

Glaser, R. F.↗
NASA NTRS2001

A Cryogenic Propellant Production Depot for Low Earth Orbit

The cost of access to space beyond low Earth orbit can be lowered if vehicles can refuel in orbit. The power requirements for a propellant depot that electrolyzes water and stores cryogenic oxygen and hydrogen can be met using technology developed for space solar power. A propellant depot is described that will be deployed in a 400 km circular equatorial orbit, receive tanks of water launched into a lower orbit from Earth by gun launch or reusable launch vehicle, convert the water to liquid hydrogen and oxygen, and store up to 500 metric tonnes of cryogenic propellants. Orbital maneuvering vehicles will transfer the Earth-launched propellant tanks from the lower orbit to the depot orbit. The propellant stored in the depot can support transportation from low Earth orbit to geostationary Earth orbit, the Moon, LaGrange points, Mars, etc. The propellant tanks on the depot are modified versions of those used in the Delta IV-Heavy launch vehicle. The tanks are configured in an in-line gravity-gradient configuration to minimize drag and settle the propellant. Temperatures can be maintained by body-mounted radiators; these will also provide some shielding against orbital debris. Power is supplied by a pair of solar arrays mounted perpendicular to the orbital plane, which rotate once per orbit to track the Sun. The majority of the power will be used to run the electrolysis system. Technology needed for an orbiting propellant depot can be tested and demonstrated in the near-term on the ground, on a Shuttle-deployed free-flyer, and on the International Space Station. Further along, an orbital depot can be deployed that stores liquid hydrogen and oxygen launched from Earth, to be followed by a full conversion and storage depot.

Potter, Seth D.↗
NASA NTRS2011

Modeling a Transient Pressurization with Active Cooling Sizing Tool

As interest in the area of in-space zero boil-off cryogenic propellant storage develops, the need to visualize and quantify cryogen behavior during ventless tank self-pressurization and subsequent cool-down with active thermal control has become apparent. During the course of a mission, such as the launch ascent phase, there are periods that power to the active cooling system will be unavailable. In addition, because it is not feasible to install vacuum jackets on large propellant tanks, as is typically done for in-space cryogenic applications for science payloads, instances like the launch ascent heating phase are important to study. Numerous efforts have been made to characterize cryogenic tank pressurization during ventless cryogen storage without active cooling, but few tools exist to model this behavior in a user-friendly environment for general use, and none exist that quantify the marginal active cooling system size needed for power down periods to manage tank pressure response once active cooling is resumed. This paper describes the Transient pressurization with Active Cooling Tool (TACT), which is based on a ventless three-lump homogeneous thermodynamic self-pressurization model1 coupled with an active cooling system estimator. TACT has been designed to estimate the pressurization of a heated but unvented cryogenic tank, assuming an unavailable power period followed by a given cryocooler heat removal rate. By receiving input data on the tank material and geometry, propellant initial conditions, and passive and transient heating rates, a pressurization and recovery profile can be found, which establishes the time needed to return to a designated pressure. This provides the ability to understand the effect that launch ascent and unpowered mission segments have on the size of an active cooling system. A sample of the trends found show that an active cooling system sized for twice the steady state heating rate would results in a reasonable time for tank pressure recovery with ZBO of a liquid oxygen propellant tank.

Guzik, Monica C.↗
NASA NTRS2016

Liquefaction and Storage of In-Situ Oxygen on the Surface of Mars

The In-Situ production of propellants for Martian and Lunar missions has been heavily discussed since the mid 1990's. One portion of the production of the propellants is the liquefaction, storage, and delivery of the propellants to the stage tanks. Two key technology development efforts are required: large refrigeration systems (cryocoolers) to perform the liquefaction and high performance insulation within a soft vacuum environment. Several different concepts of operation may be employed to liquefy the propellants based on how and where these two technologies are implemented. The concepts that were investigated include: using an accumulator tank to store the propellant until it is needed, liquefying in the flow stream going into the tank, and liquefying in the flight propellant tank itself. The different concept of operations were studied to assess the mass and power impacts of each concept. Additionally, the trade between insulation performance and cryocooler mass was performed to give performance targets for soft vacuum insulation development. It was found that liquefying within the flight propellant tank itself adds the least mass and power requirements to the mission.

Cryogenic Fluid Management↗
NASA NTRS1996

Computational Modeling of Magnetically Actuated Propellant Orientation

Unlike terrestrial applications where gravity positions liquid at the "bottom" of the tank, the location of liquid propellant in spacecraft tanks is uncertain unless specific actions are taken or special features are built into the tank. Some mission events require knowledge of liquid position prior to a particular action: liquid must be positioned over the tank outlet prior to starting the main engines and must be moved away from the tank vent before vapor can be released overboard to reduce pressure. It may also be desirable to positively position liquid to improve propulsion system performance: moving liquid away from the tank walls will dramatically decrease the rate of heat transfer to the propellant, suppressing the boil-off rate, thereby reducing overall mission propellant requirements. The process of moving propellant to a desired position is referred to as propellant orientation or reorientation. Propulsive reorientation relies on small auxiliary thrusters to accelerate the tank. The inertia of the liquid causes it to collect in the aft-end of the tank if the acceleration is forward. Liquid Acquisition Devices (LAD's) rely on surface tension to hold the liquid within special geometries, (i.e. vanes, wire-mesh channels, start-baskets), to positively position propellants. Both of these technologies add significant weight and complexity to the spacecraft and can be limiting systems for long duration missions. The subject of the present research is an alternate technique for positively positioning liquid within spacecraft propellant tanks: magnetic fields. LOX is paramagnetic (attracted toward a magnet) and LH2 is diamagnetic (repelled from a magnet). Order-of-magnitude analyses, performed in the 1960's to determine required magnet size, concluded that the magnets would be prohibitively massive and this option has remained dormant during the intervening years. Recent advances in high-temperature superconducting materials hold the promise of electromagnets with sufficient performance to support cryogenic propellant management tasks. In late 1992, NASA MSFC began a new investigation in this technology commencing with the design of the Magnetically-Actuated Propellant Orientation (MAPO) experiment. A mixture of ferrofluid and water is used to simulate the paramagnetic properties of LOX and the experiment is being flown on the KC-135 aircraft to provide a reduced gravity environment. The influence of a 0.4 Tesla ring magnet on flow into and out of a subscale Plexiglas tank is being recorded on video tape. The most efficient approach to evaluating the feasibility of MAPO is to compliment the experimental program with development of a computational tool to model the process of interest. The goal of the present research is to develop such a tool. Once confidence in its fidelity is established by comparison to data from the MAPO experiment, it can be used to assist in the design of future experiments and to study the parameter space of the process. Ultimately, it is hoped that the computational model can serve as a design tool for full-scale spacecraft applications.

Hochstein, John I.↗
NASA NTRS1974

Propellant acquisition device for use with a spinning toroidal tank

System consists of four radially disposed communication channels attached to propellant-retaining ring situated at bottom of toroidal tank. Ring-and-channel acquisition system design provides uniform propellant distribution within spinning tank during all mission phases.

Anderson, J. E.↗
NASA NTRS2021

Assessment of Governing Heat and Mass Transfer Coefficients for Cryogenic No-Vent Top-Off Modeling

No-vent fill / no-vent top-off (NVF/NVTO) is a method to enable the trans-fer of cryogenic propellants without the need to vent. Transferring propellants inmicrogravity environments is necessary to support the long-duration space missionsplanned for the coming decades. A key developmental milestone to developing thiscapability fully is the simulation and experimentation of NVF/NVTO in 1-g settings.This work seeks to advance the former by assessing the effectiveness of different heattransfer correlations used in a 1-g non-equilibrium model. Heat transfer correlationsfor natural convection and two-phase boiling heat transfer are compared against ex-perimental results for 34 different tests. Two distinct experiments, comprised of 21tests, are presented in detail here. These tests cover a variety of different injectionmethods, receiver tank geometries, receiver tank materials, cryogenic propellants, andinitial tank states. Overall for the cases tested in this work, the model was able topredict the pressure response within the receiver tank to a mean absolute percentageerror of 25.9%. The temperature response error rate was 29.5% and 24.9% for wall-gasand two-phase nodes, respectively. Compared to the worst case correlation set tested,the pressure prediction error rate represents a 31% improvement. For the cases pre-sented in this work, the mean pressure prediction error rate was 15.5%. Future workcould evaluate the effectiveness of this model against experiments conducted withdifferent propellants or different initial conditions. In its current form, however, themodel can still be used to help reduce design and testing time for 1-g experiments,enabling the quicker iteration that is necessary to meet the technological demands offuture space missions.

No-Vent Top Off↗
NASA NTRSDate not supplied

Analysis of Cryogenic Propellant Liquefaction Rates in Cooled Constant-Wall-Temperature Tanks

NASA has been focused on developing technology that would allow the production of cryogenic propellants on the Lunar and Martian surfaces. Utilizing Lunar/Martian resources, the produced gaseous propellants must first be liquefied and stored prior to use on the Moon or Mars ascent vehicle. Liquefaction of cryogenic propellants is a necessary technical development to enable NASA’s future spaceflight goals. This paper presents an overview of a proposed model for a propellant liquefaction system, and the effect of tank wall temperatures on cryogenic propellant liquefaction rates. The propellant system was assumed to be a receiver of a gas from an In-Situ Resource Utilization (ISRU) harvester and condensed the gas by cooling the tank walls. First, the heat transfer principles pertinent to condensation are summarized, followed by an overview of the model which performed the analysis, including a summary of the Fortran algorithm implementation. The sensitivity of the condensation rate relative to varying tank wall temperatures is also discussed.

Anson Koch↗
NASA NTRS2007

Radio Frequency Mass Gauging of Propellants

A combined experimental and computer simulation effort was conducted to measure radio frequency (RF) tank resonance modes in a dewar partially filled with liquid oxygen, and compare the measurements with numerical simulations. The goal of the effort was to demonstrate that computer simulations of a tank's electromagnetic eigenmodes can be used to accurately predict ground-based measurements, thereby providing a computational tool for predicting tank modes in a low-gravity environment. Matching the measured resonant frequencies of several tank modes with computer simulations can be used to gauge the amount of liquid in a tank, thus providing a possible method to gauge cryogenic propellant tanks in low-gravity. Using a handheld RF spectrum analyzer and a small antenna in a 46 liter capacity dewar for experimental measurements, we have verified that the four lowest transverse magnetic eigenmodes can be accurately predicted as a function of liquid oxygen fill level using computer simulations. The input to the computer simulations consisted of tank dimensions, and the dielectric constant of the fluid. Without using any adjustable parameters, the calculated and measured frequencies agree such that the liquid oxygen fill level was gauged to within 2 percent full scale uncertainty. These results demonstrate the utility of using electromagnetic simulations to form the basis of an RF mass gauging technology with the power to simulate tank resonance frequencies from arbitrary fluid configurations.

Zimmerli, Gregory A.↗
NASA NTRS1988

Studies of cryogenic propellant storage and handling for the lunar landing and launch facility (complex 39L)

A brief description of Complex 39L as it is currently conceived is presented. A brief discussion of lunar thermal history is then presented. From this follows a discussion of the current lunar thermal environment which will impact the design of cryogenic storage and handling facilities on the moon. Some previous studies are discussed. A conceptual design of liquid oxygen and hydrogen storage facilities is presented. The essential feature of this facility is that cryogens are to be stored in a number of small tanks which can serve as lander propellant tanks rather than as one large storage vessel. These tanks will be placed under a Fuel Inventory Tent (FIT) for shadow shielding. Methods of dealing with propellant boil-off are discussed. A base case cascade refrigeration system for requirements are such that it seems very feasible to construct a prototype boil-off recovery system in a laboratory environment.

Linsley, Jerald N.↗