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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 289 records · Page 16

Early Progress Toward the Feasibility of the Centrifugal Nuclear Thermal Rocket

The Centrifugal Nuclear Thermal Rocket (CNTR) is a Nuclear Thermal Propulsion (NTP) concept designed to heat propellant directly by the reactor fuel. The primary difference between the CNTR concept and traditional NTP systems is that rather than using traditional solid fuel elements, the CNTR uses liquid fuel with the liquid contained in rotating cylinders by centrifugal force. If the concept can be successfully realized, the CNTR would have a high specific impulse (~1800 seconds) at high thrust, which may enable (i) viable near-term human Mars exploration by reducing round-trip times to 420 days and (ii) direct injection orbits for scientific missions to the Solar System outer planets and potentially Kuiper Belt objects. The CNTR could also use storable propellants such as ammonia, methane, or hydrazine at an Isp of ~900 seconds, enabling long-term in-space storage of a dormant system. Significant engineering challenges must be addressed to establish the technical viability of the CNTR. Research is presently underway to determine resolutions for these engineering challenges. In particular, research has begun on the analytical modeling and simulation of the two-phase heat transfer between the liquid metallic uranium fuel and the gaseous propellant. A paper was presented at the 2021 IAC which described these challenges and the study plan to address them. This paper describes the analytical and experimental progress to date toward resolving these challenges and establishing the engineering feasibility of the CNTR technology

High Performance Nuclear Thermal Propulsion NTP SN↗

Program ELM: A tool for rapid thermal-hydraulic analysis of solid-core nuclear rocket fuel elements

This report reviews the state of the art of thermal-hydraulic analysis codes and presents a new code, Program ELM, for analysis of fuel elements. ELM is a concise computational tool for modeling the steady-state thermal-hydraulics of propellant flow through fuel element coolant channels in a nuclear thermal rocket reactor with axial coolant passages. The program was developed as a tool to swiftly evaluate various heat transfer coefficient and friction factor correlations generated for turbulent pipe flow with heat addition which have been used in previous programs. Thus, a consistent comparison of these correlations was performed, as well as a comparison with data from the NRX reactor experiments from the Nuclear Engine for Rocket Vehicle Applications (NERVA) project. This report describes the ELM Program algorithm, input/output, and validation efforts and provides a listing of the code.

Walton, James T.↗

Propelling Exploration to the Moon and Beyond

As the Constellation Program enters its fourth year, the Ares Projects have made substantial progress toward sending human explorers beyond Earth orbit. The Ares I crew launch vehicle, which will take six astronauts or cargo to the International Space Station or four astronauts to rendezvous with Ares V for missions to the Moon, is the first human-rated vehicle NASA has developed in over 30 years. Since the Exploration Systems Architecture Study in 2005, the Ares Projects have completed a successful system requirements review, system definition review, and preliminary design review for the Ares I crew launch vehicle. The Ares I elements are well into development, beginning with the Shuttle-derived, five-segment solid rocket motor that will provide first-stage propulsion. The first stage team has poured its first production simulation article motor and will be pouring and firing the first five-segment development motor in 2009. Large-scale tooling has been installed and tested to produce propellant tanks for the liquid-fuel upper stage at Marshall Space Flight Center (MSFC) in Alabama. The initial upper stage units and main propulsion test article will be manufactured and tested at MSFC before transferring to Michoud Assembly Facility in Louisiana. The upper stage engine team has completed powerpack testing using Apollo J-2 heritage hardware and begun construction of a new altitude test stand at Stennis Space Center in Mississippi. The flight and integrated testing group has designed and built hardware for the Ares I-X test flight scheduled for 2009, as well as begun refurbishing existing infrastructure to support ground testing. Additionally, a base configuration has been selected for the Ares V cargo launch vehicle, which will send the Altair lunar lander and Orion to the Moon. Today, the Ares Projects are well on the way to building America s next generation of exploration-capable launch vehicles.

Cook, Stephen A.↗

Status of NASA's Space Launch System

NASA's Space Launch System (SLS) continued to make significant progress in 2015 and 2016, completing hardware and testing that brings NASA closer to a new era of deep space exploration. Programmatically, SLS completed Critical Design Review (CDR) in 2015. A team of independent reviewers concluded that the vehicle design is technically and programmatically ready to move to Design Certification Review (DCR) and launch readiness in 2018. Just five years after program start, every major element has amassed development and flight hardware and completed key tests that will lead to an accelerated pace of manufacturing and testing in 2016 and 2017. Key to SLS' rapid progress has been the use of existing technologies adapted to the new launch vehicle. The existing fleet of RS-25 engines is undergoing adaptation tests to prove it can meet SLS requirements and environments with minimal change. The four-segment shuttle-era booster has been modified and updated with a fifth propellant segment, new insulation, and new avionics. The Interim Cryogenic Upper Stage is a modified version of an existing upper stage. The first Block I SLS configuration will launch a minimum of 70 metric tons (t) of payload to low Earth orbit (LEO). The vehicle architecture has a clear evolutionary path to more than 100t and, ultimately, to 130t. Among the program's major 2015-2016 accomplishments were two booster qualification hotfire tests, a series of RS-25 adaptation hotfire tests, manufacturing of most of the major components for both core stage test articles and first flight tank, delivery of the Pegasus core stage barge, and the upper stage simulator. Renovations to the B-2 test stand for stage green run testing was completed at NASA Stennis Space Center. This year will see the completion of welding for all qualification and flight EM-1 core stage components and testing of flight avionics, completion of core stage structural test stands, casting of the EM-1 solid rocket motors, additional testing of RS-25 engines and flight engine controllers This paper will discuss these and other technical and programmatic successes and challenges over the past year and provide a preview of work ahead before the first flight of this new capability.

Honeycutt, John↗

Highlights of Nanosatellite Development Program at NASA-Goddard Space Flight Center

Currently the GN&C's Propulsion Branch of the NASA's Goddard Space Flight Center (GSFC) is conducting a broad technology development program for propulsion devices that are ideally suited for nanosatellite missions. The goal of our program is to develop nanosatellite propulsion systems that can be flight qualified in a few years and flown in support of nanosatellite missions. The miniature cold gas thruster technology, the first product from the GSFC's propulsion component technology development program, will be flown on the upcoming ST-5 mission in 2003. The ST-5 mission is designed to validate various nanosatellite technologies in all major subsystem areas. It is a precursor mission to more ambitious nanosatellite missions such as the Magnetospheric Constellation mission. By teaming with the industry and government partners, the GSFC propulsion component technology development program is aimed at pursuing a multitude of nanosatellite propulsion options simultaneously, ranging from miniaturized thrusters based on traditional chemical engines to MEMS based thruster systems. After a conceptual study phase to determine the feasibility and the applicability to nanosatellite missions, flight like prototypes of selected technology are fabricated for testing. The development program will further narrow down the effort to those technologies that are considered "mission-enabling" for future nanosatellite missions. These technologies will be flight qualified to be flown on upcoming nanosatellite missions. This paper will report on the status of our development program and provide details on the following technologies: Low power miniature cold gas thruster Nanosatellite solid rocket motor. Solid propellant gas generator system for cold gas thruster. Low temperature hydrazine blends for miniature hydrazine thruster. MEMS mono propellant thruster using hydrogen peroxide.

Rhee, Michael S.↗

Space Shuttle propulsion performance reconstruction from flight data

The aplication of extended Kalman filtering to estimating Space Shuttle Solid Rocket Booster (SRB) performance, specific impulse, from flight data in a post-flight processing computer program. The flight data used includes inertial platform acceleration, SRB head pressure, and ground based radar tracking data. The key feature in this application is the model used for the SRBs, which represents a reference quasi-static internal ballistics model normalized to the propellant burn depth. Dynamic states of mass overboard and propellant burn depth are included in the filter model to account for real-time deviations from the reference model used. Aerodynamic, plume, wind and main engine uncertainties are included.

Rogers, Robert M.↗

An Overview of the NASA Ames Millimeter-Wave Thermal Launch System

The Millimeter-Wave Thermal Launch System (MTLS) is a beamed-energy propulsion concept being designed at NASA Ames Research Center. This effort is in response to the NASA Office of the Chief Technologist s announcement of the Ride the Light program. Our objective is to produce a design that goes beyond the feasibility analysis level of previous studies and provides a solid foundation for low cost access to space. The MTLS is designed to place a 500 lb payload into Low Earth Orbit (LEO) two times a day. This frequent launch, small payload niche is well suited for the particular advantages and constraints of beamed-energy propulsion, and has the potential to drastically increase access to space by reducing the cost per kilogram of placing payloads into LEO. This paper summarizes the findings of the MTLS study. The chemical rocket engine is in principle a simple device. It acts by releasing the chemical energy stored in propellants such as hydrogen and oxygen through combustion, then converting that thermal energy into kinetic energy by expansion through a nozzle. As such, it is fundamentally limited by the energy released in combustion reactions and the molecular weight of the products of those reactions. The highest performing conventional propellant combination, liquid oxygen and liquid hydrogen, can produce vacuum specific impulses of around 450 seconds. The design space of current launch vehicles (which tend to be large, multi-stage, and expendable) are defined by these limitations. An entirely new approach may be necessary in order to enable future launch vehicles of radically improved capabilities. Beamed-energy propulsion (BEP) is an alternative approach that bypasses the energy limitations of chemical propulsion. Instead of relying on a chemical reaction as the energy source, it is supplied externally via a beam of electromagnetic energy produced on the ground. In the concept examined in the MTLS, this energy is absorbed by a heat exchanger which then transfers the energy to the propellant. This decouples the energy source from the working fluid, vastly expanding the design space. For example, a launch vehicle could use only water as propellant, making it very safe and easy to handle. However, the most commonly proposed way to take advantage of this decoupling is to use pure hydrogen as the working fluid, which enables specific impulses of around 800 seconds1 if the heat exchanger material can operate at 2200 K. With such a significantly increased Isp, it may be possible to build single-stage to orbit vehicles, with enough mass margins left over to permit lower cost fabrication techniques.

Murakami, David↗

ASRM radiation and flowfield prediction status

Existing and proposed methods for the prediction of plume radiation are discussed in terms of their application to the NASA Advanced Solid Rocket Motor (ASRM) and Space Shuttle Main Engine (SSME) projects. Extrapolations of the Solid Rocket Motor (SRM) are discussed with respect to preliminary predictions of the primary and secondary radiation environments. The methodology for radiation and initial plume property predictions are set forth, including a new code for scattering media and independent secondary source models based on flight data. The Monte Carlo code employs a reverse-evaluation approach which traces rays back to their point of absorption in the plume. The SRM sea-level plume model is modified to account for the increased radiation in the ASRM plume due to the ASRM's propellant chemistry. The ASRM cycle-1 environment predictions are shown to identify a potential reason for the shutdown spike identified with pre-SRM staging.

Reardon, J. E.↗

Flight Investigation of the Performance of a Two-stage Solid-propellant Nike-deacon (DAN) Meteorological Sounding Rocket

A flight investigation of two Nike-Deacon (DAN) two-stage solid-propellant rocket vehicles indicated satisfactory performance may be expected from the DAN meteorological sounding rocket. Peak altitudes of 356,000 and 350,000 feet, respectively, were recorded for the two flight tests when both vehicles were launched from sea level at an elevation angle of 75 degrees. Performance calculations based on flight-test results show that altitudes between 358,000 feet and 487,000 feet may be attained with payloads varying between 60 pounds and 10 pounds.

MISSILES, SPECIFIC TYPES↗

A shuttle derived utility vehicle for delivery of small payloads to orbit

A small-payload utility-vehicle (UV) configuration for the Space Shuttle is proposed and illustrated with drawings, diagrams, and graphs, and tables. The primary modification to the Shuttle involves removal of the solid-rocket boosters and addition of three Shuttle main engines to the external tank, resulting in an overall weight reduction from about 4.53 to 2.07 Mlbs and a per-flight cost savings of 16 percent. For current Shuttle parameters, such a UV could carry up to 2 klbs of payload in the forebody mid-deck, the entire payload bay being occupied by fuel tanks with capacity 180 klbs; with advanced-technology weight reductions of 15 percent in Orbiter subsystem dry weights (including structures), the UV could carry up to 17 klbs of payload using only 125 klbs of internally loaded propellants, allowing a 15-ft cargo space.

Macconochie, I. O.↗

Fuel/oxidizer-rich high-pressure preburners

The analyses, designs, fabrication, and cold-flow acceptance testing of LOX/RP-1 preburner components required for a high-pressure staged-combustion rocket engine are discussed. Separate designs of injectors, combustion chambers, turbine simulators, and hot-gas mixing devices are provided for fuel-rich and oxidizer-rich operation. The fuel-rich design addresses the problem of non-equilibrium LOX/RP-1 combustion. The development and use of a pseudo-kinetic combustion model for predicting operating efficiency, physical properties of the combustion products, and the potential for generating solid carbon is presented. The oxygen-rich design addresses the design criteria for the prevention of metal ignition. This is accomplished by the selection of materials and the generation of well-mixed gases. The combining of unique propellant injector element designs with secondary mixing devices is predicted to be the best approach.

Schoenman, L.↗

Solid Hydrogen Formed for Atomic Propellants

Several experiments on the formation of solid hydrogen particles in liquid helium were recently conducted at the NASA Glenn Research Center at Lewis Field. The solid hydrogen experiments are the first step toward seeing these particles and determining their shape and size. The particles will ultimately store atoms of boron, carbon, or hydrogen, forming an atomic propellant. Atomic propellants will allow rocket vehicles to carry payloads many times heavier than possible with existing rockets or allow them to be much smaller and lighter. Solid hydrogen particles are preferred for storing atoms. Hydrogen is generally an excellent fuel with a low molecular weight. Very low temperature hydrogen particles (T < 4 K) can prevent the atoms from recombining, making it possible for their lifetime to be controlled. Also, particles that are less than 1 mm in diameter are preferred because they can flow easily into a pipe when suspended in liquid helium. The particles and atoms must remain at this low temperature until the fuel is introduced into the engine combustion (or recombination) chamber. Experiments were, therefore, planned to look at the particles and observe their formation and any changes while in liquid helium.

Palaszewski, Bryan A.↗

Nodal Modeling of Tank Pressurization and Draining using a Multi-Node-Ullage Approach

The purpose of the pressurization system in liquid rocket propulsion is to control the pressure in the gas space of the propellant tank (known as the ullage space) and the propellant mass flowrate to the engine. A mathematical model is required to predict the amount of pressurant necessary to ensure that pressure and temperature levels inside the tank remain within acceptable limits and that the propellant pressure leaving the tank satisfies the net positive suction pressure (NPSP) requirement of the pump feeding the engine. Nodal codes typically model tank pressurization and draining using a single node to represent the ullage and a single node to represent the propellant. As the tank drains, the ullage node grows and the propellant node shrinks. The heat transfer between ullage to wall and ullage to propellant is governed by natural convection. Designers of liquid propulsion systems often use empirical correlations to estimate the “Collapse Factor” which represents the ratio of pressurant required with heat transfer and the amount of pressurant required without heat transfer. A single node ullage model of tank pressurization was developed using GFSSP to compute the collapse factor reasonably well and later was used to model tank pressurization during test firing of the FASTRAC rocket engine. The predicted tank pressure compared well with the test data. In the early 1970’s, pressurization and drain tests with liquid methane were performed at NASA Lewis Research Center in a vacuum chamber. A 5 ft diameter spherical aluminum tank was tested to drain from 95% to 5% full using gaseous helium, hydrogen, nitrogen and methane as pressurant. Tests were conducted with different pressurant inlet temperatures and drain times. Measured data include pressurant requirement, amount of pressurant condensed, and ullage and wall temperatures at various heights in the ullage space at the end of draining. A single node GFSSP model was developed to simulate helium pressurization of the methane tank. Predicted helium consumption was 8-23% less than measured. The average error of the six test cases was 16%. A single ullage node with multiple solid node model was developed using Thermal Desktop. Predicted helium consumption compares with the test data within 2%. This paper describes the development of a GFSSP multi-node ullage model of the test configuration and compares the predicted pressurant consumption for both helium and autogenous pressurization using gaseous methane with experimental as well as TD predictions.

Nodal Model↗

Nuclear Engine System Simulation (NESS). Volume 1: Program user's guide

A Nuclear Thermal Propulsion (NTP) engine system design analysis tool is required to support current and future Space Exploration Initiative (SEI) propulsion and vehicle design studies. Currently available NTP engine design models are those developed during the NERVA program in the 1960's and early 1970's and are highly unique to that design or are modifications of current liquid propulsion system design models. To date, NTP engine-based liquid design models lack integrated design of key NTP engine design features in the areas of reactor, shielding, multi-propellant capability, and multi-redundant pump feed fuel systems. Additionally, since the SEI effort is in the initial development stage, a robust, verified NTP analysis design tool could be of great use to the community. This effort developed an NTP engine system design analysis program (tool), known as the Nuclear Engine System Simulation (NESS) program, to support ongoing and future engine system and stage design study efforts. In this effort, Science Applications International Corporation's (SAIC) NTP version of the Expanded Liquid Engine Simulation (ELES) program was modified extensively to include Westinghouse Electric Corporation's near-term solid-core reactor design model. The ELES program has extensive capability to conduct preliminary system design analysis of liquid rocket systems and vehicles. The program is modular in nature and is versatile in terms of modeling state-of-the-art component and system options as discussed. The Westinghouse reactor design model, which was integrated in the NESS program, is based on the near-term solid-core ENABLER NTP reactor design concept. This program is now capable of accurately modeling (characterizing) a complete near-term solid-core NTP engine system in great detail, for a number of design options, in an efficient manner. The following discussion summarizes the overall analysis methodology, key assumptions, and capabilities associated with the NESS presents an example problem, and compares the results to related NTP engine system designs. Initial installation instructions and program disks are in Volume 2 of the NESS Program User's Guide.

Pelaccio, Dennis G.↗

Five-Segment Solid Rocket Motor Development Status

In support of the National Aeronautics and Space Administration (NASA), Marshall Space Flight Center (MSFC) is developing a new, more powerful solid rocket motor for space launch applications. To minimize technical risks and development costs, NASA chose to use the Space Shuttle s solid rocket boosters as a starting point in the design and development. The new, five segment motor provides a greater total impulse with improved, more environmentally friendly materials. To meet the mass and trajectory requirements, the motor incorporates substantial design and system upgrades, including new propellant grain geometry with an additional segment, new internal insulation system, and a state-of-the art avionics system. Significant progress has been made in the design, development and testing of the propulsion, and avionics systems. To date, three development motors (one each in 2009, 2010, and 2011) have been successfully static tested by NASA and ATK s Launch Systems Group in Promontory, UT. These development motor tests have validated much of the engineering with substantial data collected, analyzed, and utilized to improve the design. This paper provides an overview of the development progress on the first stage propulsion system.

Priskos, Alex S.↗

Conceptual design study for the use of COBE rocket engines on the Tropical Rainfall Measuring Mission

The objective of this conceptual design study is to verify that the Cosmic Background Explorer (COBE) Hydrazine Propulsion Subsystem (HPS) Rocket Engine Assembly (REA) will satisfy the Tropical Rainfall Measuring Mission (TRMM) requirements and to develop a preliminary thruster module design using the existing REAs. The performance of the COBE HPS 5 lbf thrusters meet the TRMM mission requirements. The preliminary design consists of a single 5 lbf REA REM which is isolation mounted to a spacecraft interface angle bracket (5 or 10 deg angle). The REM incorporates a catalyst bed heater and sensor assembly, and propellant thermal control is achieved by thermostatically controlled heaters on the thruster valves. A ROM cost of approx. $950 K has been estimated for the phase 2 program to finalize the design, fabricate, and test the hardware using mechanical thermostats for thermal control. In the event that solid state thermostats are used, the cost is estimated to be $160 K higher. A ROM cost is approx. $145 K is estimated to study the effects of using Japanese manufactured hydrazine for the TRMM mission.

Source record↗

Establishing the Feasibility of the Centrifugal Nuclear Thermal Rocket

The Centrifugal Nuclear Thermal Rocket (CNTR) is a Nuclear Thermal Propulsion (NTP) concept designed to heat propellant directly by the reactor fuel. The primary difference between the CNTR concept and traditional NTP systems is that rather than using traditional solid fuel elements, the CNTR uses liquid fuel with the liquid contained in rotating cylinders by centrifugal force. If the concept can be successfully realized, the CNTR would have a high specific impulse (~1800 s) at high thrust, which may enable viable near-term human Mars exploration by reducing round-trip times to ~420 days. The CNTR could also use storable propellants such as ammonia, methane, or hydrazine at an Isp of ~900 s, enabling long-term in-space storage of a dormant system. Significant engineering challenges must be addressed to establish the technical viability of the CNTR, and the plan for addressing these engineering challenges is the subject of this paper.

Dale Thomas↗

Evaluation of on-board hydrogen storage methods for hypersonic vehicles

Hydrogen is the foremost candidate as a fuel for use in high speed transport. Since any aircraft moving at hypersonic speeds must have a very slender body, means of decreasing the storage volume requirements below that for liquid hydrogen are needed. The total performance of the hypersonic plane needs to be considered for the evaluation of candidate fuel and storage systems. To accomplish this, a simple model for the performance of a hypersonic plane is presented. To allow for the use of different engines and fuels during different phases of flight, the total trajectory is divided into three phases: subsonic-supersonic, hypersonic and rocket propulsion phase. The fuel fraction for the first phase is found be a simple energy balance using an average thrust to drag ratio for this phase. The hypersonic flight phase is investigated in more detail by taking small altitude increments. This approach allowed the use of flight profiles other than the constant dynamic pressure flight. The effect of fuel volume on drag, structural mass and tankage mass was introduced through simplified equations involving the characteristic dimension of the plane. The propellant requirement for the last phase is found by employing the basic rocket equations. The candidate fuel systems such as the cryogenic fuel combinations and solid and liquid endothermic hydrogen generators are first screened thermodynamically with respect to their energy densities and cooling capacities and then evaluated using the above model.

Akyurtlu, Ates↗