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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Solid rocket booster performance evaluation model. Volume 3: Sample case

The solid rocket booster performance evaluation model (SRB-11) is used to predict internal ballistics in a sample motor. This motor contains a five segmented grain. The first segment has a 14 pointed star configuration with a web which wraps partially around the forward dome. The other segments are circular in cross-section and are tapered along the interior burning surface. Two of the segments are inhibited on the forward face. The nozzle is not assumed to be submerged. The performance prediction is broken into two simulation parts: the delivered end item specific impulse and the propellant properties which are required as inputs for the internal ballistics module are determined; and the internal ballistics for the entire burn duration of the motor are simulated.

Source record↗
NASA NTRS1999

Space Shuttle Solid Rocket Nozzle Joint 2 Gas Path Study

Each Space Shuttle solid rocket nozzle contains five joints. By design, each nozzle joint utilizes room-temperature vulcanized (RTV) rubber as a thermal barrier to protect the nozzle metal parts and O-rings from heat degradation due to motor combustion gas. Typically, combustion gas does not penetrate through the RTV in nozzle Joints. However, Joint currently experiences gas penetration through the RTV over 90 percent of the time. The occurrence of Joint gas paths is a very complex phenomenon with several known contributors such as the unique geometry of the joint, motor pressure, nozzle vectoring, manufacturing induced RTV voids. RTV material capability, and joint skip (relative radial displacement of joint components). The occurrence of Joint gas paths appears to be a combination of these causes. To better understand the causes of gas paths in Joint, the circumferential locations of gas paths in the RTV were identified and correlated with nozzle vectoring, RTV closeour locations (where the RTV backfill is completed), and X-ray low-density. anomaly (LDA) indications. Results that no specific cause was determined.

Lui, R. C.↗
NASA NTRS2000

Development of a Vehicle Health Monitoring System for the Space Shuttle Solid Rocket Booster Program

During their brief flight, the space shuttle solid rocket boosters (SRBs) experience a severe environment. This environment in most cases is unknown. When the design engineers believe they understand the environments, something new occurs. For example, at water impact several SRBs have sustained noticeable structural damage. The severity of the damage is usually dependent upon the waves that the SRB encounter at splashdown. The space shuttle is presently scheduled to fly until 2030. To support the shuttle flight schedule, the avionics on the SRB's will need to be upgraded. The environments on the different sections of the SRB will need to be defined more completely to properly qualify the avionics for multiple flights. The combination of new avionics systems and unknown flight environments led Marshall Space Flight Center's (MSFC) SRB Project Office to request the Science and Engineering (S&E) Directorate to develop a stand-alone data acquisition system that could collect data from any area of the booster. The Enhanced Data Acquisition System (EDAS) was developed to meet this request. However, the EDAS has some technical drawbacks that needed resolved. To answer the EDAS problems, the SRB Project Office has funded MSFC's Avionics Department to begin investigating a new vehicle health monitoring (VHM) system. The major requirements are the system shall have 64 channels, have programmable sample rates up to 10,000 samples per second, have sufficient memory for a twenty minute flight and not interfere with existing operational flight avionics hardware. This paper will describe the effort to develop a VHM system that can meet the SRB requirements.

Crawford, Kevin↗
NASA NTRS2004

Identifying, Assessing, and Mitigating Risk of Single-Point Inspections on the Space Shuttle Reusable Solid Rocket Motor

In the production of each Space Shuttle Reusable Solid Rocket Motor (RSRM), over 100,000 inspections are performed. ATK Thiokol Inc. reviewed these inspections to ensure a robust inspection system is maintained. The principal effort within this endeavor was the systematic identification and evaluation of inspections considered to be single-point. Single-point inspections are those accomplished on components, materials, and tooling by only one person, involving no other check. The purpose was to more accurately characterize risk and ultimately address and/or mitigate risk associated with single-point inspections. After the initial review of all inspections and identification/assessment of single-point inspections, review teams applied risk prioritization methodology similar to that used in a Process Failure Modes Effects Analysis to derive a Risk Prioritization Number for each single-point inspection. After the prioritization of risk, all single-point inspection points determined to have significant risk were provided either with risk-mitigating actions or rationale for acceptance. This effort gave confidence to the RSRM program that the correct inspections are being accomplished, that there is appropriate justification for those that remain as single-point inspections, and that risk mitigation was applied to further reduce risk of higher risk single-point inspections. This paper examines the process, results, and lessons learned in identifying, assessing, and mitigating risk associated with single-point inspections accomplished in the production of the Space Shuttle RSRM.

Greenhalgh, Phillip O.↗
NASA NTRS2004

Solid Rocket Booster Hydraulic Pump Port Cap Joint Load Testing

The solid rocket booster uses hydraulic pumps fabricated from cast C355 aluminum alloy, with 17-4 PH stainless steel pump port caps. Corrosion-resistant steel, MS51830 CA204L self-locking screw thread inserts are installed into C355 pump housings, with A286 stainless steel fasteners installed into the insert to secure the pump port cap to the housing. In the past, pump port cap fasteners were installed to a torque of 33 Nm (300 in-lb). However, the structural analyses used a significantly higher nut factor than indicated during tests conducted by Boeing Space Systems. When the torque values were reassessed using Boeing's nut factor, the fastener preload had a factor of safety of less than 1, with potential for overloading the joint. This paper describes how behavior was determined for a preloaded joint with a steel bolt threaded into steel inserts in aluminum parts. Finite element models were compared with test results. For all initial bolt preloads, bolt loads increased as external applied loads increased. For higher initial bolt preloads, less load was transferred into the bolt, due to external applied loading. Lower torque limits were established for pump port cap fasteners and additional limits were placed on insert axial deformation under operating conditions after seating the insert with an initial preload.

Gamwell, W. R.↗
NASA NTRS2010

Space Shuttle Reusable Solid Rocket Motor

RSRM is a highly reliable human-rated Solid Rocket Motor: a) Largest diameter SRM to achieve flight status; b) Only human-rated SRM. RSRM reliability achieved by: a)Applying special attention to Process Control, Testing, and Postflight; b) Communicating often; c) Identifying and addressing issues in a disciplined approach; d) Identifying and fully dispositioning "out-of-family" conditions; e) Addressing minority opinions; and f) Learning our lessons.

Moore, Dennis↗
NASA NTRSDate not supplied

Dynamics and Clearance Analysis of NASA's Space Launch System Block-1 and Block 1B Solid Rocket Booster Separation Event

NASA’s Space Launch System (SLS) solid rocket booster separation event is an essential area of study requiring high fidelity modelling to capture the complexity of an intra-atmospheric stage separation event. The setup and analysis for this event leveraged the NASA-developed CLVTOPS multi-body dynamics toolchain to model aerodynamics at the separation event, booster thrust tailoff, and Core Stage engine throttling in addition to the separation system itself (booster separation motors (BSMs), pyrotechnic bolts and struts). The approach documented here will give a brief background on the CLVTOPS toolchain, how key input models are integrated and verified, and how results are quantified using an ordered-statistics approach. Specific areas discussed herein address the performance-to-orbit realized by adjusting the delay time between the separation cue and the actual separation event, and how the orientation of the aft BSMs was tuned to address small clearances between the aft diagonal attach struts and the Core Stage. Post-flight results from the inaugural Artemis I flight are also shown, and validation is performed between predicted vs. actual separation dynamics and clearances. Challenging night launch conditions necessitated comparisons that were more qualitative in nature, but still showed very good agreement to pre-flight predictions.

Carole J Addona↗
NASA NTRS2014

A Coupled Fluid-Structure Interaction Analysis of Solid Rocket Motor with Flexible Inhibitors

A capability to couple NASA production CFD code, Loci/CHEM, with CFDRC's structural finite element code, CoBi, has been developed. This paper summarizes the efforts in applying the installed coupling software to demonstrate/investigate fluid-structure interaction (FSI) between pressure wave and flexible inhibitor inside reusable solid rocket motor (RSRM). First a unified governing equation for both fluid and structure is presented, then an Eulerian-Lagrangian framework is described to satisfy the interfacial continuity requirements. The features of fluid solver, Loci/CHEM and structural solver, CoBi, are discussed before the coupling methodology of the solvers is described. The simulation uses production level CFD LES turbulence model with a grid resolution of 80 million cells. The flexible inhibitor is modeled with full 3D shell elements. Verifications against analytical solutions of structural model under steady uniform pressure condition and under dynamic condition of modal analysis show excellent agreements in terms of displacement distribution and eigen modal frequencies. The preliminary coupled result shows that due to acoustic coupling, the dynamics of one of the more flexible inhibitors shift from its first modal frequency to the first acoustic frequency of the solid rocket motor.

Yang, H. Q.↗
NASA NTRS1972

Study of solid rocket motor for space shuttle booster, volume 2, book 2

A technical analysis of the solid propellant rocket engines for use with the space shuttle is presented. The subjects discussed are: (1) solid rocket motor stage recovery, (2) environmental effects, (3) man rating of the solid propellant rocket engines, (4) system safety analysis, (5) ground support equipment, and (6) transportation, assembly, and checkout.

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NASA NTRS1999

An Instrument for Real-Time Measurement of Solid Rocket Motor Insulation Erosion

An instrument (eroding potentionmeter) has been designed to measure real-time case wall and inhibitor insulation char depth within a rocket motor during firing. Thus measurement can be close to the real-time recession of the insulation surface. The eroding potentionmeter consists of two small (3 mils 9in diameter) twisted resistive wires that are polyimide insulated. The wire pair form an electrical circuit and will recede with the erosion of the rocket motor internal insulation. A constant current applied along the wires will detect the resistance change via a voltage drop across the wires as the wire pair recedes with the decomposition fo the insulation. The eroding potentionmeter, as presently designed, can be an effective tool for real time measurement of internal insulation recession of a solid rocket motor. This tool will provide a way to accurately measure inhibitor performance or to measure flight effects of insulation erosion on a flight test. The eroding potentiometer has been verified on a plasma torch test and two static tests of a small solid rocket motor. There are some irregularities in the measured date, but the data remains useful in determining the real-time performance of internal insulation during a motor firing.

McWhorter, B. B.↗
NASA NTRS1973

Ocean recovery of Shuttle Solid Rocket Boosters.

Cost effective recovery of the expended Space-Shuttle Solid Rocket Boosters (SRB) from the ocean will result in significant overall cost savings to the Space Shuttle Program. The ocean recovery mission begins with the dispatching of the recovery team to the predicted splashdown area. The SRBs, drogue parachutes and main parachutes must be tracked, located, retrieved, and transported to land where they will be refurbished and recycled for reuse. Trade studies to be conducted will consider the recovery mission requirements and weigh the advantages, disadvantages and costs of various candidate recovery systems. Major parameters effecting the selection of the final system will ensure that the system will meet overall objectives. Large- and small-scale SRB model testing has been conducted to establish characteristics of SRBs during water entry, floating free and under tow.

Junker, L. J.↗
NASA NTRS1980

Ice nuclei measurements from solid rocket motor effluents

The ice crystal forming nuclei (IN) measured in solid rocket motor (SRM) exhaust products is discussed in relation to space shuttle exhaust. Preliminary results from laboratory investigations and flight preparations for March 1978 Titan launch are discussed. The work necessary to provide adequate measurements of IN and cloud condensation nuclei (CCN) in the stabilized ground clouds from SRM's is studied.

Hindman, E. E., II↗
NASA NTRS1979

Economics of the solid rocket booster for space shuttle

The paper examines economics of the solid rocket booster for the Space Shuttle. Costs have been held down by adapting existing technology to the 146 in. SRB selected, with NASA reducing the cost of expendables and reusing the expensive nonexpendable hardware. Drop tests of Titan III motor cases and nozzles proved that boosters can survive water impact at vertical velocities of 100 ft/sec so that SRB components can be reused. The cost of expendables was minimized by selecting proven propellants, insulation, and nozzle ablatives of known costs; the propellant has the lowest available cost formulation, and low cost ablatives, such as pitch carbon fibers, will be used when available. Thus, the use of proven technology and low cost expendables will make the SRB an economical booster for the Space Shuttle.

Rice, W. C.↗
NASA NTRS1986

Block 2 Solid Rocket Motor (SRM) conceptual design study, volume 1

Segmented and monolithic Solid Rocket Motor (SRM) design concepts were evaluated with emphasis on joints and seals. Particular attention was directed to eliminating deficiencies in the SRM High Performance Motor (HPM). The selected conceptual design is described and discussed.

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NASA NTRS2019

Design of a Nozzle for the Spyder 2nd Stage Solid Rocket Motor

During the 2019 summer term, the author worked with a group of four interns to complete the preliminary design of a 2nd stage solid rocket motor for Up Aerospace’s Spyder Launch Vehicle. The Spyder vehicle is a four stage, solid fuel rocket designed as part of collaboration between NASA and Up Aerospace to develop a vehicle capable of delivering a 10 kg, 6U CubeSat into a 350 km, circular, low Earth orbit. As part of the agreement, NASA is tasked with designing high performance 2nd, 3rd, and 4th stages while Up Aerospace will provide the 1st stage, derived from the first stage of the company’s sub-orbital Spaceloft XL vehicle. Previous intern teams have designed the 3rd and 4th stages, which left the preliminary design of the 2nd stage motor to be completed this summer. The purpose of this report is to highlight a trade study which the author conducted to determine the nozzle geometry which would most benefit the performance of the 2nd stage motor. In this study, various nozzle parameters such as throat radius (RSI), expansion ratio, mass and their effects on the Isp and Delta V of the 2nd Stage were investigated. From this study, a nozzle geometry providing the necessary performance was chosen and implemented as part of the preliminary design of the 2nd stage motor. To mature the 2nd stage motor design, a trade space was needed to determine the nozzle configuration which would most benefit the performance of the 2nd stage. The trade space established did not only evaluate different expansion ratios for the same throat radius, but also investigated the possible performance gained from decreasing the throat radius to increase the expansion ratio and Isp capable of being delivered by the nozzle. Decreasing the throat radius would cause the chamber pressure to increase, consequently increasing the case and insulation mass required to safely operate a motor at higher pressures. To account for this factor, accurate estimates of inert mass first needed to be established. After doing so, the effects of varying nozzle expansion ratios, exit half angles, and subsequently length and mass were evaluated against motor and nozzle performance factors such as delta V and Isp. For this study, four throat radii ranging from 1.75” to 2.375” and consequently four different chamber pressures ranging 550 psia to 1200 psia were investigated. BACKGROUND To launch into Low Earth Orbit, a payload needs to be accelerated to the orbital velocity necessary to keep it from falling back to Earth. The change in velocity required between launch and orbital insertion is known as Delta V. The Delta V which a rocket or stage can deliver can be calculated using the Ideal Rocket equation, 𝛥𝑉=−𝑔0∗𝐼𝑠𝑝∗ln(𝑀𝑓𝑀𝑖) (3) Where 𝑔0 is the acceleration due to gravity at the earth’s surface, 𝐼𝑠𝑝 is the specific impulse of the rocket, 𝑀𝑖 is the initial mass of the rocket, and 𝑀𝑓 is the final mass of the rocket after burnout. From preliminary calculations beyond the scope of this paper, it was determined that 30500 ft/s of delta V would be required for a payload to be inserted into a 350 km circular orbit around the Earth. Using the known masses and Isp values of the 1st, 3rd, and 4th stages and equation 3, the delta V of each stage was calculated. The delta V required by the 2nd stage could then be found by taking the difference between the total delta V required and the delta V of the 1st, 3rd, and 4th stages. From this, the required delta V of the 2nd Stage was calculated to be 7340 ft/s. Specific impulse is an efficiency factor of the nozzle which defines the impulse delivered by the motor per unit of propellant weight. The main variables of a nozzle’s specific impulse investigated in this trade were exit cone half angle, throat radius, and expansion ratio which is affected by the throat radius. The expansion ratio, ε, of a nozzle is defined as the ratio between the nozzle exit area and throat area, and can be calculated using the equation, ε=𝑅𝑒𝑥𝑖𝑡2𝑅𝑠𝑖2 (2) Where 𝑅𝑒𝑥𝑖𝑡 is the radius of the nozzle’s exit and 𝑅𝑠𝑖 is the radius of the nozzle’s throat. A larger expansion ratio and smaller exit half angle will increase the Isp of a nozzle by allowing the gas to expand more and by allowing more of the exhaust gas to produce thrust in the direction of the motor’s central axis. A cross section view of the 2nd Stage motor with the major components annotated is provided in figure 1.

Bennett, Daniel↗