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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Aerodynamic Performance of the Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) Technology Demonstration Mission

The Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) mission successfully demonstrated the deployment and entry performance of a 6 m diameter Hypersonic Inflatable Decelerator on November 10, 2022. This was the largest blunt body flown to date and demonstrated this inflatable aeroshell technology at scale and conditions relevant to Earth and Mars Entry, Descent, and Landing applications. LOFTID built upon the prior successes of the suborbital IRVE and IRVE-3 missions, leveraging and expanding on the flight experience from these and other planetary and Earth sample return missions. Both the re-entry vehicle and ejectable data module were successfully recovered from the Pacific Ocean, with LOFTID satisfying requirements for decelerator performance and stable flight from orbital entry conditions through parachute deployment and splashdown. This work discusses the pre-flight aerodynamics database and reconstructed flight performance of the LOFTID re-entry vehicle.

LOFTID↗
NASA NTRSDate not supplied

Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) Aeroshell Performance

On November 10, 2022, NASA launched the Low-earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) reentry vehicle (RV)as a secondary payload mounted inside the launch vehicle (LV) adaptor on an Atlas V 401 out of the Vandenburg Space Force Base (VSFB). The primary payload, Joint Polar Satellite System-2 (JPSS-2), was delivered successfully to a sun-synchronous trajectory shortly after launch, at which point the Centaur upper stage performed a burn to de-orbit the system. Once on the desired trajectory to enter the atmosphere, the top of the payload adaptor was ejected to expose the LOFTID RV. Next, the LOFTID aeroshell, a Hypersonic Inflatable Aerodynamic Decelerator (HIAD), was deployed and inflated without issue. The Centaur pointed the LOFTID RV to the desired attitude to enter the atmosphere, spun the assembly to three rpm, separated the LOFTID RV, and finally performed a divert maneuver to prevent the Centaur from re-contacting the LOFTID RV after atmospheric entry. The LOFTID RV maintained the design attitude and spin rate from separation to atmospheric entry, a duration of roughly 30 minutes, demonstrating the aeroshell did not experience any energy damping from inflatable structure flexibility. The LOFTID RV entered the atmosphere over Alaska at >8km/sec and decelerated as designed, demonstrating aerodynamically stable flight from hypersonic entry through subsonic parachute deployment. On-board visible-spectrum cameras captured the physical response of the heatshield through all phases of flight. Co-located infrared cameras captured the temperature distribution of the aftside of the heat shield anchored to a distribution of thermocouples on the inflatable structure (IS) in the field of view. Thermocouples were also embedded in the forward side of the aeroshell both in the Flexible Thermal Protection System (FTPS) as well as the IS. This paper will document aeroshell’s response to the atmospheric entry. The visible-spectrum cameras captured mechanical response of the deployable aeroshell to the loads encountered in the different phases of entry. Events seen on the visible-spectrum cameras correlate with the measurements of the load cell pins on webbing elements that attach the aeroshell to the centerbody structure. Thermocouple data captured verifies the aerothermal response of the aeroshell was in-kind with pre-flight analysis predictions although somewhat lower in most locations. This data will enable enhancement of HIAD predictive capability. Post-flight inspection of the aeroshell after splashdown and ocean recovery shows that all the aeroshell materials and manufacturing techniques developed over the past two decades of HIAD technology development performed as expected at large scale, a scale which cannot be replicated in ground test facilities. The LOFTID RV remained high in the water after touching down under parachute, and maintained buoyancy and integrity for the hour it took to position the recovery vessel near the vehicle after splashdown. There was no indication the HIAD would have experienced an issue maintaining buoyancy for many more hours after water impact as the component maintained adequate inflation pressure more than 24 hours after water extraction with no additional inflation gas in tanks, as the inflation gas remaining in the tank was purposely vented prior to splashdown.

HIAD↗
NASA NTRS2024

Low-Earth Orbit Flight Test of an Inflatable Decelerator Modeling and Reconstruction

The Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) mission was a flight test performed on November 10, 2022. LOFTID is an 6 meter diameter Hypersonic Inflatable Aerodynamic Decelerator (HIAD) that is stowed for launch as a secondary payload, inflated in space, and separated from launch vehicle before conducting entry, descent, and landing (EDL).The main objective of the flight test was to demonstrate EDL at scale using HIAD technology at flight conditions relevant for future Earth and Mars missions. LOFTID successfully inflated and separated with a spin rate of 18 deg/s, landed within 1 hour on-parachute off the coast of Hawaii, and was successfully recovered. LOFTID re-entered Earth’s atmosphere at 8 km/s, achieved peak deceleration of 9 Gs and peak heat rate of 40 W/cm2, and demonstrated angle-of-attack stability throughout entirety of flight. On-board instrumentation provided flight data, which was saved onto an ejectable data recorder that was ejected at 18 km and successfully recovered. Despite the loss of inertial measurement unit data, techniques were developed to reconstruct the estimated flight performance as described in this paper. This paper presents the trajectory analysis, aerodynamics modeling, and reconstructed flight performance of the LOFTID re-entry vehicle.

Rohan G Deshmukh↗
NASA NTRS1961

THE INDUCED DRAG OF A DECELERATING AIRFOIL

In a recent paper in Soaring, C.A. Moeller proposed a method for determining the performance of a sailplane by recording the deceleration history of the craft following a steep dive. The advantage claimed for this method was that it would allow performance testing to be done in relatively quiescent air near the ground. It would thus be possible to eliminate the errors and uncertainties associated with conventional testing procedures, by avoiding the effects of the extraneous air currents which exist at altitude. Unfortunately, however, deceleration evaluation technique necessarily involves unsteady aerodynamics, and is thus itself subject to certain inherent error source of unknown magnitude.

DRAG↗
DOE OSTI2014

Compact disposal of high-energy electron beams using passive or laser-driven plasma decelerating stage

A plasma decelerating stage is investigated as a compact alternative for the disposal of high-energy beams (beam dumps). This could benefit the design of laser-driven plasma accelerator (LPA) applications that require transportability and or high-repetition-rate operation regimes. Passive and laser-driven (active) plasma-based beam dumps are studied analytically and with particle-in-cell (PIC) simulations in a 1D geometry. Analytical estimates for the beam energy loss are compared to and extended by the PIC simulations, showing that with the proposed schemes a beam can be efficiently decelerated in a centimeter-scale distance.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Compact disposal of high-energy electron beams using passive or laser-driven plasma decelerating stage

A plasma decelerating stage is investigated as a compact alternative for the disposal of high-energy beams (beam dumps). This could benefit the design of laser-driven plasma accelerator (LPA) applications that require transportability and or high-repetition-rate operation regimes. Passive and laser-driven (active) plasma-based beam dumps are studied analytically and with particle-in-cell (PIC) simulations in a 1D geometry. Analytical estimates for the beam energy loss are compared to and extended by the PIC simulations, showing that with the proposed schemes a beam can be efficiently decelerated in a centimeter-scale distance.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Proton irradiation-decelerated intergranular corrosion of Ni-Cr alloys in molten salt

The effects of ionizing radiation on materials often reduce to "bad news". Radiation damage usually leads to detrimental effects such as embrittlement, accelerated creep, phase instability, and radiation-altered corrosion. Here we report that proton irradiation decelerates intergranular corrosion of Ni-Cr alloys in molten fluoride salt at 650 °C. We demonstrate this by showing that the depth of intergranular voids resulting from Cr leaching into the salt is reduced by proton irradiation alone. Interstitial defects generated from irradiation enhance diffusion, more rapidly replenishing corrosion-injected vacancies with alloy constituents, thus playing the crucial role in decelerating corrosion. Our results show that irradiation can have a positive impact on materials performance, challenging our view that radiation damage usually results in negative effects.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Discharge source coupled to a deceleration unit for anion beam generation: Application to H{sub 2}{sup −} photodetachment

A cathode discharge source coupled to a deceleration unit for anion beam generation is described. The discharge source, made of stainless steel or duralumin electrodes and Macor insulators, is attached to the exit nozzle valve plate at one end, and to an Einzel lens to the other end. Subsequently, a cylindrical retardation unit is attached to the Einzel lens to decelerate the ions in order to optimize the laser beam interaction time required for spectroscopic investigations. The compact device is able to produce beam intensities of the order of 2 × 10{sup 12} anions/cm{sup 2} s and 20 μrad of angular divergence with kinetic energies ranging from 30 to 120 eV. Using distinct gas mixtures for the supersonic expansion together with a linear time-of-flight spectrometer, anions of great relevance in molecular astrophysics like, for example, H{sub 2}{sup −}, C{sub 3}H{sup −}, C{sub 2}{sup −}, C{sub 2}H{sup −}, HCN{sub 2}{sup −}, CO{sub 2}{sup −}, CO{sub 2}H{sup −}, C{sub 4}{sup −}, C{sub 4}H{sup −}, C{sub 5}H{sub 4}{sup −}, C{sub 5}H{sub 6}{sup −}, C{sub 7}N{sup −}, and C{sub 10}N{sup −} were produced. Finally, in order to demonstrate the capability of the experimental technique the photodetachment cross-section of the metastable H{sub 2}{sup −}, predominantly in the (v = 0, J = 26) state, was measured following laser excitation at λ{sub exc}= 565 nm obtaining a value of σ{sub ph}= 0.04 Å. To the best of our knowledge, it is the first time that this anion cross-section has been measured.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2015

Deceleration, precooling, and multi-pass stopping of highly charged ions in Be{sup +} Coulomb crystals

Preparing highly charged ions (HCIs) in a cold and strongly localized state is of particular interest for frequency metrology and tests of possible spatial and temporal variations of the fine structure constant. Our versatile preparation technique is based on the generic modular combination of a pulsed ion source with a cryogenic linear Paul trap. Both instruments are connected by a compact beamline with deceleration and precooling properties. We present its design and commissioning experiments regarding these two functionalities. A pulsed buncher tube allows for the deceleration and longitudinal phase-space compression of the ion pulses. External injection of slow HCIs, specifically Ar{sup 13+}, into the linear Paul trap and their subsequent retrapping in the absence of sympathetic cooling is demonstrated. The latter proved to be a necessary prerequisite for the multi-pass stopping of HCIs in continuously laser-cooled Be{sup +} Coulomb crystals.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Development of new platforms for hydrodynamic instability and asymmetry measurements in deceleration phase of indirectly driven implosions on NIF

Hydrodynamic instabilities and asymmetries are a major obstacle in the quest to achieve ignition at the National Ignition Facility (NIF) as they cause pre-existing capsule perturbations to grow and ultimately quench the fusion burn in experiments. This paper reviews the development of two new experimental techniques to measure high-mode instabilities and low-mode asymmetries in the deceleration phase of indirect drive inertial confinement fusion implosions. In the first innovative technique, self-emission from the hot spot was enhanced with an argon dopant to “self-backlight” the shell in-flight, imaging the perturbations in the shell near peak velocity. Experiments with pre-imposed two-dimensional perturbations showed hydrodynamic instability growth of up to 7000× in areal density. These experiments discovered unexpected three-dimensional structures originating from the capsule support structures. These new 3-D structures became one of the primary concerns for the indirect drive ICF program that requires their origin to be understood and their impact mitigated. In a second complementary technique, the inner surface of the decelerating shell was visualized in implosions using x-ray emission of a high-Z dopant added to the inner surface of the capsule. With this technique, low mode asymmetry and high mode perturbations, including perturbations seeded by the gas fill tube and capsule support structure, were quantified near peak compression. Using this doping method, the role of perturbations and radiative losses from high atomic number materials on neutron yield was quantified.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Deceleration-stage Rayleigh–Taylor growth in a background magnetic field studied in cylindrical and Cartesian geometries

Experiments have identified the Rayleigh–Taylor (RT) instability as one of the greatest obstacles to achieving inertial confinement fusion. Consequently, mitigation strategies to reduce RT growth and fuel–ablator mixing in the hotspot during the deceleration phase of the implosion are of great interest. In this work, the effect of seed magnetic fields on deceleration-phase RT growth are studied in planar and cylindrical geometries under conditions relevant to the National Ignition Facility (NIF) and Omega experiments. The magnetohydrodynamic (MHD) and resistive-MHD capabilities of the FLASH code are used to model imploding cylinders and planar blast-wave-driven targets. Realistic target and laser parameters are presented that suggest the occurrence of morphological differences in late-time RT evolution in the cylindrical NIF case and a measurable difference in spike height of single-mode growth in the planar NIF case. The results of this study indicate the need for target designs to utilize an RT-unstable foam–foam interface in order to achieve sufficient magnetic field amplification to alter RT evolution. Benchmarked FLASH simulations are used to study these magnetic field effects in both resistive and ideal MHD.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Particle deceleration for collective QED signatures

Frequency upshifts have been proposed as a first experimental signature of collective effects in quantum electrodynamic cascade generated electron–positron pair plasmas. Since the high effective masses of generated pairs will reduce any frequency change, stopped pairs at a minimal Lorentz factor in the lab frame were thought to be the dominant contribution to the laser upshift. However, we demonstrate that only considering stopped particles unduly neglects the contributions of particles re-accelerated in the laser propagation direction. Re-accelerated particles should, on a per particle basis, affect the laser more strongly and over a much longer timescale. To maximize particle contributions to the laser upshift, we consider a Laguerre–Gaussian (LG) mode laser beam to better reflect generated pairs. Furthermore, the LG mode does not have an advantage in particle deceleration and re-acceleration when compared against a Gaussian beam, but the LG mode can maintain particle contributions for a longer duration, allowing for more pair density accumulation. Deceleration with a structured beam to keep pairs within the laser should create a larger upshift, thereby lowering the demands on the driving laser.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Mitigation of deceleration-phase Rayleigh–Taylor instability growth in inertial confinement fusion implosions

Rayleigh–Taylor growth during shell deceleration is one of the main limiting factors for target performance in inertial confinement fusion implosions. Here, using analytical scaling laws and hydrodynamic simulations, we show that such amplification can be mitigated by reducing the initial mass density in the central target region. The perturbation growth reduction is caused by a smaller hot-spot convergence ratio during deceleration, increased density scale length, and enhanced ablation stabilization. The required central density reduction can be achieved using the dynamic shell formation concept.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Effects of variable deceleration periods on Rayleigh-Taylor instability with acceleration reversals

The dynamics of an interfacial flow that is initially Rayleigh-Taylor unstable but becomes statically stable for some intermediate period due to the reversal of the externally imposed acceleration field is studied. We discuss scenarios that consider both single and double-acceleration reversals. The accel-decel (AD) case consists of a single reversal imposed at an instant after the constant acceleration instability has entered a self-similar regime. The layer of mixed fluid ceases to grow upon acceleration reversal, and the dominant mechanics are due to internal wave oscillations. Variation of mass flux and the Reynolds stress anisotropy is observed due to the action of the internal waves. Here, a second reversal of the AD case that is termed as accel-decel-accel, ADA is then explored; the response of the mixing layer is shown to depend strongly on the duration and the periodicity of the Reynolds stress anisotropy of the mixing layer during the deceleration period. We explore the effect of this variable deceleration period after the second acceleration reversal where the flow once again becomes Rayleigh-Taylor unstable based on metrics that include the integral mixing-layer width, bubble and spike amplitudes, mass flux, Reynolds stress anisotropy tensor, and the molecular mixing parameter.

42 ENGINEERING↗
DOE OSTI2013

Formation and nonlinear dynamics of the squeezed state of a helical electron beam with additional deceleration

Results of numerical simulations and analysis of the formation and nonlinear dynamics of the squeezed state of a helical electron beam in a vircator with a magnetron injection gun as an electron source and with additional electron deceleration are presented. The ranges of control parameters where the squeezed state can form in such a system are revealed, and specific features of the system dynamics are analyzed. It is shown that the formation of a squeezed state of a nonrelativistic helical electron beam in a system with electron deceleration is accompanied by low-frequency longitudinal dynamics of the space charge.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1966

Modified hydraulic braking system limits angular deceleration to safe values

Conventional spring actuated, hydraulically released, fail-safe disk braking system is modified to control the angular deceleration of a massive antenna. The hydraulic system provides an immediate preset pressure to the spring-loaded brake shoes and holds it at this value to decelerate the antenna at the desired rate.

Briggs, R. S.↗
NASA NTRS1973

Engineering design manual of parachute decelerator characteristics for space shuttle solid rocket booster recovery

The design criteria and characteristics of parachutes for recovery of the solid rocket boosters used with the space shuttle launch are presented. A computer program for analyzing the requirements of the parachute decelerators is described. The computer inputs for both the drogue and main parachute decelerators are; (1) parachute size, (2) deployment conditions, (3) inflation times, (4) reefing times, (5) mass properties, (6) spring properties, and (7) aerodynamic coefficients. Graphs of the parachute performance are included.

Mansfield, D. L.↗