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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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123 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Overview and Performance of the LOFTID Instrumentation Suite

On November 10, 2022, NASA launched the Low-earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) vehicle as a secondary payload mounted inside the launch vehicle adaptor on an Atlas V 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 payload adaptor canister was ejected by the payload adapter separation system to expose the packed LOFTID vehicle, then the LOFTID aeroshell, a Hypersonic Inflatable Aerodynamic Decelerator (HIAD), was deployed and inflated as planned. The Centaur pointed the LOFTID vehicle to the desired attitude to enter the atmosphere, spun the assembly to roughly three rpm, and separated the reentry vehicle. The LOFTID vehicle entered the atmosphere over Alaska at >8km/sec and decelerated as designed demonstrating stable flight from hypersonic entry through subsonic parachute deployment. On-board visible light cameras captured the reactions of the heatshield through all phases of flight, and co-located infrared light cameras captured the temperature distribution of the aft side 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. Heat Flux Gages and Pressure Transducers measured the heating rate and surface pressure experienced by the rigid nose of the reentry vehicle. Loadcells measured the interface loads between the IS and the rigid centerbody. This paper will discuss many of the key instruments flown on the successful LOFTID technology demonstration mission and will provide some high level results, while pointing to more detailed papers on the post-flight analyses.

Gregory T Swanson↗
NASA NTRSDate not supplied

LOFTID (Low-Earth Orbit Flight Test of an Inflatable Decelerator) PASS (Payload Adapter Separation System) Design & Qualification

On November 10, 2022, NASA, in partnership with United Launch Alliance (ULA), launched Low-earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) as a secondary payload on an Atlas V Centaur out of the Vandenburg Space Force Base (VSFB). After successfully delivering the primary payload, Joint Polar Satellite System-2 (JPSS-2), to a sun synchronous trajectory, the Centaur upper stage reoriented LOFTID onto the desired reentry trajectory. After conducting a de-orbit burn to enter the atmosphere the Payload Adaptor was ejected to expose the packed LOFTID vehicle. The LOFTID Hypersonic Inflatable Aerodynamic Decelerator (HIAD) was deployed and inflated. The Centaur pointed LOFTID to the desired entry attitude and spun the vehicle up to roughly three rpm before separating the reentry vehicle over the Middle East. The LOFTID vehicle flew freely before reentering the atmosphere over Alaska at >8km/sec and decelerating as designed. LOFTID demonstrated stable flight from hypersonic entry through subsonic parachute deployment. LOFTID was enabled by a mission-unique Payload Adapter Separation System (PASS) which separated the Payload Adapter prior to the start of the LOFTID flight demonstration, allowing the launch vehicle to accommodate a superstack of two independent, similarly sized payloads. This paper will discuss the design, development, and qualification effort of the LOFTID PASS.

Sean M Hancock↗
NASA NTRSDate not supplied

Overview and Performance of the LOFTID Instrumentation Suite

On November 10, 2022, NASA launched the Low-earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) vehicle as a secondary payload mounted inside the launch vehicle adaptor on an Atlas V 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 payload adaptor canister was ejected by the payload adapter separation system to expose the packed LOFTID vehicle, then the LOFTID aeroshell, a Hypersonic Inflatable Aerodynamic Decelerator (HIAD), was deployed and inflated as planned. The Centaur pointed the LOFTID vehicle to the desired attitude to enter the atmosphere, spun the assembly to roughly three rpm, and separated the reentry vehicle. The LOFTID vehicle entered the atmosphere over Alaska at >8km/sec and decelerated as designed demonstrating stable flight from hypersonic entry through subsonic parachute deployment. On-board visible light cameras captured the reactions of the heatshield through all phases of flight, and co-located infrared light cameras captured the temperature distribution of the aft side 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. Heat Flux Gages and Pressure Transducers measured the heating rate and surface pressure experienced by the rigid nose of the reentry vehicle. Loadcells measured the interface loads between the IS and the rigid centerbody. This paper will discuss many of the key instruments flown on the successful LOFTID technology demonstration mission and will provide some high level results, while pointing to more detailed papers on the post-flight analyses.

spacecraft design↗
NASA NTRSDate not supplied

LOFTID Surface Heating Reconstruction

On November 10, 2022, the Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) reentry vehicle launched to low-Earth orbit aboard a United Launch Alliance Atlas V rocket out of Vandenberg Air Force Base. The aeroshell, the largest Hypersonic Inflatable Aerodynamic Decelerator (HIAD) ever flown, was inflated to its full 6-meter diameter before successful re-entry into the atmosphere. The aeroshell was heavily instrumented in order to understand its behavior during entry. There were 82 thermocouples (TCs) distributed across the aeroshell, with 22 integrated into the flexible thermal protection system (FTPS) on the rigid nose, 36 in the FTPS on the deployable structure, and 24 on the inflatable structure. TCs were placed at different depths throughout the FTPS. Those nearest to the surface were located just beneath the two SiC outer fabric layers. The near-surface TCs on the rigid nose were Type R with flame spray alumina insulation, while those on the flank were Type N with mica/ceramic insulation. Additionally, a radiometer was placed at the center of the nose surrounded by four total heat flux gauges in a cruciform configuration at a radius of 0.41 m. The nose instrumentation is shown in Fig. 1 and a cross-section of the aeroshell with all TC locations is shown in Fig. 2. The objective of this work was to use the temperatures measured by the TCs during flight to estimate the surface heat rate across the aeroshell throughout the period of re-entry by inverse analysis methodology. The results were used to evaluate the fidelity of measurements from the total heat flux gauges on the nose, determine the surface heat flux at aeroshell locations where gauges were not present, and compare to pre-flight CFD-based heating predictions. Inversely estimated surface heat flux continues to be used to correlate FTPS thermal models to reconstruct in-flight thermal response.

H S Alpert↗
NASA NTRSDate not supplied

LOFTID Surface Heating Reconstruction

On November 10, 2022, the Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) reentry vehicle launched to low-Earth orbit aboard a United Launch Alliance Atlas V rocket out of Vandenberg Air Force Base. The aeroshell, the largest Hypersonic Inflatable Aerodynamic Decelerator (HIAD) ever flown, was inflated to its full 6-meter diameter before successful re-entry into the atmosphere. The aeroshell was heavily instrumented in order to understand its behavior during entry. There were 82 thermocouples (TCs) distributed across the aeroshell, with 22 integrated into the flexible thermal protection system (FTPS) on the rigid nose, 36 in the FTPS on the deployable structure, and 24 on the inflatable structure. TCs were placed at different depths throughout the FTPS. Those nearest to the surface were located just beneath the two SiC outer fabric layers. The near-surface TCs on the rigid nose were Type R with flame spray alumina insulation, while those on the flank were Type N with mica/ceramic insulation. Additionally, a radiometer was placed at the center of the nose surrounded by four total heat flux gauges in a cruciform configuration at a radius of 0.41 m. The nose instrumentation is shown in Fig. 1 and a cross-section of the aeroshell with all TC locations is shown in Fig. 2. The objective of this work was to use the temperatures measured by the TCs during flight to estimate the surface heat rate across the aeroshell throughout the period of re-entry by inverse analysis methodology. The results were used to evaluate the fidelity of measurements from the total heat flux gauges on the nose, determine the surface heat flux at aeroshell locations where gauges were not present, and compare to pre-flight CFD-based heating predictions. Inversely estimated surface heat flux continues to be used to correlate FTPS thermal models to reconstruct in-flight thermal response.

LOFTID↗
NASA NTRSDate not supplied

Comparison of OVERFLOW Computational and Experimental Results for a Blunt Mars Entry Vehicle Concept during Supersonic Retropropulsion

Simulations of unsteady supersonic retropropulsion (SRP) flow over a Hypersonic Inflatable Aerodynamic Decelerator (HIAD) blunt-body vehicle were performed using the OVERFLOW Computational Fluid Dynamics (CFD) solver. High-fidelity flow solver techniques, including Detached Eddy Simulation (DES) turbulence modeling and Adaptive Mesh Refinement (AMR), were employed to obtain improved realism in CFD predictions. Simulation conditions and geometry configurations were designed to match specific runs in the Descent System Study (DSS) wind tunnel testing (WTT) campaign. The accuracy of each simulation is assessed by direct comparison to experimental data. Comparisons of computational predictions of the SRP flowfield and bow shock shape to experimental schlieren imaging show reasonable prediction of mean shock shape, with approximately 10% similarity in shock standoff distance for selected conditions, as well as similarity in local, time-varying fluctuations of the shock-plume interaction. Comparisons of discrete measurements of surface pressure coefficient (Cp) indicate CFD accuracy within approximately 10% of the experiment across the majority of the model heatshield, with larger variations at some of the heatshield edge locations with stronger flow unsteadiness. Simulated unsteadiness of these chaotic flows, which were highly dynamic and multi-modal, was shown to be within 20-40% of experimentally-measured pressure standard deviation (SD) for the majority of the sampled locations.

Supersonic Retropropulsion↗
NASA NTRSDate not supplied

Comparison of OVERFLOW Computational and Experimental Results for a Blunt Mars Entry Vehicle Concept during Supersonic Retropropulsion

Simulations of unsteady supersonic retropropulsion (SRP) flow over a Hypersonic Inflatable Aerodynamic Decelerator (HIAD) blunt-body vehicle were performed using the OVERFLOW Computational Fluid Dynamics (CFD) solver. High-fidelity flow solver techniques, including Detached Eddy Simulation (DES) turbulence modeling and Adaptive Mesh Refinement (AMR), were employed to obtain improved realism in CFD predictions. Simulation conditions and geometry configurations were designed to match specific runs in the Descent System Study (DSS) wind tunnel testing (WTT) campaign. The accuracy of each simulation is assessed by direct comparison to experimental data. Comparisons of computational predictions of the SRP flowfield and bow shock shape to experimental schlieren imaging show reasonable prediction of mean shock shape, with approximately 10% similarity in shock standoff distance for selected conditions, as well as similarity in local, time-varying fluctuations of the shock-plume interaction. Comparisons of discrete measurements of surface pressure coefficient (Cp) indicate CFD accuracy within approximately 10% of the experiment across the majority of the model heatshield, with larger variations at some of the heatshield edge locations with stronger flow unsteadiness. Simulated unsteadiness of these chaotic flows, which were highly dynamic and multi-modal, was shown to be within 20-40% of experimentally-measured pressure standard deviation (SD) for the majority of the sampled locations.

Supersonic Retropropulsion↗
NASA NTRSDate not supplied

Precision Landing Navigation Performance of Human-Scale Lunar and Mars Landers

To meet the unique challenges of crewed Lunar and Mars precision landings, NASA’s Safe and Precise Landing Integrated Capabilities Evolution project has worked to advance autonomous spacecraft navigation by increasing the technology readiness level of key deorbit, entry, descent, and landing systems, including navigation sensors. Different sensors and their effects on overall system performance are evaluated using six-degree-of-freedom simulations with physics-based engineering models that capture the relevant vehicle systems and environmental effects. Building on an existing simulation framework, this work demonstrates how improved modeling fidelity enables rapid and detailed assessment of various navigation sensors on human-scale Lunar and Mars landing vehicles using NASA reference architectures.

navigation↗
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

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 NTRS2024

Experimental and Computational Study of Convective Heating on the Aeroshell Back Side and Payload of the LOFTID Vehicle

A wind tunnel test program was conducted to obtain experimental convective heating data on models of the Low Earth Orbital Flight Test of an Inflatable Decelerator (LOFTID) vehicle in support of the flight test program. Wind tunnel testing was conducted at Mach 6 and Mach 10 at unit Reynolds numbers from 0.5×106/ft to 4.0×106/ft on 6.0inch diameter aeroshell models. Global heating data were obtained through phosphor thermography measurements on the front and back of the aeroshell and on the payload. For all test conditions, attached, laminar flow was definitively produced on the front of the aeroshell, while in the wake the flow was separated, unsteady and possibly transitional or turbulent. A complementary computational study was performed to assess the accuracy of heating predictions for LOFTID wake flow environments. A new grid topology was developed for the study to allow the use of structured grid solvers for complex, open-backed geometries such as that of LOFTID. Close agreement between measurements and predictions was obtained on the front of the aeroshell. Comparisons were more challenging in the wake because of both the extremely low heating rates and the accompanying high uncertainties and the unsteady nature of the separated wake flow simulations. While the differences between heating predictions and measurements for the wake flow were higher than for the forebody flow, these differences were used to assist in the definition of conservative uncertainty margins for predictions of the flight environments for the successful flight test of the LOFTID vehicle in November 2022.

LOFTID↗
NASA NTRSDate not supplied

PLIF for Space Technology and Exploration Applications

Highlights from recent PLIF test campaigns at large-scale NASA facilities and lab-scale developments are summarized. The measurements presented here have the potential to aid researchers in validating complex simulations and inform designs for spaceflight vehicles.

PLIF↗