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At least 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Qualification of Domestic Lyocell Based Phenolic Impregnated Carbon Ablator (PICA-D) for NASA Missions

Phenolic Impregnated Carbon Ablator (PICA) is a low-density ablator that has been used as the planetary entry heatshield for several NASA missions since the late 90’s. Its low density and efficient performance characteristics have proven effective for use from Discovery to Flag-ship class missions, from Sample Return missions such as Stardust, OSIRIS-REx to large Mars Lander missions such as Mars Science Lab (MSL) and Mars 2020. The rayon-based carbon precursor raw material used in PICA preform manufacturing has experienced multiple supply chain issues. The challenge involved in finding a replacement fiber source is in processing as well as in the final performance of the ablator. Each replacement necessitates the requalification of the PICA. This has happened at least twice in the past 25 years, and a third substitution is now needed. Due to the obsolescence of the input foreign rayon fiber source, a new variant of PICA has been developed using a domestic rayon-like fiber source, Lyocell. Due to its flight heritage and proven capability, PICA is baselined as the Thermal Protection System (TPS) for Dragonfly and Mars Sample Return Sample Retrieval Lander mission and is being considered for the backshell of the Mars Sample Return Earth Entry System. All three missions are due to be launched between 2026 and 2028. The challenge this time is to ensure the PICA made with domestic material is a suitable replacement to the heritage PICA used in MSL and Mars 2020 so that the design of the heatshield can be matured without much risk. Results are presented from the recent efforts of 22 PICA-D billets that were Lot Acceptance Tested. Thermal, mechanical, and representative environment arc-jet tests have been conducted. Testing of PICA-Domestic (PICA-D) indicates very comparable performance with respect to “heritage” PICA materials and thus PICA-D is expected to be a sustainable and nearly a “drop-in” replacement solution for future NASA missions.

PICA↗
NASA NTRS1966

Entry capsule orbit determination accuracy

On-board tracking system of two-way coherent Doppler between entry capsule and orbiting bus for determining orbit of entry capsule and estimating atmospheric parameters.

COHERENT RADAR↗
NASA NTRSDate not supplied

Parametric Cost Modeling of a Mid-Lift-to-Drag Ratio Vehicle for Human Mars Entry, Descent, and Landing

Cost is one of the biggest obstacles to sending humans to Mars. However, spacecraft costs are typically estimated after the preliminary vehicle and mission concepts have been designed. By automating the cost estimation process, the effect of any change in vehicle or mission design on the mission cost can be determined more rapidly. This paper uses the tool SAPE-C (Systems Analysis for Planetary Entry, Descent, and Landing-Cost). SAPE-C integrates the cost modeling software SEER-H (System Estimation and Evaluation of Resources-Hardware) with a number of systems analysis tools and enables large design tradespace exploration early in the design process. SAPE-C is used to analyze several tradespaces of the Mid-Lift-to-Drag ratio rigid entry vehicle for human Mars missions. Key findings include quantifying the impacts of payload, vehicle length, and main engine specific impulse on the overall cost of the vehicle, and how the payload per lander and number of landers affects the cost of a campaign to Mars.

Mid L/D↗
NASA NTRSDate not supplied

Parametric Cost Modeling of a Mid-Lift-to-Drag Ratio Vehicle for Human Mars Entry, Descent, and Landing

Cost is one of the biggest obstacles to sending humans to Mars. However, spacecraft costs are typically estimated after the preliminary vehicle and mission concepts have been designed. By automating the cost estimation process, the effect of any change in vehicle or mission design on the mission cost can be determined more rapidly. This paper uses the tool SAPE-C (Systems Analysis for Planetary Entry, Descent, and Landing-Cost). SAPE-C integrates the cost modeling software SEER-H (System Estimation and Evaluation of Resources-Hardware) with a number of systems analysis tools and enables large design tradespace exploration early in the design process. SAPE-C is used to analyze several tradespaces of the Mid-Lift-to-Drag ratio rigid entry vehicle for human Mars missions. Key findings include quantifying the impacts of payload, vehicle length, and main engine specific impulse on the overall cost of the vehicle, and how the payload per lander and number of landers affects the cost of a campaign to Mars.

Paul D Friz↗
NASA NTRSDate not supplied

Parametric Cost Modeling of a Mid-Lift-to-Drag Ratio Vehicle for Human Mars Entry, Descent, and Landing

Cost is one of the biggest obstacles to sending humans to Mars. However, spacecraft costs are typically estimated after the preliminary vehicle and mission concepts have been designed. By automating the cost estimation process, the effect of any change in vehicle or mission design on the mission cost can be determined more rapidly. This paper uses the tool SAPE-C (Systems Analysis for Planetary Entry, Descent, and Landing-Cost). SAPE-C integrates the cost modeling software SEER-H (System Estimation and Evaluation of Resources-Hardware) with a number of systems analysis tools and enables large design tradespace exploration early in the design process. SAPE-C is used to analyze several tradespaces of the Mid-Lift-to-Drag ratio rigid entry vehicle for human Mars missions. Key findings include quantifying the impacts of payload, vehicle length, and main engine specific impulse on the overall cost of the vehicle, and how the payload per lander and number of landers affects the cost of a campaign to Mars.

Paul D Friz↗
NASA NTRS2011

An Overview of NASA's Current Materials Development Efforts for Mars EDL

Current roadmaps point to landing heavy masses (cargo, followed by manned vehicles) on Mars in the 2030's and the existing entry, descent and landing (EDL) technology will not be sufficient to facilitate such missions. In 2009 the Exploration Technology Development Program (ETDP) established the Entry, Descent and Landing Technology Development Project (EDL TDP), to be managed programmatically at Langley Research Center (LaRC) and technically a Ames Research Center (ARC). The purpose of the project is to further the technologies required to land heavy (approximately 40 metric ton) masses on Mars to facilitate exploration. The EDL TDP contains three technical elements. They are: 1) Thermal Protection Systems (TPS) development 2) Modeling and Tools (MAT) development 3) Supersonic Retropropulsion (SRP) development The primary goals of the EDL TDP TPS element is to design and develop TPS materials capable of withstanding the severe aerothermal loads associated with aerocapture and entry into the Martian atmosphere while significantly decreasing the TPS mass fraction contribution to the entry system. Significant advancements in TPS materials technology are needed in order to enable heavy mass payloads to be successfully landed on the Martian surface for robotic precursors and subsequent human exploration missions. The EDL TDP TPS element is further divided into two different TPS concepts for Mars EDL those being: 1) Rigid TPS for a mid L/D aeroshell with the capability to withstand dual pulsed heating environments as high as 500 W/square cm for aerocapture and 130 W/square cm for entry 2) Flexible TPS for a deployable aerodynamic decelerator with the capability to withstand dual pulsed heating environments as high as 120 W/square cm for aerocapture and 30 W/square cm for entry NASA, along with its vendors, has begun developing and testing materials for each of the deceleration approaches. These include multi-layer rigid ablators and flexible ablative materials. In order to model the response of these types of materials, new and improved modeling techniques will be required. This presentation will outline the types of materials that are under development and illustrate the need for advancement in modeling of ablative materials.

Beck, Robin A.↗
DOE OSTI2020

Kensor: Coordinated Intelligence from Co-Located Sensors

Internet of Things (IoT) is becoming more pervasive in many installations, including homes, manufacturing plants, and industrial facilities of all kinds. The data that IoT produces is a reflection of usual behavior such as daily routines and scheduled tasks, but also from unexpected behavior due to unintentional or undesirable abnormalities. Here, we focus on achieving coordinated intelligence about normal and abnormal phenomena from multiple sensors that are geographically colocated in close proximity, monitoring and controlling a set of co-located devices. Given a set of co-located sensors, we seek an intelligent approach that would automatically determine the “normal” patterns of behaviors among the correlated sensors. After normal behavior is extracted, later monitoring should detect any deviant variations over time. An example application is an entry monitoring and alert system for facilities such as nuclear reactors, where badge readers, door locks, lights, weight trackers and other co-located sensors at the entry point are collectively tracked. To address this problem, we identify the possible solution approach that can be used to solve its different variants. The implemented model is developed as a combination of rules and Markov Chain methods.

Kotevska, Olivera↗
NASA NTRS2019

The Entry Descent and Landing Instrumentation (MEDLI2) Suite for the Mars 2020 Mission

This presentation will discuss the current state of each of the main measurements systems for MEDLI2. The first system is a network of pressure transducers, the Mars Entry Atmospheric Data System (MEADS). Improving upon MEDLI, separate MEDLI2 pressure transducers span the measurement range suitable for both hypersonic and supersonic flows. The MEADS will also measure pressure on the backshell of the vehicle to better characterize the contribution of backshell pressure on the overall forces and moments on the entry probe. The second system is the thermal instrumentation, or Mars Instrumented Sensor Plugs. This system includes a network of high-temperature thermocouples embedded in the thermal protection system across the heatshield and backshell. The MISP also includes two types of sensors for directly measuring incident heatflux on the backshell of the vehicle. In addition, a radiometer is included on the backshell to measure radiative heating. The presentation will also cover the current state of the MEDLI2 hardware, expected environments that will be measured, and data analysis techniques being developed to infer vehicle entry performance from both the MISP and MEADS sensor systems.

White, Todd↗
NASA NTRS2020

TPS and Entry Technologies for Future Outer Planet Exploration

The lack of knowledge about the Ice Giants (Voyager being the only probe to briefly visit them) and literally narrow window of planetary alignment for pragmatic missions to the Ice Giants, make them high priority targets in the next decade. The purpose of this white paper is to provide an overview to the NRC Decadal Survey on thermal protection system (TPS) technologies required for future Outer Planet exploration missions. A prime conclusion is that several of the most significant recommendations made during the last decadal survey were addressed positioning the TPS community to better support missions to the Outer Planets. These include maturation of the Heatshield for Extreme Entry Environment Technology (HEEET) to TRL 6 as replacement for Carbon Phenolic (that requires requalification itself), TPS test facility upgrades, and design tool improvements. These new materials and test methods are enabling for Outer Planet missions. However, there are limitations in the HEEET technology and available ground based test facilities that could become mission constraints depending on the science objectives. This white paper discusses opportunities to mitigate those constraints. In addition, if a mission is not scheduled in the near future, these new developments are at risk of becoming unavailable. Therefore, we recommend that NASA invest in a cross-cutting technology program that focuses on sustainment of relevant TPS materials, entry systems, test facilities, design tools, and flight instrumentation.

Outer Planets↗
NASA NTRS2016

Design and Flight Performance of the Orion Pre-Launch Navigation System

Launched in December 2014 atop a Delta IV Heavy from the Kennedy Space Center, the Orion vehicle's Exploration Flight Test-1 (EFT-1) successfully completed the objective to test the prelaunch and entry components of the system. Orion's pre-launch absolute navigation design is presented, together with its EFT-1 performance.

Zanetti, Renato↗
NASA NTRS1981

Thermal and aerothermal performance of a titanium multiwall thermal protection system

A metallic thermal protection system (TPS) concept the multiwall designed for temperature and pressure at Shuttle body point 3140 where the maximum surface temperature is approximately 811 K was tested to evaluate thermal performance and structural integrity. A two tile model of titanium multiwall and a model consisting of a low temperature reusable surface insulation (LRSI) tiles were exposed to 25 simulated thermal and pressure Shuttle entry missions. The two systems performed the same, and neither system deteriorated during the tests. It is indicated that redesign of the multiwall tiles reduces tile thickness and/or weight. A nine tile model of titanium multiwal was tested for radiant heating and aerothermodynamics. Minor design changes that improve structural integrity without having a significant impact on the thermal protection ability of the titanium multiwall TPS are identified. The capability of a titanium multiwall thermal protection system to protect an aluminum surface during a Shuttle type entry trajectory at locations on the vehicle where the maximum surface temperature is below 811 K is demonstrated.

Avery, D. E.↗
NASA NTRS2017

Parametric Structural Model for a Mars Entry Concept

This paper outlines the process of developing a parametric model for a vehicle that can withstand Earth launch and Mars entry conditions. This model allows the user to change a variety of parameters ranging from dimensions and meshing to materials and atmospheric entry angles to perform finite element analysis on the model for the specified load cases. While this work focuses on an aeroshell for Earth launch aboard the Space Launch System (SLS) and Mars entry, the model can be applied to different vehicles and destinations. This specific project derived from the need to deliver large payloads to Mars efficiently, safely, and cheaply. Doing so requires minimizing the structural mass of the body as much as possible. The code developed for this project allows for dozens of cases to be run with the single click of a button. The end result of the parametric model gives the user a sense of how the body reacts under different loading cases so that it can be optimized for its purpose. The data are reported in this paper and can provide engineers with a good understanding of the model and valuable information for improving the design of the vehicle. In addition, conclusions show that the frequency analysis drives the design and suggestions are made to reduce the significance of normal modes in the design.

Lane, Brittney M.↗
NASA NTRS2019

Modeling Heatshield Erosion Due to Dust Particle Impacts for a Martian Entry Vehicle

Because planetary missions to Mars take years from initial design to arrival at Mars, and because of the unpredictability of major global dust storms, the de-sign of the thermal protection system (TPS) of a Mars entry vehicle requires an estimation for the potential damage caused by dust particle impacts on the heat-shield. This paper will review previous analytical and experimental approaches to modeling dust particle ero-sion and will compare the legacy models against more modern computational techniques and new dust ero-sion models that will be based on upcoming experi-ments in the German Aerospace Center (DLR) GBK facility. The various models will be compared by incorporating them into the Icarus material response code applied to a representative vehicle entering the Martian atmosphere.

planetary entry↗
NASA NTRS1990

Fractal boundaries in magnetotail particle dynamics

It has been recently established that particle dynamics in the magnetotail geometry can be described as a nonintegrable Hamiltonian system with well-defined entry and exit regions through which stochastic orbits can enter and exit the system after repeatedly crossing the equatorial plane. It is shown that the phase space regions occupied by orbits of different numbers of equatorial crossings or different exit modes are separated by fractal boundaries. The fractal boundaries in an entry region for stochastic orbits are examined and the capacity dimension is determined.

Chen, J.↗
NASA NTRS2007

Overview of the Mars Science Laboratory Parachute Decelerator Subsystem

In 2010 the Mars Science Laboratory (MSL) mission will deliver NASA's largest and most capable rover to the surface of Mars. MSL will explore previously unattainable landing sites due to the implementation of a high precision Entry, Descent, and Landing (EDL) system. The parachute decelerator subsystem (PDS) is an integral prat of the EDL system, providing a mass and volume efficient some of aerodynamic drag to decelerate the entry vehicle from Mach 2 to subsonic speeds prior to final propulsive descent to the sutface. The PDS for MSL is a mortar deployed 19.7m Viking type Disk-Gap-Band (DGB) parachute; chosen to meet the EDL timeline requirements and to utilize the heritage parachute systems from Viking, Mars Pathfinder, Mars Exploration Rover, and Phoenix NASA Mars Lander Programs. The preliminary design of the parachute soft goods including materials selection, stress analysis, fabrication approach, and development testing will be discussed. The preliminary design of mortar deployment system including mortar system sizing and performance predictions, gas generator design, and development mortar testing will also be presented.

Entry, Descent, and Landing (EDL)↗
NASA NTRS1980

Analysis of space shuttle orbiter entry dynamics from Mach 10 to Mach 2.5 with the November 1976 flight control system

A six-degree-of-freedom simulation analysis was performed for the space shuttle orbiter entry from Mach 10 to Mach 2.5 with realistic off-nominal conditions using the flight control system referred to as the November 1976 Integrated Digital Autopilot. The off-nominal conditions included: (1) aerodynamic uncertainties in extrapolating from wind tunnel of flight characteristics, (2) error in deriving angle of attack from onboard instrumentation, (3) failure of two of the four reaction control-system thrusters on each side (design specification), and (4) lateral center-of-gravity offset. Many combinations of these off-nominal conditions resulted in a loss of the orbiter. Control-system modifications were identified to prevent this possibility.

Powell, R. W.↗
NASA NTRS2021

The Mars 2020 Perseverance Navigation Filter

The Mars 2020 (M2020) Entry Descent and Landing (EDL) system delivered a rover named “Perseverance” at Jezero crater (Mars) on February 18th, 2021. M2020 EDL used a Guidance Navigation and Control (GN&C) system to achieve its landing target objectives. The navigation filter (NavFilter) integrated Descent Inertial Measurement Unit (DIMU) measurements to estimate position and attitude. The NavFilter also used the Terminal Descent Sensor (TDS) to es-timate surface-relative position and velocity corrections. The NavFilter provided all of the dynamic state information to the entry controller, entry guidance, Lander Vision System (LVS) and powered descent guidance and control algo-rithms. The NavFilter for Perseverance is based on Curiosity’s NavFilter with a couple of modifications.

Casoliva, Jordi↗