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Brian Tulaba

Publications and source records attributed to Brian Tulaba.

8 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

The Effect of Impingement Angle on Bipropellant Thruster Plume Degradation of Spacecraft Materials

Unburned and partially combusted liquid propellant present in bipropellant thruster plumes can contaminate and damage external spacecraft materials. Microscopic impact features due to high-speed droplet impacts have been observed on space shuttle flight experiments and International Space Station (ISS) returned flight hardware. Analytical results have shown that particle impingement angle greatly affects surface damage, with normal impacts being the most severe and highly oblique impacts being more benign. The effect of thruster plume impingement angle on material degradation has now been further studied following a bipropellant thruster plume test performed at the high-vacuum plume test facility for chemical thrusters at DLR Göttingen, STG-CT. Several spacecraft material samples were exposed to the freely expanding pulsed thruster plume at a range of impingement angles (from 0 to 75 deg). Results of post-test evaluations and potential spaceflight applications are summarized.

Gateway↗
NASA NTRS2024

Overview of the Lunar Gateway External Contamination Environment

As a part of the Artemis mission, Gateway will be a long duration space station in a near rectilinear halo orbit around the Moon. Gateway will be exposed to a variety of external contamination sources, which can degrade external hardware / surfaces and impact science utilization objectives. Requirements and methodologies addressing material outgassing, chemical and electric thruster plumes, vacuum venting, and visiting vehicle interactions have been developed by the Gateway Induced Environments team to ensure vehicle performance and mission success. The external contamination requirements and integration process are described along with required data deliverables. Integrated external contamination analyses are conducted by the Gateway Environments Team to assess compliance with external contamination requirements. This paper provides a current status of integration activities and analysis results, as well as future plans to improve external contamination characterization.

Crystal A Quiroz↗
NASA NTRSDate not supplied

The NASA JSC Hypervelocity Impact Technology (HVIT) Office

The Hypervelocity Impact Technology (HVIT) office at the National Aeronautical and Space Administration (NASA) Johnson Space Center (JSC) is dedicated to support NASA flight programs in meeting their meteoroid and orbital debris (MMOD) protection requirements both efficiently and effectively, with a minimum of shielding mass, volume, and cost. This paper provides an overview of HVIT capabilities in providing hypervelocity tests, analyses, MMOD risk assessments and shielding expertise. HVIT personnel work closely with NASA program and safety/mission assurance personnel to develop program-specific MMOD protection requirements which are both achievable based on initial risk assessments and will meet overall safety and mission success requirements. HVIT then proceeds with hypervelocity impact testing and hydrocode assessments to update and verify ballistic limit equations used in the MMOD risk assessment. Hypervelocity impact tests are primarily performed at the NASA WSTF Remote Hypervelocity Test Laboratory (RHTL). Other hypervelocity facilities that provide complementary test capabilities are called on when necessary to fill data gaps. The goal of the final pre-flight MMOD risk assessment is to show compliance with MMOD requirements prior to flight. This final assessment will also incorporate changes in the MMOD environment from meteoroid showers and orbital debris breakups. After the mission is flown, post-flight inspections are performed by HVIT to document and trend MMOD damage to returned spacecraft surfaces and hardware. HVIT accomplishments in NASA mission support are described. In addition, current HVIT activities to aid on-going NASA crewed missions and science missions are presented.

Meteoroid↗
NASA NTRSDate not supplied

The NASA JSC Hypervelocity Impact Technology (HVIT) Office

- HVIT’s operational objectives for NASA, commercial, and international partners are to 1) help to define MMOD risk requirements 2) provide assessments that identify risk drivers for a specific spacecraft design, and 3) work to design and optimize shielding technologies based on increasing performance and reducing mass. - The use of Bumper-code underpins all risk assessments provided by HVIT – by using a complete FEM model, Bumper can provide a wholistic view of risk for a given design and mission profile. - A full risk assessment, however, requires an iterative approach, where Bumper is first used to identify potential risk drivers. Subsequent analysis can focus on iterating the shield design in highest risk areas. And may include the refinement of BLEs through testing, design modification, or reexamination of the failure criteria. - HVIT utilizes a wide-range of expertise to provide the most accurate risk assessments possible – areas of active research are highlighted below.

hypervelocity impact↗
NASA NTRSDate not supplied

Overview of the Lunar Gateway External Contamination Environment

As a part of the Artemis mission, Gateway will be a long duration space station in a near rectilinear halo orbit around the Moon. Gateway will be exposed to a variety of external contamination sources, which can degrade external hardware / surfaces and impact science utilization objectives. Requirements and methodologies addressing material outgassing, chemical and electric thruster plumes, vacuum venting, and visiting vehicle interactions have been developed by the Gateway Induced Environments team to ensure vehicle performance and mission success. The external contamination requirements and integration process are described along with required data deliverables. Integrated external contamination analyses are conducted by the Gateway Environments Team to assess compliance with external contamination requirements. This paper provides a current status of integration activities and analysis results, as well as future plans to improve external contamination characterization.

Crystal A. Quiroz↗
NASA NTRSDate not supplied

The Effect of Impingement Angle on Bipropellant Thruster Plume Degradation of Spacecraft Materials

Unburned and partially combusted liquid propellant present in bipropellant thruster plumes can contaminate and damage external spacecraft materials. Microscopic impact features due to high-speed droplet impacts have been observed on space shuttle flight experiments and International Space Station (ISS) returned flight hardware. Analytical results have shown that particle impingement angle greatly affects surface damage, with normal impacts being the most severe and highly oblique impacts being more benign. The effect of thruster plume impingement angle on material degradation has now been further studied following a bipropellant thruster plume test performed at the high-vacuum plume test facility for chemical thrusters at DLR Göttingen, STG-CT. Several spacecraft material samples were exposed to the freely expanding pulsed thruster plume at a range of impingement angles (from 0 to 75 deg). Results of post-test evaluations and potential spaceflight applications are summarized.

Gateway↗
NASA NTRSDate not supplied

Overview of the Lunar Gateway External Contamination Environment

As a part of the Artemis mission, Gateway will be a long duration space station in a near rectilinear halo orbit around the Moon. Gateway will be exposed to a variety of external contamination sources, which can degrade external hardware / surfaces and impact science utilization objectives. Requirements and methodologies addressing material outgassing, chemical and electric thruster plumes, vacuum venting, and visiting vehicle interactions have been developed by the Gateway Induced Environments team to ensure vehicle performance and mission success. The external contamination requirements and integration process are described along with required data deliverables. Integrated external contamination analyses are conducted by the Gateway Environments Team to assess compliance with external contamination requirements. This paper provides a current status of integration activities and analysis results, as well as future plans to improve external contamination characterization.

thruster plumes↗