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NASA NTRSDate not supplied

NASA Environmental Control and Life Support Technology Development for Exploration: 2020 to 2021 Overview

This PowerPoint presentation supports the following paper submission's abstract (STRIVES 20210015025). This paper provides an overview of NASA supported activities developing Environmental Control and Life Support (ECLSS) technologies in the following capability areas: life support, environmental monitoring, fire safety, and logistics. NASA has been refining technology needs for deep space missions including Gateway, lunar surface, Mars transit, and Mars surface missions. Validating technologies in relevant environments, both in low earth orbit (LEO) and ground tests is critical in understanding technology performance and long duration performance. On-orbit and ground tests inform NASA’s technology decisions to fill exploration gaps. NASA has multiple technology projects across the technology readiness spectrum with potential to fill or partially fill exploration gaps. For each capability area, this paper will describe select capability gaps, NASA technology project maturation over the past year, and key performance parameters (KPPs). KPPs are evolving but they still provide a useful measure in communicating progress and identifying development needs to fill exploration gaps. The intent is to provide a very high-level overview describing the projects that are supporting gap closure and provide references to additional technical details, progress, and KPPs.

Life Support↗
NASA NTRS1984

Module Hipot and ground continuity test results

Hipot (high voltage potential) and module frame continuity tests of solar energy conversion modules intended for deployment into large arrays are discussed. The purpose of the tests is to reveal potentially hazardous voltage conditions in installed modules, and leakage currents that may result in loss of power or cause ground fault system problems, i.e., current leakage potential and leakage voltage distribution. The tests show a combined failure rate of 36% (69% when environmental testing is included). These failure rates are believed easily corrected by greater care in fabrication.

Griffith, J. S.↗
NASA NTRS1985

Dynamic verification of very large space structures

A research program in spacecraft structures, structural dynamics, and controls verification using a relatively large, flexible beam as a focus is introduced. This research effort addresses fundamental problems applicable to the verification of large, flexible space structures and combines ground tests, flight behavior prediction, and instrumented orbital tests. The program is expected to produce quantitative results for use in improving the validity of ground tests for verifying flight performance analyses.

Hanks, B. R.↗
NASA NTRS1995

(abstract) Wide Dynamic Range Porous Plug and Vent Line for SIRTF

The most recent approach to the Space Infrared Telescope Facility (SIRTF) uses a new design concept in which the telescope is launched warm and subsequently cooled to operating temperture on orbit. At launch the cryostat is at 2 K and the telescope is at room temperature. Cooldown of the telescope will be accomplished initially through radiation to space. Final cooldown to the 5.5 K operating temperature is done with helium vapor. Initially the helium flow on orbit will be 10 to 20 times larger than required for steady-state operation. The vent line and the liquid-vapor phase separator (porous plug) therefore must accomodate a large dynamic operational range. For ground testing of IR instruments, the required temperature is 1.5 K. The helium tank temperature for both ground testing and space operations thus needs to be 1.4 K. We will present a discussion of the requirements, a conceptual design, and initial laboratory test results with candidate porous plugs and associated instrumentation. A discussion of possible connections to the design of Gravity Probe-B cryostat will also be presented.

infrared space helium cryostat↗
NASA NTRS1995

Wide Dynamic Range Porous Plug for SIRTF

The most recent approach to the Space Infrared Telescope Facility (SIRTF) uses a new design concept in which the telescope is launched warm and subsequently cooled to operating temperature on orbit. At launch, the cryostat is at 2 K and the telescope is at room temperature. Cooldown of the telescope will be accomplished initially through radiation to space. Final cooldown to the 5.5 K operating temperature is done with helium vapor. Initially, the helium flow on orbit will be 20 to 30 times larger than required for steady-state operation. The vent line and the liquid/vapor phase separator (porous plug) therefore must accommodate a large dynamic operational range.For ground testing of IR instruments, the required temperature is 1.5 K. The helium tank temperature for both ground testing and space operations thus needs to be at 1.4 K. We present a discussion of the requirements, a conceptual design, and initial laboratory test results with candidate porous plugs and associated instrumentation. A discussion of possible connections to the design of the Gravity Probe-B cryostat will be presented also.

SIRTF, Liquid/Vapor Phase, Separator, Porous Plug↗
NASA NTRSDate not supplied

Zero-G Experiments of the BionicWingsat - A 2U-Cubesat with Deployable, Biologically-Inspired Wings

In this paper, recent testing of a novel deployable structure with several potential applications in space will be described, with the focus on performed deployment experiments in a DLR Zero-g flight campaign and in ground tests. Through a cooperative effort of the German Aerospace Center (DLR) and the National Aeronautics and Space Administration (NASA), a biologically-inspired structurally-integrated membrane featuring distributed functional elements has been developed and integrated into the 2U CubeSat called BionicWingSat. Such a membrane structure could be useful for all sorts of applications in which a relatively flat area is desirable such as solar sails, drag sails, or solar shades. For SmallSats and CubeSats, the design proposed also has the desirable property of being self-deploying without the need for powered deployment mechanisms. Building on previous work inspired by the wings of earwigs, the research presented in this paper focuses on testing of developed design concepts for such structural systems. To do so 24 fully integrated wings on two BionicWingSats in 2U Cubesat format were experimentally deployed in a microgravity environment during a dedicated DLR Zero-g flight campaign in 2021. The results of these experiments, the built hardware and test articles, the test arrangement, as well as a comparison to ground tests are discussed in this paper.

Spacecraft structures↗
NASA NTRS1986

Multiple boundary condition test (MBCT) approach to update mathematical models of large flexible structures

A major challenge to the structural dynamicist is to validate mathematical models of large space structures which cannot be ground tested because of its size and/or flexibility. The paper presents a Multiple Boundary Condition Test (MBCT) approach which allows a systematic validation of the mathematical model by performing a number of ground tests on a large structure with variable boundary conditions. A numerical simulation is presented which illustrates the validity of the MBCT including some of the potential limitations.

Wada, B. K.↗
NASA NTRS2010

Design Considerations for Human Rating of Liquid Rocket Engines

I.Human-rating is specific to each engine; a. Context of program/project must be understood. b. Engine cannot be discussed independently from vehicle and mission. II. Utilize a logical combination of design, manufacturing, and test approaches a. Design 1) It is crucial to know the potential ways a system can fail, and how a failure can propagate; 2) Fault avoidance, fault tolerance, DFMR, caution and warning all have roles to play. b. Manufacturing and Assembly; 1) As-built vs. as-designed; 2) Review procedures for assembly and maintenance periodically; and 3) Keep personnel trained and certified. c. There is no substitute for test: 1) Analytical tools are constantly advancing, but still need test data for anchoring assumptions; 2) Demonstrate robustness and explore sensitivities; 3) Ideally, flight will be encompassed by ground test experience. III. Consistency and repeatability is key in production a. Maintain robust processes and procedures for inspection and quality control based upon development and qualification experience; b. Establish methods to "spot check" quality and consistency in parts: 1) Dedicated ground test engines; 2) Random components pulled from the line/lot to go through "enhanced" testing.

Parkinson, Douglas↗
NASA NTRS2011

Positively Verifying Mating of Previously Unverifiable Flight Connectors

Current practice is to uniquely key the connectors, which, when mated, could not be verified by ground tests such as those used in explosive or non-explosive initiators and pyro valves. However, this practice does not assure 100-percent correct mating. This problem could be overcome by the following approach. Errors in mating of interchangeable connectors can result in degraded or failed space mission. Mating of all flight connectors considered not verifiable via ground tests can be verified electrically by the following approach. It requires two additional wires going through the connector of interest, a few resistors, and a voltage source. The test-point voltage V(sub tp) when the connector is not mated will be the same as the input voltage, which gets attenuated by the resistor R(sub 1) when the female (F) and male (M) connectors are mated correctly and properly. The voltage at the test point will be a function of R(sub 1) and R(sub 2). Monitoring of the test point could be done on ground support equipment (GSE) only, or it can be a telemetry point. For implementation on multiple connector pairs, a different value for R(sub 1) or R(sub 2) or both can be selected for each pair of connectors that would result in a unique test point voltage for each connector pair. Each test point voltage is unique, and correct test point voltage is read only when the correct pair is mated correctly together. Thus, this design approach can be used to verify positively the correct mating of the connector pairs. This design approach can be applied to any number of connectors on the flight vehicle.

Pandipati R. K. Chetty↗
NASA NTRSDate not supplied

Characterizing Electrical Arc Behavior in Ion Engines

Test results using an engineering model Advanced NEXT thruster are presented to identify different arc types utilizing ground test hardware. Three distinct arc types were observed: grid-to-grid arcs, high voltage-to-chassis arcs, and a combination of both. The frequency of high voltage-to-chassis arcs ranged from 4-30%, depending on operating conditions and hardware configuration. Higher beam currents were typically associated with more frequent high voltage-to-chassis arcs. During these arcs, the measured chassis current levels ranged from 20-70 A, however a significant portion of the output beam current returned to the beam supply via the neutralizer cathode plasma, which may be a ground test facility effect. The paper also discusses conducted susceptibility tests that can be performed at the spacecraft level to address the transients associated with arcing events.

electric propulsion↗
NASA NTRS1992

Liquid Motion in a Rotating Tank Experiment (LME)

The Liquid Motion in Rotating Tank Experiment (LME) will investigate and quantify liquid motions occurring in spin-stabilized spacecraft; acquire representative data to validate ground-test scaling procedures; and obtain scientific understanding to formulate better analytical models. LME eliminates the limitations of ground testing. LME design is nearing the end of phase B: the breadboard hardware model has been completed; the load cells have been fabricated and tested; the experiment computer has been flight qualified; and other electronics have been breadboarded. Various aspects of this experiment are presented in viewgraph form.

Dodge, F. T.↗
NASA NTRS2005

Forward Technology Solar Cell Experiment (FTSCE) for MISSE-5 Verified and Readied for Flight on STS-114

The Forward Technology Solar Cell Experiment (FTSCE) is a space solar cell experiment built as part of the Fifth Materials on the International Space Station Experiment (MISSE-5): Data Acquisition and Control Hardware and Software. It represents a collaborative effort between the NASA Glenn Research Center, the Naval Research Laboratory, and the U.S. Naval Academy. The purpose of this experiment is to place current and future solar cell technologies on orbit where they will be characterized and validated. This is in response to recent on-orbit and ground test results that raised concerns about the in-space survivability of new solar cell technologies and about current ground test methodology. The various components of the FTSCE are assembled into a passive experiment container--a 2- by 2- by 4-in. folding metal container that will be attached by an astronaut to the outer structure of the International Space Station. Data collected by the FTSCE will be relayed to the ground through a transmitter assembled by the U.S. Naval Academy. Data-acquisition electronics and software were designed to be tolerant of the thermal and radiation effects expected on orbit. The experiment has been verified and readied for flight on STS-114.

Jenkins, Phillip P.↗
NASA NTRS1976

Development of thermal control methods for specialized components and scientific instruments at very low temperatures (follow-on)

Many payloads currently proposed to be flown by the space shuttle system require long-duration cooling in the 3 to 200 K temperature range. Common requirements also exist for certain DOD payloads. Parametric design and optimization studies are reported for multistage and diode heat pipe radiator systems designed to operate in this temperature range. Also optimized are ground test systems for two long-life passive thermal control concepts operating under specified space environmental conditions. The ground test systems evaluated are ultimately intended to evolve into flight test qualification prototypes for early shuttle flights.

Wright, J. P.↗
NASA NTRS2004

Upgrades at the Propulsion Systems Lab (PSL)

The Propulsion Systems Lab (PSL) does ground testing on full size air breathing engines. These engines range from those on commercial airplanes to fighter jets. At the PSL, engineers receive test requirements from customers and put together the necessary instrumentation, data systems, power requirements, electrical control valves, and engine controls. The engineers are also responsible for facility maintenance, repairs and upgrades. There are four major sections at the PSL; the Test floor, the Data room, the Control room and, the WDPF room. On the test floor are two test cells, cell #3 and cell #4. It is within these cells that the actual engine resides for ground testing. The cells, once sealed and taken up to altitude, are capable of reaching engine inlet temperatures of 1000 F to -90 F, and various atmospheric pressures. The engine, when operational, takes in air and gives out exhaust of up to 2000 F. The exhaust is led to another section of the cell where it is cooled to 150 F before finally redirected to the appropriate disposer. Temperature and pressure transducers detect the conditions within the cell and transmit them to the data room where the results are captured, processed, analyzed, and translated to a more comprehensive language. This is made possible with the aid of several programmable logic controllers (PLCs) and instrumentation and control systems. The translated data is then sent, via the LAN, to the control room where the results can be viewed on monitors by the engineers and customers. From the control room, the test cell conditions can be changed whenever desired. During tests, a lot takes place in the facility. The WDPF control system monitors and controls all facility parameters. This summer, I will assist the engineers; on an upgrade to the facility's distributed control and dynamic data system, in preparation for an engine test that will begin in September, the installation of control systems and various miscellaneous projects around the PSL.

Audu, Abdullahi M.↗
NASA NTRS2003

Recent Advances in Hydrogen Peroxide Propulsion Test Capability at NASA's Stennis Space Center E-Complex

In recent years, the rocket propulsion test capability at NASA's John C. Stennis Space Center's (SSC) E-Complex has been enhanced to include facilitization for hydrogen peroxide (H2O2) based ground testing. In particular, the E-3 test stand has conducted numerous test projects that have been reported in the open literature. These include combustion devices as simple as small-scale catalyst beds, and larger devices such as ablative thrust chambers and a flight-type engine (AR2-3). Consequently, the NASA SSC test engineering and operations knowledge base and infrastructure have grown considerably in order to conduct safe H2O2 test operations with a variety of test articles at the component and engine level. Currently, the E-Complex has a test requirement for a hydrogen peroxide based stage test. This new development, with its unique set of requirements, has motivated the facilitization for hydrogen peroxide propellant use at the E-2 Cell 2 test position in addition to E-3. Since the E-2 Cell 2 test position was not originally designed as a hydrogen peroxide test stand, a facility modernization-improvement project was planned and implemented in FY 2002-03 to enable this vertical engine test stand to accomodate H2O2. This paper discusses the ongoing enhancement of E-Complex ground test capability, specifically at the E-3 stand (Cell 1 and Cell 2) and E-2 Cell 2 stand, that enable current and future customers considerable test flexibility and operability in conducting their peroxide based rocket R&D efforts.

Jacks, Thomas E.↗
NASA NTRS2003

Expanding Hydrogen Peroxide Propulsion Test Capability at NASA's Stennis Space Center E-Complex

In recent years, the rocket propulsion test capability at NASA s John C. Stennis Space Center's (SSC) E-Complex has been enhanced to include facilitization for hydrogen peroxide (H2O2) based ground testing. In particular, the E-3 test stand has conducted numerous test projects that have been reported in the open literature. These include combustion devices as simple at small-scale catalyst beds, and larger devices such as ablative thrust chambers and a flight-type engine (AR2-3). Consequently, the NASA SSC test engineering and operations knowledge base and infrastructure have grown considerably in order to conduct safe H2O2 test operations with a variety of test articles at the component and engine level. Currently, the E-Complex has a test requirement for a hydrogen peroxide based stage test. This new development, with its unique set of requirements, has motivated the facilitization for hydrogen peroxide propellant use at the E-2 Cell 2 test position in addition to E-3. Since the E-2 Cell 2 test position was not originally designed as a hydrogen peroxide test stand, a facility modernization- improvement project was planned and implemented in FY 2002-03 to enable this vertical engine test stand to accommodate H2O2. This paper discusses the ongoing enhancement of E-Complex ground test capability, specifically at the E-3 stand (Cell 1 and Cell 2) and E-2 Cell 2 stand, that enable current and future customers considerable test flexibility and operability in conducting their peroxide based rocket R&D efforts.

Jacks, Thomas E.↗
NASA NTRS2004

Development of Modal Test Techniques for Validation of a Solar Sail Design

This paper focuses on the development of modal test techniques for validation of a solar sail gossamer space structure design. The major focus is on validating and comparing the capabilities of various excitation techniques for modal testing solar sail components. One triangular shaped quadrant of a solar sail membrane was tested in a 1 Torr vacuum environment using various excitation techniques including, magnetic excitation, and surface-bonded piezoelectric patch actuators. Results from modal tests performed on the sail using piezoelectric patches at different positions are discussed. The excitation methods were evaluated for their applicability to in-vacuum ground testing and to the development of on orbit flight test techniques. The solar sail membrane was tested in the horizontal configuration at various tension levels to assess the variation in frequency with tension in a vacuum environment. A segment of a solar sail mast prototype was also tested in ambient atmospheric conditions using various excitation techniques, and these methods are also assessed for their ground test capabilities and on-orbit flight testing.

Gaspar, James L.↗
NASA NTRS2001

Accomplishments of the Advanced Reusable Technologies (ART) RBCC Project at NASA/Marshall Space Flight Center

The focus of the NASA / Marshall Space Flight Center (MSFC) Advanced Reusable Technologies (ART) project is to advance and develop Rocket-Based Combined-Cycle (RBCC) technologies. The ART project began in 1996 as part of the Advanced Space Transportation Program (ASTP). The project is composed of several activities including RBCC engine ground testing, tool development, vehicle / mission studies, and component testing / development. The major contractors involved in the ART project are Aerojet and Rocketdyne. A large database of RBCC ground test data was generated for the air-augmented rocket (AAR), ramjet, scramjet, and ascent rocket modes of operation for both the Aerojet and Rocketdyne concepts. Transition between consecutive modes was also demonstrated as well as trajectory simulation. The Rocketdyne freejet tests were conducted at GASL in the Flight Acceleration Simulation Test (FAST) facility. During a single test, the FAST facility is capable of simulating both the enthalpy and aerodynamic conditions over a range of Mach numbers in a flight trajectory. Aerojet performed freejet testing in the Pebble Bed facility at GASL as well as direct-connect testing at GASL. Aerojet also performed sea-level static (SLS) testing at the Aerojet A-Zone facility in Sacramento, CA. Several flight-type flowpath components were developed under the ART project. Aerojet designed and fabricated ceramic scramjet injectors. The structural design of the injectors will be tested in a simulated scramjet environment where thermal effects and performance will be assessed. Rocketdyne will be replacing the cooled combustor in the A5 rig with a flight-weight combustor that is near completion. Aerojet's formed duct panel is currently being fabricated and will be tested in the SLS rig in Aerojet's A-Zone facility. Aerojet has already successfully tested a cooled cowl panel in the same facility. In addition to MSFC, other NASA centers have contributed to the ART project as well. Inlet testing and parametrics were performed at NASA / Glenn Research Center (GRC) and NASA / Langley Research Center (LaRC) for both the Aerojet and Rocketdyne concepts. LaRC conducted an Air-Breathing Launch Vehicle (ABLV) study for several vehicle concepts with RBCC propulsion systems. LaRC is also performing a CFD analysis of the ramjet mode for both flowpaths based on GASL test conditions. A study was performed in 1999 to investigate the feasibility of performing an RBCC flight test on the NASA / Dryden Flight Research Center (DFRC) SR-71 aircraft. Academia involvement in the ART project includes parametric RBCC flowpath testing by Pennsylvania State University (PSU). In addition to thrust and wall static pressure measurements, PSU is also using laser diagnostics to analyze the flowfield in the test rig. MSFC is performing CFD analysis of the PSU rig at select test conditions for model baseline and validation. Also, Georgia Institute of Technology (GT) conducted a vision vehicle study using the Aerojet RBCC concept. Overall, the ART project has been very successful in advancing RBCC technology. Along the way, several major milestones were achieved and "firsts" accomplished. For example, under the ART project, the first dynamic trajectory simulation testing was performed and the Rocketdyne engine A5 logged over one hour of accumulated test time. The next logical step is to develop and demonstrate a flight-weight RBCC engine system.

Nelson, Karl W.↗