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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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NASA NTRS2017

Centrifuge in Free Fall: Combustion at Partial Gravity

A centrifuge apparatus is developed to study the effect of variable acceleration levels in a drop tower environment. It consists of a large rotating chamber, within which the experiment is conducted. NASA Glenn Research Center 5.18-second Zero-Gravity Facility drop tests were successfully conducted at rotation rates up to 1 RPS with no measurable effect on the overall Zero-Gravity drop bus. Arbitrary simulated gravity levels from zero to 1-g (at a radius of rotation 30 cm) were produced. A simple combustion experiment was used to exercise the capabilities of the centrifuge. A total of 23 drops burning a simulated candle with heptane and ethanol fuel were performed. The effect of gravity level (rotation rate) and Coriolis force on the flames was observed. Flames became longer, narrower, and brighter as gravity increased. The Coriolis force tended to tilt the flames to one side, as expected, especially as the rotation rate was increased. The Zero-Gravity Centrifuge can be a useful tool for other researchers interested in the effects of arbitrary partial gravity on experiments, especially as NASA embarks on future missions which may be conducted in non-Earth gravity.

microgravity↗
NASA NTRS1981

Exploratory flight test of advanced piloted spacecraft - Circa 1963

The NASA early experimental program for parawing and lifting body spacecraft recovery concepts is discussed. Simple hand drawings, in-house construction, and crude drop tests were used in lieu of a thorough stress analysis. The parawing (parasev) was controlled by manually shifting the center of gravity with respect to the center of pressure; the craft would take off while being towed at 40 KIAS. The M-2 lifting body was originally constructed with a 3/32 in. mahogany skin by a glider manufacturer and employed general aviation aircraft nose and main wheel assemblies. A minimum altitude of 200 ft was found acceptable for release of the parasev, allowing the pilot time to adjust for transients incurred at the tow release. A small landing assist rocket was furnished for the M-2/F-2 and X-24A lifting bodies to enhance stability, and landings at a maximum lift/drag ratio of 2.8 were successfully completed. The data gained were eventually applied in the development of the Shuttle.

Thompson, M. O.↗
NASA NTRS2017

Sub-Scale Orion Parachute Test Results from the National Full-Scale Aerodynamics Complex 80- By 120-ft Wind Tunnel

A two-week test campaign was conducted in the National Full-Scale Aerodynamics Complex 80 x 120-ft Wind Tunnel in support of Orion parachute pendulum mitigation activities. The test gathered static aerodynamic data using an instrumented, 3-tether system attached to the parachute vent in combination with an instrumented parachute riser. Dynamic data was also gathered by releasing the tether system and measuring canopy performance using photogrammetry. Several canopy configurations were tested and compared against the current Orion parachute design to understand changes in drag performance and aerodynamic stability. These configurations included canopies with varying levels and locations of geometric porosity as well as sails with increased levels of fullness. In total, 37 runs were completed for a total of 392 data points. Immediately after the end of the testing campaign a down-select decision was made based on preliminary data to support follow-on sub-scale air drop testing. A summary of a more rigorous analysis of the test data is also presented.

Anderson, Brian P.↗
NASA NTRS1975

Wind tunnel investigation of Space Shuttle Solid Rocket Booster drogue parachutes and deployment concepts

A wind tunnel test has been conducted on one-eighth scale models of the Space Shuttle Solid Rocket Booster drogue parachute system. The test included an investigation of four candidate drogue deployment concepts and a parametric steady state drag study of 20-degree conical ribbon parachutes. The results show that at least two of the four deployment concepts tested are viable candidates for the full scale deployment system. The interference free steady state drag results obtained show excellent agreement with available drop test results on large 20-degree conical ribbon parachutes.

Bacchus, D. L.↗
NASA NTRS2008

Ares I and Ares V First Stage - Powering Exploration

The National Aeronautics and Space Administration (NASA) Ares Projects Office (APO) is continuing to make progress toward the final design of the first stage propulsion system for the Ares I crew launch vehicle and the Ares V cargo launch vehicle. Ares I and Ares V will provide the space launch capabilities needed to fulfill NASA' s exploration strategy of sending human beings to the Moon, Mars, and beyond. As primary propulsion for the Ares launch vehicles, the Space Shuttle-derived Reusable Solid Rocket Motor (RSRM) is one of the first and most important components to be tested. The first flight of Ares I, called Ares I-X, will occur in April 2009, with booster integration to begin at Kennedy Space Center (KSC) by autumn 2008. The Ares I-X flight will use a combination of flight and simulation hardware to obtain data on controlling the long and narrow crew launch vehicle configuration. The test will use a four-segment RSRM from the Shuttle inventory and a fifth spacer segment to simulate the size and weight of the operational five-segment motor to be used on later flights. The upper stage, Orion crew exploration vehicle, and launch abort system will all be replaced with simulator hardware. Manufacturing work has begun on the spacer segment, as well as the new forward hardware for the booster. Atlas V avionics will be adapted to control Ares I-X' s first stage. That hardware is undergoing hardware-in-the-loop testing in a contractor-provided systems integration laboratory (SIL); a critical design review (CDR) was completed in December 2007. Drogue and main parachute drop tests have also been conducted successfully at Yuma Proving Grounds, allowing the First Stage team to begin fabricating parachutes for Ares I-X. The Ares I-X flight test will be the first flight test for the parachutes. A series of preliminary design technical interchange meetings is being conducted prior to the Ares I-X CDR in January 2007 to ensure readiness for the flight. Much of the First Stage activity in 2007 has focused on a series of preliminary design (PDR) activities associated with each booster subsystem. These events will culminate in a formal preliminary design review in 2008, where subsystems and component specifications will be developed and associated analyses and drawings will be evaluated for technical adequacy. The first stage also has been undergoing a series of trade studies to determine means for upgrading booster performance and reducing operational costs. Performance improvement studies have included changing from polybutadiene acrylonitrile (PBAN) propellant to hydroxyl-terminated polybutadiene (HTPB); replacing aluminum with composite motor casings; and optimizing or upgrading the propellant grain and nozzle structures. Some or all of these changes could result in a block upgrade to the Ares I first stage, after becoming the standard configuration for the Ares V. The cost reduction studies included a change from reusable or recoverable boosters to completely expendable boosters; changing from hydrazine-powered to more environmentally friendly electrohydrostatic actuators (EHAs) on the thrust vector control (TVC) system; and changing the location of the separation plane to reduce the likelihood of recontact upon booster separation. The expendability trade study resulted in a decision to keep the recoverable boosters, as the new hardware costs significantly outweighed the potential operational cost savings due to reduced ground operations. Likewise, due to cost considerations, the team continued using existing hydrazine-powered actuators for the TVC system. The separation plane location for Ares I is still being studied, with results to be announced in 2008. In short, the Ares launch vehicles' first stage is building upon NASA's close familiarity with this Shuttle-derived system, while continuing to seek out improvements for long-term exploration.

Priskos, Alex S.↗
NASA NTRS1977

Conceptual design for spacelab two-phase flow experiments

KC-135 aircraft tests confirmed the gravity sensitivity of two phase flow correlations. The prime component of the apparatus is a 1.5 cm dia by 90 cm fused quartz tube test section selected for visual observation. The water-cabin air system with water recycle was a clear choice for a flow regime-pressure drop test since it was used satisfactorily on KC-135 tests. Freon-11 with either overboard dump or with liquid-recycle will be used for the heat transfer test. The two experiments use common hardware. The experimental plan covers 120 data points in six hours with mass velocities from 10 to 640 kg/sec-sq m and qualities 0.01 to 0.64. The apparatus with pump, separator, storage tank and controls is mounted in a double spacelab rack. Supporting hardware, procedures, measured variables and program costs are defined.

Bradshaw, R. D.↗
NASA NTRS1992

Material selection and evaluation aimed at resolving deficiencies of a space technology material

NASA-Kennedy Space Center propellant handlers' visors are undergoing conversion from Plexiglass G to a Surlyn 8920-based material; various Surlyn compositions are here subjected to a battery of environmental and mechanical-properties tests under the relevant conditions. Specially-molded Surlyn samples have exhibited much higher impact strengths than either Plexiglass G or Lexan, and passed the ANSI weight-drop test. DSC results show that Surlyn and Plexiglass G exhibit strikingly different thermal transitions.

Ray, Asit K.↗
NASA NTRS2013

Extraction and Separation Modeling of Orion Test Vehicles with ADAMS Simulation

The Capsule Parachute Assembly System (CPAS) project has increased efforts to demonstrate the performance of fully integrated parachute systems at both higher dynamic pressures and in the presence of wake fields using a Parachute Compartment Drop Test Vehicle (PCDTV) and a Parachute Test Vehicle (PTV), respectively. Modeling the extraction and separation events has proven challenging and an understanding of the physics is required to reduce the risk of separation malfunctions. The need for extraction and separation modeling is critical to a successful CPAS test campaign. Current PTV-alone simulations, such as Decelerator System Simulation (DSS), require accurate initial conditions (ICs) drawn from a separation model. Automatic Dynamic Analysis of Mechanical Systems (ADAMS), a Commercial off the Shelf (COTS) tool, was employed to provide insight into the multi-body six degree of freedom (DOF) interaction between parachute test hardware and external and internal forces. Components of the model include a composite extraction parachute, primary vehicle (PTV or PCDTV), platform cradle, a release mechanism, aircraft ramp, and a programmer parachute with attach points. Independent aerodynamic forces were applied to the mated test vehicle/platform cradle and the separated test vehicle and platform cradle. The aero coefficients were determined from real time lookup tables which were functions of both angle of attack ( ) and sideslip ( ). The atmospheric properties were also determined from a real time lookup table characteristic of the Yuma Proving Grounds (YPG) atmosphere relative to the planned test month. Representative geometries were constructed in ADAMS with measured mass properties generated for each independent vehicle. Derived smart separation parameters were included in ADAMS as sensors with defined pitch and pitch rate criteria used to refine inputs to analogous avionics systems for optimal separation conditions. Key design variables were dispersed in a Monte Carlo analysis to provide the maximum expected range of the state variables at programmer deployment to be used as ICs in DSS. Extensive comparisons were made with Decelerator System Simulation Application (DSSA) to validate the mated portion of the ADAMS extraction trajectory. Results of the comparisons improved the fidelity of ADAMS with a ramp pitch profile update from DSSA. Post-test reconstructions resulted in improvements to extraction parachute drag area knock-down factors, extraction line modeling, and the inclusion of ball-to-socket attachments used as a release mechanism on the PTV. Modeling of two Extraction parachutes was based on United States Air Force (USAF) tow test data and integrated into ADAMS for nominal and Monte Carlo trajectory assessments. Video overlay of ADAMS animations and actual C-12 chase plane test videos supported analysis and observation efforts of extraction and separation events. The COTS ADAMS simulation has been integrated with NASA based simulations to provide complete end to end trajectories with a focus on the extraction, separation, and programmer deployment sequence. The flexibility of modifying ADAMS inputs has proven useful for sensitivity studies and extraction/separation modeling efforts. 1

Fraire, Usbaldo, Jr.↗
NASA NTRS2001

Low Velocity Earth-Penetration Test and Analysis

Modeling and simulation of structural impacts into soil continue to challenge analysts to develop accurate material models and detailed analytical simulations to predict the soil penetration event. This paper discusses finite element modeling of a series of penetrometer drop tests into soft clay. Parametric studies are performed with penetrometers of varying diameters, masses, and impact speeds to a maximum of 45 m/s. Parameters influencing the simulation such as the contact penalty factor and the material model representing the soil are also studied. An empirical relationship between key parameters is developed and is shown to correlate experimental and analytical results quite well. The results provide preliminary design guidelines for Earth impact that may be useful for future space exploration sample return missions.

Fasanella, Edwin L.↗
NASA NTRS2009

NASA Tech Briefs, November 2009

Topics covered include: Cryogenic Chamber for Servo-Hydraulic Materials Testing; Apparatus Measures Thermal Conductance Through a Thin Sample from Cryogenic to Room Temperature; Rover Attitude and Pointing System Simulation Testbed; Desktop Application Program to Simulate Cargo-Air-Drop Tests; Multimodal Friction Ignition Tester; Small-Bolt Torque-Tension Tester; Integrated Spacesuit Audio System Enhances Speech Quality and Reduces Noise; Hardware Implementation of a Bilateral Subtraction Filter; Simple Optoelectronic Feedback in Microwave Oscillators; Small X-Band Oscillator Antennas; Free-Space Optical Interconnect Employing VCSEL Diodes; Discrete Fourier Transform Analysis in a Complex Vector Space; Miniature Scroll Pumps Fabricated by LIGA; Self-Assembling, Flexible, Pre-Ceramic Composite Preforms; Flight-speed Integral Image Analysis Toolkit; Work Coordination Engine; Multi-Mission Automated Task Invocation Subsystem; Autonomously Calibrating a Quadrupole Mass Spectrometer; Determining Spacecraft Reaction Wheel Friction Parameters; Composite Silica Aerogels Opacified with Titania; Multiplexed Colorimetric Solid-Phase Extraction; Detecting Airborne Mercury by Use of Polymer/Carbon Films; Lattice-Matched Semiconductor Layers on Single Crystalline Sapphire Substrate; Pressure-Energized Seal Rings to Better Withstand Flows; Rollerjaw Rock Crusher; Microwave Sterilization and Depyrogenation System; Quantifying Therapeutic and Diagnostic Efficacy in 2D Microvascular Images; NiF2/NaF:CaF2/Ca Solid-State High-Temperature Battery Cells; Critical Coupling Between Optical Fibers and WGM Resonators; Microwave Temperature Profiler Mounted in a Standard Airborne Research Canister; Alternative Determination of Density of the Titan Atmosphere; Solar Rejection Filter for Large Telescopes; Automated CFD for Generation of Airfoil Performance Tables; Progressive Classification Using Support Vector Machines; Active Learning with Irrelevant Examples; A Data Matrix Method for Improving the Quantification of Element Percentages of SEM/EDX Analysis; Deployable Shroud for the International X-Ray Observatory; Improved Model of a Mercury Ring Damper; Optoelectronic pH Meter: Further Details; X-38 Advanced Sublimator; and Solar Simulator Represents the Mars Surface Solar Environment.

Source record↗
NASA NTRS2015

Multi-Level Experimental and Analytical Evaluation of Two Composite Energy Absorbers

Two composite energy absorbers were developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research program. A conical-shaped energy absorber, designated the conusoid, was evaluated that consisted of four layers of hybrid carbon-Kevlar plain weave fabric oriented at [+45 deg/-45 deg/-45 deg/+45 deg] with respect to the vertical, or crush, direction. A sinusoidal-shaped energy absorber, designated the sinusoid, was developed that consisted of hybrid carbon-Kevlar plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical direction and a closed-cell ELFOAM P200 polyisocyanurate (2.0-lb/cu ft) foam core. The design goal for the energy absorbers was to achieve average floor-level accelerations of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in both designs were assessed through dynamic crush testing of component specimens. Once the designs were finalized, subfloor beams of each configuration were fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorbers prior to retrofit into TRACT 2. The retrofitted airframe was crash tested under combined forward and vertical velocity conditions onto soil, which is characterized as a sand/clay mixture. Finite element models were developed of all test articles and simulations were performed using LS-DYNA, a commercial nonlinear explicit transient dynamic finite element code. Test-analysis results are presented for each energy absorber as comparisons of time-history responses, as well as predicted and experimental structural deformations and progressive damage under impact loading for each evaluation level.

Jackson, Karen E.↗
NASA NTRS2015

The Development of Two Composite Energy Absorbers for Use in a Transport Rotorcraft Airframe Crash Testbed (TRACT 2) Full-Scale Crash Test

Two composite energy absorbers were developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research program. A conical-shaped energy absorber, designated the conusoid, was evaluated that consisted of four layers of hybrid carbon-Kevlar plain weave fabric oriented at [+45deg/-45deg/-45deg/+45deg] with respect to the vertical direction. A sinusoidal-shaped energy absorber, designated the sinusoid, was developed that consisted of hybrid carbon-Kevlar plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical direction, and a closed-cell ELFOAM P200 polyisocyanurate (2.0-lb/cu ft) foam core. The design goal for the energy absorbers was to achieve average floor-level accelerations of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in both designs were assessed through dynamic crush testing of component specimens. Once the designs were finalized, subfloor beams of each configuration were fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorbers prior to retrofit into TRACT 2. The retrofitted airframe was crash tested under combined forward and vertical velocity conditions onto soft soil. Finite element models were developed of all test articles and simulations were performed using LS-DYNA, a commercial nonlinear explicit transient dynamic finite element code. Test-analysis results are presented for each energy absorber as comparisons of time-history responses, as well as predicted and experimental structural deformations and progressive damage under impact loading for each evaluation level.

Littell, Justin D.↗
NASA NTRS1990

Advanced recovery systems wind tunnel test report

Pioneer Aerospace Corporation (PAC) conducted parafoil wind tunnel testing in the NASA-Ames 80 by 120 test sections of the National Full-Scale Aerodynamic Complex, Moffett Field, CA. The investigation was conducted to determine the aerodynamic characteristics of two scale ram air wings in support of air drop testing and full scale development of Advanced Recovery Systems for the Next Generation Space Transportation System. Two models were tested during this investigation. Both the primary test article, a 1/9 geometric scale model with wing area of 1200 square feet and secondary test article, a 1/36 geometric scale model with wing area of 300 square feet, had an aspect ratio of 3. The test results show that both models were statically stable about a model reference point at angles of attack from 2 to 10 degrees. The maximum lift-drag ratio varied between 2.9 and 2.4 for increasing wing loading.

Geiger, R. H.↗
NASA NTRS2022

Design of Rigid-Flex PCB Robotics Leveraging Validated Finite Element Simulations

The use of rigid-flex printed circuit board (PCB) as primary structure has the potential to reduce the weight and volume of robotic systems. In the case of robotics for interplanetary exploration, these systems can leverage origami-inspired folding for increased mobility options and reduced storage volume. Folding rigid-flex PCB robotics can be constructed with rigid PCB connected by short Nomex fabric hinges coupled with flex PCB ribbon cables that permits enhanced system flexibility and energy dissipation to promote impact survivability. This paper presents a design methodology of rigid-flex PCB systems with an emphasis on impact resistance. The design process considers solder joint adequacy, panel bending, and fracture using a finite element (FE) model. The proposed design methodology is developed using a case study with NASA JPL's Pop-Up Folding Flat Explorer Robot (PUFFER). First, the finite-element (FE) modeling methodology is presented with consideration to both frequency and time-domain modeling applications, which include operational self-contact analysis and high impact scenarios. The time-domain impact modeling methodology utilizes hyperelastic material properties for the Nomex hinges. This modeling method is validated using image correlation of PUFFER drop tests. A flowchart is presented to guide users through a validated Abaqus modeling procedure for highly flexible rigid-flex systems. Next, a case study is presented in which PUFFER is subject to drop heights representative of falls into Lunar pits and then the design is refined for a more optimum impact performance. Finally, the results of the case study are used to inform a generalized design methodology for rigid-flex PCB robotics subject to high-impact loads with the considerations presented.

John Bell↗
NASA NTRS2022

Design of Rigid-Flex PCB Robotics Leveraging Validated Finite Element Simulations

The use of rigid-flex printed circuit board (PCB) as primary structure has the potential to reduce the weight and volume of robotic systems. In the case of robotics for interplanetary exploration, these systems can leverage origamiinspired folding for increased mobility options and reduced storage volume. Folding rigid-flex PCB robotics can be constructed with rigid PCB connected by short Nomex fabric hinges coupled with flex PCB ribbon cables that permits enhanced system flexibility and energy dissipation to promote impact survivability. This paper presents a design methodology of rigidflex PCB systems with an emphasis on impact resistance. The design process considers solder joint adequacy, panel bending, and fracture using a finite element (FE) model. The proposed design methodology is developed using a case study with NASA JPL’s Pop-Up Folding Flat Explorer Robot (PUFFER). First, the finite-element (FE) modeling methodology is presented with consideration to both frequency and time-domain modeling applications, which include operational self-contact analysis and high impact scenarios. The time-domain impact modeling methodology utilizes hyperelastic material properties for the Nomex hinges. This modeling method is validated using image correlation of PUFFER drop tests. A flowchart is presented to guide users through a validated Abaqus modeling procedure for highly flexible rigid-flex systems. Next, a case study is presented in which PUFFER is subject to drop heights representative of falls into Lunar pits and then the design is refined for a more optimum impact performance. Finally, the results of the case study are used to inform a generalized design methodology for rigid-flex PCB robotics subject to high-impact loads with the considerations presented.

de la Croix, Jean-Pierre↗
NASA NTRS2012

Antenna Measurements: Test & Analysis of the Radiated Emissions/Immunity of the NASA/Orion Spacecraft Dart Parachute Simulator & Prototype Capsule - The Crew Exploration Vehicle

For future NASA Manned Space Exploration of the Moon and Mars, a blunt body capsule, called the Orion Crew Exploration Vehicle (CEV), composed of a Crew Module (CM) and a Service Module (SM), with a parachute decent assembly is planned for reentry back to Earth. A Capsule Parachute Assembly System (CPAS) is being developed for preliminary prototype parachute drop tests at the Yuma Proving Ground (YPG) to simulate high-speed reentry to Earth from beyond Low-Earth-Orbit (LEO) and to provide measurements of position, velocity, acceleration, attitude, temperature, pressure, humidity, and parachute loads. The primary and secondary (backup) avionics systems on CPAS also provide mission critical firing events to deploy, reef, and release the parachutes in three stages (extraction, drogues, mains) using mortars and pressure cartridge assemblies. In addition, a Mid-Air Delivery System (MDS) is used to separate the capsule from the sled that is used to eject the capsule from the back of the drop plane. Also, high-speed and high-definition cameras in a Video Camera System (VCS) are used to film the drop plane extraction and parachute landing events. Intentional and unintentional radiation emitted from and received by antennas and electronic devices on/in the CEV capsule, the MDS sled, and the VCS system are being tested for radiated emissions/immunity (susceptibility) ~ (RE/RS). To verify Electromagnetic Compatibility (EMC) of the Orion capsule, Electromagnetic Interference (EMI) measurements are being made inside a semi-anechoic chamber at NASA/JSC on the components of the CPAS system. Measurements are made at 1m from the components-under-test (CUT). In addition, EMI measurements of the integrated CEV system are being made inside a hanger at YPG. These measurements are made in a complete circle, at 30◦ angles or less, around the Orion Capsule, the spacecraft system under-test (SUT). Near-field B-Dot probe measurements on the surface of the Orion capsule are being extrapolated outward to the 1m standard distance for comparison to the MIL-STD radiated emissions limit, and far-field hybrid antenna measurements at 3m are being extrapolated inward to the 1m distance for similar comparisons.

Norgard, John D.↗
NASA NTRS1986

Structural analysis of the controlled impact demonstration of a jet transport airplane

An analytical method has been developed for assessing crash dynamics of large transport aircraft, such as in the NASA Controlled Impact Demonstration (CID) jet crash test on December 1, 1984. The DYCAST nonlinear finite-element computer code was used in a series of progressively more difficult tasks to model complete transport aircraft crashes. Single aircraft frames and fuselage section vertical drop tests were modeled and analyzed to obtain comparisons with experimental data and to develop hybrid element crash springs for use in the large CID model. Predictions of crash and acceleration levels from a symmetric CID model agreed well with data from the CID experiment.

Fasanella, E. L.↗
NASA NTRS1995

Research on ignition and flame spread of solid materials in Japan

Fire safety is one of the main concerns for crewed missions such as the space station. Materials used in spacecraft may burn even if metalic. There are severe restrictions on the materials used in spacecraft from the view of fire safety. However, such restrictions or safety standards are usually determined based on experimental results under normal gravity, despite large differences between the phenomena under normal and microgravity. To evaluate the appropriateness of materials for use in space, large amount of microgravity fire-safety combustion data is urgently needed. Solid material combustion under microgravity, such as ignition and flame spread, is a relatively new research field in Japan. As the other reports in this workshop describe, most of microgravity combustion research in Japan is droplet combustion as well as some research on gas phase combustion. Since JAMIC, the Japan Microgravity Center, (which offers 10 seconds microgravity time) opened in 1992, microgravity combustion research is robust, and many drop tests relating to solid combustion (paper combustion, cotton string combustion, metal combustion with Aluminium or Magnesium) have been performed. These tests proved that the 10 seconds of microgravity time at JAMIC is useful for solid combustion research. Some experiments were performed before JAMIC opened. For example, latticed paper was burned under microgravity by using a 50 m drop tower to simulate porous material combustion under microgravity. A 50 m tower provides only 2 seconds microgravity time however, and it was not long enough to investigate the solid combustion phenomena.

Ito, Kenichi↗