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At least 199 records · Page 11

Worldwide Spacecraft Crew Hatch History

The JSC Flight Safety Office has developed this compilation of historical information on spacecraft crew hatches to assist the Safety Tech Authority in the evaluation and analysis of worldwide spacecraft crew hatch design and performance. The document is prepared by SAIC s Gary Johnson, former NASA JSC S&MA Associate Director for Technical. Mr. Johnson s previous experience brings expert knowledge to assess the relevancy of data presented. He has experience with six (6) of the NASA spacecraft programs that are covered in this document: Apollo; Skylab; Apollo Soyuz Test Project (ASTP), Space Shuttle, ISS and the Shuttle/Mir Program. Mr. Johnson is also intimately familiar with the JSC Design and Procedures Standard, JPR 8080.5, having been one of its original developers. The observations and findings are presented first by country and organized within each country section by program in chronological order of emergence. A host of reference sources used to augment the personal observations and comments of the author are named within the text and/or listed in the reference section of this document. Careful attention to the selection and inclusion of photos, drawings and diagrams is used to give visual association and clarity to the topic areas examined.

Johnson, Gary↗

High modulus filament wound vessels for cryogenic containers in spacecraft.

Compared to metallic vessels, filament-wound vessels for containment of cryogens and high pressure gases offer high potential weight savings for NASA spacecraft applications. Since carbon fiber/epoxy resin composites exhibit high strength-to-density ratios, high-cycle fatigue life, and excellent strain compatibility with internal metallic liners, filament-wound carbon fiber/epoxy resin composites were evaluated for application to cryogenic internal pressure vessels. Compared to room temperature values, the cryogenic strengths of the composites were reduced by about 15% at -423 F (with the exception of one composite) while moduli increased as much as 25%. Filament-wound carbon fiber/epoxy resin vessel specimens, made by three fabricators, defined and solved problems in the processing of these friable high-modulus fibers into structurally efficient vessel specimens.

Simon, R. A.↗

Dynamics of spacecraft control laboratory experiment (SCOLE) slew maneuvers

This is the first of two reports on the dynamics and control of slewing maneuvers of the NASA Spacecraft Control Laboratory Experiment (SCOLE). In this report, the dynamics of slewing maneuvers of SCOLE are developed in terms of an arbitrary maneuver about any given axis. The set of dynamical equations incorporate rigid-body slew maneuver and three-dimensional vibrations of the complete assembly comprising the rigid shuttle, the flexible beam, and the reflector with an offset mass. The analysis also includes kinematic nonlinearities of the entire assembly during the maneuver and the dynamics of the interaction between the rigid shuttle and the flexible appendage. The final set of dynamical equations obtained for slewing maneuvers is highly nonlinear and coupled in terms of the flexible modes and the rigid-body modes. The equations are further simplified and evaluated numerically to include the first ten flexible modes and the SCOLE data to yield a model for designing control systems to perform slew maneuvers.

Kakad, Y. P.↗

Agile Approach to Assuring Software for NASA's Orion Spacecraft

Agile software development is prevalent throughout the Government, and NASA is no exception. NASA's Orion spacecraft is being developed to return Astronauts to the moon in the next 5 years, and the role of software in achieving the ambitious mission objectives has expanded dramatically in the last few decades. This presentation is the story of how the Independent Verification and Validation team for Orion adapted to the Agile approach that the Orion Program was using to develop the flight software. Consider attending this session if you are working with software developers utilizing Agile development approaches, or are interested in learning about Agile and Lean principles that could help improve communication within your own team.

Smith, Justin↗

ERBS orbit ascent utilizing continuous low thrust maneuvers

The Earth Radiation Budget Satellite (ERBS) is a National Aeronautics and Space Administration (NASA) spacecraft whose purpose is to investigate the components of the earth's radiation budget. The ERBS was deployed in a 57 degree inclined, 352.2 kilometer altitude circular orbit by the NASA Space Transportation System (STS) on October 5, 1984. The spacecraft then ascended to its 603 kilometer, near-circular mission orbit by a series of continuous low-thrust maneuvers. The ERBS was the first free-flyer mission to rely on continuous low thrust to spiral from one circular orbit to another. Careful planning and monitoring of these maneuvers were essential to their successful execution. Errors in the prediction of the propulsion system performance or in burn duration would result in loss of contact with the spacecraft during a maneuver and could result in a premature end to the maneuver and difficulty in computing a definitive orbit.

Hoge, S. L.↗

NASA-STD-4005 and NASA-HDBK-4006, LEO Spacecraft Solar Array Charging Design Standard

Two new NASA Standards are now official. They are the NASA LEO Spacecraft Charging Design Standard (NASA-STD-4005) and the NASA LEO Spacecraft Charging Design Handbook (NASA-HDBK-4006). They give the background and techniques for controlling solar array-induced charging and arcing in LEO. In this paper, a brief overview of the new standards is given, along with where they can be obtained and who should be using them.

Ferguson, Dale C.↗

Control of Spacecraft Control Laboratory Experiment (SCOLE) slew maneuvers

This is the second report of a set of two reports on the dynamics and control of slewing maneuvers of NASA Spacecraft Control Laboratory Experiment (SCOLE). The control problem of slewing maneuvers of SCOLE is developed in terms of an arbitrary maneuver about any given axis. The control system is developed for the combined problem of rigid-body slew maneuver and vibration suppression of flexible appendage. The control problem is formulated by incorporating the nonlinear equations derived in the previous report and is expressed in terms of a two-point boundary value problem utilizing a quadratic type of performance index. The two-point boundary value problem is solved as a hierarchical control problem with the overall system being split in terms of two subsystems, namely the slewing of the entire assembly and the vibration suppression of the flexible antenna. The coupling variables between the two dynamical subsystems are identified and these two subsystems for control purposes are treated independently in parallel at the first level. Then the state-space trajectory of the combined problem is optimized at the second level.

Kakad, Y. P.↗

Development and Qualification of the Primary Structure of the Orion European Service Module

This paper presents an overview of the development and qualification test campaign for the primary structure of the European Service Module of ORION, the NASA spacecraft which will serve the future human exploration missions to the Moon, Mars and beyond. Under an agreement between NASA and ESA, the ORION will be powered by a European Service Module (ESM), providing also water and oxygen for astronauts' life sustainability. The development and qualification of the European Service Module (ESM) is under ESA responsibility with Airbus Defense and Space as the prime contractor. Thales Alenia Space Italia is responsible for design development, manufacturing, assembly and qualification of the Structure subsystem. The European Service Module, installed onto the launch adapter, shall support the crew module with its adapter and a launch abort system. It shall sustain: - A combination of global and local launch loads during lift off and ascent phases, - On orbit loads induced by engine firing for orbital transfers and attitude control. The ESM structure is based on a core made of Composite Fiber Reinforced Polymer (CFRP) sandwich panels complemented by aluminum alloy platforms, longerons and secondary structures. A development campaign has been implemented in order to define and validate composite parts' strength allowable values for design: coupon tests at material level, test at component level up to breadboards tests performed on main structural components (composite to metallic joints, and at panels' discontinuities). An incremental approach as defined in [1] has been followed. A qualification static test campaign at primary structure assembly level has been implemented in order to validate the design against static stiffness and ultimate strength as well as to correlate the structural Finite Element Model (FEM) used for sizing and confirm the margins of safety. The tests have been performed successfully by Thales Alenia Space Italia (TAS-I) on two flight representative structural models (STA1, STA2), in Turin facilities (Italy) between August 2015 and March 2017, with engineering support of technical representatives from Airbus, ESA, NASA and LMCO. The main development and qualification test activities and associated results are presented and discussed in the paper

Structural Testing↗

International Solar Terrestrial Physics (ISTP) program

The International Solar Terrestrial Physics (ISTP) Program is a large, multi-national program involving three space agencies and up to eight spacecraft. NASA, together with the Institute of Space and Astronomical Science (ISAS) and the European Space Agency (ESA), has agreed in principle to coordinate their efforts in investigating the Sun and the Earth. Each agency is planning to construct and operate different spacecraft as part of this cooperative venture: Geotail provided by ISAS, the Solar Heliospheric Observatory (SOHO) and Cluster (four spacecraft) contributed by ESA, and Wind and Polar by NASA. A general description of the program is presented.

Sanford, R.↗

Fire-Resistant Textile Development for Exploration Vehicles With Enriched-Oxygen Cabin Environments

Material selection is a key part of the National Aeronautics and Space Administration (NASA) spacecraft fire safety management plan. Non-flammable textiles are necessary to ensure large-scale flame propagation events do not occur inside a spacecraft. An increased use of textiles and other softgood material is crucial to the pursuit of exploration spaceflight to reduce mass and volume. Exploration spaceflight missions benefit from enriched oxygen cabin environments (>21% O2) by allowing a reduced prebreathe protocol before Extravehicular Activity (EVA). However, materials become exponentially more flammable the higher the O2 levels become. Recent testing within the agency has revealed the lack of commercial-off-the-shelf (COTS) materials that can meet safety requirements in oxygen-enriched environments. Most of the fibers and textiles developed during Apollo (100% O2 cabin environment) and Skylab (>70% O2 cabin environment) are no longer commercially available due to those Programs ending and the discontinuation of raw materials or closure of the original manufacturers. As NASA returns to higher oxygen concentrations inside spacecraft, non-flammable textile development efforts have begun to meet the agency’s needs. This paper discusses those efforts including overall fire safety approach, state-of-the-art textile review and testing, an agency-wide assessment of textile needs performed by the NASA Engineering and Safety Center (NESC), the textile development strategy and expected challenges.

Mary Walker↗

Earth Radiation Budget Satellite

The Earth Radiation Budget Experiment (ERBE) waqs designed to examine the thermal equilibrium between the sun, the earth, and space. The major space-based component of the experiment is the Earth Radiation Budget Satellite (ERBS) which was launched from Shuttle (Mission 41-G) on October 5, 1984. The ERBS is a three-axis momentum-biased spacecraft containing its own subsystems for attitude control, power generation, thermal control, and data handling. The satellite transmits data via the NASA Spacecraft Tracking and Data Network (STDN) and the Tracking and Data Relay Satellite System (TDRSS). The ERBS instrument package includes eight channels in two sensor packages: a nonscanning radiometer and a scanning radiometer. The combined spectral range of the two instruments is 0.2-5.0 microns and the scale of the radiometer measurements can be changed to collect regional, zonal, or global data. A series of schematic diagrams of the ERBS spacecraft and its instrument package is provided.

Dezio, J. A.↗

Cryogenic and low temperature heat pipe/cooler studies for spacecraft application

The prime purpose of the present work is to examine cryogenic heat pipe/cooler feasibility in the 80 to 100 K temperature range and in the regimes of operation required for NASA spacecraft. Present requirements within these regimes are (1) cooling load of less than 1 to 2 watt per cooler, (2) small detector/heat pipe interface area, and (3) high system reliability and long lifetime operations. The cooling capacity of practical radiant coolers is very low in this temperature range, and very temperature sensitive. Detector performance is also strongly dependent on temperatures in this regime. It is, therefore important to understand the interplay of the heat pipe and its effects on overall system performance.

Sherman, A.↗

Fire-Resistant Textile Development for Exploration Vehicles With Enriched-Oxygen Cabin Environments

Material selection is a key part of the National Aeronautics and Space Administration (NASA) spacecraft fire safety management plan. Non-flammable textiles are necessary to ensure large-scale flame propagation events do not occur inside a spacecraft. An increased use of textiles and other softgood material is crucial to the pursuit of exploration spaceflight to reduce mass and volume. Exploration spaceflight missions benefit from enriched oxygen cabin environments (>21% O2) by allowing a reduced prebreathe protocol before Extravehicular Activity (EVA). However, materials become exponentially more flammable the higher the O2 levels become. Recent testing within the agency has revealed the lack of commercial-off-the-shelf (COTS) materials that can meet safety requirements in oxygen-enriched environments. Most of the fibers and textiles developed during Apollo (100% O2 cabin environment) and Skylab (>70% O2 cabin environment) are no longer commercially available due to those Programs ending and the discontinuation of raw materials or closure of the original manufacturers. As NASA returns to higher oxygen concentrations inside spacecraft, non-flammable textile development efforts have begun to meet the agency’s needs. This paper discusses those efforts including overall fire safety approach, priorities, interactions with industry, flammability testing and expected challenges.

Karim Aly↗

Recent developments in space-borne zodiacal light photometry

The zodiacal light experiment to be flown aboard the International Solar Polar Mission in 1985 is presented. Overall objectives of the Zodiacal Light/Background Starlight Experiment include the study of the brightness, polarization, and color of the diffuse sky brightness and the determination of the spatial distributions and physical properties of the interplanetary dust as a function of spacecraft position in and out of the ecliptic. To meet these objectives, a multicolor sky-scanning photopolarimeter will be carried on the NASA spacecraft which will provide optimized stray light suppression and a capability for changing the viewing cone angle based on the use of a stepping device. Brightness and polarization measurements will be made for 11 center wavelengths in the UV and visible with 5.6 deg circular and 1.0 sq deg rectangular fields of view.

Schwehm, G. H.↗

Hot-Fire Testing of a 1N AF-M315E Thruster

This hot-fire test continues NASA investigation of green propellant technologies for future missions. To show the potential for green propellants to replace some hydrazine systems in future spacecraft, NASA Marshall Space Flight Center (MSFC) is continuing to embark on hot-fire test campaigns with various green propellant blends. NASA completed a hot-fire test of a 1N AF-M315E monopropellant thruster at the Marshall Space Flight Center in the small altitude test stand located in building 4205. The thruster is a ground test article used for basic performance determination and catalyst studies. The purpose of the hot-fire testing was for performance determination of a 1N size thruster and form a baseline from which to study catalyst performance and life with follow-on testing to be conducted at a later date. The thruster performed as expected. The result of the hot-fire testing are presented in this paper and presentation.

Burnside, Christopher G.↗

Hot-Fire Testing of 5N and 22N HPGP Thrusters

This hot-fire test continues NASA investigation of green propellant technologies for future missions. To show the potential for green propellants to replace some hydrazine systems in future spacecraft, NASA Marshall Space Flight Center (MSFC) is continuing to embark on hot-fire test campaigns with various green propellant blends.NASA completed hot-fire testing of 5N and 22N HPGP thrusters at the Marshall Space Flight Center’s Component Development Area altitude test stand in April 2015. Both thrusters are ground test articles and not flight ready units, but are representative of potential flight hardware with a known path towards flight application. The purpose of the 5N testing was to perform facility check-outs and generate a small set of data for comparison to ECAPS and Orbital ATK data sets. The 5N thruster performed as expected with thrust and propellant flow-rate data generated that are similar to previous testing at Orbital ATK. Immediately following the 5N testing, and using the same facility, the 22N testing was conducted on the same test stand with the purpose of demonstrating the 22N performance. The results of 22N testing indicate it performed as expected.The results of the hot-fire testing are presented in this paper and presentation.

Burnside, Christopher G.↗