Criteria

Text:
Sector:
Topic:
Display:

Results

Viewing 1 to 30 of 1419
2004-07-19
Technical Paper
2004-01-2320
Marco Molina, Paolo Vercesi
The paper presents the simulation and the performance evaluation for an innovative Temperature and Humidity Control in a manned orbiting module. Starting from the EcosimPro® modelling capabilities, a Space Station Module has been built and a standard Temperature and Humidity Control (THC) has been designed, based on a classical PID (Proportional, Integral, Derivative) controller, suitably developed. After that, a fuzzy logic controller has been dsigned and thanks to EcosimPro programmability a fuzzy logic controller block has been created. The controller have been sized and its performances suitably simulated. Performances of the innovative controller are checked against the standard control techniques.
1999-10-19
Technical Paper
1999-01-5551
Michael Vujcich, Terry Scharton
Combining the quasi-static loads, workmanship verification, and model validation tests of aerospace hardware into a single vibration test sequence can considerably reduce schedule and cost. The enabling factor in the implementation of the combined dynamic testing approach is the measurement of the dynamic forces exerted on the test item by the shaker. The dynamic testing of the QuikSCAT spacecraft is discussed as an example of a successful combined loads, workmanship, and model validation test program.
1999-10-19
Technical Paper
1999-01-5550
Daniel Anthony, Terry Scharton, Albert Leccese
A novel direct acoustic test was performed on the Quik- SCAT spacecraft at Ball Aerospace Technology Corporation (BATC) in Boulder, Colorado, in October 1998. The QuikSCAT spacecraft was designed and built by BATC in an accelerated, one-year, program managed by the NASA Goddard Space Flight Center. The spacecraft carries the SeaWinds scatterometer developed by the Jet Propulsion Laboratory to measure the near-surface wind speed over Earth’s oceans. Instead of conducting the acoustic test with the spacecraft in a reverberant room, as is the usual practice, the test was conducted with the spacecraft mounted on a shaker slip-table in a nearly anechoic, vibration test cell. The spacecraft was surrounded with a three-meter high ring of large, electro-dynamic speakers, spaced approximately 1.3 meters away from the two-meter diameter, 900 kg. spacecraft. The thirty-one speaker cabinets were driven with 40,000 rms watts of audio amplifier power.
1999-10-19
Technical Paper
1999-01-5520
Mark S. Grahne, David P. Cadogan
The planned increase in satellite launches over the next decade will emphasize reduction of space hardware mass and launch costs. Inflatable structures present many benefits over current state-of-the-art +mechanical technologies and are principally attractive because they can be packaged into small volumes, thereby reducing program costs. Reduced costs are realized in development and production as well as in enabling smaller launch vehicle size. Inflatable structures will reduce total system mass and complexity, thereby increasing system reliability. This paper describes several types of inflatable structures and applications being developed for space flight. Rigidization methods and results from preflight test programs are also presented to support the viability of the technology.
2010-10-06
Technical Paper
2010-36-0330
Humberto Manelli Neto, Marcelo Lopes de Oliveira e Souza
On several engineering applications high Reliability is one of the most wanted features. The aspects of Reliability play a key role in design projects of aircraft, spacecraft, automotive, medical, bank systems, and so, avoiding loss of life, property, or costly recalls. The highly reliable systems are designed to work continuously, even upon external threats and internal Failures. Very convenient is the fact that the term 'Failure' may have its meaning tailored to the context of interesting, as its general definition refers to it as "any deviation from the specified behavior of a system". The above-mentioned 'deviation' may refer to: performance degradation, operational misbehavior, deviation of environmental qualification levels, Safety hazards, etc. Nevertheless, Reliability is not the only requirement for a modern system. Other features as Availability, Integrity, Security and Safety are always part of the same technical specification, in a same level of importance.
2004-07-19
Technical Paper
2004-01-2388
C. D. Thompson, Brienne Shkedi
The International Space Station (ISS) Environmental Control and Life Support System (ECLSS) is designed to be maintainable. During the 3 years since the ISS US Lab became operational, there have been numerous ECLSS Orbital Replacement Units (ORU’s) launched and returned to maintain the ECLSS operation in the US segments. The maintenance logistics have provided tools for maintenance, replaced limited life ORU’s and failed ORU’s, upgraded ECLSS hardware to improve reliability and placed critical spares onboard prior to need. In most cases, the removed ORU’s have been returned for either failure analysis and repair or refurbishment. This paper describes the ECLSS manifesting history and maintenance events and quantifies the numbers of ECLSS items, weights, and volumes.
2004-07-19
Technical Paper
2004-01-2532
R. A. Maijinn Chen
This paper describes the design of a Media and Observation Module (MOM) for a future space orbital facility. MOM is based upon the idea that media operations can coexist with some of the station’s primary operations through design interventions. MOM would take the place of a space cupola, supporting station-keeping and observational operations while meeting media and commercial goals of the orbital facility. Advanced wearable technologies in display, sensing, and control are being proposed as the means to integrate seemingly opposing operations within MOM. The paper provides a general summary of these technologies. In addition to designing the technological and environmental subsystems of MOM, the author conducts systematic analyses, including an evaluation of all target operations based on their human, operational, and technological requirements.
2012-10-02
Technical Paper
2012-36-0378
Jairo Cavalcanti Amaral, Marcelo Lopes de Oliveira e Souza
The Multimission Platform (MMP) is a generic service module currently in Project at INPE. In the 2001 version, its control system can be switched between nine main Operation Modes and other submodes, according to information from satellite sensors and ground commands. The Nominal Mode stabilizes the MMP in three axes and takes it to a nominal attitude, using three reaction wheels. Each wheel has coarse and fine acquisition submodes. The use of multiple modes of control for specific situations frequently is simpler than projecting a single controller for all cases. However, besides being harder to warrant its general stability, the mere switching between these submodes generates bumps, which can reduce the performance and even damage the actuator or plant. In this work, we present an application of diverse methods to smooth the transition between control submodes of the Nominal Mode of the MMP.
2014-09-30
Technical Paper
2014-36-0297
Leonardo Navarenho de Souza Fino, Rafael Navarenho de Souza
Abstract The detailed study of cosmic ray's influence is recent, as well as the invention of the transistor. Ionizing particles from space that focus on silicon integrated circuits (IC) can cause many undesirable effects. These particles are mainly from solar activity, and can be classified into two basic groups: charged particles, e.g, electrons, protons or heavy ions, and electromagnetic radiation (photons), as X-rays, Gamma -rays, or Ultraviolet (UV) light. When they collide in an IC, these energetic particles cause a current pulse, which can affect the correct functioning of the device. These electronic circuits have become increasingly susceptible to the effects of radiation, due to miniaturization, thus increasing the incidence of failures.
2015-09-22
Technical Paper
2015-36-0160
Alexandre Garcia, Guilherme da Silveira
Abstract Unguided rockets must be stable to fly the planned trajectory. During the launch phase the velocity of the rocket is relatively low and, consequently, the wind has more influence on the trajectory. After the vehicle lives the launch rail it encounters a horizontal wind. In this event, known as lift-off, the rocket is disturbed by the wind and opens the maximum angle of attack (AoA). If the center of pressure (CP) - point of application of aerodynamic force - moves forward as the AoA increases from zero, the vehicle may become unstable depending on the velocity of the wind. For each rocket, there is a corresponding range of AoA for which the vehicle remains stable. The maximum value within this range is the angle at which the center of pressure coincides with the center of gravity, situation that corresponds to the limit of stability of the vehicle.
1959-01-01
Technical Paper
590080
R. HARVEY ANSELM
1959-01-01
Technical Paper
590078
W. V. STACKHOUSE
1958-01-01
Technical Paper
580378
E. R. BUXTON
1959-01-01
Technical Paper
590171
A. C. MONTEITH
1958-01-01
Technical Paper
580099
ROBERT C. TRUAX
1958-01-01
Technical Paper
580081
ALFRED M. MAYO
1959-01-01
Technical Paper
590247
ROBERT D. ROCHE
1952-01-01
Technical Paper
520098
C. T. AUBREY
2009-05-19
Technical Paper
2009-01-2247
Jerry R. Goodman
The acoustics environment in enclosed habitable space vehicles and modules is important to mission safety, crew health, and efficient operations. Noise is unwanted sound that can interfere with crew communications and sleep, creating habitability concerns, hearing loss, or other health issues. This paper discusses the acoustic environment and the noise control efforts in the Space Shuttle Orbiter and the International Space Station, and the lessons learned from these efforts. Included is the need to apply the design discipline of acoustics early in the design process, to establish reasonable acoustic limits and “design them into” vehicles/modules, and to apply noise control to ensure that limits are met. Program management needs to be supportive of these efforts.
2009-07-12
Technical Paper
2009-01-2585
Gary L. Harris, Pablo de León
The objective of this paper is to detail a proposal for an Androgynous Docking Airlock/Utility Module (ADAM) that would allow extravehicular (EVA) crews, working from the Orion spacecraft, to avoid depressurizing the command module of the Orion vehicle for planned EVA repair, maintenance and interdiction of orbital structures. Unlike the Space Shuttle, Russian Soyuz vehicle or the Chinese Shenzhou manned spacecraft, the proposed Orion space vehicle has no airlock. This necessitates the depressurizing of the entire Command Module cabin during EVA activity. It also means that all crewmembers will have to wear space suits during contingency and planned EVAs. This inordinately dangerous situation will require all crewmembers to be exposed to the space vacuum for as much as seven hours or more if a working EVA becomes necessary.
2009-11-10
Technical Paper
2009-01-3276
Clint Baggerman, Mary McCabe, Dinesh Verma
It has been 30 years since the National Aeronautics and Space Administration (NASA) last developed a crewed spacecraft capable of launch, on-orbit operations, and landing. During that time, aerospace avionics technologies have greatly advanced in capability, and these technologies have enabled integrated avionics architectures for aerospace applications. The inception of NASA's Orion Crew Exploration Vehicle (CEV) spacecraft offers the opportunity to leverage the latest integrated avionics technologies into crewed space vehicle architecture. The outstanding question is to what extent to implement these advances in avionics while still meeting the unique crewed spaceflight requirements for safety, reliability and maintainability. Historically, aircraft and spacecraft have very similar avionics requirements. Both aircraft and spacecraft must have high reliability.
2009-11-10
Technical Paper
2009-01-3275
Roscoe C. Ferguson, Zulema Olivas
The purpose of the Space Shuttle Cockpit Avionics Upgrade project (1999 – 2004) was to reduce crew workload and improve situational awareness. The upgrade was to augment the Shuttle avionics system with new hardware and software. A major success of this project was the validation of the hardware architecture and software design. This was significant because the project incorporated new technology and approaches for the development of human rated space software. An early version of this system was tested at the Johnson Space Center for one month by teams of astronauts. The results were positive, but NASA eventually cancelled the project towards the end of the development cycle. The goal to reduce crew workload and improve situational awareness resulted in the need for high performance Central Processing Units (CPUs). The choice of CPU selected was the PowerPC family, which is a reduced instruction set computer (RISC) known for its high performance.
2009-07-12
Technical Paper
2009-01-2468
David L. Urban, Gary A. Ruff, George W. Mulholland, Thomas G. Cleary, Jiann C. Yang, Zengguang Yuan, Victoria Bryg
This paper presents results from a smoke detection experiment entitled Smoke Aerosol Measurement Experiment (SAME) which was conducted in the Microgravity Science Glovebox on the International Space Station (ISS) during Expedition 15. Five different materials representative of those found in spacecraft were pyrolyzed at temperatures below the ignition point with conditions controlled to provide repeatable sample surface temperatures and air flow conditions. The sample materials were Teflon®, Kapton®, cellulose, silicone rubber and dibutylphthalate. The transport time from the smoke source to the detector was simulated by holding the smoke in an aging chamber for times ranging from 10 to1800 seconds. Smoke particle samples were collected on Transmission Electron Microscope (TEM) grids for post-flight analysis.
2008-10-07
Technical Paper
2008-36-0282
Sérgio Duarte Penna, Marcelo Lopes de Oliveira e Souza
Computer systems aboard aerospace vehicles have become more and more distributed in an attempt to solve “real-life” problems such as commonality and longevity of components and subsystems. On the other hand, distributed systems pose a much bigger challenge in system design than traditional, “monolithic” systems, whereby functions are performed by a single component combining hardware and software. “Determinism” (predictability in the occurrence of events), “causality” (temporal ordination of occurrence of events) and “synchronism” (simultaneousness in the occurrence of events) can be pointed out as major challenges in system design. This paper shall survey methods of analyzing determinism in network communications in distributed computer systems aboard aerospace vehicles in different network topologies using a representative model.
2008-06-29
Technical Paper
2008-01-2102
Barrett S. Caldwell
The Mission Control Center (MCC) at the NASA Johnson Space Center has operated to provide teams of flight controllers with the ability to effectively coordinate controller expertise and enhance distributed problem-solving during simulator-based training and live mission operations. However, assembly, integration, and test operations during pre-launch vehicle preparation do not have the same capabilities of providing real-time information alignment or systems engineering knowledge synchronization. This paper investigates concepts of information alignment and knowledge synchronization in distributed supervisory coordination contexts. Ongoing projects address device, infrastructure, and process factors to improve alignment for current and future generations of human spaceflight vehicle operations.
2005-07-11
Technical Paper
2005-01-2900
A. Denaro, E. Brach Prever, C. Chiarelli, M. Antonacci
Activities performed during the phase B of the EXPERT capsule highlighted tight coupling between design solutions outlined for the thermal management architecture and the aerothermal phenomena expected during the re-entry trajectory. Ceramic and high temperature resistant metallic Thermal Protection System (TPS) form the aerodynamic shape of the capsule, so contributing to the aerothermal and structural flight verification, and also accomplish system functions, as TPS is part of a thermo-mechanical architecture that has to ensure the integrity of the capsule. Typical aerothermal phenomena to be tested, such as laminar to turbulent transition, roughness effects, active oxidation and catalycity, need a synergistic coupling with the TPS design called to play an active part during the experimentation (materials characteristics affect and are influenced by aerothermodynamics).
2005-07-11
Technical Paper
2005-01-2959
Jessica Mock, Darcy Miller
The Self Contained Atmospheric Protective Ensemble (SCAPE) suits, worn at the Kennedy Space Center (KSC) have been updated from the original 1970's design. The suits were renamed Propellant Handlers Ensemble (PHE) but are still commonly referred to as SCAPE. Several modifications to the suit were done over the last 20 years to improve the design for operational use. However, anthropometric changes in the user population over time have not been addressed. The following study addressed anthropometric concerns in the current SCAPE population. It was found that all suits had at least one area in which the recommended upper limit was exceeded by technicians. The most common areas to exceed the upper limit were: waist circumference, chest circumference and upper thigh circumference. Forearm circumference posed the least concern unless using long gauntlet glove which cause the twist lock ring to be located at the forearm rather than the wrist.
2005-06-14
Technical Paper
2005-01-2685
Liming Zhao, Ying Liu, Norman I. Badler
Simulating human reach is still challenging when considering complex interactions with the environment. Standard approaches involve inverse kinematics (IK) methods and usually require a complete but exponential cost search in configuration space. In ergonomic applications, both “naturalness” and interactive performance are important. We describe a real-time, collision-free, sternum-rooted IK solution for an articulated human figure based on motion capture data, human strength models, and multi-joint coordination functions. Movement paths are discovered through spatial search in a partitioned workspace. The system generates natural collision-free reach motions in real-time. The resulting animations and statistics demonstrate the efficacy of this approach.
Viewing 1 to 30 of 1419

Filter

  • Range:
    to:
  • Year: