The Experts below are selected from a list of 117 Experts worldwide ranked by ideXlab platform

Robert W Young - One of the best experts on this subject based on the ideXlab platform.

  • sonic booms of Space Shuttles approaching edwards air force base 1988 1993
    Journal of the Acoustical Society of America, 2002
    Co-Authors: Robert W Young
    Abstract:

    From 1988 to 1993 13 sonic booms of Space Shuttles approaching Edwards Air Force Base were measured at a site 10 miles west of EAFB, with one to seven different sound level meters for each measurement. Results from five of these measurements are here presented. Maximum differences in measured levels between instruments for the same flight varied from 0 to 6 dB depending on the measurement descriptor and model of sound level meter. The average difference between predicted and measured values was 0.7±1.5 dB. For sound level meters with adequate bandwidth the waveforms measured varied from a near perfect N-wave to a more distorted form reflecting the influence of the varying condition of the atmosphere during propagation to the ground.

  • thirteen sonic booms of Space Shuttles approaching edwards air force base 1988 1993
    Journal of the Acoustical Society of America, 1998
    Co-Authors: Robert W Young
    Abstract:

    Thirteen sonic booms of Space Shuttles approaching Edwards Air Force Base, 1988–1993, were measured at a site 10 miles west of EAFB with Bruel & Kjaer 2230 Precision Integrating sound level meter ♯1082228; CEL‐493/2 Precision Integrating Impulse sound level meter ♯198107; CEL‐238A Secondary Processor ♯151020; GenRad 1982 Precision sound level meter ♯0169; Rion NL‐11 Precision Integrating sound level meter ♯1140255; RACAL 4D7680‐3 tape recorder ♯11224. On 30 Jan 1992 sound‐pressure levels were peak flaT 133 dB; peak Awt 127 dB; max fast Cwt 113dB; max fast Awt 98 dB. Sound exposure levels flaT 126 dB; Cwt 108 dB; Awt 90 dB. On 16 May 1992 sound‐pressure levels PKT 131 dB; MXFC 112 dB; MXFA 95 dB. Sound exposure levels CSEL 107 dB and ASEL 91 dB. Some 8 min before a Space shuttle landing the latitude, longitude, altitude, and Mach number at 1‐s intervals were supplied by AEROPAC. By Carlson theory, W. J. Galloway calculated for 30 Jan 1992 slant distance of 89 kft to sound‐measurement site from origin of th...

Stuart Fox - One of the best experts on this subject based on the ideXlab platform.

  • 6 Private Companies That Could Launch Humans Into Space
    Space.com, 2010
    Co-Authors: Stuart Fox
    Abstract:

    The era of private Spaceflight is breaking new ground with the first test launch of the new Falcon 9 rocket by the company Space Exploration Technologies (SpaceX), which hopes to use the booster to fly its Dragon Spaceship on Space station trips. And with NASA's Space Shuttles retiring this year, SpaceX is not alone in the bid to launch cargo and astronauts into Space.

Markus Jochim - One of the best experts on this subject based on the ideXlab platform.

  • SAFER: System-level architecture for failure evasion in real-time applications
    Proceedings - Real-Time Systems Symposium, 2012
    Co-Authors: Junsung Kim, Gaurav Bhatia, Ragunathan Raj Rajkumar, Markus Jochim
    Abstract:

    Recent trends towards increasing complexity in distributed embedded real-time systems pose challenges in designing and implementing a reliable system such as a self- driving car. The conventional way of improving reliability is to use redundant hardware to replicate the whole (sub)system. Although hardware replication has been widely deployed in hard real-time systems such as avionics, Space Shuttles and nuclear power plants, it is significantly less attractive to many applications because the amount of necessary hardware multiplies as the size of the system increases. The growing needs of flexible system design are also not consistent with hardware replication techniques. To address the needs of dependability through redundancy operating in real-time, we propose a layer called SAFER (System-level Architecture for Failure Evasion in Real-time ap- plications) to incorporate configurable task-level fault-tolerance features to tolerate fail-stop processor and task failures for dis- tributed embedded real-time systems. To detect such failures, SAFER monitors the health status and state information of each task and broadcasts the information. When a failure is detected using either time-based failure detection or event-based failure detection, SAFER reconfigures the system to retain the functionality of the whole system.We provide a formal analysis of the worst-case timing behaviors of SAFER features.We also describe the modeling of a system equipped with SAFER to analyze timing characteristics through a model-based design tool called SysWeaver. SAFER has been implemented on Ubuntu 10.04 LTS and deployed on Boss, an award-winning autonomous vehicle developed at Carnegie Mellon University. We show various measurements using simulation scenarios used during the 2007 DARPA Urban Challenge. Finally, we present a case study of failure recovery by SAFER when node failures are injected.

Ajay Kumar - One of the best experts on this subject based on the ideXlab platform.

  • Specialized Solar Panel Hinge Characterisation Test System
    Cyber-physical Systems and Digital Twins, 2020
    Co-Authors: Panchaksharayya S. Hiremath, G. Harshita, Kalyan Ram B., Preeti Biradar, Ajay Kumar
    Abstract:

    The upcoming Spacecrafts are to be built such that it requires lesser Space, lower cost and highly reliable, for implementing solar panels on the wings of the Shuttles; in order to achieve these qualities the Spacecrafts are built in such a way that the wings of these Shuttles can be folded and unfolded during the utilization process. For obtaining this requirement the Spacecrafts are built by making use of various components, which also includes hinges placed at solar panel wings on the rockets and many other Space Shuttles, wings are built with hinges which helps the process of folding and unfolding of the solar panel wings on the Shuttles during its energy generation operation. These hinges placed are of different types, the main purpose is to test its torque rotational and characteristics and to generate and provide the test report for all the combinations of hinges, before it has been deployed into the actual setup. The existing method was to manually test the hinges for its accuracy and proper working conditions, whereas this testing method is automated and is done on automated test equipment (ATE), with the help of sensors and actuators which is done to reduce the failure rate during the process by placing the hinge on the specialized solar hinge test bench in prior before deployment.

L Spirkovska - One of the best experts on this subject based on the ideXlab platform.

  • Human Factors
    System Health Management: With Aerospace Applications, 2011
    Co-Authors: R S Mccann, L Spirkovska
    Abstract:

    Since the early days of the Industrial Revolution, people have been managing the operational health of a wide variety of mechanical engineering systems, including industrial equipment and machinery, manufacturing plants, and transportation vehicles. Health management duties typically include monitoring the operational status of the system, diagnosing the source of an abnormal operating mode when one arises (typically, some form of component malfunction), and executing the procedures necessary to isolate and minimize the harmful effects of the malfunction and restore critical functionality. As the scope and complexity of mechanical systems has grown, so has the health management load on human operators. Fortunately, system health management (SHM) technologies have now advanced to the point where they can automate many health management (HM) activities. However, integrating SHM automation into what has traditionally been a human-centered activity raises a host of cutting-edge human factors issues. These issues include how to display systems information in a way that maximally supports human situation awareness and decision-making capabilities, how to determine appropriate levels of human-automation function allocation, and how to develop human-machine interfaces that most effectively support human-machine collaboration. In this chapter, we discuss these issues within the context of crewed Spacecraft operations. Human-rated Spacecraft contain very complex and often highly interconnected engineering systems, including propulsion systems; electrical and mechanical power generation and distribution systems; guidance, navigation, and control (GN&C) systems; data processing systems; life support systems; and communications systems. Particularly during the dynamic mission phases of launch, ascent, and entry, these systems must perform to precise operational specifications in very harsh environments, whose cumulative effects on system functioning are often poorly understood. Consequently, systems malfunctions are an ever-present threat to mission success and crew safety, and HM is a major element of mission operations. Current-generation Spacecraft such as the Space Shuttles were designed and built several decades ago. Although quite advanced for their time, the Shuttle cockpits feature very little in the way of SHM automation and what designers of today's aeroSpace vehicles would describe as legacy crew-vehicle interfaces. The Shuttles thus provide an ideal platform to identify the human factor difficulties that accompany HM of very complex systems without the benefit of recent advances in SHM technology, and then illustrate the issues that arise when attempting to improve legacy operations with modern interfaces and improved SHM technology. We will therefore begin with a crew-centered overview of Shuttle HM operations, with a particular focus on the challenges crew members face when detecting, diagnosing, isolating, and recovering from time-critical systems malfunctions. This description provides a platform from which to launch a detailed discussion of a more advanced operational concept, targeted to next-generation vehicles, that blends modern cockpit interface concepts with SHM capabilities. Although the specific details of our concept are crew-centric, the underlying design issues (and examples of possible solutions) are generic enough to apply to a wide variety of operational environments, including mission control centers on the ground. © 2011 John Wiley & Sons, Ltd.