Specification • The JAS mechanical structure shall remain within given displacements as applied by determining gravity release impacts on the mechanical structure.
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Grounding
Specification • Grounding provisions are required for the mechanical design to eliminate the potential for ESD charging on floating metal. Any component members with surface areas greater than 20 cm2 shall have a grounding provision. Bolted fittings are acceptable as grounding provisions if the joint meets the electrical resistance requirement for bonding....
Host Vehicle Interface
Profile • The primary function of this instantiation is to enable connection between the CH node and host vehicle by providing appropriate connectors and bridging differing electrical signaling standards. A mezzanine connector, active transceivers, level shifters, and connectors for cabling to the host vehicle are common examples of components that would be...
Humidity
Specification • The JAS housing shall meet all performance specifications during exposure to relative humidity varying from 0% to 60%.
Humidity Impact
Specification • The JAS mechanical structure shall maintain the electronics/PCBs within given displacements as applied by determining humidity impacts on the mechanical structure. If composite structures are used, the humidity should remain between a saturated composite at nominal 60% RH test area and a dry composite at 0% RH humidity vacuum environment...
Hybrid Fat Trees
Other • A hybrid fat-tree is an extension to the fat-tree topology. Hybrid fat-trees perform well when minimizing average path length and network diameter. One advantage to this design is typically about half of the nodes in this design will have a fixed degree of 2. However, other nodes have large degree,...
Interface Control
Specification • The JAS mechanical structure shall be designed to a prescribed Interface Control Drawing (ICD) as required by the application. Requirements called out in the ICD should include an answer to most of the design considerations in this specification.
JAS Essential Elements
Other • The following essential elements are the minimum required to develop a JAS-compliant system. Communication Interface (physical, preferably serial) Protocols to communicate over the physical interface Network-connected nodes that implement the communication interface and protocols Network routing and addressing scheme(s) All of these items are tailorable based on recommendations in the...
JAS Profile Introductions
Other • The JAS architecture defines a small number of Profiles that form the basis for building the components required for a sensor interface and data processing electronics system. A node inherits the attributes of one or more Profiles. A Profile describes the purpose of that node within the Architecture and defines...
JAS Rationale and Motivation
Other • JAS is a versatile, scalable, tailorable, SWAP-efficient, node-based concept for implementing embedded systems. Such systems include sensor suites, host platform interfaces, signal and data processors, data buffering and storage, command and data handling, and other supporting hardware and software. JAS Origin Sandia National Laboratories, Los Alamos National Laboratories, and others...
JAS Toolbox Introduction
Other • The JAS standard is captured in the JAS Toolbox, and presented using a web-based content management system known as the Interactive Standards Publication Tool (ISPT). In addition to the JAS standard, the JAS Toolbox includes a set of Systems Engineering (SE) Tools, which provide system examples and modeling capabilities. The...
JAS versus PROPIN Trade Study
Other • Feature Comparison JAS has a number of positive impacts on budget, schedule, and performance. Below is a table that illustrates these advantages when comparing a JAS-based system to a PROPIN approach. Advantage Benefit Budget Schedule Performance Scalable processing systems Ability to add/remove as many nodes as are needed to support...
Joint Architecture Standard Overview
Other • The purpose of JAS is to realize a reusable set of common hardware and software module designs that can be easily scaled, configured, adapted, interconnected and integrated with industry standards and internally supported intellectual property (IP) to provide the functionality needed to support any payload sensor suite. JAS also provides...
Junction Temperatures
Specification • The design shall show positive margin against thermal design so junction temperatures do not exceed maximum component values for worst case orbits at beginning (BOL) and end of life (EOL).
Life
Specification • The JAS mechanical structure shall be constructed of materials capable of performing for the necessary mission life time (for example, 3 years storage in an inert atmosphere and 10 years on orbit). This analysis will require extensive parts and materials screening and processing.
Loads
Specification • Loads shall be determined per the program Strength Qualification Plan.
MAGE Strength
Specification • The JAS mechanical structure shall consider tooling to hold it while installing and transporting components. Features for mounting the hardware that supports the system shall be included. A static 4 G load shall be used with positive margins per this document. Mechanical Aerospace Ground Equipment (MAGE)
Margins of Safety
Specification • Margin of Safety (MS) is defined as MS = 1/R - 1, where R is the ratio of the factored applied load (or stress) to the allowable load (or stress) and shall be greater than 0. Margin of Safety Calculation The specific failure theory used to determine the allowable load...
Mass Properties
Specification • The JAS mechanical structure shall attempt to optimize mass, center of gravity, and moments of inertia.
Material Properties and Allowables
Specification • The JAS mechanical structure design of the metallic parts shall use A Basis allowables from MIL-HDBK-5 or equivalent. The design of the composite parts shall use B Basis allowables generated using the methodology in MIL-HDBK-17 or equivalent.
Materials
Specification • The JAS mechanical structure shall be constructed of materials capable of performing at the specified orbit for a minimum of ten years after being stored in an inert gas environment and after exposure to clean air during testing, launch, and ascension. The use of the following materials is prohibited: Zinc,...
Mechanical
Profile • Exact mechanical specifications will vary widely depending on the type of module and the location where it will be integrated into the system. However, there are two predominant applications for the expansion module: a mezzanine board for CH or RP profiles or a RTM to attach to a backplane. Mezzanine...
Mechanical Interface Design
Specification • The JAS mechanical structure as described in this Mechanical specification will support applications intended for a space environment and will provide stable mechanical structure for the electronics during launch and while operating in a high vacuum.
Mechanical Specification
Specification • The Mechanical Specification provides details about mechanical interface design, environmental impacts, and design constraints that should be considered for implementing mechanical structures in a JAS-based system. The figure below provides context of where the Mechanical Specification resides in the JAS standard. JAS Standard Hierarchy
Memory Storage
Profile • Another possible instantiation of this profile is to include non-volatile memory and/or SRAM/SDRAM storage on a CH or RP node. Memory Storage Instantiation
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