Specification • Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) are important design considerations which can be mitigated by the mechanical structure. EMI limits may be in place due to application-specific requirements, but more importantly, EMI can be detrimental to electronics because of the sensitive nature of many of the modern systems and...
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Entangled Networks
Other • Entangled networks are a class of networks that attempt to maximize the algebraic connectivity of the topology. These networks can be constructed with explicit complex mathematical methods or approximated by a repetitive random optimization algorithm (which is the method chosen for this analysis) (see Figure). Sample Entangled Networks The repetitive...
Envelope
Specification • The assembled JAS mechanical structure shall attempt to fit the space available without violating any system-level keep out zones.
Environmental Exposure
Specification • Unless otherwise specified, the JAS mechanical structure shall meet these specifications during or after exposure to all environmental conditions specified in the Environmental specification. All of the intended application’s performance parameters must be considered to determine if the mechanical design can withstand the impacts of all environments.
Environmental Specification
Specification • The Environmental Specification provides details about environmental design considerations that should be considered for space applications of JAS. The figure below provides context of where the Environmental Specification resides in the JAS standard. JAS Standard Hierarchy
Environmental Test Flow
Specification • Programs using JAS should practice testing per industry standards wherever possible. The following tests and operational environments shall be applied to the components or structure in the following order. Events 1 through 5 shall be used for qualification acceptance testing. Events 1-6 shall be considered for fatigue calculations. 1) 24ea,...
Error Detection
Specification • Packet errors shall be detected by adding a CRC to each packet transmitted, checking it at the receiver, and discarding any erroneous packet.
Ethernet
Specification • Ethernet comprises a family of networking technologies with numerous media types and standards; 100Base-T (IEEE 802.3-2008:section 8) and 1000Base-T (IEEE 802.3-2008:section 40) the most popular in use today.
Expansion Profile
Other • The Expansion Profile describes a board that provides new capabilities and/or additional resources that would otherwise not be available in standard node instantiations. These modules are not intended to operate standalone and will usually not have individual processing capabilities. Rather, these boards will be populated with components that allow for...
Expansion Profile
Profile • The Expansion Profile describes a board that provides new capabilities and/or additional resources that would otherwise not be available in standard node instantiations. These modules are not intended to operate standalone and will usually not have individual processing capabilities. Rather, these boards will be populated with components that allow for...
Exposure to Space Environment
Specification • This section is a system level consideration and is included for information purposes only. The view to space shall be considered for both thermal and radiation effects. Thermal-related issue: heat-dissipation Radiation-related: TID (lifetime), SEE, shielding and impact on mass
Extended Capabilities
Profile • CH Node Extended Capabilities Customization and extension of CH node capabilities can be realized through instantiations of the Expansion Profile. In instances where custom electronics are needed (for example, spacecraft interfaces or attachments to expansion memory), mezzanines or custom backplane routing to other boards connect electronics to the CH node...
Extended Capabilities
Profile • RP Node Extended Capabilities The flexibility provided by FPGAs allows nodes built upon the RP profile to accommodate custom connectivity to other components, devices, or even other nodes. Customization and extension of RP node capabilities can be realized through instantiations of the Expansion Profile. In instances where custom electronics are...
External Interfaces
Profile • Depending on the nature of the expansion module and its integrated components, electronics modules built to the Expansion Profile will have varying needs with regard to communications interfaces. The Communication Specification is the authoritative document when the expansion module requires network connectivity. Discrete signals may be brought directly in to...
Factors of Safety
Specification • The JAS mechanical structure shall have strength margins of safety greater than zero when calculated from analytically derived structural loads. The factors of safety (FS), shown in the first table below, and test load factors, shown in the second table below, shall be applied to the limit loads. All laminated...
Fatigue
Specification • The JAS mechanical structure metallic elements shall be designed to withstand the effects of cyclic load condition caused by the design environment. The design environment includes all ground handling transportation, testing, launch and on orbit operational environments indicated in the Environmental Specification. MSFC-HDBK-505 Chapter 7 shall be implemented for fatigue...
File Access Service
Specification • The file access service, service type address 129 is used to read from or write to files within a file system. The currently defined file access service parameters are shown in the following table. Service Type Service Subtype Subtype Description Cmd Tlm Service Parameters Data Types and Description 129 1...
Form Factor
Specification • While no specific form factor standard is specified in JAS it is highly recommended that programs make use of a standards-based mechanical design such as VPX defined by VITA. Although VPX is preferred, other standards may be considered for use as well. The consideration of alternate standards should carefully consider...
Fully Connected
Other • Fully connected networks are constructed by wiring every node to every other node present in the network (see Figure). For obvious reasons, these networks are the ideal topology when considering overall speed, diameter, routing complexities, reliability, and ease of construction. However, they require a massive number of links; hence, cost...
Functional Description
Profile • The CH profile defines the technologies that comprise the CH node, including both required and recommended components to define this standard node type. A CH node should be universally designed to minimize the number of unique instantiations of this profile. A block diagram of a CH node is shown below....
Functional Description
Profile • The Communication Profile defines standard methods for transferring data between two JAS nodes. This includes the use of protocols and packet formats by hardware and software. Applications become portable and reusable by using layered communication architecture. The applications should be agnostic to the choice of physical interconnect technology, which allows...
Functional Description
Profile • The Expansion Profile describes a class of supplemental boards designed to augment the capabilities of other profiles. These modules are not intended to operate standalone and will usually not have individual processing capabilities. Rather, these boards will be populated with components that allow for expanded capacity, expanded communications, or both....
Functional Description
Profile • The PS profile defines the technologies that comprise the PS node, including both required and recommended components to define this standard node type. A block diagram of a node instantiated against the PS profile is shown below: PS Profile Block Diagram The primary components for PS node instantiations will include...
Functional Description
Profile • The RP profile defines the technologies that comprise the RP node, including both required and recommended components to define this standard node type. An RP node should be universally designed to minimize the number of unique instantiations of this profile. A block diagram of an RP node is shown below:...
Functional Description
Profile • The SMAC is responsible for enabling the following capabilities on JAS nodes: Network (typically SpaceWire) router for command and control Control to read and drive discrete digital I/O and data buses Configuration of node FPGA(s) SOH reporting, including node temperatures, voltages, and currents Local and neighboring node power control Connectivity...
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