Specification • All JAS mechanical structure components shall be placed to prevent obscuration of the system view of space if the JAS electronics box will be used to radiate. Structural elements shall be kept an appropriate distance away from the JAS electronics housings.
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Operating Temperatures
Specification • Operational temperatures are provided in thermal study for the nominal orbit. Excursions from predicted operational temperatures shall be increased by 11C (bilateral) when these temperatures are utilized in all fatigue analysis. For the purposes of fatigue the temperature excursion within an orbital season may be considered. For the purposes of...
Operational Vibrations
Specification • The JAS housing shall meet all of the displacement budgets, while subjected to the operational environment produced by the acceleration in file, TBD. These shall be used as base inputs.
Orientation
Specification • The JAS housing shall meet mechanical alignment performance specifications in any direction.
Packaging for Thermal Dissipation
Specification • The preliminary JAS mounting details are defined by the baseplate details in ICD drawing xxxxxx. The JAS electronics box is meant to mount through the blue baseplate shown in the figure below. The figure shows a nominal 3x3 stack in an exploded view. JAS Mounting Exploded View Conducted Self-radiated panels...
Particulate Contamination
Specification • Internal Cavities will be wiped clean with isopropyl alcohol and allowed to air dry for 30 minutes prior to close out; the structure will be covered during the drying process. The surfaces will be visibly clean. Visibly clean is defined as no contamination visible when viewed from 6-18 inches away...
PCI Express
Specification • PCI Express, or PCIe, is another multi-lane high speed serial interconnect technology. Each lane is a full-duplex data stream comprised of two differential signaling pairs, one for transmitting and one for receiving.
Potential Flight Capability
Specification • Each component of the JAS mechanical structure should consider Flight capability as this will force consideration of design, flight, and test environments described in this specification. The JAS mechanical structure should be designed for the specific application intended.
Power Distribution Architecture
Specification • JAS will accept at least one primary input power source supplied to the system. The primary input power will connect directly to the Power Supply or PS node in a JAS arrangement. The PS node converts the primary input voltage to a lower voltage which is then sent to all...
Power Supply Profile
Other • The PS profile defines a high-performance power solution, suitable for powering JAS nodes. The PS profile works alongside other nodes within the JAS architecture. The SMAC and Communications profile implement connectivity and data transfer from PS nodes to other nodes in the system. Power Supply Node The figure below illustrates...
Power Supply Profile
Profile • The PS profile defines a high-performance power solution, suitable for powering JAS nodes. The PS profile works alongside the CH and RP profiles to implement groups of nodes (i.e., boxes) within the JAS architecture. The SMAC and Communications profile implement connectivity and data transfer from PS nodes to other nodes...
Pressure
Specification • The JAS structure shall meet all performance specifications during and after exposure to pressures varying from atmospheric to the space environment of 10-14 Torr. All thermal-vacuum ground based testing shall be conducted at pressures less than 10-6 Torr.
Pressure Change
Specification • The structure shall be designed to survive the change of pressure specified in the figure below. The launch and ascent pressure environment will lie between Pc(Max) and Pc(MIN). Pressure Change Within the envelope defined in figure above, the local rates of change will remain between the values shown in the...
Primary DC to DC Conversion
Profile • PS Node DC-DC Converters The PS node utilizes isolated DC-DC switching converter devices, which provide the primary power conversion capability for this node type. The DC-DC converter converts the primary bus voltage to a regulated secondary voltage that is distributed to the nodes in the system.
Primary Power Conversion
Specification • JAS will provide the capability to convert primary power to secondary power.
Primary Power Conversion Efficiency
Specification • The converter should be optimized for efficiency to reduce power consumption and avoid unnecessary heat generation through power dissipation. The exact design of the primary converter will depend upon the required efficiency and the exact nature of the input power.
Primary Power Conversion Galvanic Isolation
Specification • The primary power converter should provide galvanic isolation between the primary power and the secondary power.
Primary Power Conversion Noise Reduction
Specification • The converter should reduce or eliminate noise and/or fluctuations in the primary input power.
Primary Power Redundancy
Specification • JAS will implement the application requirements for primary power supply redundancy.
Protocols
Specification • The protocols described in the following sections are used for various SpaceWire applications depending on the needs of the communication interface. Remote Memory Access Protocol (RMAP) is a SpaceWire standard used for memory access. JAS Efficient Exchange Protocol (JEEP) and JAS Reliable Data Delivery Protocol (JRDDP) are both specific to...
Quasi-Static Loads
Specification • Quasi-static loads shall be applied per the program Strength Qualification Plan. The axial and radial acceleration loads are to be applied simultaneously for an 11 g (TBD?) load in the worst case direction.
Radiation Effects Mitigation
Specification • The primary space effect requiring mitigation is the radiation environment, which causes gradual degradation of electronic devices and single event effects (SEE). Parts that have demonstrated destructive SEE, such as SEL or SEGR, should not be incorporated into the node unless absolutely necessary. It is equally important to test the...
Rear Transition Module
Specification • The rear transition module (RTM) of the VPX standard is a plug-in module at the back of the circuit card chassis that is in line with the front plug-in module or node. The backplane connectors on the RTM are the same as those used on the plug-in nodes. Also, as...
Reconfigurable Processing Profile
Other • The Reconfigurable Processing (RP) profile defines a high-performance processing solution suitable for constructing nodes for mission data processing, sensor interfaces, and other applications requiring high-bandwidth processing and communications. Nodes based on the RP profile work alongside other nodes within the JAS architecture. The SMAC Profile and the Communication Profile implement...
Screened Venting
Specification • Where venting requires a screen to maintain cleanliness requirements, based on a 5µ Pall Rigidmesh screen, there shall be 1.5 in^2 or greater screen area per ft^3 of volume where the volume is the sum of multiple daisy-chained volumes. The daisy chained volumes shall be vented.
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