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Cleanliness

Specification • Cleanliness is an important design consideration which can be mitigated by the mechanical structure and processes. Systems adjacent to an optical payload may have more strict cleanliness requirements than non-optical payload. The following sections describe the requirements which deal with Cleanliness considerations for the JAS mechanical structure.

Mechanical Specification > Design Constraints > Cleanliness

Custom Communications

Specification • Custom communications specifications by definition are not described by any single specification. The electrical parameters will be determined by the components involved in the design. For example, if the communications utilize gigabit (GTX) transceivers in an FPGA then the electrical requirements will be prescribed by the GTX specifications.

Electrical Specification > Communication Data Links > Custom Communications

Data Types

Specification • The JAS standard does not require a specific length or encoding format for data types. Systems can define these based on what best suits their needs. Sizes, endianness, byte ordering, and bit ordering are typically driven based on the processing and memory architectures that are used. However, in order to...

Communication Specification > JAS Packets > JAS Packet Definition > Data Types

Design Constraints

Specification • The following sections define some important design constraints that the program will levy on the system. The constraints will drive many of the choices in designing the mechanical system.

Mechanical Specification > Design Constraints

Device Access Service

Specification • The device access service, service type address 128, is used to request parameters from or command parameters to a specific device. The currently defined device access service parameters are shown in the following table. Service Type Service Subtype Subtype Description Cmd Tlm Service Parameters Data Types and Description 128 1...

Communication Specification > JAS Packets > Packet Service Definitions > JAS Specific Services Definitions > Device Access Service

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,...

Environmental Specification > Environmental Test Flow

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

Mechanical Specification > Environmental Exposure > Exposure to Space Environment

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...

Communication Specification > JAS Packets > Packet Service Definitions > JAS Specific Services Definitions > File Access Service

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...

Mechanical Specification > Mechanical Interface Design > Form Factor

Humidity

Specification • The JAS housing shall meet all performance specifications during exposure to relative humidity varying from 0% to 60%.

Environmental Specification > Humidity

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).

Mechanical Specification > Environmental Exposure > Junction Temperatures

Loads

Specification • Loads shall be determined per the program Strength Qualification Plan.

Environmental Specification > Loads

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 > Mechanical Interface Design