Mechanical Specification

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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

Coordinate Definition

Specification • The JAS mechanical structure shall implement a coordinate system as a reference point for the design. The mounting of each component should be considered as the coordinate reference. The coordinate frame can originate on a pin-and-slot mounting. [Placeholder: Defining a coordinate frame helps to determine center of gravity, mass, envelopes...

Mechanical Specification > Mechanical Interface Design > Coordinate Definition

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

Design Thickness

Specification • For strength and buckling analyses, minimum material thickness shall be used. Minimum thickness is defined as the nominal thickness minus the lower tolerance and applies to metallic and nonmetallic structural elements. For modeling purposes and stiffness calculations, use nominal or expected values. For flexures the Maximum blade thickness shall be...

Mechanical Specification > Design Constraints > Structural Integrity > Design Thickness

Electrical Bonding

Specification • Each equipment design shall provide electrical continuity across mechanical interfaces in accordance with the design requirements of this specification. Electrical continuity will be achieved to the maximum practical extent by direct metal-to-metal contact across the entire interface surface. If the electrical resistance across mechanical interfaces is measured to be less...

Mechanical Specification > Environmental Exposure > Electromagnetic Compatibility > Electrical Bonding

Electromagnetic Compatibility

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...

Mechanical Specification > Environmental Exposure > Electromagnetic Compatibility

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.

Mechanical Specification > Environmental Exposure

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

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...

Mechanical Specification > Design Constraints > Structural Integrity > Factors of Safety

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...

Mechanical Specification > Design Constraints > Structural Integrity > Fatigue

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

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....

Mechanical Specification > Environmental Exposure > Electromagnetic Compatibility > Grounding

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...

Mechanical Specification > Environmental Exposure > Humidity Impact

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.

Mechanical Specification > Mechanical Interface Design > Interface Control

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.

Mechanical Specification > Design Constraints > Life

Results 1–25 of 48