NASA-STD-6016 provides a unified framework for selecting, deploying, and assessment of materials and process applications. Spacecrafts with their complex engineering and extreme operating environments, require materials and processes that can withstand the challenges posed by space travel. From the vacuum of space to extreme temperatures and radiation, these materials must not only endure but also maintain their functionality and structural integrity. This standard establishes a comprehensive set of minimal requirements governing the selection, deployment, and assessment of Materials and Processes (M&P) integral to the design, manufacturing, and testing of a wide range of NASA's space program components.

Importance of Materials and Processes

The materials and processes used in spacecraft construction are essential elements that influence every aspect of mission success. These components impact structural integrity, thermal performance, electrical conductivity, radiation resistance, and more. Additionally, the space environment introduces unique factors, such as atomic oxygen exposure, solar radiation, and micrometeoroid impacts, which necessitate specialized material properties and processing techniques.

Engineering Properties

A comprehensive range of engineering properties are considered under NASA-STD-6016 to ensure the durability, reliability, and functionality of spacecraft materials and processes. These properties span a diverse array of characteristics, including flammability and toxic off-gassing potential, corrosion resistance, susceptibility to stress corrosion, thermal and mechanical fatigue resilience, glass-transition temperature, compatibility with various fluids, resistance to microbial growth, moisture protection, resistance to fretting and galling, susceptibility to electrostatic discharge (ESD), and sensitivity to contamination.

Components of NASA-STD-6016 Standard

• Material Selection: The standard outlines the criteria for selecting materials based on mechanical, thermal, electrical, and environmental properties. It emphasizes the importance of understanding the materials' behavior under different conditions, ensuring compatibility, and considering factors like outgassing, flammability, and toxicity.
• Material Qualification: NASA-STD-6016 provides procedures for qualifying materials through rigorous testing and evaluation. This process involves subjecting materials to relevant simulated space environments to assess their performance, durability, and compatibility. Qualification ensures that selected materials can withstand the demands of space travel.
• Processes and Fabrication Techniques: The standard addresses various manufacturing processes, including machining, welding, brazing, and adhesive bonding. It defines requirements for each process, considering factors like joint strength, thermal expansion compatibility, and the prevention of contamination. This section also covers surface treatments, coatings, and finishes necessary to enhance material performance in space.
• Contamination Control: Given the sensitivity of space instruments and optics to contamination, the standard addresses contamination control measures. It provides guidelines for handling, cleaning, and packaging materials to prevent the introduction of foreign particles that could compromise spacecraft functionality.

Implementing NASA-STD-6016 Standard

• Design Phase: During the design phase, engineers must evaluate the mission requirements and select materials and processes that align with the spacecraft's intended mission profile. This involves considering factors like thermal expansion, outgassing rates, and radiation resistance to ensure long-term performance.
• Testing and Qualification: Materials selected for spacecraft components undergo rigorous testing to simulate the harsh space environment. Qualification testing assesses how materials respond to thermal cycling, radiation exposure, and other conditions they will encounter during the mission.
• Manufacturing and Quality Control: Manufacturing processes must adhere to the guidelines set by NASA-STD-6016. Quality control measures ensure that materials are processed correctly, joints are strong and durable, and contamination is minimized.

NASA-STD-6016 establishes a series of critical requirements to be adhered to in the selection, management, and implementation of materials and processes. This includes the development of a robust plan for material and process selection, control, and application. The coordination, approval, and monitoring of engineering documents that establish or modify materials and processes are outlined. An approval process for new or alternate materials and processes is specified. Stringent controls are mandated for the utilization of Commercial Off-The-Shelf Hardware (COTS), coupled with the need for comprehensive materials usage documentation through tools like the Materials Identification and Usage List (MIUL). The standard considers the distinction between human-rated and non-human-rated spacecraft, and materials usage agreements (MUAs) are stipulated for cases where technically acceptable materials or processes don't conform to approved selection, control, and implementation plans. Essential aspects such as manufacturing planning, material certification and traceability, materials design allowances, flammability control, toxic off-gassing mitigation, fluid compatibility, and electrical wire insulation materials are addressed.

Approved Metallic and Non-Metallic Materials

NASA-STD-6016 identifies a broad spectrum of approved metallic and non-metallic materials suitable for spacecraft construction. This encompasses a variety of metals such as aluminum, steel, titanium, magnesium, beryllium, cadmium, and zinc, along with refractory metals, superalloys (both nickel-based and cobalt-based), elastomeric materials, polyvinylchloride, composite materials, lubricants, limited-life items, and substances resilient to thermal vacuum conditions, external environment challenges, fungal growth, and glycols.

Processes Included

The standard acknowledges a suite of essential manufacturing processes to be followed in accordance with its guidelines. These include forging, castings, adhesive bonding, welding, brazing, and structural soldering, as well as electrical discharge machining and laser machining techniques.

Material Non-Destructive Inspection (NDI)

A structured approach to material non-destructive inspection (NDI) is emphasized within the standard. This entails the formulation of a non-destructive evaluation (NDE) plan, coupled with the utilization of techniques such as NDE etching and nickel plating for enhanced inspection capabilities.

Special Materials Requirements

Certain specialized materials requirements are acknowledged by NASA-STD-6016 to address specific challenges. These considerations include the management of residual stresses, sandwich assemblies, corrosion prevention, and control strategies (encompassing passivation and sealing techniques), hydrogen embrittlement mitigation, optimal fastener installation practices (including liquid locking compounds and silver-plated fasteners), stringent contamination control measures, and meticulous packaging to ensure material integrity.

Click here to learn more about other NASA Space Standards.