Blog: Harnessing COTS Frequency Control and Timing Components for Space Applications
The demand for space-based frequency control and timing components has been growing rapidly in recent years. This new trend is driven by the need for better communication, navigation, Earth observation, and scientific research. To meet these demands, missions require highly reliable and precise frequency control and timing solutions. In the past, these components were custom-designed and manufactured at great cost and with long lead times. However, Commercial Off-The-Shelf (COTS) components have emerged as a game-changer, offering cost-effective and reliable performance for space-based frequency control and timing applications.
Pictured: Artist Rendering of LEO CubeSat Constellation
Custom Frequency Control and Timing Component Challenges
Frequency control and timing components are responsible for synchronizing spacecraft systems, communication links, and scientific instruments. Precise timing is crucial for coordinating data collection, navigation, and communication, ensuring that missions operate smoothly and achieve their objectives.
Traditionally, space agencies and organizations relied on custom-designed components for frequency control and timing applications. These components were often expensive to develop and manufacture, requiring extensive testing and qualification to ensure they could withstand the harsh conditions of space, including extreme temperatures, radiation, and vacuum.
Custom components also posed a challenge when it came to upgrades and replacements. Spacecraft typically have long operational lifetimes, and as technology advances, custom components can become obsolete. This necessitates costly and time-consuming redesigns and replacements.
The COTS Revolution and the Influence of the DoD
In 1994, then Secretary of Defense William Perry issued a memo, “Specifications & Standards – A New Way of Doing Business,” which directed the undersecretaries and directors of the various Department of Defense (DoD) branches to implement the recommendations of the Process Action Team, DoD, Military Specifications and Standards, which had produced a report titled “Blueprint for Change.”
Pictured: Department of Defense Headquarters, Washington, D.C.
In this report, the group concluded that component manufacturers’ processes and controls had advanced to the point that their “commercial” grade components generally had as good reliability as the expensive, long lead components manufactured and upscreened per military specifications. They recommended that the Secretary of Defense direct suppliers to use these alternatives to military performance specification components whenever possible. Additionally, the report stated that these commercial components could be used without general upscreening tests, except for radiation environment survivability.
What emerged from this directive was a significant change in the way the DoD and, by extension, the aerospace industry as a whole, approached the use of components for its systems. This pivotal moment in 1994 marked a turning point that would influence the broader acceptance of Commercial Off-The-Shelf (COTS) components.
Benefits of COTS Frequency Control and Timing Components:
Cost Efficiency- COTS components are significantly cheaper than custom-designed alternatives because the development costs are spread across a broader range of applications. This cost savings is particularly beneficial for organizations with limited budgets.
Availability- COTS components are readily available! This reduces lead times and allows for faster mission development and deployment. This is crucial in an industry where timing is often of the essence (no pun intended).
Technological Advancements- COTS components leverage the latest technological advancements, ensuring that organizations have access to cutting-edge technology without the need for custom development.
Easy Upgrades and Replacements– COTS components can be easily replaced or upgraded as technology evolves, extending the operational life of space missions and reducing the risk of obsolescence.
Validation and Testing- Many COTS components undergo rigorous testing and validation for their intended applications in various industries, which can be leveraged for space applications, saving time and resources. We’ll dive into certification and qualification standards in a little more detail below.
Challenges and Considerations:
While COTS frequency control and timing components offer significant advantages, they are not without challenges and considerations for space applications:
Adaptation- COTS components may require modifications to meet the specific requirements of space missions, including radiation hardening, thermal management, and integration into spacecraft systems.
Reliability- While COTS components are designed for reliability in their intended applications, they may not be inherently radiation-resistant. Additional testing and hardening may be necessary to ensure their reliability in space environments.
Risk Management- Space missions are inherently risky, and any component failure can have severe consequences. Organizations must carefully assess and mitigate the risks associated with using COTS components.
Qualification Standards for COTS Frequency Control and Timing Components
Space missions demand a level of reliability and durability that goes beyond what most commercial components are designed to withstand. To bridge the gap between readily available COTS frequency control and timing components and the stringent requirements of space, the aerospace industry has established a myriad of qualification standards. These standards establish the framework for adapting COTS components to space applications while ensuring they meet the high standards of reliability and performance.
Pictured: Frequency Control and Timing Electronics Manufacturing in Austin, Texas
It is important to note that when COTS components undergo full space qualification processes, they become true space-qualified components, meeting the stringent requirements of space missions. However, these standards provide foundations, not frameworks, for evaluating COTS suitability. While they set benchmarks for space-qualified components, they do not mandate specific testing procedures. COTS components for space applications occupy a middle ground. They inherently possess key reliability and robustness criteria for space but don’t undergo full qualification. Engineers may apply limited testing or modifications to adapt them to specific mission needs. COTS components offer cost-effective solutions but lack the same assurance as fully space-qualified ones. Engineers and designers must grasp this nuanced landscape when selecting components for space missions, ensuring informed decision-making.
Qualification and Test Standards:
MIL-PRF (Military Performance Specification) MIL-PRF can be described as a collection of military specifications that were originally designed for use by the U.S. Department of Defense. However, they have also been widely adopted for space applications due to their rigorous testing and quality control requirements. MIL-PRF specifications cover various aspects of components and materials used in space electronics, including vibration resistance, thermal performance, radiation tolerance, and more.
For example, MIL-PRF-38534/-38535 outlines the requirements for hybrid microcircuits used in space and military applications. MIL-PRF-38534/-38535 qualification does not just validate the final product alone, but all the sub-components and materials that go into the assembly.
AS9100 AS9100 is a quality management system standard specifically tailored for the aerospace industry. It encompasses all aspects of the aerospace supply chain, including design, development, production, and servicing. AS9100 certification indicates that a manufacturer adheres to stringent quality and reliability standards.
EEE-INST-002 This NASA document outlines fundamental criteria for the selection, screening, qualification, and derating of EEE (Electrical, Electronic, and Electromechanical) components for NASA GSFC space flight projects. Its purpose is to ensure the appropriate selection of components, maintain mission reliability, and adhere to budget constraints when fabricating space hardware.
PEM-INST-001 This NASA document establishes a product assurance framework for PEMs (Plastic-Encapsulated Microcircuits) to implement the GSFC PEM policy. It draws from existing qualification systems for military and aerospace components, the collective experience of the parts engineering community, and industry-established practices. The purpose of this product assurance system is to mitigate the risks associated with using PEMs, assess their long-term reliability, and prevent failures. Commercial PEMs are primarily designed for benign environments and pose a high risk when used in space applications. As a result, no PEMs are considered acceptable in high-reliability scenarios without undergoing additional testing and analysis to ensure sufficient reliability and radiation tolerance.
MIL-STD-883 This standard outlines the testing techniques and protocols designed for microelectronic devices, including those intended for utilization in space-related applications. It encompasses a range of environmental testing procedures, including assessments for temperature cycling, thermal shock, and radiation resilience.
ECSS (European Cooperation for Space Standardization) ECSS standards find extensive application in European space missions, serving as a structural basis for the development and evaluation of space systems and components.
JAXA (Japan Aerospace Exploration Agency) Standards JAXA has established its own set of standards that oversee the design, production, and examination of components destined for use in Japanese space missions.
Conclusion
The use of COTS frequency control and timing components for space applications represents a significant paradigm shift in the industry. These components offer cost-effective, readily available, and technologically advanced solutions that can accelerate mission development and enhance the capabilities of spacecraft. However, their adoption also requires careful consideration of adaptation, reliability, and risk management to ensure the success of space missions. Looking ahead, the integration of COTS frequency control and timing components will play an even more prominent role in shaping the future of space exploration and communication.
