The critical need for interaction design in the aerospace industry
The space industry is experiencing exponential growth, driven by technological advances, decreasing launch costs, and increased investment from governments and private enterprises. Traditional aerospace giants and a bevy of new startups are pushing the boundaries of space exploration, satellite deployment, and commercial development from low Earth orbit to the Moon. This rapid development parallels a surge in human interaction with space technologies, from the proliferation of satellite-based communication and navigation systems to the emerging opportunities in scientific and commercial development. As space becomes more accessible, the integration of space technologies into everyday life is accelerating, transforming industries, enhancing global connectivity, and opening new frontiers for exploration and innovation.
Human Factors Engineering (HFE) and Interaction Design (IxD) are pivotal in developing aerospace systems yet are often overlooked due to various challenges and constraints. In industries requiring high levels of situational awareness, such as aerospace, energy, transportation, logistics, and complex enterprise applications, integrating Interaction Design and Human Factors Engineering is not just beneficial — it is critical. Designers in these disciplines ensure that systems are functional and efficient but also safe, intuitive, and user-friendly. By leveraging the strengths of these disciplines that cross the boundaries between design and engineering, we can create interfaces and systems that optimize human performance, minimize errors, and enhance overall user experience. It is helpful for both designers and engineers to understand how HFE and IxD overlap and complement one another.
Human Factors Engineering focuses on designing systems that accommodate human capabilities and limitations to enhance performance, safety, and usability. It involves the study of ergonomics, cognitive psychology, and human behavior to create products and environments that fit users’ needs. HFE methodologies include task analysis, usability testing, and ergonomic assessments to minimize human errors and fatigue and optimize efficiency. The mental model in HFE emphasizes a scientific, empirical approach where quantitative data and iterative testing drive design decisions. The ultimate goal is to create systems that are safe, effective, and aligned with the physical and cognitive characteristics of users.
Interaction Design, conversely, centers on crafting engaging and intuitive interactions between users and products or systems. It draws on principles from design thinking, user experience (UX) design, and cognitive psychology to create interfaces that are functional and enjoyable to use. IxD methodologies include user research, prototyping, and iterative design, strongly focusing on qualitative feedback and user empathy. The mental model in IxD is more holistic and creative, emphasizing aesthetics, user satisfaction, and emotional impact. While HFE and IxD share the goal of improving user interactions, HFE is more focused on safety and performance through empirical data. In contrast, IxD prioritizes usability and user experience through creative and empathetic design processes.
Human Factors Engineering (HFE) and Interaction Design (IxD) often converge in practice because both fields aim to optimize the interaction between humans and systems, albeit from slightly different perspectives. This convergence becomes crucial in high-stakes environments like aerospace, energy, and transportation, where the stakes for usability, safety, and efficiency are exceptionally high. HFE contributes a rigorous understanding of human capabilities, limitations, and ergonomics, ensuring that systems are physically and cognitively accessible and reduce the potential for error. Meanwhile, IxD focuses on creating intuitive, engaging, and aesthetically pleasing interfaces that enhance user satisfaction and ease of use. By integrating HFE’s empirical, data-driven methodologies with IxD’s creative, user-centered approaches, designers can develop comprehensive solutions that address users’ functional and experiential needs. This collaboration ensures that systems are safe, efficient, enjoyable, and straightforward to use, ultimately leading to better overall performance and user satisfaction.
Interaction Design is critical not only for human spaceflight missions involving controls for spacecraft and space stations but also for ground-based mission control operators, robotic missions, and scientists gathering and analyzing critical scientific data. Every interaction between humans and technology represents a potential point of failure, underscoring the need for expertise in designing intuitive, reliable, and user-friendly interfaces. For mission control operators, clear and consistent displays and controls are essential for effective monitoring and decision-making under pressure. In robotic missions, operators need interfaces that provide precise control and feedback to ensure successful navigation and operation of remote systems. Scientists analyzing data require tools that present complex information in an accessible and actionable manner. By addressing these diverse needs, interaction designers help minimize errors, enhance situational awareness, and improve mission success across all touchpoints between humans and technology.
Reasons for being overlooked
Despite their importance, HFE and IxD are often overshadowed by other pressing concerns and priorities in aerospace development. Integrating HFE and IxD from the outset can add to the initial cost and complexity, which some stakeholders may be reluctant to accept despite the long-term benefits. Aerospace engineering traditionally focuses on systems’ mechanical, electronic, and structural aspects, often overshadowing the importance of human factors design.
A lack of awareness or understanding among engineers and managers about the benefits of HFE and interaction design can lead to deprioritizing these aspects in favor of seemingly more tangible engineering goals. Cultural barriers in some organizations may undervalue the role of HFE and IxD professionals compared to traditional engineers, leading to insufficient resources and support for human factors work. Additionally, the aerospace industry’s heavy regulation and the focus on compliance can detract from efforts to optimize human factors and interaction design. Historical precedents in the design of aerospace systems primarily focused on technical and performance specifications, which may further challenge the shift towards a more integrated approach between engineering and design.
Often, engineers discredit visual interface design as “just aesthetics.” However, the aesthetics of interfaces and interactions extend far beyond mere attractiveness, profoundly impacting usability, error rates, efficiency, and situational awareness. Thoughtful selection of form, layout, color, and typography can guide user attention, reduce cognitive load, and enhance clarity, making it easier for users to process information and make decisions quickly. Well-designed interfaces help prevent errors by providing intuitive cues and feedback, improving overall efficiency and safety. By integrating aesthetic principles with ergonomic and cognitive considerations, interfaces can be artfully designed and meticulously engineered to optimize human-system interaction.
Case Study: The Mars Climate Orbiter
One notable example of a space mission compromised due to a human factors error or interface design flaw is NASA’s Mars Climate Orbiter in 1999, which I witnessed and studied extensively in the following years. This mission provides a significant lesson in the importance of human factors engineering and interface design in space missions.
The Mars Climate Orbiter was a robotic space probe launched by NASA on December 11, 1998, intended to study the Martian climate, atmosphere, and surface changes. The probe was designed to function as a communications relay for the Mars Polar Lander and to conduct scientific observations. I was working at NASA/JPL in the mid-1990s and documented this and other missions, and I followed this entire mission closely.
The mission failed on September 23, 1999, when the orbiter was supposed to enter orbit around Mars. I was no longer working at NASA/JPL, but I had secured a guest pass and watched it from the viewing gallery at JPL Mission Control. The moment of successful orbital entry never came; instead, we waited silently, dreading that something had gone wrong. Eventually, they announced that the spacecraft entered the Martian atmosphere at a much lower altitude than planned, destroying it. At the time, there was almost a total lack of situational awareness for mission control operators, and the mission control software offered no help. Eventually, investigators at NASA discovered that the primary cause of this failure was a simple yet catastrophic human factors error involving unit conversion.
The Interaction Design Failure
The error stemmed from a mismatch in the units used by different teams working on the mission. The spacecraft’s navigation software, developed by Lockheed Martin, produced thrust data in pound-force seconds (lbf·s). However, NASA’s navigation team expected the data in the Newton-second metric unit (N·s). This failure to properly convert the units resulted in the spacecraft receiving incorrect navigational data, which led it to approach Mars at a dangerously low altitude.
I did not realize until several years later, when I was reading a thorough analysis of the mission failure, that this unit mismatch was fundamentally an interface design flaw. The interface used by mission control operators did not indicate the measurement units and lacked automatic unit conversion capabilities. The absence of clear unit labels or conversion functions on the interface meant that operators needed a way of verifying whether the data they were using matched the expected format. This critical oversight failed to afford operators the situational awareness necessary to identify and correct the discrepancy, ultimately leading to the mission’s failure. Properly designed interfaces should include clear unit indicators and automatic conversions to prevent such errors and ensure accurate data interpretation.
However, this was not a single-source failure but rather due to several human factors and interaction design flaws. More precise and consistent documentation and communication between the teams were needed regarding the units of measurement, highlighting a fundamental flaw in how information was shared and validated. Additionally, the systems lacked adequate error-checking mechanisms to detect and correct such an essential yet critical error. Effective human factors engineering should include robust error-checking mechanisms to prevent such oversights. Furthermore, the user interfaces and software systems did not provide clear indications or warnings about the unit discrepancy. A well-designed interface should help users understand the context and units of the input and output data, reducing the likelihood of such errors.
Lessons Learned
The Mars Climate Orbiter disaster underscored several critical lessons in HFE and IxD. Ensuring consistency in units and measurements across all teams and systems requires rigorous documentation and adherence to standardized protocols. Clear and effective communication channels between different teams are essential to avoid misunderstandings and ensure all members know critical details. Implementing thorough verification and validation processes can catch errors early, including automated checks within software systems to flag inconsistencies and potential issues. Additionally, designing user-centric interfaces that display crucial contextual information, such as units of measurement, can help users detect and correct errors before propagating into mission-critical operations.
The failure of the Mars Climate Orbiter mission due to a simple unit conversion error highlights the profound impact that human factors and interface design can have on the success or failure of space missions. By learning from such incidents, aerospace engineers and designers can develop more robust, user-friendly systems that minimize the risk of human error and enhance the reliability of space missions. This case is a stark reminder of the importance of meticulous attention to detail in designing and operating complex technological systems and the critical need for human factors design throughout the entire mission lifecycle. Employing interaction designers to help design interfaces, systems, and processes at every level could have prevented these issues by ensuring clear documentation, effective communication, robust error-checking mechanisms, and situation awareness interfaces that highlight critical contextual information.
Case Study: The Boeing 737 Max MCAS
A notable recent example of fatal aeronautical accidents attributed to user interface problems is the two crashes involving the Boeing 737 MAX aircraft in 2018 and 2019. Specifically, the crashes of Lion Air Flight 610 on October 29, 2018, and Ethiopian Airlines Flight 302 on March 10, 2019, were linked to issues with the Maneuvering Characteristics Augmentation System (MCAS).
The MCAS was designed to automatically correct the aircraft’s nose position if it sensed that the plane was climbing too steeply, potentially causing a stall. However, the system relied on a single angle of attack sensor, which, if malfunctioned, could trigger MCAS erroneously. This led to repeated, uncommanded nose-down movements that the pilots struggled to counteract and the failure of the interfaces to provide adequate situation awareness.
A critical aspect of the problem was the need for more training and information regarding MCAS provided to pilots. The system was not sufficiently documented, and the user interface did not indicate when MCAS was active, leaving pilots confused during emergencies. This shocking failure of design for situation awareness on the pilot’s dashboard and the lack of clear communication and training on the new system’s operation were the most significant factors contributing to the crashes. A lack of robust interaction design led to the tragic loss of 346 lives and the subsequent global grounding of the Boeing 737 MAX fleet.
More robust attention to HFE and IxD could have significantly mitigated or even prevented the Boeing 737 MAX accidents by ensuring that pilots were fully aware of and adequately trained on the MCAS system. More explicit, intuitive user interfaces would have provided pilots real-time feedback on the system’s status and actions, reducing confusion during critical moments. Enhanced alert systems, displaying unambiguous warnings and instructions when MCAS activated, could have helped pilots diagnose and respond to erroneous nose-down commands more effectively. Additionally, comprehensive pilot training programs integrating detailed MCAS behavior simulations would have prepared crews to manage unexpected scenarios confidently.
The aviation industry has achieved remarkable safety standards through a concerted effort in HFE and IxD, meticulously refining user interfaces, pilot training, and operational procedures.
Conclusion
New aerospace systems increasingly require robust HFE and IxD to ensure safety, reliability, and efficiency in complex, high-stakes environments. For instance, the trendy adoption of touchscreens in modern spacecraft highlights a significant oversight in human-centered design principles. Touchscreens, though sleek and modern, become virtually unusable during launch and reentry due to high g-forces and vibrations, and they present challenges in zero gravity, where precise finger control is difficult. These design failures undermine the usability and effectiveness of critical systems, compromising astronaut performance and safety. A more robust approach to IxD and HFE would prioritize physical controls and interfaces designed for the unique conditions of spaceflight, ensuring functionality and ease of use in all operational scenarios. Adhering to human-centered design principles is crucial to developing aerospace systems that genuinely support their users rather than imposing additional challenges.
Poorly designed software costs aerospace companies significant time, money, and safety, leading to mission delays, increased expenses, and heightened risks for crew and equipment. The crash of the Mars Climate Orbiter is just one example of years of work and hundreds of millions of dollars lost to preventable interaction design failures. The Boeing 737 Max MCAS disasters are a stark reminder of the potential human costs of design failures.
Human factors engineering and interaction design are essential for developing effective human-machine interfaces in aerospace systems. Their combined efforts ensure that the interfaces are visually appealing and easy to use but also safe, efficient, and supportive of optimal human performance. Aesthetics in interface design are more about cognitive engineering than surface-level attractiveness. While these disciplines are often overlooked due to various challenges, recognizing their critical role can lead to more robust, user-friendly, and safer aerospace systems. As the industry continues to recognize the importance of the human operator, there needs to be an increasing emphasis on integrating these disciplines into the design and development process from the beginning, as well as continuing testing and validation throughout the project lifecycle.
Sources
The Failures of the Mars Climate Orbiter and Mars Polar Lander: A Perspective From the People Involved. February 4, 2001. Edward A Euler and Steven D. Jolly, Lockheed Martin Astronautics Operations. H. H. “Lad” Curtis, ITN Engery Systems.
https://web.mit.edu/16.070/www/readings/Failures_MCO_MPL.pdf
Human Factors & Aviation Safety Testimony to the United States House of Representatives Hearing on Boeing 737-Max8 Crashes — December 11, 2019 Mica R. Endsley, PhD — Human Factors and Ergonomics Society.
https://democrats-transportation.house.gov/imo/media/doc/Endsley Testimony.pdf
