1.3.      The Example of Lunar Habitat Design

A second argument for understanding design as a process of interpretation is presented in Chapter 3. Here, a protocol analysis of designers collaborating shows that most of what went on was interpretation.

As part of the research for this dissertation, a study was undertaken of lunar habitat design. Lunar habitat design is a task that is not well understood compared to many other, more mundane design tasks. It is not a routine matter that can be done according to well-formulated rules or by applying available template solutions. Furthermore, it is representative of a broad range of high-tech design tasks. Such tasks typically involve extensive technical knowledge. They seem to call for computer support.

The volume of information available to people is increasing rapidly. For many professionals this “information overload” means that the execution of their jobs requires taking into account far more information than they can possibly keep in mind. The lunar habitat designers here provide a prime illustration of such professionals. In working on their high-tech design tasks, they must take into account architectural knowledge, ergonomics, space science, NASA regulations, and lessons learned in past lunar missions. These designers turn to computers for help with their complex, technical problems. That is why a group of lunar habitat designers initiated the software development effort that led to this dissertation.

Providing the computer support needed by lunar habitat designers is not straight-forward. Designers need to be able to consider wide varieties of experience, professional know-how, technical concerns, and previous solutions that are relevant to their current tasks. However, the problem is not so much one of storing large amounts of information as one of deciding what information to retain that might be relevant to novel future tasks and how to present it to designers in formats that support their mode of work. It is a problem of how to manage the information and present it so that it can usefully serve the design process. The necessary decisions must be made by the designers who are involved with these tasks. Computer techniques for capture and display of information must be under the control of people engaged in the interpretation of the information.

As part of the effort at developing computer support for lunar habitat designers, thirty hours of design sessions were videotaped and analyzed. The designers were asked to design a 23 foot long by 14 foot wide cylindrical habitat to accommodate four astronauts for 45 days on the moon. A protocol analysis of segments of the video recording was conducted.

The analysis of the videotape of the designers’ activities shows that design time is dominated by processes of interpretation, i.e., the explication of previously tacit knowledge in response to discoveries of surprises. As part of the interpreting by the designers, graphical representations were developed for describing pivotal features of the design situation that had not been included in the original specification; perspectives were created for looking at the task in different ways; and language terminology was defined for explicitly naming, describing, and communicating formerly tacit understandings. The definitions of the situated understanding, perspectives, and language continually evolved as part of the design process in an effort to achieve an adequate understanding of the design task and the evolving artifact.

The nature of interpretation and the three dimensions of preunderstanding are illustrated in Chapter 3 with an example from the lunar habitat design sessions. This designing primarily consisted of sketching and discussion that explicated visual and conceptual expressions used for understanding, explaining, and guiding the emerging design. The example analyzed has to do with the tacit notion of privacy and a default perspective on bathroom design related to this notion. The following paragraph briefly summarizes the example.

The designers felt that a careful balance of public and private space would be essential given the long-term isolation in the habitat. This is an important concern that receives limited treatment in official NASA design guidelines. An early design decision proposed that there be private crew compartments for each astronaut. An initial sketch revealed problems with adjacencies of public and private areas, leading to an interpretation of privacy as determining a “gradient” along the habitat from quiet sleep quarters to a public activity area. In the process, the conventional American idea of a bathroom was subjected to critical reflection when it was realized that the placement of the toilet and that of the shower were subject to different sets of constraints based on life in the habitat. The tacit American assumption of the location of the toilet and shower together was made explicit by comparing it to alternative European perspectives. The revised conception permitting a separation of the toilet from the shower facilitated a major design reorganization.

In this way, a traditional conception of “private space” as a place for one person to get away was made explicit and explored within graphical representations of the design situation. As part of the designing process, this concept was revised into a notion of “degrees of privacy”, which facilitated the design process. The failure of the NASA guidelines to provide significant guidance despite a clear recognition by NASA of the importance of habitability and privacy considerations raises the problem of how to represent effectively notions like privacy that are ordinarily tacit. This problem provides the central test case for this dissertation. In Chapter 9, a scenario shows how designers using Hermes can define interpretive critics to evaluate the distribution of public and private spaces in a lunar habitat. A detailed analysis of how these critics are defined in the Hermes language is then presented in Chapter 10.

In this and other examples, the designers needed to revise their representations to enhance their understanding of the problem situation. They went from looking at privacy as a matter of individual space to reconceptualizing the whole interior space as a continuum of private to public areas. The conventional American notion of a bathroom was compared with other cultural models and broken down into separable functions that related differently to habitat usage patterns. The new views resulted from argumentative discussions motivated by design constraints—primarily spatial limitations and psychological factors of confinement. In these discussions, various perspectives were applied to the problem, suggesting new possibilities and considerations. Through discussion, the individual perspectives merged and novel solutions emerged. In the process, previously tacit features of the design became explicit by being named and described in the language that developed. For instance, the fact that quiet activities were being grouped toward one end of the habitat design and interactive ones at the other became a topic of conversation at one point and the terminology of a “privacy gradient” was proposed to clarify this emergent pattern.

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