IDE spatio-temporal impact fluxes and high time-resolution studies of multi-impact events and long-lived debris clouds

The purpose of the Interplanetary Dust Experiment (IDE) on the Long Duration Exposure Facility (LDEF) was to sample the cosmic dust environment and to use the spatio-temporal aspect of the experiment to distinguish between the various components of the environment: zodiacal cloud, beta meteoroids, meteor streams, interstellar dust, and orbital debris. It was found that the introduction of precise time and even rudimentary directionality as co-lateral observables in sampling the particulate environment in near-Earth space produces an enormous qualitative improvement in the information content of the impact data. The orbital debris population is extremely clumpy, being dominated by persistent clouds in which the fluxes may rise orders of magnitude above the background. The IDE data suggest a strategy to minimize the damage to sensitive spacecraft components, using the observed characteristics of cloud encounters

Long Duration Exposure Facility (LDEF) attitude measurements of the Interplanetary Dust Experiment

Analysis of the data from the Long Duration Exposure Facility (LDEF) Interplanetary Dust Experiment (IDE) sun sensors has allowed a confirmation of the attitude of LDEF during its first year in orbit. Eight observations of the yaw angle at specific times were made and are tabulated in this paper. These values range from 4.3 to 12.4 deg with maximum uncertainty of plus or minus 2.0 deg and an average of 7.9 deg. No specific measurements of pitch or roll were made but the data indicates that LDEF had an average pitch down attitude of less than 0.7 deg

A Laboratory Experience for Teaching Participatory Design in a Human-Computer Interaction Course

The ability of computer technology to improve productivity and enhance quality of life rests squarely on how well the technology application fits our conceptual understanding of how things work [1]. Left to their own devices, computer programmers take a "systems-centered point of view", concerned about "how the software works and what parts of it do what" [1, p. 217-218]. While it is important for a software product to provide the necessary functionality to perform its intended use, it is also important that this functionality be presented in a manner consistent with the user's understanding. In the area of Human-Computer Interaction (HCI) research, a number of approaches have evolved to meet this challenge. Though they differ in techniques, each find ways to interject the designer in the user's world and the user in the designer's world in order to develop a shared conceptual model of the task and the context in which it is being done The HCI course is structured around the steps in the Contextual Design approach [3]: user interviewing & observation, data modeling & model consolidation, brainstorming, paper prototyping, and usability testing. Contextual design relies on ethnographic techniques from anthropology Two aspects of the redesigned curriculum for the HCI course have focused on students' development of these skills. First, materials and exercises that focus on observation, interview and data interpretation skills are now part of the course. Second, students in the course have the opportunity to use these skills with real potential users of their term long design project. The HCI course solicits potential software users from the introductory computer science courses in an approach similar to the way upper division psychology courses on empirical methods are taught by soliciting voluntary subjects from lower division courses. The use of these volunteers provides members of the design team with data from potential users to develop, validate, and refine their designs. A low cost lab was developed to support team design activities and user interaction. The lab is a split room configuration with a Design Team "War Room" and a User Interaction Room. Page 1 of 3 ASEE Annual Conference 2002 Session Number 1526 The Design War Room is intended for team design and brainstorming sessions. The Design War Room has 3 writing walls and 1 pin-up wall. Teams use a "working-on-the-wall" approach to meetings (See The revised HCI curriculum with the inclusion of ethnographic techniques and the use of the HCI laboratory has increased students' understanding and appreciation of participatory design. In the words of two different students, "this course has made me look at my job in new ways." Over the two semesters of this study, each group completed all stages of the conceptual design process to successfully design a product based on user input. Based on preliminary results of studying long-term attitudes toward design, the approach taken in the revised HCI course seems particularly successful in raising student awareness of the importance of the user as a partner in the design process