The PLAID graphics analysis impact on the space program

Jennifer P. Nguyen & Aneice L. WheatonLockheed Engineering & Sciences Company2400 Nasa Road 1, Mail Code C44Houston, Texas 77058(713) 483-3755email NGUYEN@GRAF2 JSC.NASA.GOVJames C. MaidaNASA -Johnson Space CenterMail Code SP34Houston, Texas 77058(713) 483-1113email MAIDA@GRAF6.ISC.NASA.GOVAbstract. An ongoing project design often requires visual verification at various stages. These requirements are criticallyimportant because the subsequent phases of that project might depend on the complete verification of a particular stage.Currently, there are several software packages at the Johnson Space Center 0SC) that provide such simulation capabilities.In this paper, we present the simulation capabilities of the PLAID modeling system used in the Flight Crew Support Divisionfor human factors analyses. We will summarize some ongoing studies in kinematics, lighting, EVA activities and brieflydiscuss various applications in the mission planning of the current Space Shuttle flights and the assembly sequence of theSpace Station Freedom with emphasis on the redesign effort.1. IntroductionA complex engineering project is often divided intoseveral stages. For economic purposes, management musthave the capability to exercise options at the end of each ofthe stages [1], which often includes such decisions as:continue or abandon a project, the modification of design,the re-planning the remaining stages, etc. In order to beable to select these options, two major assessments must beprovided: (i) financial assessment, and (ii) technicalassessment. Financial assessment is the calculation of cashflows for the projects [2]. Technical assessment is theproof of correctness or demonstration of workability [3].The scope of this paper is concentrated on the technicalassessment capability via software simulations, withemphasis on the ongoing projects at NASA Johnson SpaceCenter.There are several techniques used to verify the technicalmerit of a design, and since many of the advanced projectsat JSC are in the designing stages, test bedding is oftenaugmented, prefixed or substituted by computersimulations. The type of simulation testing most often usedis the scenario analysis, which is the testing of a few specialcases. The system discussed here is most often used forscenario analysis in order to perform a quick lookverification of well-known cases, to test and review newideas or designs [1,2] or to analyze contingency cases.There are several software packages that providesimulation capabilities [4,6,7]. In this paper, we present thesimulation capabilities of the PLAID system [4] used in theFlight Crew Support Division.Since 1978, the PLAID system has been used to servemany groups at the NASA Johnson Space Center. Thesegroups include Space and Life Sciences, MissionOperations, Engineering, Space Station Project Office,Astronaut Office, etc. In addition, other NASA centerssuch as Marshall Space Flight Center, Goddard SpaceFlight Center, and Ames Research Center have also madeuse of the system.These groups have primarily used the system forengineering analyses, visualization of designs, and, onoccasion, public relations pictures of NASA high-techprojects. The PLAID system has successfully fulfiUed theseobjectives by serving as a computer aided engineering toolto provide rapid, economical mission support; to developand apply unique, state of the art, computerized HumanModeling; and to perform system engineering analyses tooptimize crew station design, development, and operation.2. Facilities DescriptionThe PLAID system is a three dimensional computermodeling system, which enables the creation of thegeometry and kinematics of humans, as well as theirenvironments.Figure 2.1 depicts basic components of PLAID.Figure 2.1. Basic Components of PLAID2.1 Hardware Components. The system currentlyuses a local area network (Ethemet) of Silicon Graphics Irisworkstations (IRIS) TM and personal computers, withconnectivity to a network of DEC VAX computers. Theworkstations axe high performance machines with hardwaregraphics rendering capabilities such as smooth shading, Zbuffering and texture mapping. The other machines supportimage conversions for documentation purposes, as well asgeometry and bitmap conversions for building, exportingand importing of models and images.Copyright (C) 1993 by the Authors.468All Rights Reserved.