CHALLENGER DISASTER : CASE STUDY – TO BE Samiul A. Chowdhury [2021298272] mac151830@utdallas.edu EMSE-6361 Fall-2015 Dr. Lawrence Chung Term paper – Final http://www.utdallas.edu/~mac151830/emse6361

Recap Space Shuttle Challenger was second reusable orbiter of NASA's space shuttle program Challenger Broke apart 73 seconds into its flight and exploded in midair Which led the deaths of its all seven crew members

Organizations Involved Marshall Space Flight Center was in charge of booster rocket development Morton Thiokol - Contracted by NASA to build the Solid Rocket Booster The shuttle was built by Rockwell International's Space Transportation Systems Division

Root Cause Direct cause of the explosion was technical – faulty design of the SRB, insufficient low temperature testing of the O-ring material that the O-ring sealed Indirect cause: NASA's decision-making processes and lack of communication between different levels of NASA management had been key contributing factors to the accident. The unrealistically optimistic launch schedule also possible contributing cause to the accident

Solution Analysis RECOMMENDATIONS: Solid Rocket Booster Design: Evaluated several design alternatives and analysis Determine the preferred approaches which minimize hardware redesign. Also develop concept definition, a new design which does not utilize existing hardware. Independent Oversight: Established a near-term plan that includes briefings and visits to review inflight loads; assembly processing; redesign status.

Solution Analysis Cont. Shuttle Management Structure: Study every aspect of how NASA manages its programs, including relationships between various field centers and NASA Headquarters. In addition, roles and responsibilities at all levels of program management will be reviewed to specify the relationship between the program organization and the field center organizations. Flight Rate: Reduce flight rate to meet realistic launch schedule Critical Item Review and Hazard Analysis: All Criticality 1 and 1R critical item waivers have been cancelled. Reassess and resubmit waivers in categories recommended for applicability.

Solution Analysis Cont. Improved Communications: Implementation of effective management communications at all levels. Conduct of Flight Readiness Review and Mission Management Team meetings, including requirements for documentation and flight crew participation. . Maintenance Safeguards: Hardware inspections and schedules, Planned maintenance activities, Maintenance procedures configuration control, and Maintenance logistics.

Class Diagram

Problem Interdependency Graph

Softgoal Interdependency Graph

Through the eyes of the Reference Model P = Program D = Domain W R P M S = Specification S R = Requirements C = Computer S, D ⊭ R and P, C ⊭ S Domain failed to collaborate Critically-1 component excluded from specification Requirements were not satisfied Design error was present in the Machine Implementation not satisfied according to specification

Avoid myth of perfect engineering practice The only way to have a perfect system is to have perfect humans design and operate the systems. That is not possible. So failures will happen. ‐ Dr. Lawrence Chung

References Engineering Ethics: The Challenger Disaster [https://www.cedengineering.com/userfiles/ethics_challenger_disaster_2283.pdf] http://ethics.tamu.edu/Portals/3/Case%20Studies/Shuttle.pdf https://en.wikipedia.org/wiki/Space_Shuttle_Challenger https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster http://pirate.shu.edu/~mckenndo/pdfs/The%20Space%20Shuttle%20Challenger%20Disaster.pdf http://softwarephysics.blogspot.com/2014/07/new-introduction-to-softwarephysics.html

Thank You