The Space Shuttle Columbia Failure

During the early morning hours of February 1, 2003, many people across the Southwestern United States awoke to a loud noise, sounding like the boom associ- ated with supersonic aircraft. This was the space shuttle Columbia breaking up during

Chapter 1 Introduction 13

reentry to the earth’s atmosphere. This accident was the second loss of a space shut- tle in 113 fl ights—all seven astronauts aboard the Columbia were killed—and pieces of the shuttle were scattered over a wide area of eastern Texas and western Louisiana. Over 84,000 individual pieces were eventually recovered, comprising only about 38% of the shuttle.

This was the 28th mission fl own by the Columbia, a 16-day mission involving many tasks. The fi rst indication of trouble during reentry came when temperature sensors near the left wheel well indicated a rise in temperature. Soon, hydraulic lines on the left side of the craft began to fail, making it diffi cult to keep control of the vehicle. Finally, it was impossible for the pilots to maintain the proper position- ing of the shuttle during reentry—the Columbia went out of control and broke up.

The bottom of the space shuttle is covered with ceramic tiles designed to dissi- pate the intense heat generated during reentry from space. The destruction of the Columbia was attributed to damage to tiles on the leading edge of the left wing. During liftoff, a piece of insulating foam on the external fuel tank dislodged and

Explosion of the space shuttle Challenger soon after liftoff in January 1986. NASA/ Johnson Space Center

14 1.8 Case Studies

struck the shuttle. It was estimated that this foam struck the shuttle wing at over 500 miles per hour, causing signifi cant damage to the tiles on the wing over an area of approximately 650 cm2. With the integrity of these tiles compromised, the wing structure was susceptible to extreme heating during reentry and ultimately failed.

Shuttle launches are closely observed by numerous video cameras. During this launch, the foam separation and strike had been observed. Much thought was given during Columbia ’s mission to attempting to determine whether signifi cant damage had occurred. For example, there was some discussion of trying to use ground- based telescopes to look at the bottom of the shuttle while in orbit. Unfortunately, even if it had been possible to observe the damage, there would have been no way to repair the damage in space. The only alternatives would have been to attempt to launch another shuttle on a dangerous rescue mission, or attempt to get the astro- nauts to the space station in the hopes of launching a later rescue mission to bring them back to earth. In the end, NASA decided that the damage from the foam strike had probably not been signifi cant and decided to continue with the mission and reentry as planned.

This was not the fi rst time that foam had detached from the fuel tank during launch, and it was not the fi rst time that foam had struck the shuttle. Apparently numerous small pieces of foam hit the shuttle during every launch, and on at least seven occasions previous to the Columbia launch, large pieces of foam had detached and hit the shuttle. Solutions to the problem had been proposed over the years, but none had been implemented. Although NASA engineers initially identifi ed foam strikes as a major safety concern for the shuttle, after many launches with no safety problems due to the foam, NASA management became complacent and overlooked the potential for foam to cause major problems. In essence, the prevailing attitude suggested that if there had been numerous launches with foam strikes before, with none leading to major accidents, then it must be safe to continue launches without fi xing the problem.

In the aftermath of this mishap, an investigative panel was formed to deter- mine the cause of the accident and to make recommendations for the future of the shuttle program. The report of this panel contained information on their fi nd- ings regarding the physical causes of the accident: the detachment of the foam, the damage to the tiles, and the subsequent failure of critical components of the shuttle. More signifi cantly, the report also went into great depth on the cultural issues within NASA that led to the accident. The report cited a “broken safety cul- ture” within NASA. Perhaps most damning was the assessment that many of the problems that existed within NASA that led to the Challenger accident sixteen years earlier had not been fi xed. Especially worrisome was the fi nding that schedule pressures had been allowed to supercede good engineering judgment. An acci- dent such as the Challenger explosion should have led to a major change in the safety and ethics culture within NASA. But sadly for the crew of the Columbia, it had not.

After the Columbia accident, the space shuttle was once again grounded until safety concerns related to foam strikes could be addressed. By 2005, NASA was con- fi dent that steps had been taken to make the launch of the shuttle safe and once again restarted the launch program. In July of 2005, Discovery was launched. During this launch, another foam strike occurred. This time, NASA was prepared and had planned for means to photographically assess the potential damage to the heat shield, and also planned to allow astronauts to make a space walk to assess the dam- age to the tiles and to make repairs as necessary. The damage from this strike was

Chapter 1 Introduction 15

repaired in space and the shuttle returned to earth safely. Despite the success of the in-orbit repairs, NASA again grounded the shuttle fl eet until a redesign of the foam could be implemented. The redesign called for removal of foam from areas where foam detachment could have the greatest impact on tiles. The shuttle resumed fl ight with a successful launch in September of 2006 and no further major accidents through early 2011.

SUMMARY

Engineering ethics is the study of moral decisions that must be made by engineers in the course of engineering practice. It is important for engineering students to study ethics so that they will be prepared to respond appropriately to ethical chal- lenges during their careers. Often, the correct answer to an ethical problem will not be obvious and will require some analysis using ethical theories. The types of prob- lems that we will encounter in studying engineering ethics are very similar to the design problems that engineers work on every day. As in design, there will not be a single correct answer. Rather, engineering ethics problems will have multiple cor- rect solutions, with some solutions being better than others.

REFERENCES

Roger Boisjoly , “The Challenger Disaster: Moral Responsibility and the Working Engineer,” in Deborah G. Johnson, Ethical Issues in Engineering, Prentice Hall, Upper Saddle River, NJ, 1991 , pp. 6–14.

Norbert Elliot , Eric Katz , and Robert Lynch , “The Challenger Tragedy: A Case Study in Organizational Communication and Professional Ethics,” Business and Professional Ethics Journal, vol. 12, 1990 , pp. 91–108.

Joseph R. Herkert , “Management’s Hat Trick: Misuse of ‘Engineering Judgment’ in the Challenger Incident,” Journal of Business Ethics, vol. 10, 1991 , pp. 617–620.

Patricia H. Werhane , “Engineers and Management: The Challenge of the Challenger Incident,” Journal of Business Ethics, vol. 10, 1991 , pp. 605–616.

Russell Boisjoly , Ellen Foster Curtis , and Eugene Mellican , “Roger Boisjoly and the Challenger Disaster: The Ethical Dimensions,” Journal of Business Ethics, vol. 8, 1989 , pp. 217–230.

David E. Sanger , “Loss of the Shuttle: The Overview; Shuttle Breaks Up, Seven Dead,” February 2, 2003 , Section 1, p. 1. Numerous other articles can be found in The New York Times on February 2, 2003 and subsequent days or in any local U.S. newspaper.

Columbia Accident Investigation Board , Information on the investigation including links to the fi nal report can be found at the board’s website, caib. nasa.gov, or on the NASA website, www.nasa.gov .

16 Problems

PROBLEMS

1.1 How different are personal ethics and professional ethics? Have you found this difference to be signifi cant in your experience?

1.2 What are the roots of your personal ethics? Discuss this question with a friend and compare your answers.

1.3 Engineering design generally involves fi ve steps: developing a statement of the problem and/or a set of specifi cations, gathering information pertinent to the problem, designing several alternatives that meet the specifi cations, analyzing the alternatives and selecting the best one, and testing and imple- menting the best design. How is ethical problem solving like this?

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