SPACECRAFT ACCIDENTS: EXAMINING THE PAST, IMPROVING THE FUTURE Overview and Challenger Case Study Bryan Palaszewski working with the Digital Learning Network NASA Glenn Research Center

Introduction Why discuss this subject? Past failures Learning from those failures Observations

Why Discuss This Subject? Many failures have occurred in large space projects, as well as all very complex projects. Learning from our mistakes makes us smarter and more efficient, wasting less time and money, as well as possibly saving human lives.

Past Failures (1/4) Early experiments ( ’s) Early big robotic rockets (1950’s and 1960’s) Early human flights (1967, 1971) –Soyuz 1 (1 lost in flight, 1967) –Apollo 1 (3 lost in a ground test, 1967)

Past Failures (2/4) Early human flights (continued) –Soyuz 11 (3 lost during reentry, 1971) More-recent human flights –STS-51L, Challenger (7 persons lost, 1986) –STS-107, Columbia (7 persons lost, 2003)

Past Failures (3/4) Many robotic missions have had accidents or failures –Tracking and Data Relay Satellite (TDRS-1, ground control enabled recovery, 1983) –INTELSAT-VI communication satellite (Space Shuttle Endeavour used for recovery, 1992)

Past Failures (4/4) Many robotic missions have had accidents or failures (continued) –Mars Observer (lost, 1993) –Mars Climate Orbiter (lost, 1999) –Mars Polar Lander (crashed, 1999) With each accident, an investigation is conducted to find the reason(s) for the failure. Often there is a chain of incidents rather than just one cause.

Learning From Those Failures (1/2) If a failure occurs, a major investigation committee is typically formed to find the cause. –Causes are identified (as with a detective) and solutions are suggested.

Learning From Those Failures (2/2) Sharing information is critical to success. –Databases are created to teach those who follow what went wrong and how to prevent similar accidents in the future. –Investigation committee reports are part of the information gathering and sharing.

Observations Communication is key to all successes. –Teams must understand one another to succeed. Sharing information is critical to success. “Teaching by doing” is important. –Hands-on work is very important.

Example Case Study STS-51L, Challenger Accident, January 28, 1986

Dark smoke from SRB leak

Accident Cause (1/2) Launched while Solid Rocket Booster (SRB) was at a low temperature (about 32 degrees F) At this low temperature, the rubber O-rings in the SRB were less soft and allowed escape of the hot gases from the booster (6000 degrees F).

Accident Cause (2/2) A hot plume of gas was created, weakening the SRB metal attachments to the rest of the Shuttle. Finally, the SRB broke the External Tank, which led to the destruction of the Space Shuttle.

Results of the Accident (1/5) A Presidential Commission, including Neil Armstrong and Sally Ride, was formed to investigate the accident. The Space Shuttle was grounded for 32 months. Improvements were made to increase the sealing ability of the field joints where the leak of hot gases occurred.

Results of the Accident (2/5) Heaters were added to the field joints to keep them warm. And, many other improvements were made including: –Crew escape procedures –No commercial satellite flights –No civilians without specialized career astronaut training. For many years, safer and higher reliability flights occurred.

Results of the Accident (3/5) Many people lost their NASA positions including: –Lawrence B. Mulloy – project manager of the Solid Rocket Booster program at NASA Marshall Space Flight Center, Huntsville, Alabama –William R. Lucas, Center Director, NASA Marshall Space Flight Center, Huntsville, Alabama –William R. Graham, acting NASA Administrator, Washington, DC

Results of the Accident (4/5) At Morton Thiokol, a private engineering firm, there were other effects: –Safety improvements were analyzed and created. –Many large-scale tests of the new SRB were conducted. –Roger Boisjoly, a program manager working on the SRB, had many problems (both mental and physical).

Results of the Accident (5/5) Many other effects were noted throughout NASA: –Reductions of advanced propulsion research until safe flight was achieved. –Focus on near-term operational activities rather than more advanced thinking.

Thoughts of Roger Boisjoly (Morton Thiokol, 1/2) The bench tests showed that temperature can adversely affect the resiliency and, therefore, the effectiveness of the O-rings. Yet management at Thiokol and NASA showed no interest in planning a design change.

Thoughts of Roger Boisjoly (Morton Thiokol, 2/2) What general courses of action are reasonable for an engineer in this or a similar situation? –Consult personal advisors. –Gather knowledge of the problem. –Perform more experiments. –Consult peers at work. –Take concerns to a supervisor. –Write memos far up the corporate ladder. –Contact a professional society.

With advanced propulsion, one must always look to the past and look to the future.