From Space, Down to Earth Nigel J. Packham, Ph.D. Associate Director, Safety and Mission Assurance NASA, Johnson Space Center Houston, Texas 1

The Final Flight Mission STS-135 2

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The Debris Field from the Columbia Accident was 400 miles long and 10 miles wide

Is it Safe? Is it Safe? Space Shuttle Columbia break-up during entry BP/Transocean Deepwater Horizon explosion on April 20th, 2010, resulting in the loss of eleven crewmembers Space Shuttle Columbia break-up during entry on February 3rd, 2003, resulting in the loss of all seven crewmembers

Is it Safe? Is it Safe? Space Shuttle Columbia break-up during entry United Airlines Flight 232 Incident, Sioux City, Iowa (registration N1819U) July 19th 1989. 185 Survivors; 111 Fatalities Space Shuttle Columbia break-up during entry on February 3rd, 2003, resulting in the loss of all seven crewmembers

Is it Safe? Is it Safe? Space Shuttle Columbia break-up during entry on February 3rd, 2003, resulting in the loss of all seven crewmembers Union Carbide India Limited Pesticide Plant, Bhopal, Madhya Pradesh, India, December 2nd, 1984. 40 tons of methyl isocyanate release, resulting in (estimated) 25,000 fatalities

“Is it Safe?”

A Real Life Scenario A critical circulation pump in a thermal control system is malfunctioning Required to deliver 1.5 Liters/min @ 950 mmHg Delivering 0.75 Liters/min @ 175 mmHg Thermal Control Systems Engineer asks several questions How long has this been going on – what’s the pumps history? Gradual decline over several months What does the real-time X-Ray show? Shows potential leakage around inlet and outlet valve seals What is the effect on downstream systems Lower cooling capacity in the system; could reach critical point in 6 months at present rate of decay, leading to shutdown of life support systems

These are all Risk versus Risk Trades A Path Forward What are the options? Remove and replace the pump Pump no longer manufactured; will take 12 months and $5 Million to build a new one from scratch Remove and replace the valve seals Assumes seal integrity is the contributing factor Can an astronaut be trained to perform the procedure in zero-G? Do nothing to the pump; provide secondary cooling to the life support system until replacement pump can be manufactured Secondary cooling system is available on-orbit Relatively simple operation Astronaut is on orbit that has experience with this pump Refresher training available by “Just-in-Time” training Do nothing Space Station life has already exceeded expectations Evacuate and terminate Program These are all Risk versus Risk Trades

The Medical Equivalent 82 year-old male Patient presents with symptoms of circulatory problems Hypotensive Physician asks several questions How long has this been going on – what’s the patient’s history? What other symptoms are associated with the potential diagnosis? What diagnostic tools are available? ECG?, Angiography?

These are all Risk versus Risk Trades A Path Forward What are the options? Option A Option B Option C Do nothing These are all Risk versus Risk Trades

“Is it Safe?” Is that really the right question? “Prove to me that it’s unsafe” versus “Prove to me that it is safe” Management of risk is the key Know what the risk is Identify the cause(s) Determine the likelihood (probability) and the consequence(s) (loss of life, mission, $’s) if the event were to happen Mitigate the risk wherever possible Accept any residual risk Who accepts that residual risk?

The Shuttle Risk At the time of the first Shuttle flight (1981), estimated risk to loss of crew (LOC) was calculated at between 1:1,000 to 1:10,000 Based on tools available at the time

The “Real” Shuttle Risk 1:17 1:90 Flight Sequence # Probability 1:10 0.02 0.04 0.06 0.08 0.1 0.12 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 1 STS-1 STS-51L, STS-26 and STS-29 STS-49 STS-133 STS-41B STS-77 1:38 1:21 STS-86 STS-89 1:47 STS-110 STS-114 1:36 1:37 1:73 STS-103 1:12 STS-5 Wiggins Analysis (1:1000 to 1:10000) (1:1000 to 1:10000)

The Shuttle Risk At the time of the first Shuttle flight (1981), estimated risk to loss of crew was calculated at between 1:1,000 to 1:10,000 Based on tools available at the time At the completion of the Shuttle Program (2011) after 135 flights, the modern tools estimated the risk for the first flight at 1:12 Demonstrates that your understanding of risk depends upon the tools and data that you have available at the time

Human Spaceflight Incidents How many fatalities in human spaceflight history have there been? 3 17 21 18 10

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Soyuz 11, 1967 Soyuz TMA-12, 2008

Human Spaceflight Incidents How many fatalities in human spaceflight history have there been? 3 17 21 18 10

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