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NASA NTRS2009

The Integrated Hazard Analysis Integrator

Hazard analysis addresses hazards that arise in the design, development, manufacturing, construction, facilities, transportation, operations and disposal activities associated with hardware, software, maintenance, operations and environments. An integrated hazard is an event or condition that is caused by or controlled by multiple systems, elements, or subsystems. Integrated hazard analysis (IHA) is especially daunting and ambitious for large, complex systems such as NASA s Constellation program which incorporates program, systems and element components that impact others (International Space Station, public, International Partners, etc.). An appropriate IHA should identify all hazards, causes, controls and verifications used to mitigate the risk of catastrophic loss of crew, vehicle and/or mission. Unfortunately, in the current age of increased technology dependence, there is the tendency to sometimes overlook the necessary and sufficient qualifications of the integrator, that is, the person/team that identifies the parts, analyzes the architectural structure, aligns the analysis with the program plan and then communicates/coordinates with large and small components, each contributing necessary hardware, software and/or information to prevent catastrophic loss. As viewed from both Challenger and Columbia accidents, lack of appropriate communication, management errors and lack of resources dedicated to safety were cited as major contributors to these fatalities. From the accident reports, it would appear that the organizational impact of managers, integrators and safety personnel contributes more significantly to mission success and mission failure than purely technological components. If this is so, then organizations who sincerely desire mission success must put as much effort in selecting managers and integrators as they do when designing the hardware, writing the software code and analyzing competitive proposals. This paper will discuss the necessary and sufficient requirements of one of the significant contributors to mission success, the IHA integrator. Discussions will be provided to describe both the mindset required as well as deleterious assumptions/behaviors to avoid when integrating within a large scale system.

Morris, A. Terry↗
NASA NTRS2009

An Update on Mortality in the U.S. Astronaut Corps: 1959-2009

Although it has now been over 50 years since mankind first ventured into space, the long-term health impacts of human space flight remain largely unknown. Identifying factors that affect survival and prognosis among those who participate in space flight is vitally important, as the era of commercial space flight approaches and NASA prepares for missions to Mars. The Longitudinal Study of Astronaut Health is a prospective study designed to examine trends in astronaut morbidity and mortality. The purpose of this analysis was to describe and explore predictors of overall and cause-specific mortality among individuals selected for the U.S. astronaut corps. All U.S. astronauts (n=321), regardless of flight status, were included in this analysis. Death certificate searches were conducted to ascertain vital status and cause of death through April 2009. Data were collected from medical records and lifestyle questionnaires. Multivariable Cox regression modeling was used to calculate the mortality hazard associated with embarking on space flight, adjusted for sex, race, and age at selection. Between 1959 and 2009, there were 39 (12.1%) deaths. Of these deaths, 18 (42.2%) were due to occupational accidents; 7 (17.9%) were due to other accidents; 6 (15.4%) were attributable to cancer; 6 (15.4%) resulted from cardiovascular/circulatory diseases; and 2 (5.1%) were from other causes. Participation in space flight did not significantly increase mortality hazard over time (adjusted hazard ratio=0.57; 95% confidence interval=0.26-1.26. Because our results are based on a small sample size, future research that includes payload specialists, other space flight participants, and international crew members is warranted to maximize statistical power.

Amirian, E.↗
NASA NTRS2009

NASA Standard for Models and Simulations (M and S): Development Process and Rationale

After the Columbia Accident Investigation Board (CAIB) report. the NASA Administrator at that time chartered an executive team (known as the Diaz Team) to identify the CAIB report elements with Agency-wide applicability, and to develop corrective measures to address each element. This report documents the chronological development and release of an Agency-wide Standard for Models and Simulations (M&S) (NASA Standard 7009) in response to Action #4 from the report, "A Renewed Commitment to Excellence: An Assessment of the NASA Agency-wide Applicability of the Columbia Accident Investigation Board Report, January 30, 2004".

Zang, Thomas A.↗
NASA NTRS2010

Commercial Aircraft Integrated Vehicle Health Management Study

Statistical data and literature from academia, industry, and other government agencies were reviewed and analyzed to establish requirements for fixture work in detection, diagnosis, prognosis, and mitigation for IVHM related hardware and software. Around 15 to 20 percent of commercial aircraft accidents between 1988 and 2003 involved inalftfnctions or failures of some aircraft system or component. Engine and landing gear failures/malfunctions dominate both accidents and incidents. The IVI vl Project research technologies were found to map to the Joint Planning and Development Office's National Research and Development Plan (RDP) as well as the Safety Working Group's National Aviation Safety Strategic. Plan (NASSP). Future directions in Aviation Technology as related to IVHlvl were identified by reviewing papers from three conferences across a five year time span. A total of twenty-one trend groups in propulsion, aeronautics and aircraft categories were compiled. Current and ftiture directions of IVHM related technologies were gathered and classified according to eight categories: measurement and inspection, sensors, sensor management, detection, component and subsystem monitoring, diagnosis, prognosis, and mitigation.

Reveley, Mary S.↗
NASA NTRS2010

Changing the Safety and Mission Assurance (S and MA) Paradigm

This slide presentation reviews the change in the work and impact of the Safety and Mission Assurance directorate at Marshall Space Flight Center. It reviews the background and the reasons given for a strong Safety & Mission Assurance presence in all planning for space flight. This was pointed out by the Rogers Commission Report after the Space Challenger accident, by the Columbia Accident Investigation Board (CAIB) and by a 2006 NASA Exploration Safety Study (NESS) Team. The overall objective of the work in this area was to improve and maintain S&MA expertise and skills. Training for this work was improved and the S&MA organization was reorganized. This has resulted in a paradigm shift for NASA's safety efforts, which is described. The presentation then reviews the impact of the new S&MA work in the Ares I design and development.

Malone, Roy W.↗
NASA NTRS2010

Progress in Development of the Axel Rovers

Progress has been made in the development of a family of robotic land vehicles having modular and minimalist design features chosen to impart a combination of robustness, reliability, and versatility. These vehicles at earlier stages of development were described in two previous NASA Tech Briefs articles: "Reconfigurable Exploratory Robotic Vehicles" (NPO-20944), Vol. 25, No. 7 (July 2001), page 56; and "More About Reconfigurable Exploratory Robotic Vehicles" (NPO-30890), Vol. 33, No. 8 (August 2009), page 40. Conceived for use in exploration of the surfaces of Mars and other remote planets, these vehicles could also be adapted to terrestrial applications, including exploration of volcanic craters or other hostile terrain, military reconnaissance, inspection of hazardous sites, and searching for victims of earthquakes, landslides, avalanches, or mining accidents. In addition, simplified versions of these vehicles might be marketable as toys. The most basic module in this family of reconfigurable robots is the Axel rover, which has a cylindrical body with two main wheels and a trailing link. Inside its body are three motors and associated mechanisms for driving the two wheels and for rotating the link 360 around its symmetrical body. The actuated link serves several purposes: It is used as a lever arm to react to the wheels thrust to move Axel in multiple directions. It is used to rotate the Axel housing in order to tilt, to the desired angle, any sensors and instruments mounted on or in the Axel housing. It provides an alternative mobility mode, which is primarily used in its tethered configuration. Turn ing the link into the ground in lieu of driving the wheels causes the Axel housing and wheels to roll as a unit and thereby leads to a tumbling motion along the ground. With a tether mounted around Axel s cylindrical body, the link serves as a winch mechanism to reel and unreel the tether raising and lowering Axel over steep and vertical surfaces (Figure 1). Sensors, computation, and communication modules are also housed inside Axel s body. A pair of stereo vision cameras provides three-dimensional view for autonomous navigation and avoiding obstacles. Inertial sensors determine the tilt of the robot and are used for estimating its motion. In a fully developed version, power would be supplied by rechargeable batteries aboard Axel; at the time of reporting the information for this article, power was supplied from an external source via a cable. In and of itself, the Axel rover is fully capable of traversing and sampling terrains on planetary surfaces. By use of only the two main wheel actuators and the caster link actuator, Axel can be made to follow an arbitrary path, turn in place, and operate upside- down or right-side-up. If operated in a tethered configuration, as shown in Figure 1, it can be made to move down and up a steep crater wall, descend from an overhang to a cave, and ascend from the cave back to the overhang, all by use of the same three actuators. Such tethered operation could be useful in searching for accident victims or missing persons in mines, caves, and rubble piles. Running the tether through the caster link enhances the stability of Axel and provides a restoring force that keeps the link off the ground for the most part during operation on a steep slope. In its extended configuration, two Axel modules can dock to either side of a payload module to form the four wheeled Axel2 rover (Figure 2). Additional payload and Axel modules can dock to either side of the Axel2 to form the Axel3 rover, extending its payload capacity and its mobility capabilities.

Nesnas, Issa A.↗
NASA NTRS2010

NASA Contingency Shuttle Crew Support (CSCS) Medical Operations

The genesis of the space shuttle began in the 1930's when Eugene Sanger came up with the idea of a recyclable rocket plane that could carry a crew of people. The very first Shuttle to enter space was the Shuttle "Columbia" which launched on April 12 of 1981. Not only was "Columbia" the first Shuttle to be launched, but was also the first to utilize solid fuel rockets for U.S. manned flight. The primary objectives given to "Columbia" were to check out the overall Shuttle system, accomplish a safe ascent into orbit, and to return back to earth for a safe landing. Subsequent to its first flight Columbia flew 27 more missions but on February 1st, 2003 after a highly successful 16 day mission, the Columbia, STS-107 mission, ended in tragedy. With all Shuttle flight successes come failures such as the fatal in-flight accident of STS 107. As a result of the STS 107 accident, and other close-calls, the NASA Space Shuttle Program developed contingency procedures for a rescue mission by another Shuttle if an on-orbit repair was not possible. A rescue mission would be considered for a situation where a Shuttle and the crew were not in immediate danger, but, was unable to return to Earth or land safely. For Shuttle missions to the International Space Station (ISS), plans were developed so the Shuttle crew would remain on board ISS for an extended period of time until rescued by a "rescue" Shuttle. The damaged Shuttle would subsequently be de-orbited unmanned. During the period when the ISS Crew and Shuttle crew are on board simultaneously multiple issues would need to be worked including, but not limited to: crew diet, exercise, psychological support, workload, and ground contingency support

Adams, Adrien↗
NASA NTRS2010

Checklists and Monitoring in the Cockpit: Why Crucial Defenses Sometimes Fail

Checklists and monitoring are two essential defenses against equipment failures and pilot errors. Problems with checklist use and pilots failures to monitor adequately have a long history in aviation accidents. This study was conducted to explore why checklists and monitoring sometimes fail to catch errors and equipment malfunctions as intended. Flight crew procedures were observed from the cockpit jumpseat during normal airline operations in order to: 1) collect data on monitoring and checklist use in cockpit operations in typical flight conditions; 2) provide a plausible cognitive account of why deviations from formal checklist and monitoring procedures sometimes occur; 3) lay a foundation for identifying ways to reduce vulnerability to inadvertent checklist and monitoring errors; 4) compare checklist and monitoring execution in normal flights with performance issues uncovered in accident investigations; and 5) suggest ways to improve the effectiveness of checklists and monitoring. Cognitive explanations for deviations from prescribed procedures are provided, along with suggestions for countermeasures for vulnerability to error.

Dismukes, R. Key↗
NASA NTRS2009

The Reconstruction and Failure Analysis of the Space Shuttle Columbia

Several days following the Columbia accident a team formed and began planning for the reconstruction of Columbia. A hangar at the Kennedy Space Center was selected for this effort due to it's size, available technical workforce and materials science laboratories and access to the vehicle ground processing infrastructure. The Reconstruction team established processes for receiving, handling, decontamination, tracking, identifying, cleaning and assessment of the debris. Initially, a 2-dimensional reconstruction of the Orbiter outer mold line was developed. As the investigation progressed fixtures which allowed a 3-dimensional reconstruction of the forward portions of the left wing's leading edge was developed. To support the reconstructions and forensic analyses a Materials and Processes (M&P) 'team was formed. This M&P team established processes for recording factual observations, debris cleaning, and engineering analysis. Fracture surfaces and thermal effects of selected airframe debris were assessed, and process flows for both nondestructive and destructive sampling and evaluation of debris were developed. The Team also assessed left hand airframe components that were believed to be associated with a structural breach of Columbia. A major portion of this analysis was evaluation of metallic deposits were prevalent on left wing leading edge components. Extensive evaluation of the visual, metallurgical and chemical nature of the deposits provided conclusions that were consistent with the visual assessments and interpretations of the NASA lead teams and the findings of the Columbia Accident Investigation Board. Analytical data collected by the M&P Team showed that a significant thermal event occurred at the left wing leading edge in the proximity of LH RCC Panels 8-9, and a correlation was formed between the deposits and overheating in these areas to the wing leading edge components. The analysis of deposits also showed exposure to temperatures in excess of 1649 C (3200 F), which would severely degrade support structure, tiles, and RCC panel materials. The integrated failure analysis of wing leading edge debris and deposits strongly supported the hypothesis that a breach occurred at LH RCC Panel 8.

Russell, Richard↗
NASA NTRS2011

Space Shuttle Propulsion Finishing Strong

Numerous lessons have been documented from the Space Shuttle Propulsion elements. Major events include loss of the SRB's on STS-4 and shutdown of an SSME during ascent on STS- 51F. On STS-112 only half the pyrotechnics fired to release the vehicle from the launch pad, a testament for redundancy. STS-91 exhibited freezing of a main combustion chamber pressure measurement and on STS-93 nozzle tube ruptures necessitated a low liquid level oxygen cut off of the main engines. A number of on pad aborts were experienced during the early program resulting in delays. And the two accidents, STS-51L and STS-107, had unique heritage in history from early Program decisions and vehicle configuration. Following STS-51L significant resources were invested in developing fundamental physical understanding of solid rocket motor environments and material system behavior. Human rating of solid rocket motors was truly achieved. And following STS-107, the risk of ascent debris was better characterized and controlled. Situational awareness during all mission phases improved, and the management team instituted effective risk assessment practices. These major events and lessons for the future are discussed. The last 22 flights of the Space Shuttle, following the Columbia accident, were characterized by remarkable improvement in safety and reliability. Numerous problems were solved in addition to reduction of the ascent debris hazard. The propulsion system elements evolved to high reliability and heavy lift capability. The Shuttle system, though not a operable as envisioned in the 1970's, successfully assembled the International Space Station (ISS) and provided significant logistics and down mass for ISS operations. By the end of the Program, the remarkable Space Shuttle Propulsion system achieved very high performance, was largely reusable, exhibited high reliability, and is a heavy lift earth to orbit propulsion system. The story of this amazing system is discussed in detail in the paper.

Owen, James W.↗
NASA NTRS2011

The Psychology of Safety

Many studies of mishaps show that human error is a factor in a significant majority of accidents. Trying to decide how to change human behavior to be safer is generally the biggest challenge of any safety program. However, understanding the human psyche is the first step to changing behavior. Many studies focus on the before and after of an accident, but what about the thoughts of a person in the commission of an unsafe act? This is a less understood area. Examining it reveals why it is not well comprehended. This paper attempts to examine a part of the thought process, with an eye to helping influence people to less hurtful actions.

Anderson, Brenda Lindley↗
NASA NTRS2011

Shuttle Program Loads Integration: Going From Concept to Operations and Staying Successful

From the beginning of the Shuttle Program to its end, integrated loads and dynamics analyses and tests have been critical in shaping the vehicle design and operational decisions for NASA and its customers. Starting with scaled models and simple mathematical simulations of the structural dynamics, engineers defined the required structural stiffness and predicted the limit loads for each element of the system. Early structural tests provided reasonable confidence that the models and predictions were good. The first launch of the Space Shuttle brought surprises, though, when the ignition overpressure event caused a forward fuel tank support strut to buckle, among several unexpected effects. The launch pad and other ground equipment became an integral part of the system integration, especially where the acoustic and pressure environments of ignition and lift-off were concerned. Following the Challenger accident, operating limits were changed in response to new understandings of how the integrated system performed. Controlling loads while maximizing performance was a key tenet of the Performance Enhancement design process, which enabled construction of the International Space Station. During the return to flight after the Columbia accident, engineers grew to understand that loads during the roll maneuver were also important to the vehicle s structural margin and life. At this point the crawler transport from the Vehicle Assembly Building to the launch pad also became a part of the integrated loads analysis. Even in the last years of the Space Shuttle Program, new data still provided interesting insights into this complicated and fascinating spaceship. This paper will present some examples of the important findings by the team of specialists that supported the Integrated Loads and Dynamics Panel for the Space Shuttle Program.

Bernstein, Karen↗
NASA NTRS2011

Origins of Protein Functions in Cells

In modern organisms proteins perform a majority of cellular functions, such as chemical catalysis, energy transduction and transport of material across cell walls. Although great strides have been made towards understanding protein evolution, a meaningful extrapolation from contemporary proteins to their earliest ancestors is virtually impossible. In an alternative approach, the origin of water-soluble proteins was probed through the synthesis and in vitro evolution of very large libraries of random amino acid sequences. In combination with computer modeling and simulations, these experiments allow us to address a number of fundamental questions about the origins of proteins. Can functionality emerge from random sequences of proteins? How did the initial repertoire of functional proteins diversify to facilitate new functions? Did this diversification proceed primarily through drawing novel functionalities from random sequences or through evolution of already existing proto-enzymes? Did protein evolution start from a pool of proteins defined by a frozen accident and other collections of proteins could start a different evolutionary pathway? Although we do not have definitive answers to these questions yet, important clues have been uncovered. In one example (Keefe and Szostak, 2001), novel ATP binding proteins were identified that appear to be unrelated in both sequence and structure to any known ATP binding proteins. One of these proteins was subsequently redesigned computationally to bind GTP through introducing several mutations that introduce targeted structural changes to the protein, improve its binding to guanine and prevent water from accessing the active center. This study facilitates further investigations of individual evolutionary steps that lead to a change of function in primordial proteins. In a second study (Seelig and Szostak, 2007), novel enzymes were generated that can join two pieces of RNA in a reaction for which no natural enzymes are known. Recently it was found that, as in the previous case, the proteins have a structure unknown among modern enzymes. In this case, in vitro evolution started from a small, non-enzymatic protein. A similar selection process initiated from a library of random polypeptides is in progress. These results not only allow for estimating the occurrence of function in random protein assemblies but also provide evidence for the possibility of alternative protein worlds. Extant proteins might simply represent a frozen accident in the world of possible proteins. Alternative collections of proteins, even with similar functions, could originate alternative evolutionary paths.

Seelig, Burchard↗
NASA NTRS2011

Reliability and Maintainability Engineering - A Major Driver for Safety and Affordability

The United States National Aeronautics and Space Administration (NASA) is in the midst of an effort to design and build a safe and affordable heavy lift vehicle to go to the moon and beyond. To achieve that, NASA is seeking more innovative and efficient approaches to reduce cost while maintaining an acceptable level of safety and mission success. One area that has the potential to contribute significantly to achieving NASA safety and affordability goals is Reliability and Maintainability (R&M) engineering. Inadequate reliability or failure of critical safety items may directly jeopardize the safety of the user(s) and result in a loss of life. Inadequate reliability of equipment may directly jeopardize mission success. Systems designed to be more reliable (fewer failures) and maintainable (fewer resources needed) can lower the total life cycle cost. The Department of Defense (DOD) and industry experience has shown that optimized and adequate levels of R&M are critical for achieving a high level of safety and mission success, and low sustainment cost. Also, lessons learned from the Space Shuttle program clearly demonstrated the importance of R&M engineering in designing and operating safe and affordable launch systems. The Challenger and Columbia accidents are examples of the severe impact of design unreliability and process induced failures on system safety and mission success. These accidents demonstrated the criticality of reliability engineering in understanding component failure mechanisms and integrated system failures across the system elements interfaces. Experience from the shuttle program also shows that insufficient Reliability, Maintainability, and Supportability (RMS) engineering analyses upfront in the design phase can significantly increase the sustainment cost and, thereby, the total life cycle cost. Emphasis on RMS during the design phase is critical for identifying the design features and characteristics needed for time efficient processing, improved operational availability, and optimized maintenance and logistic support infrastructure. This paper discusses the role of R&M in a program acquisition phase and the potential impact of R&M on safety, mission success, operational availability, and affordability. This includes discussion of the R&M elements that need to be addressed and the R&M analyses that need to be performed in order to support a safe and affordable system design. The paper also provides some lessons learned from the Space Shuttle program on the impact of R&M on safety and affordability.

Safie, Fayssal M.↗
NASA NTRS2011

Shuttle Propulsion System Major Events and the Final 22 Flights

Numerous lessons have been documented from the Space Shuttle Propulsion elements. Major events include loss of the Solid Rocket Boosters (SRB's) on STS-4 and shutdown of a Space Shuttle Main Engine (SSME) during ascent on STS-51F. On STS-112 only half the pyrotechnics fired during release of the vehicle from the launch pad, a testament for redundancy. STS-91 exhibited freezing of a main combustion chamber pressure measurement and on STS-93 nozzle tube ruptures necessitated a low liquid level oxygen cut off of the main engines. A number of on pad aborts were experienced during the early program resulting in delays. And the two accidents, STS-51L and STS-107, had unique heritage in history from early program decisions and vehicle configuration. Following STS-51L significant resources were invested in developing fundamental physical understanding of solid rocket motor environments and material system behavior. And following STS-107, the risk of ascent debris was better characterized and controlled. Situational awareness during all mission phases improved, and the management team instituted effective risk assessment practices. The last 22 flights of the Space Shuttle, following the Columbia accident, were characterized by remarkable improvement in safety and reliability. Numerous problems were solved in addition to reduction of the ascent debris hazard. The Shuttle system, though not as operable as envisioned in the 1970's, successfully assembled the International Space Station (ISS). By the end of the program, the remarkable Space Shuttle Propulsion system achieved very high performance, was largely reusable, exhibited high reliability, and was a heavy lift earth to orbit propulsion system. During the program a number of project management and engineering processes were implemented and improved. Technical performance, schedule accountability, cost control, and risk management were effectively managed and implemented. Award fee contracting was implemented to provide performance incentives. The Certification of Flight Readiness and Mission Management processes became very effective. A key to the success of the propulsion element projects was related to relationships between the MSFC project office and support organizations with their counterpart contractor organizations. The teams worked diligently to understand and satisfy requirements and achieve mission success.

Owen, James W.↗
NASA NTRS2006

Characterization of Deposits on Glass Substrate as a Tool in Failure Analysis: The Orbiter Vehicle Columbia Case Study

In connection with the accident investigation of the space shuttle Columbia, an analysis methodology utilizing well established microscopic and spectroscopic techniques was implemented for evaluating the environment to which the exterior fused silica glass was exposed. Through the implementation of optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, and electron diffraction, details emerged regarding the manner in which a charred metallic deposited layer formed on top of the exposed glass. Due to nature of the substrate and the materials deposited, the methodology proved to allow for a more detailed analysis of the vehicle breakup. By contrast, similar analytical methodologies on metallic substrates have proven to be challenging due to strong potential for error resulting from substrate contamination. This information proved to be valuable to not only those involved in investigating the break up of Columbia, but also provides a potential guide for investigating future high altitude and high energy accidents.

Olivas, J. D.↗
NASA NTRS2012

Aircraft Design Considerations to Meet One Engine Inoperative (OEI) Safety Requirements

Commercial airlines are obligated to operate such that an aircraft can suffer an engine failure at any point in its mission and terminate the flight without an accident. Only minimal aircraft damage is allowable, such as brake replacement due to very heavy application, or an engine inspection and/or possible removal due to use of an emergency rating. Such performance criteria are often referred to as zero exposure, referring to zero accident exposure to an engine failure. The critical mission segment for meeting one engine inoperative (OEI) criteria is takeoff. For a given weight, wind, and ambient condition, fixed wing aircraft require a balanced field length. This is the longer of the distance to take off if an engine fails at a predetermined critical point in the takeoff profile, or the distance to reject the takeoff and brake to a stop. Rotorcraft have requirements for horizontal takeoff procedures that are equivalent to a balanced field length requirements for fixed wing aircraft. Rotorcraft also perform vertical procedures where no runway or heliport distance is available. These were developed primarily for elevated heliports as found on oil rigs or rooftops. They are also used for ground level operations as might be found at heliports at the end of piers or other confined areas.

Scott, Mark W.↗