Aeronautics Degree Program as Enrolled

¶ … Aeronautics degree program as enrolled in by the student who wrote this report. There were several topics looked at for this project including increased visual intraocular pressure and other impairments during human spacefl9ight, the effects on space travel of the increase commercialization of the space programs around the world, the utilization of flight simulators by NASA and the pros and cons therein, the effects of transient vibrations and/or shock loads on spacecraft engines as well as with the structural integrity and the effect of space weather phenomenon such as geomagnetic storms, radiation blasts from the Sun and other radiation-giving bodies on NASA missions and aviation missions around the country in general. Relating to the last of those topics, how the data from the Next Generation Air Transportation System (NGATS), the National Oceanic and Atmospheric Association (NOAA) and the Federal Aviation Administration (FAA) is collected, used, shared, analyzed and parsed is something that is also worthy of review.

Proposal

Comprehensive Question 1

Statement of the question. What is the anticipated effect on space travel if the National Aeronautics and Space Administration (NASA) allowed for the commercialization of space travel and private sector participation in human spaceflight? What are the national security and legal ramifications of dual use of space technology?

Program outcomes addressed by this question.

Outcome 1. The critical thinking competency is addressed as a result of looking at and analyzing the ramifications and implications of NASA moving towards a privatization of space travel logistics and equipment rather than keeping the operations entirely within governmental agencies, as has been the pattern in the past even if some of the equipment came from private sources. The student also looked at the commercial and civilian history of NASA's path, which has led to the United States coming at a major pivot point due to the Shuttle being shuttered permanently with no clear NASA-issued replacement in the works.

Outcome 3. The information literacy competency was satisfied through research avenues and pathways that led to the student reviewing material related to space-related law and policy and it was all collected from scholarly sources. The use of dual-use launch technology was also assessed, as these applications can be used to deploy nuclear weapons as well as other weapons of mass destruction (WMD). An additional review was made as to the effects on the United States' technical, national security and economic infrastructures that have resulted because of the United States using Russia's spacecraft to launch and retrieve astronauts from the International Space Station (ISS).

Outcome 4. The communication competency was be addressed via the materials collected from NASA experiences as well as studies conducted by the Federal Aviation Administration and the influences these studies had on the broad aerospace industry. Lastly, discussions made focused on the future of space travel, human spaceflight and the technologies that encompass them.

Outcome 9. The competency of Aviation Legislation and Law was fulfilled by reviewing the implications that the United States may experience as NASA progresses with the commercialization of the space industry. The national security implications were analyzed through access gained from partner nations building domestic partnerships for economic strengthening through technological interoperability. This discussion also tackled the legislative actions such as proliferation control and arms control regulations essential to the transition into this new era of commercial space travel, and the effects of privatization on national security and space policy.

Comprehensive Question 2

Statement of the question. What are the increased visual impairments/intraocular pressure associated with long-duration spaceflight? How have new inventions such as advanced resistance exercise devices and fundus examinations helped identify, treat or reverse the negative effects of microgravity on astronauts? What are the countermeasures that astronauts have had to take in order to reduce the risks of microgravity induced visual impairments/intraocular pressure?

Program outcomes addressed by this question.

Outcome 1. The Critical Thinking competency was fulfilled by exploring how various new technologies such as photorefractive keratectomy could affect changes in visual acuity experienced in long-term space missions. In addition, the optics and ultrasound testing fields where technology has been successful in building countermeasures to combat these effects on astronaut health was investigated.

Outcome 2. The competency of Quantitative Reasoning was fulfilled with an analysis of visual acuity degradation on charts such as the Visual Induced Impairment/Intracranial Pressure (VIIP) chart created by the NASA Human Research Program, and other research was gathered from reliable ophthalmological studies on the neuro-physical parameters of astronauts.

Outcome 3. The Information Literacy competency was fulfilled through exploring the new advancements in technology. Research was performed by gathering statistical data from NASA flight surgeons that have resources and methods of surveying astronauts on the effects of space on their visual perception during different phases of flight and onboard the International Space Station.

Outcome 4. The Communication competency was fulfilled through analyzing research collected from NASA's Human Research Program and scientific experiments conducted to better assist NASA and the commercial space industry in understanding and combating these long-term effects to the visual system.

Outcome 10. The Aviation Safety competency was fulfilled through an analysis of visual degradation and its effect on aerospace safety. The various countermeasures that were researched included exercises performed by astronauts aboard the space station and genetic markers that give early detention signs of Visual Impairment and Intraocular Pressure (VIIP). A determination was made if the countermeasures have supported astronauts in their space environments.

Comprehensive Question 3.

Statement of the question. Beside monetary savings and safety, what are the pros and cons for utilizing advanced flight simulators in operations and evaluation training for astronauts to pilot spacecraft and perform operations on board the International Space Station? How reliable are these simulators in the rigorous training process and what are the foreseen advances in these technologies?

Program outcomes addressed by this question.

Outcome 1. The Critical Thinking competency was fulfilled by evaluating the use of flight simulators within various aerospace training programs including the space shuttle pre-flight trainers for space shuttle pilots. Further research was made into what approaches are taken by designers to increase simulator fidelity and the implications of cockpit automation on crew performance.

Outcome 3. The Information Literacy competency was fulfilled through the research efforts made by the student gathering applicable data retrieved from the FAA advisory circulars on aircraft simulator qualification. Human factor expert analyses were reviewed on human-centered aircraft automation, its effects on the task handling capabilities of the human operator with the information, and concentration required to monitor and manage the automated systems.

Outcome 4. The Communication competency was fulfilled through research collected from NASA experiments and FAA studies and their influence on simulator fidelity and flight deck automation in the aerospace/aviation industry. Inclusive to those discussions was a focus on recommendations on human factor considerations such as human limitations and what objective standards should define PC-based flight instruction like Microsoft Flight Simulator.

Outcome 6. The Cultural Literacy competency was fulfilled with an investigation of the historical evolution of simulators and cockpit automation. The examination highlights how simulators and cockpit automation have transformed the aviation/aerospace culture. Also, the inquiry focused on how simulators and cockpit automation have affected astronaut training requirements and flight procedures.

Outcome 7. The competency of Life-long Personal Growth was fulfilled through conveying insight, as both a private pilot and future career astronaut, about the benefits of understanding the effects of advanced simulator training on pilots and astronauts. This enhanced knowledge in the topic not only informed the undergraduate student on the aviation safety aspect of this training, but as cockpit automation and simulators evolve becoming more complex and realistic, the student consistently remained updated with training in order to remain current in a lifelong aviation/aerospace career.

Outcome 10. The Aviation Safety competency was fulfilled by researching the positive and negative effects flight simulators and cockpit automation have had on aviation/aerospace safety by reducing astronaut workload. Inclusive to the studies were a systems safety approach through the use of the MIL-STD-882D to explain procedure and training development and designs to minimize risks through simulators.

Comprehensive Question 4.

Statement of the question. What are the effects of shock loads and transient vibrations on engine and structural components of spacecraft/aircraft? How have these issues changed system engineering philosophies and methodologies? What new techniques and devices are being utilized to overcome these forces in order to make structurally sound spacecraft and aircraft? Techniques including Fatigue Damage Spectrum (FDS), Laser Vibrometry for Damage Detection using Lamb Waves and devices such as vibrometers and accelerometers were reviewed thoroughly.

Program outcomes addressed by this question.

Outcome 1. The Critical Thinking competency was fulfilled by examining how the utilization of devices like vibrometers and vibration reduction composite materials have affected structural design of a spacecraft and aircraft. An assessment was made on the various types of composites that are utilized such as aluminum alloys, steel and heat-resistant steel, beryllium, titanium, and composites. In addition, an assessment was made in regards to spaceflight missions where transient shock loads were a major factor in the demise of the spacecraft and flight crew. The student has provided research on various vibration analytic techniques such as the use of Laser Vibrometry for Damage Detection using Lamb Waves in discovery processes to detect microcracks.

Outcome 3. The Information Literacy competency was satisfied through the research efforts made by the student through data gathering regarding aircraft structures and vibrations qualification techniques retrieved from the MIL-STD-810F and NASA Langley Research Laboratory. Techniques include Fatigue Damage Spectrum (FDS) which enables the use of testing and servicing evidence to be utilized on more than one aircraft platform and Shock Response Spectrum (SRS). All of these techniques are used to promote spacecraft/aircraft airworthiness and sustainment.

Outcome 4. The Communication competency was fulfilled through an analysis of the research collected from NASA experiments and FAA studies and their influence on dealing with structural failure through shock loads and transient vibrations. Furthermore, discussions focused on how these results have shaped methodologies in the manufacturing, design, and maintenance of new materials for future spacecraft/aircraft.

Outcome 5. The competency of Scientific Literacy was fulfilled through an analysis of measured explosive shock motion data in regards to vehicle sensitivity to pyrotechnic shock loads. Within the analysis, a discussion of the Titan II, Gemini, and Titan III launch vehicles were made in regards to faring separation analyses made by NASA during spaceflights, and these studies covered Equivalent Sinusoidal (ES) testing that simulates maximum transient levels encountered by the vehicles during re-entry and launch phases to and from Earth.

Outcome 8. The Aeronautical Science competency was fulfilled by providing research in regards to how the aerodynamic components of spacecraft are affected during re-entry phases but also during sonic speeds on aircraft. An explanation was made on how transient vibration frequencies cause aerodynamic heating on wing structures which has a negative effect on airworthy structures. Furthermore, to accurately address the aeronautical science outcome, a review on the effects of payload faring induction of aerodynamic buffeting during spaceflights.

Outcome 11. The Aviation Management and Operations competency was fulfilled through the discussion of the application of system safety management styles resulting in changes to system engineering philosophies and protocols. A comprehensive investigation explained the various techniques system safety management specialists would utilize in an effort to improve aerospace operations. The analytical techniques include fault tree analysis and project evaluation tree charts while dealing with the sophistication of spacecraft advancement and the evolving principles in the system safety management of transient vibrations and acoustic load inputs.

Comprehensive Question 5.

Statement of the question. New issues have begun to emerge as the aviation/aerospace industry increases the understanding of the major impacts and effects of space weather. These issues include spaceflight mission cancellations and severe impacts to aviation operations. Currently, the National Oceanic and Atmospheric Administration (NOAA) Space Environment Center (SEC) provides space weather forecasts and products useful to the aviation/aerospace industry. What advances in space weather detection systems and education curricula are the FAA and NOAA implementing to help the aviation industry understand space weather effects and their impact on aviation operations? What policy issues need to be addressed to ensure the best use of current space weather information?

Program outcomes addressed by this question.

Outcome 1. The Critical Thinking competency was fulfilled by addressing the issues surrounding the aviation industry and its failure to understand the effects of space weather phenomena including degradation or loss of HF radio transmission and satellite navigation signals; navigation system disruptions, avionic errors, not to mention solar radiation being extremely harmful to human life. The analysis included what is at stake if the space weather phenomenon is not taken seriously by the aviation industry. Inclusive to this discussion was an explanation of the damage that can be caused by Corona Mass Ejections (CMEs) type events and the best way to develop hazard mitigation strategies as well as how to provide hazard and disaster information where and when it is needed through the forerunning centers of early detection of solar weather events by the NOAA Space Weather Prediction Center (SPWC).

Outcome 3. The Information Literacy competency was satisfied through research efforts made by the student collecting data in application to space weather and forecast detection systems retrieved from the National Oceanic and Atmospheric Administration (NOAA) and the FAA. The discussion focused on the economic, operational, and safety concerns such as cross-polar air traffic routes, history of space weather events and the effects solar radiation and cosmic rays on human health.

Outcome 4. The Communication competency was fulfilled through analyzing research collected from NASA, FAA, and National Oceanic and Atmospheric Administration (NOAA) studies and their influence in addressing the impacts, effects and understanding of space weather phenomena in the aviation/aerospace industry. Other discussions focused on the recommendations for improving the policies and procedures associated with developing, distributing, and using space weather information.

Outcome 6. The Cultural Literacy competency was fulfilled by effectively analyzing how space weather events have influenced the aerospace/aviation industry to address policy issues including establishing educational programs for decision makers (ATC, crew, operations managers, pilots, dispatchers and engineers). The review addressed the specific recommendations for the integration of space weather observations and forecasts into aviation operations to raise awareness on space weather impacts to aviation safety as well as commercial and non-commercial space travel.

Comprehensive Question One

Statement of the Comprehensive Examination Question.

What is the anticipated effect on space travel if the National Aeronautics and Space Administration (NASA) allowed for the commercialization of space travel and private sector participation in human spaceflight? What are the national security and legal ramifications of dual use of space technology?

Research & Answering of the Question

The interconnection and correlation of commercial and/or private ventures with governmental space operations such as NASA has already begun. As any versed person knows, the Space Shuttle is no longer in use and this will not be changing in the future. Rather than NASA designing a revised and revamped space vehicle, more has been diverted towards private companies taking over the design, maintenance and actual execution of space flights, up to and including issuing government contracts for companies to do just that (Hertzfeld, 2005)(Congress, 2011)(MIT, 2008)(Waldrop, 2003).

The most prominent (but far from the only) company engaging in this is Space Exportation Technologies Incorporated, often shortened to Space-X. Founded in 2002, Space-X is the creation of PayPal co-founder Elon Musk. The Dragon spacecraft and Falcon launch vehicles are fast becoming the standard vehicles used for space flights initiating from the United States. Space-X's contracts and arrangements include some with NASA but also involve contracts with private sector companies, such as those launching satellites, and other government agencies such as the United States military (Hertzfeld, 2005)(Congress, 2011)(MIT, 2008)(Waldrop, 2003).

There are a number of implications that are not necessarily positive as it relates to the commercialization of space flight and the ramifications involved must be taken very seriously. These implications include concerns over property rights, so to speak, in space (not unlike the battles over Antarctica) and national security concerns. It is messy enough to have Russia (especially when they were still the U.S.S.R.) and the United States hashing it out during the Cold War. Now it is even more complex with private companies, some perhaps with less than good intentions and motives, entering into the space fray (Hertzfeld, 2005)(Congress, 2011)(MIT, 2008)(Waldrop, 2003).

Omnipresent in any discussion about the militarization or commercialization of space is the possibility of weapons of mass destruction and/or nuclear devices being deployed in space. This has not verifiably happened as of yet but it certainly could in the future and there are a number of powerful nations that could do so using one method or another. The list of countries in play is not limited to the United States and Russia. Even countries like Iran and North Korea have the capability or act as if they do, at the very least (Hertzfeld, 2005)(Congress, 2011)(Waldrop, 2003).

Information collected from NASA and FAA experiments and general flight data is useful but there are some entities that do not trust that data or feel that the data is based on incomplete or short-sighted data sets. Another ramification is that opening up space travel to the commercial sphere opens up a literal Pandora's Box of opportunities for illicit equipment and arms trading (or stealing) and there is perhaps an advantage to be touted when only governmental agencies have the ability (or they are the only ones that are allowed by their applicable nation state) to enter the realm of space (Hertzfeld, 2005)(Congress, 2011) (Waldrop, 2003).

Indeed, it is clear that there must be significant regulation and monitoring of private companies that engage in space travel or supply the same. To leave this business avenue unregulated and uncontrolled will only lead to problems and all nations allowing for commercial space travel must keep very close tabs on what is going on and that the utmost standards of quality and ethics are maintained (Hertzfeld, 2005)(Congress, 2011)(Waldrop, 2003).

Thus far, the international precedent regarding space as it relates to property rights is that no single or collective of government bodies or organizations, let alone individuals, can claim rights to celestial bodies or areas. This makes the entire idea of "sovereignty" as we know and enjoy it on the planet Earth a moot point. However, just because sovereignty cannot be defined in the heavens does not mean that it is not an issue, so some sort of resolution will have to be crafted to regulate and assign rights to parties that do business in space, whether one is talking of private enterprise or governmental agencies and/or bodies (Hertzfeld, 2005).

One great example of the above in motion is the idea of engaging in harvesting or other business on the Earth's moon. Since it is generally accepted that the Moon is the property of "mankind" rather than the dominion and property of any particular person, nation or organization, it is generally accepted that any proceeds and profits realized from doing business on the moon would have to be shared with everyone. This may sound all well and good, but it effectively blunts any and all incentive that a body may have in doing just that. Whether that is considered a good thing or a bad thing may vary from person to person. However, it is clear that the general principles in play at this basically eliminate any incentive to even try it in the first place (Hertzfeld, 2005).

Similarly, private businesses often point to this fact as an inhibitor of developing space travel and infrastructure as there is no inherent protection to property and investments made in that regard. Businesses also kvetch that a lack of defined property rights prevents them from obtaining financing or a reliable stream of income, thus making any investments in space infrastructure and/or travel very risky to say the least (Hertzfeld, 2005).

However, even with the "property" of space not being claimable by any certain party, it is an established principle and fact that vehicles and other equipment launched into space is the property of the organization, government or other body that is sending the craft into space. Any damage or other havoc that is wreaked by such objects and vehicles can cause liability to be assigned to the owner and/or operator of the vehicle. For example, if a launch vehicle clips a satellite and the satellite becomes damaged or even inoperable, then any and all costs to remedy the satellite becoming broken would almost certainly fall upon the operator or owner of the vehicle or equipment that caused the damage, not unlike the way it would work if the even happened on the ground (Hertzfeld, 2005).

There are other dimensions to property rights and intellectual property rights that pertain to items crafted and developed in space. As it stands right now, there is no provision that assigns property or intellectual rights for something that is crafted, created or concocted in space, such as would be the case if the invention or creation was done on the ground. Indeed, it's an example of the laws of the national and international bodies not keeping up with the implications of what is already happening vis-a-vis space travel. It is not unlike the digital revolution that has enveloped the world in the last 20-30 years and how many laws are obsolete or at least barely applicable to modern situations (Hertzfeld, 2005).

One field of thought and "property" rights that is clearly regulated is the spectrums that satellites use for their communications. Swaths of frequencies are assigned to the different companies and satellites that exist in the orbit of the planet Earth, so as to avoid two different bodies using the same frequency and thus potentially disrupting another. It is not unlike the FM and AM radio bands, whereby different communication companies rent out a certain frequency on the radio dial so that people seeking out their channel know precisely where to go and other companies are forbidden from using that same frequency (Hertzfeld, 2005).

Comprehensive Question Two

Statement of the Question.

What are the increased visual impairments/intraocular pressure associated with long-duration spaceflight? How have new inventions such as advanced resistance exercise devices and fundus examinations helped identify, treat or reverse the negative effects of microgravity on astronauts? What are the countermeasures that astronauts have had to take in order to reduce the risks of microgravity induced visual impairments/intraocular pressure?

Research & Answering of the Question

Research has borne out that photorefractive keratectomy could lead to changes in the visual quality and acuity of astronauts as they engage in space and other aviation missions over the long haul. However, the news is not all bad given that some effective countermeasures are being employed to counteract and combat this condition being the case (Lane, 2012).

It is accepted across the board that the bodies of astronauts are definitely affected and changed when they engage in flight. Effects are apparent when looking at scans of brains, blood vessels, eyes, ears and even basic cellular structure. One thing that happens a lot with astronauts is spatial disorientation. In other words, the question is asked "which way is down." Eye to hand coordination can also be impacted as well as sleeping patterns and efficacy (Lane, 2012).

One major part of the body that is affected during space travel is the eye. in-flight factors can include evidence of ocular degeneration, spaceflight-induced cardiovascular adaptation issues, spaceflight-induced central nervous system adaptation issues, and so forth. A summary of VIID case data clearly showed some definite and protracted effects from spaceflight in a series of seven cases that all showed some sort of negative effect, or more than one (NASA, 2012). Another study found the same thing regarding eyesight as well as intracranial issues with returning astronauts that had been on long-duration space travel (Marshall-Bowman, 2011). The International Space Station (ISS) has been used as a test-bed to combat all of these nefarious health effects (ISS R&D Conference, 2012).

Other studies of the effects on crewmembers engaging in space flight have yielded similar results. Even though spaceflight has been occurring regularly since the 1960's, there has been a sharp uptick in ocular and intracranial effects detected in astronauts over the more recent years and missions of spaceflight. Crewmembers in long-duration flights clearly showed a higher rate of negative effects (about 60%) as opposed to crewmembers that engaged in shorter flights (less than 25%). Examples of the former would be crewmembers on the International Space Station and examples of the latter would include United States Shuttle missions. Similar rates and effects were seen both with Astronauts in the United States as well as from Russia (Marshall-Bowman, 2011).

Using a similar swath of data, nearly half (46%) of ISS/Mir members showed decreased near-visual activity whereas about a fifth (21%) of Shuttle crew members showed the same problems. In general, there was a shift of 1-2 diopters among the people looked at. It is asserted by the data collectors that this phenomena was probably happening just as strongly and as frequently in the earlier days of spaceflight but it was likely overlooked or sufficiently complex and quality equipment did not exist at the time, so it was likely just missed (Marshall-Bowman, 2011).

The same study found similar problems with the intracranial space. The skull (or cranium) of a person contains the brain, blood and cerebrospinal fluid (CSF). When the amount of fluid (blood or CSF) is increased, it almost automatically causes an increase in the blood pressure (and other relevant pressures) in the head and this can have very deleterious effects on a crewmember. The Monro-Kellie hypothesis explains that since intracranial components are not compressible, the amount of pressure rise can be significant (Marshall-Bowman, 2011).

Further analysis on eye effects stemming from space flight founds results that had never been found on patients staying on Earth. Specifically, crewmembers on long-duration space flights (such as stays on the International Space Station) led to instances of optic disc edema, choroid folds and cotton wool spots. Magnetic resonance imaging (MRI's) scans found posterior flattening of the globe, papilledema and optic nerve sheath distension. These conditions manifesting themselves are compared to people with idiopathic intracranial hypertension, which has led many to believe that intracranial pressure incurred and enduring during space flight is what is leading to all of these events happening to the eyes of spaceflight crewmembers, long-duration crewmembers in particular (Marshall-Bowman, 2011).

Resistive exercise, high sodium (salt) intake and in-flight pharmaceuticals are seen as aggravating factors that lead to intracranial pressure and, by extension, damage to the eyes of crewmembers. The presence (and level) of carbon dioxide is also a factor to many medical minds (Otto, 2012)

There is a significant amount of pre-flight, in-flight and post-flight reviews and scans that take place with astronauts in the modern era, and around the world. Using NASA as an example, preflight examinations include an MRI of the brain and orbits, a fundoscopy, tonometry, visual acuity measurement, bio-microscopy, high resolution retinal photography, OCT, a-scans, ultrasounds, blood pressure readings, vascular compliance and a few other tests. Several of these tests are done at intervals prior to the flight rather than them just being done once so as to rule out non-space flight causes and events prior to the space flight even happening (Otto, 2012).

In-flight examinations very much mirror those done pre-flight, with visual acuity tests happening at several different intervals. The same can be said of ultrasounds, fundoscopy, tonometry, visual acuity and vascular compliance. The latter includes a blood pressure reading. Post-flight exams include another magnetic resonance image scan (MRI), an ultrasound of the eye and orbit, a fundoscopy, a blood pressure reading, tonometry, vascular compliance, and other tests such as bio-microscopy, high resolution retinal photography, OCT (high-resolution) and a-Scans. Intervals for these post-flight tests run the gamut from just after a flight to a year after the flight with interim tests done at the 30 day mark, the 90 day mark and the 180 day mark (Otto, 2012).

In-flight studies have been engaged in by both Russian and American astronauts. NASA, from the United States, has looked at the use of a Braslet Occlusion Cuff, a strap-like harness that wraps around the upper thighs and buttocks of the astronaut. Scans of the femoral artery have shown a clear different in astronauts who wear the cuff as opposed to those that don't. The Russians have used their own device, referred to as the Chibis LBNP Device, or Negative Pressure. Rather than being limited to a strap, the device is actually a full set of leggings, boots and an enclosure around the waist and hips of the crewmember (Otto, 2012).

Comprehensive Question Three

Statement of the question.

Beside monetary savings and safety, what are the pros and cons for utilizing advanced flight simulators in operations and evaluation training for astronauts to pilot spacecraft and perform operations on board the International Space Station? How reliable are these simulators in the rigorous training process and what are the foreseen advances in these technologies?

Research & Answering of the Question

There are several significant pros to using simulators to test and prepare astronauts and aviation experts in general but there are also some cons as well that are perhaps insurmountable, or at least close to it in the near-term at least. One significant pro-is stated in the question, that being a much lower price point in testing something in a simulator as opposed to doing it "for real" and having a lot more expenditures and risk to the crewmembers as a result (Dillard, 2002)(NASA, 2012).

However, there are several other very tangible benefits to be had. The first one worth of mention is that simulations can be done over and over in a short period of time, rather than having to wait a long amount of time before everything can be reset, which runs completely counter to what occurs when testing and monitoring is done during live missions. Another pro-is that the risk to life and limb is significantly less and is almost always zero which is absolutely not the case when talking about a live mission (Dillard, 2002)(NASA, 2012).

However, as mentioned above there are a few cons. The first and most important one is that it is sometimes impossible (or at least impractical) to completely replicate exactly how a live field operation would go in a simulated environment. It is true that a lateral-G feeling can be simulated and tested on astronauts, just as one example, but nothing really replicates a real live mission. Similarly, the astronauts know full well they are in a simulator and this can cause several issues with them when they actually enter the live flight arena. Even with all the simulations, there are no "do-overs" in a live flight and people can absolutely die if a live mission goes wrong. Add in the fact that nervousness and fear can enter the equation, which makes that course of events even more likely (Dillard, 2002)(NASA, 2012).

Another con that is related to the above is that not every contingency can be planned for. Sometimes, something that is entirely expected and perhaps impossible to expect can and does happen. The Columbia Shuttle burning up on re-entry is perhaps proof of this in motion. Surely, if the crew (on the ground or in the craft) knew that the heat shield was compromised, they would have used some sort of backup plan such as jettisoning from the craft or doing inspecting/repairs up in space. Much the same thing can be said about the Apollo 13 craft. The crew of the latter survived in large part of their ingenuity and not because of their training, at least not JUST because of their training. The training certainly helped, but there was almost certainly no specific simulation that allowed them to do what they did and survive (Dillard, 2002)(NASA, 2012).

Actual flight experiences and data should more influence flight simulators and not the other way around. However, as intimated above there are certain potential happenstances and events that have not happened before but certainly could happen given the right combination of events and conditions on a future mission. Even with the cons, the use of simulators is invaluable because aviation and space flight in general are two fields where "on the job training" and "learning as you go" should be kept to a stark minimum given the razor-thin margin for error that exists within many parts of the job (Dillard, 2002)(NASA, 2012).

There is plenty of private industry precedent for significant use of simulators. All of the major air carriers in the United States make extensive use of air flight simulators to train their pilots. The companies that have these extensive frameworks in place include American at Dallas Fort-Worth Airport, Delta in Atlanta's Hartsfield-Jackson Airport, Alaska Airlines in the Seattle airport (Sea-Tac) and United Airlines in Denver International Airport (Dillard, 2002).

Another pro-to simulators not mentioned above but certainly worth mentioning when speaking of regular airplane simulators is that the daily operational run-time of simulators is double that of a real live flight. The air flight simulators of the major carriers, as mentioned in the last paragraph, can literally be up and running 18 to 20 hours a day, which is roughly double of what could be done with a live flight situation. Even though NASA and the FAA have clearly set the standard for air flight simulators, privately held, developed and simulators are all over the world and even some colleges and other institutions of higher learning have use of (or access to) flight simulators (Dillard, 2002).

One major fact that lends much more credence to use of flight simulators is that when something new comes up that needs to be adapted into flight simulations, the amount of time and resources it takes to integrate such new scenarios into simulators is a lot less than it used to be. It used to take an prohibitive amount of time to integrate such changes but the main limiting factors nowadays is selecting what should be integrated and what should not be integrated. Now, once a change is settled upon the turnaround time is actually not that bad. The key, as noted by the scholarly research done for this report, is that changes are reviewed and implemented in a sound scientific manner. Failing to do that only slows down the process and greatly increases the likelihood that the FAA and other regulatory or reviewing bodies will reject the efficacy and applicability to real-world flight situations and happenstances. This is especially relevant when talking of simulators that are used by the National Transportation Safety Board (NTSB) when researching the cause and course of events of disasters so as to ascertain what truly happened, in what sequence and what exactly was to blame (Dillard, 2002).

Simulators that are created and crafted by companies that are more nascent in nature and that do not follow the proper protocols should not be used and can actually worsen the conditioning and training of a NASA or regular flight crew member. Training a person bound for the International Space Station using equipment that is not fully realistic and up-to-date could lead to cataclysmic results and should never be happening. As such, all simulators engaged in by ISS-bound crewmembers need to be applicable to exactly what that person will be doing or there is no point in using the simulators even if the costs are less (Dillard, 2002).

The advances in technology is making simulators more and more applicable to what missions truly end up being like, the turnaround time to integrate new and current scenarios is greatly improved and the closeness of the simulation to reality is closing quite quickly. That margin will probably never be entirely closed, but the ability to very closely mimic real mission scenarios better and better will only make crew performance better over time. In general, advances will be based on making the simulation as much like the real mission as possible, but without the potential loss of life if a miscue is made (Dillard, 2002).

Comprehensive Question Four

Statement of the question.

What are the effects of shock loads and transient vibrations on engine and structural components of spacecraft/aircraft? How have these issues changed system engineering philosophies and methodologies? What new techniques and devices are being utilized to overcome these forces in order to make structurally sound spacecraft and aircraft? Techniques including Fatigue Damage Spectrum (FDS), Laser Vibrometry for Damage Detection using Lamb Waves and devices such as vibrometers and accelerometers were reviewed thoroughly.

Research & Answering of the Question

As was made clear by the Columbia disaster, structural integrity of an aircraft or spacecraft is vital. However, contrary to the concerns realized by the Columbia disaster, which involved a penetration of the foam and heat shield on the craft, things like vibrations and general fatigue are also concerns. Before the Columbia fell to Earth in pieces, it had been through 28 missions spanning nearly 22 years. The craft spent a total of 300 days (and change) in space and orbited the Earth nearly five thousand times (Polytec, 2012)(Halfpenny, 2012).

What this translates to over the long haul is the spacecraft wearing down due to vibrations and general flight fatigue and the signs of decay and wear are not always obvious. As a result, significant inspection must happen at required intervals so as to detect breaches in structural and mechanical integrity between flights so that a catastrophic event does not occur while the spacecraft or aircraft is in flight. One major technique and technology used to detect damage is laser vibrometry for damage detection using lamb waves. Even the smallest micro-crack or fissure in the fuselage of an air or spacecraft can be detected using this technology. Damages found are characterized using Fatigue Damage Spectrum (FDS) and Shock Response Spectrum (SRS) testing techniques. These measurement methods are codified in Annex a of MIL-STD-810F, RTCA DO-160E and GAM-EG-13 (NASA, 1969)(Polytec, 2012)(Halfpenny, 2012).

The Shock Response Spectrum is used to determine the highest amplitude of loading seen during a flight or testing event. Overall, it is a plot graph of peak amplitude vs. frequency. The testing is considered conservative in nature. It was developed in 1932 by Biot. The Fatigue Damage Spectrum (FDS) was developed by Lalanne as work was being done with the aforementioned Shock Response Spectrum technique. A random qualification is compared to actual test results. If the variance between the two graphs is little to none, then there is minimal chance of damage occurring. However, if there is a high amount of difference and variance, then the horizion of potential damage is greatly increased (Halfpenny, 2012).

Kehoe (1987) explains that such testing is done regularly at the Ames-Dryden Flight Research Facility. The positioning and total weight of payload is another concern that has to be taken seriously (Brooks, 1967). A certain amount of flex and "give" is sometimes a way to prevent damage and ear over the long-term (Nassar, 2004). Both primary and secondary structures must be sufficient and must work together (Annarella, 1991).

One piece of equipment that takes an enhanced beating when it is used, and something that is much more obvious to the curious observer, is the landing gear of a vessel. Of course, NASA's space shuttle has landing gear just like an Airbus A320 would have landing gear. Polytec (2012) gives a great example of the latter under a proverbial microscope in its look at vibration and other damage incurred by flight. Polytec describes that low-frequency vibrations in a plane's landing gear can cause a fatigue-inducing vibrations, also referred to as a "shimmy," and this condition (at a minimum) causes premature wear and can cause much worse things to happen at the more extreme end of the spectrum (Polytec, 2012).

Polytec took the landing gear of an Airbus A320 and subjected it to main resonances of 37, 69 and 353 hertz. At 37 hertz, there was a pure tire bending. At 353 hertz, a hub-bending oscillation was detected. These anomalies were detected using 3-D scanning vibrometry. The same article makes mention of lamb wave inspection, whereby damage can be detected in airplane structures. The use of lamb waves has been attempted or even ongoing over the last two decades, but it is just now starting to be perfected and it is now being applied to the composite materials in newer airplanes. There are a few draw-backs inherent to using lamb waves. First, the number of actuator and sensor transducers is quite high when using lamb waves. This fact makes the use of the technology quite costly and very labor-intensive. Second, the data collection and interpretation inherent to the use of lamb waves is very complex and the technicians brought aboard to do that collect and interpretation must be very adept and good at their jobs. This leads to higher labor costs and a common inability to find the people that are properly trained to harness and use the data garnered during lamb wave analysis (Polytec, 2012).