ai-aerospace/ams_data_full_2000-2020 huggingface dataset:
Where     ∆–the length variation of the cable   A, A’ –the tangency point between the cable and guide pulley   B, B’ –the other tangency point between the cable and guide pulley    C –the point where the cable contacts with fixed pulley      O –the center of the fixed pulley and also the axis of root hinge   OC –equal to the radii of the fixed pulley  The model can be simplified if the radii of guide pulley is ignored. Equation 1 can be simplified to:  ∆=+−=+−=√+−2∙∙∙cos+− (2)  Where   θ–the angle of root hinge rotation  Equation 2 defines phase 2. Particularly, at the end of phase 2:  OA = (3)  If root hinge rotated an angle α in phase 1, then ∆ and θ must meet the constraint:  2(π−α−θ )= π−∆ (4)  In Equation 4, (π−α−θ ) is the angle of root hinge rotation in phase 3, while π−∆  is the angle of the  panel hinge rotating in phase 3  Figure 6. Mathematical model of the fixed pulley  The mathematical model of the swing pulley can be created similarly, which is shown in Figure 7. The  relationship of the parameters can be described by Equation 5.  ∆= +− + (5)  Where   ∆–the length variation of the cable  , –the tangency point between the cable and guide pulley  , –the other tangency point between the cable and guide pulley  , –the point where the cable contacts with the swing pulley Beginning of phase 2 End of phase 2 Cable Guide pulley Fixed pulleyOA B CA' B' OCA A' θ Simplify  NASA/CP—2018-219887 436
–the axis of the root hinge  The model can be simplified with the radii of guide pulley ignored. Equation 5 can be simplified to:  ∆=−=+− =+−+−2∙∙∙cos(−)  (6)  Where   θ–the angle of root hinge rotation  –the axis of the swing pulley  Equation 6 defines phase 2. Particularly, at the end of phase 2:  θ = sin + sin  (7)  Where    OC –equal to the radii of the fixed pulley or swing pulley  Figure 7. Mathematical model of the swing pulley  Examining Equations 2 and 6, we draw the conclusion that either the cable rolling on the fixed pulley or  rolling off the swing pulley uses the characteristic of a triangle in geometry ( ∆ in Figure 6 and  ∆ in Figure 7), though there is an obvious structural difference between them.  In order to make the fixed pulley and swing pulley work consistently during phase 2, ∆ must be equal to  ∆ at any moment. Unfortunately, the radii of guide pulley cannot be ignored due to its effect on ∆ and  ∆. The equations should be more complicated in engineering application, and it is too difficult to find an  analytic solution. It is a simple and effective way to perform a numerical analysis.  Result of Design  In the development of the synchronization mechanism, the dimensioning parameters were determined by  the result of numerical analysis. The length variation tolerance between rolling on cable and rolling off  cable (∆ - ∆) is shown in Figure 8. The minimum was -0.47 mm during the deployment while the  maximum was +0.65 mm. The tolerance was small enough to be accepted because the total length of  each cable was more than 2000 mm.  NASA/CP—2018-219887 437
Figure 8. The length variation tolerance  The synchronization characteristic is shown in Figure 9. The nominal characteristic was fully compatible  with the ideal one before 70° and after 110° of root hinge rotation. There was a transient and smooth  transition in nominal characteristic between 70° and 110°of root hinge rotation.   Figure 9. The synchronization characteristic  Figure 10 shows the configuration of the fixed pulley and swing pulley that are installed on the root hinge  at the deployed state. The deployment of root hinge can be divided into three stages that shown in Figure  11. It illustrates the state of the pulleys and cables during the deployment. 90°180° 180° 0° Panel hinge deployment angle (°) NASA/CP—2018-219887 438
Figure 10. Deployed configuration of root hinge  Figure 11. The three-stage deployment of root hinge  Deployment Test  The performance of the synchronization mechanism was verified in ground test using both an engineering  model and flight model. The solar array was off-loaded by an air pad for testing (see Figure 12). The  trajectories of the air pads were controlled by the synchronization mechanism, and it had to be confined  to the area of the table, which corresponded to the requirements.   Phase 1 Phase 2 Phase 3Fixed pulley Swing pulleyRoot hingeGuide pulley NASA/CP—2018-219887 439
Figure 12. Using air pad for ground testing  The process of deployment using the flight model is shown in Figure 13. The realized synchronization  characteristic was similar to the nominal characteristic, and the main difference between the two was that  each panel hinge deployed a small angle in phase 1 of testing because of the flexibility of the cables.  Nevertheless, the more important consideration was that the trajectories of the panels met the  requirements excellently, as the angle was too small to affect trajectories significantly.   Figure 13. The deployment of the flight model  There were several tests in the development, and the performance of the synchronization mechanism  was stable. Furthermore, the GF-3 was launched in August 2016, and the solar array deployed  successfully on orbit. The synchronization mechanism demonstrated excellent performance during flight.   NASA/CP—2018-219887 440
Conclusion  The synchronization mechanism of the solar array in this paper performs a three-stage deployment in  order to meet the requirement to confine the trajectories of all panels to a limited area. The main design  challenge of the synchronization mechanism is to change the ratio smoothly from 0:1 to 2:1 by adding a  transient transition. The root pulley is divided to two parts called the fixed pulley and swing pulley in order  to achieve the function. Although there is an obvious structural difference between the fixed pulley and  swing pulley, they both use the characteristic of a triangle in the mathematical model to change the length  of the cable rolling-on or rolling-off that performs a non-linear ratio. The coordination between fixed pulley  and swing pulley is complex, and the dimensioning parameters are determined by the result of numerical  analysis. The primary advantage of the method is that the trajectories of the panels meet the  requirements excellently. The performance of the synchronization mechanism has proven to be effective  and stable by ground test and flight usage. The synchronization mechanism is not significantly bulkier  than the standard one, and it can be adapted to other multiple elements deployment that have a similar  requirement.  References  1. Zhang Qingjun. System Design and Key Technologies of the GF-3 Satellite[J]. Acta Geodaetica et Cartographica Sinica . 2017, 46(3): 269-277 (in Chinese). 2. Yannick Baudasse, Laurent D'Abrigeon, Nicolas Pingault.  "A New Synchronization Concept for Solar Array Deployments." Proceedings of the 11th European Space Mechanisms and Tribology Symposium , (2005), 219-224. 3. Frans Doejaaren, Marcel Ellenbroek.  "The Damper Spring Unit of the Sentinel 1 Solar Array." Proceedings of the 41st Aerospace Mechanisms Symposium , (May 2012), 97-110. NASA/CP—2018-219887 441
Mechanisms and New Space  Bill Purdy* Abstract  The objective of this paper is to provide the mechanisms community an understanding of “New Space”  applications, giving insight on how to specify, design, produce, and test mechanisms for this emerging  paradigm. An in-depth study of how New Space does and does not change the landscape for space  mechanisms will be provided. The paper will study these questions generically to provide understand of  the adaptation needed but does not intend to specify a recipe for success. The spectrum of applications  and programs is very diverse, so the paper will focus on key thought processes, potentially applicable  techniques, and the questions to consider for New Space mechanisms. The desired outcome of this  paper is to help smart mechanism engineers create wise and unique solutions for specific New Space  mechanisms.  Introduction  New Space changes a programmatic paradigm but cannot change physics, nor the space environment,  nor the realities of a riding a rocket to space. The most impactful elements of this programmatic change  are a very strong emphasis on low cost, usage of volume manufacturing and much tighter schedules than  is the norm for current programs. This paper is written from the perspective of learning to thrive in this  new paradigm. The author has spent a 30-year career primarily working research and development  satellites and their mechanisms within the American space program but has recently refocused his career  on the world of New Space. The paper will share the author’s growing understanding of the New Space  paradigm and its impact on the mechanisms life cycle.    What is New Space?  We must understand the motivations and expectations of New Space enterprises to successfully provide  mechanisms for their programs.    New Space Description  The trade magazine New Space Global  defines New Space well. “New Space is a global industry of  private companies and entrepreneurs who primarily target commercial customers, are backed by risk  capital seeking a return, and seek to profit from innovative products or services developed in or for  space.”    New Space will be examined in comparison to the most conventional approach to space, referred to in  this paper as ‘Big Space.’  Big Space is defined for the purposes of this paper as large, very high  reliability programs, including major NASA and ESA programs, DoD programs, and long-life  Geostationary communication satellites.  The strongest motivation of New Space is simply to use space to make money, which drives a very  different approach to satellite design and production than the Big Space motivation of extremely high  reliability of each satellite. Low-cost production of satellites is a cornerstone of financial success for New  Space enterprises. Programs using the New Space paradigm are endeavoring to build space hardware at  a small fraction of the conventional cost by challenging the standard practices of big aerospace programs.  *Purdy Engineering, Poolesville, MD Proceedings of the 44th Aerospace Mechanisms Symposium, NASA Glenn Research Center, May 16-18, 2018 NASA/CP—2018-219887 443
New Space has emerged in recent years as a sizable business from its roots in the small satellite and  CubeSat communities. More than 1000 electro-optical satellites are proposed and more than 10,000  communications satellites are proposed by various companies. Proposals are easy, but it takes a lot of  money to become real. Commercial funding for New Space (Figure 2) has grown to an average level of  $3 Billion annually from 2015 through 2017. Three of the largest New Space ventures in current  production are the SpaceX Falcon rockets, the Planet constellation of imaging satellites and the OneWeb  constellation of internet communication satellites (Figure 1). The production programs and funding levels  confirm this new paradigm is serious business. Multiple projections show this expenditure level growing in  the coming years.  Figure 1. Major New Space Constellations Presently in Production  Figure 2. New Space Investment by Year Shows a dramatic increase from 2015 through 2017  NASA/CP—2018-219887 444
Key Point: Reducing and eliminating unnecessary requirements is one of the best ways to  reduce cost and schedule for New Space programs and should be a joint effort between  provider and customer.   Concept Design  The book Design for Manufacturability, by David M. Anderson (Ref. 3) puts forth that 60% of the total  lifecycle cost is decided simply by the concept architecture (Figure 3). This makes a lot of sense simply by  thinking about the costs of complexity that can be eliminated by a great concept. Not only does a great  concept drive down costs, it drives down schedule and risk simply because there are less opportunities  for problems to arise.    When one looks at this chart another way, a new design is the only method to achieve a cost reduction  for an existing product to below 80% of the present cost, since reductions greater than 20% are not  available by manufacturing improvements alone. Cost reductions to below 60% call for an innovative new  concept.  Figure 3. Costs Committed and Costs Incurred vs. Life Cycle. This figure shows the majority of total life  cycle costs are committed by the completion of the concept architecture plus design phases even though  these costs are not realized until the production phase. Plot courtesy of Dr. David Anderson  Many lessons from the referenced text and from the world of production emphasize a rapid cycle of  conceive, test, iterate, and repeat as one of the best methods to evolve to a great concept. The speed at  which this rapid design iteration can now be accomplished is greatly improved by leveraging additive  manufacturing for rapid prototyping. It is also taught that extra time spent in the search for a great concept  can ultimately save a program time when the benefits of the great concept are realized in development  and production schedules.  One concept often seen in New Space is usage of mass-produced industrial components for flight even  though they were not designed for space applications. With proper testing many industrial items can be  NASA/CP—2018-219887 448
restaurants. These restaurants manufacture custom burritos in an assembly line with remarkable  efficiency. The author observed one of these outlets finding the following truly impressive statistics:  •It took only one minute twelve seconds from “Hi may I take your order” to “thank you for paying” for the author to receive a burrito custom ordered with nine individually selected ingredients. •28 burritos were made in a 10 minute period – 2.8 burritos per minute. •There were 8 workers involved in burrito production, including the cashier. •This works out to just 2.8 man-minutes labor per assembled burrito. Figure 3. Efficient Burrito Assembly Diagram serves as an example for efficient mechanism assembly  One will see many principles of lean manufacturing of which two will be described. The basic burrito  production line and key features is shown in Figure 3.  •Principle one – eliminate waste. The burrito manufacturing employees spend very little time walking from their work station. The principle is that walking around is waste and to be minimized. Four of the eight employees, identified as ‘static’ in the figureFigure 3  never took more than three steps from their work station. Four of the employees had tasks to replenish supplies and their walk was typically only eight steps from work station to supply location. •Principle two – excess inventory is waste. In any assembly line, if worker A gets ahead of worker B and keeps piling up inventory, there is waste in building the inventory pile, waste in the floor space for the inventory and waste in pulling material off the inventory pile. At the restaurant, the burrito ingredient supplies for the servers are only replenished when they fall below half full. The servers communicate to the cooks when it is time for the cooks to make more supplies. The communication is timed so that the server’s supplies will be replenished at some point betweenLEGEND STATIONARY  EQUIPMENTWORKER Motion of food or peopleCOOK COOK COOK WARM SUPPLY  STORAGECOLD SUPPLY STORAGEGRILL AND FOOD PREP CHOP AND FINISH FOOD TRANSFER FOOD TO SERVERS STATIC  SERVERSTATIC  SERVERMOVING  SERVERSTATIC SERVERSTATIC CASHIER BURRITO ASSEMBLY BENCH BURRITO INGREDIENT BINS Customer Walks Down Assembly line with Burrito~8 STEPS ~8 STEPS ~8 STEPSIngredient Prep Flow Burrito Assembly FlowWARM SUPPLY  STORAGE NASA/CP—2018-219887 453
drives concurrently on a single fixture. This is an example of creatively driving testing costs out of a  volume production mechanism.  Key Point: Modern automated testing methods can provide accurate testing very quickly  while minimizing the documentation burden.  Test architecture Design: The author proposes that a mechanism engineer consider the following  questions in designing a low-cost test program:  •What type of performance test provides great insight into mechanism performance yet is easy to perform? •What combination of qualification, acceptance and sampling tests will be best? •Do I need to test each individual mechanism for: oVibration? oThermal? oVacuum? •How can I automate the tests performed on each unit? •How can I automate the test reporting and deliverable documentation? •What testing will provide me confidence that problems have not crept into the production line? •How much does this test really cost?  And what is its true value? •Can I create a single test that provides confidence in multiple aspects of performance? Key Point: A wide variety of opportunities for streamlining during acceptance testing of  volume produced mechanisms are available but need tailoring for the unique aspects of  each mechanism production program.  Spacecraft Integration and Test  New Space programs are looking to simplify the satellite level integration and test process for recurring  production. The testing for qualification satellites and early prototype satellites will tend to be extensive,  much like Big Space programs. Once a new satellite design and its production processes have been  qualified, however, the integration and test emphasis shifts towards confirming that each satellite has  been built and performs the same as those units qualified. The biggest difference is that New Space will  consider satellite level environmental testing as a choice to be made rather than something that simply  must be done.    Mechanisms for New Space satellites may receive requirements to be compatible with streamlined  satellite assembly processes. For example, satellite builders may ask for certain features to enable  automated handling, and, will certainly desire mechanisms interfaces that make for fast and easy  installation.  Flight Operations  There should be no fundamental differences in the flight operations of mechanisms between Big Space  and New Space. In both cases mechanism operations are typically performed with very little intervention  by human operators. New Space constellations will desire even more automation of satellite operations,  so they will certainly not want any mechanisms that require complex operations with intensive human  intervention. Any space program will benefit from an analysis of flight operations to either (i) simplify  mechanism requirements or (ii) expose mechanism requirements which had inadvertently been missed.    NASA/CP—2018-219887 456
Conclusions  1. The New Space effort is presently very active with significant continuing commercial funding. 2. Done right, the New Space objective of satellites produced in volume at low cost is achievable although it adds some risk of individual satellite failures. 3. New Space requires mechanisms very similar to Big Space but at greatly reduced cost and schedule. 4. New Space programs will tend to be accepting of simplifications in mechanism performance and mission assurance requirements in support of cost and schedule targets. 5. Design excellence is a far more powerful cost saver than manufacturing engineering. 6. No amount of manufacturing brilliance can make a poor design cheaper than a great and simple design. 7. The move into volume production of mechanisms needs to leverage the tremendous knowledge base for lean manufacturing. 8. Readily available equipment for the automation of inspection and testing offers significant advantages over more labor intensive manual efforts presently common in mechanism production. There is no reason the space mechanisms community  cannot produce reliable products at low cost,   many other industries do.  References  1. Maus, Daryl and Monick, Doug. "Changing Paradigms: Manufacturing vs. Fabricating a High Volume Hold Down and Release Mechanism." Proceedings of the 29th Aerospace Mechanisms Symposium, 1995, pp. 94-108.  2. Lajoie, J., Horth, R., Lemelin-Auger, B., Gregorio, P., "Development, Qualification and Manufacturing of Antenna Pointing Mechanism Rotary Actuators." Proceedings of the European Space Mechanisms and Tribology Symposium , (September 2017).  3. Design for Manufacturability: How to Use Concurrent Engineering to Rapidly Develop Low-Cost, HighQuality Products for Lean Production; by David M. Anderson (2014, Productivity Press, 486 pages). 4. Toyota Production System; Beyond Large-Scale Production; by David M. Anderson (2014, Productivity Press, 486 pages). 5. https://www.newspaceglobal.com/, Definition of New Space 6. https://www.spaceangels.com/post/space-investment-quarterly, “Space Investment quarterly”, 4th quarter 2017 7. The Goal: A Process of Ongoing Improvement; by Eliyahu M. Goldratt, Jeff Cox, and David Whitford, (4th Edition, 2014, The North River Press Publishing Corporation) 8. GSFC-STD-7000A, General Environmental Verification Standard (GEVS) for GSFC Flight Programs and Projects, 4/22/2013 NASA/CP—2018-219887 457
Development of the Multi-Purpose Transportation System for the  Space Launch System Core Stage Flight Article Sarah Sandridge*, Hue Lien**, Ronald Hunt**, Ayana Reese** and Christopher Doktor** Abstract  NASA’s Multi-Purpose Transportation System (MPTS) is designed to transport the Space Launch System  (SLS) vehicle segments by waterway and roadway. It is tasked with transporting the vehicle from where it  is manufactured to its intermediate test location and final launch destination. Its design incorporates  mechanisms that release degrees of freedom to prevent excessive loading during transit and ensure a  successful delivery of the vehicle to its intended destination. In addition to the Core Stage (CS) flight article,  the system will also move three Structural Test Articles (STAs), the Dynamic Demonstration Unit, and a  simulated CS Pathfinder (weight, center of gravity, outer mold line dimensions, and overall length) over  road terrain at four NASA centers and on the Pegasus barge. The MPTS independently supports the article  at both ends while operating as a combined unit through automated monitoring of its released degree of  freedom and corrective responses. This allows the system to constrain its payload in a statically determinate  manner while traversing highly variable terrain. Multi-body simulation of the transportation route is useful to  predict free-body motion within its range of mobility. The MPTS has completed its design and analysis  developmental cycles. This paper describes the design challenges encountered in developing this system  of large-scale structure, which incorporates complex mechanisms. The unique techniques and  methodologies developed for analytical assessment of the hardware are also discussed.  Introduction In large launch vehicle programs, the design challenges presented during launch are apparent. However,  many efforts leading up to launch are not so obvious. Included in those many efforts is the development of  Ground Support Equipment (GSE), i.e., equipment that interfaces directly to the flight hardware after it  leaves the production line. The MPTS supports the delivery of the NASA’s latest launch vehicle, SLS. This  hardware interfaces directly with the flight vehicle after it has been built, and is therefore classified as GSE.  Historically, different GSE designs have transported flight hardware. Developers customized the designs to  meet the particular needs of each program. Every launch vehicle has depended on this equipment to  transport it between various locations without inadvertently damaging it. NASA’s past launch programs,  including Apollo and Shuttle as shown in Figures 1 and 2, used customized equipment to transport flight  hardware between NASA facilities.  *NASA Marshall Space Flight Center, AL ** Jacobs Space Exploration Group, Huntsville, AL Proceedings of the 44th Aerospace Mechanisms Symposium, NASA Glenn Research Center, May 16-18, 2018  NASA/CP—2018-219887 459