Low Shock Payload Separation System. Final Proposal

Transcription

1 Low Shock Payload Separation System Final Proposal Team 7 Dylan McAdams Craig Choate John Buskirk Brett Larzalere Neal Murphy Project Sponsor: Orbital ATK Faculty Advisor: Dr. Sarah Oman Sponsor Mentor: Steven Hengl Instructor: Dr. Sarah Oman

2 Table of Contents Table of Contents BACKGROUND Introduction Project Description Orbital ATK 38 Separation System Orbital ATK 38 Separation System Structure Orbital ATK 38 Separation System Operation Orbital ATK 38 Separation System Performance Orbital ATK 38 Separation System Deficiencies REQUIREMENTS Customer Requirements (CRs) Engineering Requirements (ERs) Testing Procedures (TPs) Separation Testing Vibration Testing Strength Testing Thermal Vacuum Testing Shock Testing EMI Testing Safety Testing Design Links (DLs) Low Shock Vibration Inertial Loads Temperature Requirements Cost Interface System Reliability Tip-Off Rate Safety Mechanism Repeatability EMI House of Quality (HoQ) EXISTING DESIGNS Design Research System Level Existing Design #1: Mark II Existing Design #2: RUAG/Sierra Nevada Existing Design #3: Frangible Joint Subsystem Level Subsystem #1: Payload Locking Existing Design #1: Clamp Band Existing Design #2: Grooved Leaflets Existing Design #3: Shearing Bolts Subsystem #2: Payload Release Existing Design #1: Servo Motor Existing Design #2: Ordnance Release... 15

3 3.3.3 Subsystem #3: Payload Separation Existing Design #1: Spring Force Existing Design #2: Ordnance DESIGNS CONSIDERED Design #1: Servo Motor Band with Springs Design #2: Shape Memory Band with Springs Design #3: Shape Memory with Magnets Design #4: Shape Memory with Pneumatic Jets Design #5: Shape Memory Clamps with Lever Separation Design #6: Magnetic Clamp with Springs Design #7: Magnetic Locking & Separation Design #8: Pneumatic Seal & Release with Springs Design #9: Pneumatic Seal & Release with Jets Design #10: Pneumatic Seal & Release with Balloon DESIGN SELECTED Rationale for Design Selection Design Description Magnets Springs Structure Material Coating PROPOSED DESIGN References APPENDICES Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F... 34

4 1 BACKGROUND 1.1 Introduction Focused on providing safe, reliable, and affordable technologies, the space systems group of Orbital ATK designs and constructs innovative propulsion systems, satellites, and composite aerospace structures. Orbital ATK s spacecraft and aerospace components contribute to many multimillion dollar functions such as orbiting satellite communication, weather monitoring, and NASA International Space station delivery. By providing the means for these functions, Orbital ATK s revenue and business continues to grow, launching almost 30 missions per year [1]. As a result of the cost and importance of these missions, Orbital ATK s spacecraft require high precision equipment and components with near perfect reliability. However, due to the complexity of these aerospace systems, there are often many points where component reliability can affect mission success or failure. Payload separation, the detachment and separation of a heavy propulsion system from the spacecraft, is one of these points [2]. Payload separation systems aim to separate the spacecraft from the launch vehicle or propulsion systems during launch. This requires that the spacecraft be pushed away at velocity just high enough that the spacecraft will not collide with the launch vehicle. Due to the nature of this operation, payload separation induces random vibration and shock to the spacecraft, thus potentially damaging or negatively affecting flight instruments [2]. Being that every spacecraft component is critical, payload separation system reliability is at the utmost importance. Failure of the payload separation system could result in the system not separating, thus falling back to earth due to high mass, or in damaging the payload with high impacting forces. All failed results end in millions of dollars in losses and bad reputation for Orbital ATK. For these important reasons, the team plans to generate multiple feasible concepts and design a 15-inch bolt diameter separation system that releases the payload at a low shock vibratory modes. This document briefs over the design process of this new payload separation system, including background research, requirements, concept generation, and design analysis. 1.2 Project Description The team is responsible for designing and fabricating a 15 sub-scale model prototype of the payload release system. This process includes background research, concept generation, quality analysis and testing, and manufacturing. The team will travel to Orbital ATK to separately conduct a Preliminary Design Review (PDR) and a Critical Design Review (CDR) with the Orbital engineering team. The project description as provided by the sponsor, Steve Hengl, reads as follows: Orbital ATK s Space Lift Program is a class of launch vehicles which lift payloads into low earth orbit. Historically Orbital ATK procures commercially available payload separation system from a number of manufacturers. Unfortunately, these commercially available systems are complex and cost prohibitive. Orbital ATK is interested in developing a payload separation system that is simple, cost efficient and imparts minimal shock when activated. Typically, spacecraft carry sensitive optics and components which are sensitive to shock environments. This project will include trades studies, design, analysis and sub-scale model prototype. The subscale model will be a separation system with a 15 bolted interface. As part of the design effort, a Preliminary Design Review (PDR) and Critical Design Review (CDR) will be required. The PDR will entail a presentation for the trade studies, down selection and tasks required prior to CDR. The CDR will entail a presentation of the selected design and will include analysis results, 1

5 testing plan and manufacturing drawings. Orbital ATK s scope for the project is to have our team work with Orbital ATK s Mechanical Engineers such that we might provide the needed deliverables. These deliverables include research on commercially available separation systems, engineering requirement compatible designs, trade studies, a completely manufactured prototype, design reviews, and a fully analyzed and manufactured product. By completing this project, Orbital ATK aims to acquire a reliable and low shock design with capabilities to be produced in house, such that they can build their market presence and reduce outsourcing. 1.3 Orbital ATK 38 Separation System Orbital ATK currently supplies a payload separation system known as the Orbital ATK 38 Separation System. As mentioned in the introduction, the overall goal of the system is to separate the spacecraft at a velocity just high enough that it does not re-contact the launch vehicle or propulsion system. While this project focuses on separation of smaller payload applications. This section gives a brief overview of how Orbital ATK s current system operates and its current deficiencies Orbital ATK 38 Separation System Structure The Orbital ATK 38 Separation System consists of a 38 diameter metallic ring that can connect to a 38 diameter bolt pattern on both the payload and rocket. This can be seen in Figure 1 below. Figure 1: Orbital ATK 38 Separation System [2] Weighing pounds, this simplistic design fits the current launch vehicle bolt interface and allows for reliable separation of the payload from the launch vehicle [2]. The midsection of the ring consists of a Marmon clamp band locked with a bolt mechanism. These two devices are later broken using ordnance Orbital ATK 38 Separation System Operation Operation of Orbital ATK s 38 separation system consists of three main sub-functions, including payload locking, release, and separation. Figure 2 represents a functional model of the current system below. 2

6 Figure 2: Orbital ATK 38 Functional Model Essentially, this system converts potential and chemical energy to kinetic energy through ordnance. First, the system is manually attached to the rocket and payload using a 38-inch diameter bolt pattern. The system then locks the payload using a Marmon clamp band and releases the payload using redundant bolt cutting action. This ordnance action also acts as the propulsion system, which separates the payload from the rocket Orbital ATK 38 Separation System Performance While this project does not focus on benchmarking the 38-inch application, Table 1 shows the present statistics open to the public on Orbital ATK s 38 separation system. Table 1: Orbital ATK 38 Separation System Statistics [2] Statistic: Value/Method: Height 3.95 in SV Interface Diameter in Total Mass kg Mass Attached to SV Post 4.0 kg In this table, height represents the total height of the separation system ring, the SV Interface Diameter represents the total diameter of the separation system (not the bolt pattern), the total mass represents the mass of the separation system when completely attached, and the Mass Attached to SV Post represents the mass that remains on the payload after separation [2]. 3

7 1.3.4 Orbital ATK 38 Separation System Deficiencies While no actual engineering specifications were given for this project, the sponsor did express that the redundant bolt cutting action negatively impacted the launch experience. Based on Orbital ATK s information, their current method of separating the payload emits too much shock compared to other systems on the market, and as a result, our team plans to benchmark the other systems available. 4

8 2 REQUIREMENTS It is important to note that this document discusses the design of a separation system for a 15-inch bolt pattern application. With that being stated, the original system mentioned prior is not being redesigned or altered to fit this application. Orbital ATK gave a large amount of engineering specifications required by the new 15-inch separation system. This section discusses those specifications and the requirements derived from them. 2.1 Customer Requirements (CRs) In order to meet the demands of the spacecraft, Orbital ATK set very specific requirements and specifications for the payload separation design. To help our team understand the important aspects of the design, the customer requirements (CR s) provided in Table 2 have been derived from the engineering requirements that Orbital ATK provided. These CR s were weighted on a 1 (least important) to 10 (most important) scale to reflect their importance to the overall project. The client reviewed the CR s and the weightings to ensure that they align with the client s goals. These CR s and weightings will support all future project decisions because they accurately reflect the needs of the customer. Table 2: Customer requirements and importance weighting, 10 being the highest Low shock and reliability proved to be the most important requirements for Orbital ATK. Since their current systems already produce high shock and affect reliability, increased reliability and low shock capabilities are a priority for the new design. Similarly, system mass is another important requirement for the design. How much an aerospace system weighs significantly affects how much fuel is required to launch the vehicle into orbit. With that fact in mind, a low system mass has been rated at top priority. In addition to mass, stability, how much load and vibration the system can withstand, is another important performance related requirement. While strength is an important factor to reliability, strong systems are considerably more massive, and as a result, the stability has been weighted less than mass. Similar to these other requirements, cost efficiency and manufacturability are key requirements for the separation system design. While it is Orbital ATK s goal to manufacture and sell this product in house, performance is much more crucial for these missions. The space craft that go into orbit often cost huge sums of money, and thus, a loss due to performance is much more critical compared to a compromise in cost and manufacturability. Due to the high heat that the spacecraft experiences during departure from the atmosphere, the client also highlighted temperature resistance as a requirement, but weighted it very low compared to the other performance related requirements. 5

9 2.2 Engineering Requirements (ERs) Team 7 received a document containing multiple ERs and tolerances from Orbital ATK. Most of the engineering requirements were taken from this document. Other engineering requirements were generated during a meeting with representatives from Orbital ATK or based on the project budget. The full list of ERs and tolerances can be seen in Table 3 below. Table 3: Engineering Requirements with Correlated Customer Requirements and Tolerances Engineering Requirement Correlated Customer Requirement Tolerances Removed for client confidentiality Low Shock ft-lbf Vibrations (Tables 1-2,1-4,1-5, 2-1) Stability/Durability NA Inertial Loads (Tables 1-1A & 1-1B) Stability/Durability FS 1.25 Temperature requirements (Table 1-3) Temperature resistant NA Under $2500 Cost <$3000 Interface System (Appendix 1.1.1) Stability/Durability, Manufacturable NA Reliability of Reliability Removed for client confidentiality Low Shock, Stability/Durability <=1 Removed for client confidentiality Low Mass NA Safety Mechanism included Safety NA Removed for client confidentiality Repeatability >10 trials As mentioned above, each engineering requirement corresponds to the specifications given by Orbital ATK. The tables corresponding to vibration in Appendix A give the frequency and magnitude of vibration acceptable at each phase during launch. The table correlating with inertial loads show the maximum moment, shear, and axial compression at each launch phase, with maximum values of 28,085 in-lbf, 1630 lbf, and 4360 lbf respectively. The temperature requirements in Table 1-3 in Appendix A show the maximum temperature ranges for storage, prelaunch, and separation, with a maximum temperature range of -10 C to 75 C. 2.3 Testing Procedures (TPs) The following testing procedures describe how each engineering requirement of the design will be tested to ensure customer specifications are met Separation Testing Tests will be conducted to ensure the separation is reliable and repeatable. The separation system will be 6

10 secured to a fixture via 24 quarter inch bolts, and actuated 20 times being reset between each cycle. The success rate will then be statistically evaluated to determine if it meets the.999 reliability specified. After each test cycle the system will undergo a visual inspection. The visual inspection will assess the system did not plastically deform, fracture, or fail to deploy. To be considered acceptable the system must deploy over an inch and have a separation duration of three seconds or less. The equipment this test requires is a fixture with a 24-inch bolt pattern to secure the system, a timer to gage separation time, and dial calipers measure the final distance traveled Vibration Testing During this test, the separation system will be exposed to a controlled random vibration profile in three orthogonal axes. This will be accomplished by securing a separation system to a random vibration table supplied by Orbital ATK test facility and allowing it to vibrate for up to ten seconds. Upon completion of vibration, the separation system will be released in order to see if the system still functions properly. Vibration magnitude and frequencies for each test shall correlate to Table 1-5 in the engineering requirements. By visual inspection, the system passes if the system separates properly after the test Strength Testing Strength testing will be performed to ensure the system structure can withstand early ascent and late ascent inertial loads. The specific tests to be performed will be moment load, shear load, and axial load. The minimum requirements for moment, shear, and axial loads are 28,085 in-lbf, 1,630 lbf, and 4,360 lbf respectively. To conduct all three tests, a scaled down prototype may be used to reduce the required applicable forces. Forces will be incrementally increased until the system yields or reaches 110% of the customer load requirements. A failure occurs if the material does not reach 110% load before yield or fracture. The moment load test will be performed by attaching a rod to the system and applying a perpendicular force at the end of the rod. The maximum moment will occur when the system exhibits material deformation. For shear force testing, the system will be bolted to a wall and a weight will be hung from it. The weight will be increased incrementally until maximum loading conditions are reached. Axial loads will be tested by placing weights on top of the separation system Thermal Vacuum Testing Thermal testing will be completed via a thermal vacuum at the Orbital ATK facility. This test ensures the system can handle the temperatures and pressures that will be seen during launch. The thermal vacuum will be set to the cycle between and minimum temperature of -10 C and 75 C respectively at a humidity of 89%. The system will be placed into the thermal vacuum for a period over ten minutes, which cycles between the extreme temperatures four times or as specified by Orbital ATK. After the last cycle, the separation system will be deployed once to check the success of the deployment. To be considered acceptable the system must deploy over an inch, and pass a visual inspection to ensure no plastic deformation occurred, nor fractures in materials. This test requires a thermal vacuum to control the temperature, pressure, and humidity. The test also requires dial calipers to check the final deployment distance Shock Testing Shock testing will be completed using a custom designed hammer. This hammer will be rotated to a specified angle and then released to impact the system. The magnitude of the impulse will be measured based on the weight and angle of the hammer. Any value recorded larger than those shown in Table (1-2) 7

11 in Appendix A will be considered a failure, while values equal to or lower will be considered acceptable EMI Testing EMI testing will be completed to determine and confirm the EMI output of the magnets. This test will consist of reading the EMI with an EMI reader at distances ranging from one to six inches (one test per inch). A successful test will consist of a reading of less than 10 V/m. Any reading higher than 10 V/m will result in a failed test. This test will be carried out at least ten times Safety Testing Safety testing will be completed to determine the reliability of the safety mechanism. This test will consist of turning off the magnets while the safety mechanism is engaged and ensuring the device remains connected. The test will have a duration of no less than ten minutes and be repeated at least ten times. This test will require the final design and a switch to disengage the power source. A successful test must last for the full duration with no visible damage to the system. Any visible damage or release of the system will result in a failed test. 2.4 Design Links (DLs) To ensure engineering requirements were met, design links to features in the system were related to each engineering requirement. Each design link is numbered according to the engineering requirement it is referring to Low Shock The design will meet low shock requirements by utilizing springs. The spring needs to be able to produce energy within the range of 4.5 to 18 ft-lbf. The springs will be made from chrome-silicon. The displacement of payload separation versus time and acceleration versus time were plotted via Matrix Laboratory (MATLAB), and the response determined that the maximum acceleration imparted on the payload will be ft/s 2. Based on the response of the system to the initial spring displacement, the maximum acceleration creates a smooth separation process Vibration The design will withstand the vibration levels specified in the engineering specifications in Appendix A without any loss in performance. Due to the separation process being guided by the ring structure, tipoff angle is removed. Our team performed a vibration analysis in MATLAB, and based on the response of the system, the system fully clears separation Inertial Loads The system handles the specified in axial, momentary and shear loads as seen in Table 1-1A & B in Appendix A. The two separation ring thicknesses and material will handle all the applied loads to the system. The flanges that guide the profile will protect against moments and shear, while the ring contact areas support the compressive loads. 8

12 2.4.4 Temperature Requirements The design will withstand the temperatures specified in Table 1-3 in Appendix A. Aluminum 7075 was chosen for the design to withstand these temperatures. Based on specifications given by manufacturers, all magnets and springs can withstand the temperatures given in Table Cost The total separation system must total under $2500. Parts will be ordered in bulk to get discount pricing and to have extras for testing. Additionally, cost efficient manufacturing methods shall be considered while machining the ring structures. This will be accomplished by cutting all features in one direction Interface System Team 7 received a requirement for a 15-inch, 24 hole, quarter inch bolt pattern for the system to interface. As a result, twenty-four quarter-inch bolt holes were placed around the outer structure to ensure compatibility Reliability The magnets and springs selected will perform to a reliability of.999. All tests performed will be statistically evaluated to ensure this reliability Tip-Off Rate While releasing, the tip off rate must be below 1 /s. A minimum of six springs were included to ensure this angle remains perpendicular to the rocket surface. Extra spring guides can be added to decrease tipoff angle. Additionally, the frame of the structure shall act as a guiding profile for the separation process to reduce tip-off during separation Safety Mechanism The design will meet the safety requirement by including two clamps. These clamps will be placed over both rings to ensure the rings cannot separate. These clamps can easily be removed prior to use and provide a secure mechanical feature for protection Repeatability To ensure the system maintains functionality after repetitive use, the device separation process will be conducted ten times. If the system does not successfully perform for all test mentioned prior in this document, the device will fail this engineering requirement. Additionally, by attaching all actuators and circuitry to the rocket side of the payload, all equipment can be reused if the rocket is recycled EMI The electromagnetic interference produced by all magnets must be under 10 V/m. The electronic components in the payload are sensitive and cannot be disrupted. The magnets are the only source for this EMI. 9

13 2.5 House of Quality (HoQ) After deriving customer requirements, our team put together a house of quality (HoQ) to identify and prioritize the metrics for the payload separation system design based on the customer requirements and their relative importance to the customer (Table 4). Table 4: House of Quality The house of quality currently only shows the CR s and weightings of each. As the project progresses, the HoQ will reflect all requirements, including specific engineering requirements. For this project, Orbital ATK identified and supplied engineering requirements that meet the rigorous flight conditions. As a result, our design will focus primarily on the low shock standards that Orbital ATK has put in place. 10

14 3 EXISTING DESIGNS The team researched various payload release systems currently on the market. We started by considering methods that our sponsor suggested to us. Our sponsor suggested we consider the Mark II and the RUAG release systems. From these ideas, our team could branch into other similar systems. The frangible joint was discovered during team research. All the systems are similar in that they work to release two components from each other, but they each accomplish the task differently. The Mark II and RUAG/Sierra Nevada system proved better suited for our design than the frangible joint, as the frangible joint requires explosives and a testing environment not available to our team. 3.1 Design Research As mentioned prior, our sponsor requested our team to become familiar with two preexisting systems developed by Planetary Systems and RUAG; the Mark II and RUAG Low Shock Separation System respectively. Due to the nature of business, detailed information on these systems are near unobtainable unless the system is purchased, so our team utilized Orbital ATK s Minotaur user s manuals and product catalogues to gather information on the system and subsystem level of the devices. Utilizing the Planetary Systems Mark II User s Manual, our team could gather detailed schematics and operational data on the Mark II Separation System. However, the RUAG separation systems did not have detailed schematics or operational data available, and resulted in the use of a product catalogue. Regardless of the lack or wealth of information, these sources gave our team enough information to understand what mechanisms the devices use to operate, as well as some public statistics. While researching these systems, our team also came across another separation system developer, Sierra Nevada Corporation, which utilizes a very similar method to that of the RUAG separation system. Being that the Sierra Nevada system is relatively new, our team utilized Sierra Nevada s product catalogue to further investigate the new product. Additionally, to gain a better understanding of what Orbital ATK already uses, our team researched the frangible joint method through the Ensign-Brickford Aerospace and Defense Company website and an ASME Joint Propulsion Conference article published by James E. Fritz on separation joint technology. Through these mentioned sources, our team grasped the basic information on the system and subsystem level required o benchmark for this project. 3.2 System Level Based on the sources mentioned above, there are three main system level designs that differ significantly enough at the system level, including Planetary System s Mark II, RUAG PAS 381S/Sierra Nevada QwkSep-15 Low-Shock Clamp Band, and the Frangible Joint utilized in Orbital ATK s 38 Separation System. Note, the RUAG and Sierra Nevada systems utilize almost the same principles for payload separation, and are discussed together to avoid redundancy. Each system or group utilizes its own principle or technology for payload separation, and as a result, are discussed in the following sections in more detail Existing Design #1: Mark II The Mark II by Planetary Systems Corporation, Figure 3, provides a low shock and very lightweight solution for payload release. It is a complex system with many moving parts, and thus tends to be difficult to work with compared to the RUAG or Frangible Joint. The Mark II uses a band with hinged leaves to secure the payload [2] [3]. The actuation of a release motor disconnects the leaves from the band, and a spring force separates the payload from the launch vehicle. The ring itself is very lightweight, at 5.79 lbm [2] [3], but unfortunately, Orbital ATK informed our team that this system costs a significant sum, costing around $200,

15 Figure 3: Mark II Separation System Existing Design #2: RUAG/Sierra Nevada RUAG has a variety of payload separation systems, ranging from diameters of 15 to 103. Being only 15 in diameter and 8.16 lbm, the RUAG PAS 381S provides low-shock separation and outstanding loading capabilities. The RUAG Systems utilize a clamping band to secure the payload to the rocket, and spring forces to separate the payload and rocket. The clamp band opening device uses an initiated pin puller device to convert band tension into kinetic energy for controlled separation [2] [4]. An example of the 15 diameter RUAG Separation System can be seen in Figure 4 below. Figure 4: RUAG Separation System [4] The RUAG systems are simple, reliable, average cost (compared to other systems per the sponsor), and can accommodate most standard rocket sizes. As a result, other companies, such as Sierra Nevada Corporation (Figure 5), have adopted similar approaches to payload separation [5]. Figure 5: Sierra Nevada Separation System [5] 12

16 3.2.3 Existing Design #3: Frangible Joint The Frangible Joint system is an ordnance based payload release system. It used the forces of an explosion to disconnect and separate the launch vehicle from the payload, thus providing an instantaneous separation [6] [7]. The system has a confinement tube which provides a housing enclosure for the explosion to occur in, which prevents excessive debris from spreading. All in one, this explosion containment mechanism functions as locking, separation, and release mechanism for the payload. Figure 6 shows an image of this joint. Figure 6: Frangible Joint [6] While the frangible joint excels at being simple and providing sufficient velocity to the spacecraft during separation, this joint induces high pyrotechnic shock from the explosion [7]. 3.3 Subsystem Level Based on the research of the existing systems, general payload separation can be broken into the following functional model (Figure 7). Figure 7: Separation System Functional Model 13

17 From observations during research, our team concluded there are three main sub-functions that allow the system to operate, including the payload locking, release, and separation. This section of the document will discuss each critical sub-function, and describe existing methods of performing the respective function Subsystem #1: Payload Locking When separation between a rocket and payload is needed, often the separation system acts as the connection between the two objects. Payload locking is the function that secures the payload to the rocket, ensuring stability during launch and flight. This function can be performed in multiple different ways, but the three major locking mechanisms are grooved release, clamping bands, or shearing bolts. The following sections will describe each mechanism, and how it performs the task of locking the payload Existing Design #1: Clamp Band Clamping bands compresses a band around the separation system to hold all components together. This method accomplishes locking through radial forces on the payload side of the interface, and does not loosen until actuated by another device [2] [4] [5]. Often, this device is paired with a servo motor, which actuates the band release. This method is currently used on Orbital ATK s 38 Separation System, the RUAG 381S Separation System, and Sierra Nevada Corporation s QwkSep-15 Low-Shock Clamp Band [2] [4] [5] Existing Design #2: Grooved Leaflets Grooved release mechanisms use a tongue and groove system to secure the payload. This ensures payload attachment through normal support forces [2] [3]. Figure 8 shows an example of this device. Figure 8: Mark II Grooved Leaflets [3] Based on our team s research, Planetary System s Mark II is the only separation system that uses this method, which is paired with a servo motor for release actuation [2] [3] Existing Design #3: Shearing Bolts Alternatively, to the other two methods, the shearing bolts mechanism uses bolts to hold the separation 14

18 system together. These bolts are then paired with the ordnance release mechanism to shear the bolts and allow for separation [6] [7]. An image of a frangible bolt joint can be seen in Figure 6 under the frangible joint section. This method is currently used in pair with the clamp band on Orbital ATK s 38 Separation system, and is paired with ordnance redundant bolt shearing [2] Subsystem #2: Payload Release When the rocket and payload need to be separated during flight, the release mechanism decouples the payload from the rocket, allowing for separation. This function essentially unlocks the payload from the body of the separation system. There are currently two methods researched that perform this action, including the servo motor and ordnance release. This section describes each method, and how it performs the task of payload release Existing Design #1: Servo Motor The servo motor is one of the most common mechanisms for releasing the payload. The servo motor is used in the Mark II, RUAG 381S, and Sierra Nevada QwkSep-15 Low-Shock Clamp Band. Figure 9 shows an example of a servo motor release system [3] [4] [5]. Figure 9: Servo Motor Release System [4] To actuate release, the servo motor receives an electrical signal from the command interface to start the motor. The motor gears then rotate to mechanically move the locking mechanism, such as the clamp band or grooved leaflets. This essentially lowers the locking forces of the locking mechanism, thus releasing the payload from the separation system [2] [4] Existing Design #2: Ordnance Release Ordnance release mechanisms use explosives of some kind to break the locking mechanism, allowing for release of the payload. Ordnance is generally simple and can be used to shear bolts or initiate pin pulling mechanisms [2] [6]. However, this method induces high pyrotechnic shock to the system during release due to the explosion it absorbs in the locking joints [6] [7]. This method is currently used on Orbital ATK s 38 Separation System [2], and is unsatisfactory due to the induced shock. 15

19 3.3.3 Subsystem #3: Payload Separation After release, the payload often needs excess force to separate the payload from the relatively moving rocket. Based on the research conducted, springs and ordnance were found to be the only mechanisms currently used to add additional force for separation. The following sections describe these respective methods and how they perform payload separation Existing Design #1: Spring Force The spring force mechanism utilizes potential energy from the locking mechanism to force the payload away from the rocket after payload release. This method directly converts the potential energy from a spring-damper system to kinetic energy [2]. This action can be seen in Figure 10 below. Figure 10: Mark II Spring Separation Mechanism [3] Based on the research conducted, the Planetary Systems Mark II and Sierra Nevada QwkSep-15 Low- Shock Clamp Band utilize spring mechanism for payload separation [2] [3] [5] Existing Design #2: Ordnance Unlike the spring system, the ordnance method used to release the payload also acts as the separation mechanism for ordnance based systems. The force from the explosion naturally separates the payload and rocket [6]. Due to the small timeframe, the force is applied over, this mechanism causes relatively high shock compared to spring separation systems [7]. This mechanism is currently used on Orbital ATK s 38 Separation System [2]. 16

20 4 DESIGNS CONSIDERED Based on the functional model derived for this project, our team brainstorm devices that could perform the three major sub-functions for a separation system using the Gallery Method. Through this method, each team member drew ideas that could potentially perform one sub-function. To create a fully functional design, the concepts generated were placed in a morphological matrix for each sub-function category. This can be seen in Table 5 below. Table 5: Morphological Matrix Subsystem Concepts Lock Payload Shape Memory Band Shape Memory Clamps Magnets Pneumatic Seal Leaflets Servo Band Release Payload Shape Memory Band Shape Memory Clamps Magnets Actuator Pneumatic Release Separate Payload Springs Magnets Pneumatic Balloon Shape Memory Lever Gear Lift After the designs were placed in the morphological matrix, our team proceeded to combine the concepts together to create a fully functional design. Some of the designs that resulted from this process are described below. 4.1 Design #1: Servo Motor Band with Springs Design #1 utilizes a tensional locking band, actuated by a servo motor, and is separated by springs as seen in Figure

21 Figure 11: Servo Motor Band with Springs This design uses the radial compressive forces from a surrounding band which locks the payload to the rocket. A servo motor releases the provided tension from the band, which decouples the payload from the rocket. Springs will then effectively push the payload away from the rocket. This system is paralleled with systems currently used in the aerospace industry, and has been proven to be effective. Clamping bands are a simply designed technology and can be manufactured to various shapes and sizes to accommodate a variety of missions. Servo motors are reliable and can be utilized over many cycles. Springs are reliable, low shock, and can be characterized for specific applications. While this design is widely used in the industry, it is generally expensive and is produced by a limited amount of companies. 4.2 Design #2: Shape Memory Band with Springs Design #2 utilizes a shape memory alloy retention band with a spring release system, as seen in Figure 12. Figure 12: Shape Memory Band with Springs This design effectively utilizes the radial compressive forces from a surrounding band to lock the payload in place. Release of this payload is actuated with an electric current, where the shape memory alloy 18

22 changes shape due to change in temperature, and the payload is released. Once the compressive radial forces are removed springs then release to separate the payload from the rocket. This system has multiple beneficial characteristics. By eliminating actuators such as servo motors and ordinance pins, the system only requires connected electrical wires to provide a current to heat the shape memory alloy, and as a result, the overall weight of the system is decreased. Additionally, the spring separation provides a reliable low shock separation for the payload. While this design is state of the art, there are concerns about the manufacturability and repeatable use of this design. Shape memory alloys are relatively difficult to obtain and treat to a particular shape, as a result, the manufacturability of the shape memory band will require some high temperature ovens. Additionally, the ability to test a shape memory alloy band could prove to be difficult if the band does not retain the same properties after consistent use. 4.3 Design #3: Shape Memory with Magnets Design #3 utilizes a shape memory alloy retention band with a magnetic release system, as seen in Figure 13. Figure 13: Nitinol Band with Magnets Similar to Design #2, this design takes advantage of the properties of shape memory alloy to apply radial compressive forces around the separation system to lock it in place. The energy retaining the band s shape is then released by heating the band through an electric current. However, this design utilizes oppositely poled magnets to provide a separation force. Similar to the other design, this design reduces the number of actuating components required by the separation system. Additionally, the magnets used to separate they payload from the rocket will produce a very low shock separation force, due to the minimized number of mechanical components. While this design does provide a great solution, there are concerns with the tip off velocity at separation. Due to the fact that magnets cannot accurately force the payload away at every point, the force could prove to be unevenly distributed, resulting in an unpredictable tip off velocity of the payload. Similar to Design #2, the manufacturability of the shape memory alloy will be a concern. 19

23 4.4 Design #4: Shape Memory with Pneumatic Jets Similar to Designs #2 and #3, this design utilizes a shape memory band to lock and release the payload, however, for separation, this design takes advantage of compressed gases to separate the payload from the rocket (Figure 14). Figure 14: Shape Memory Band with Pneumatic Jets In this design, the pneumatic jets provide a very low shock separation mechanism for the payload by reducing almost all contact with the rocket system. This system contains all the other advantages of shape memory alloy, as mentioned for Designs #2 and #3. While this design does provide a unique solution for separation, there are concerns with the separation method. For example, setting off gas jets at the same rate could prove difficult, and result in an unpredictable tip off angle. Additionally, the design is more complicated, and would need more actuation measures including valves and switches. 4.5 Design #5: Shape Memory Clamps with Lever Separation Unlike other designs mentioned, this design uses shape memory alloy that acts as both a locking and separation mechanism (Figure 15). Figure 15: Shape Memory Clamps with Lever Separation 20

24 In this design, shape memory alloy is used to mechanically lock the payload side of the separation system in place. Then, once an electric current is applied to those mechanical locks, the alloy will change shape, and lift the payload away from the rocket. The benefit of this design, is the use of one component for all sub-functions, as a result, the design can be relatively simplistic with fewer actuators. Additionally, the shape memory alloy will act as a spring, thus providing a low shock and continuous separation force to the payload during separation. Cons to this design lie entirely with the manufacturability. The shape memory alloy pieces would be very complex to machine, as well as treat for the shape memory properties. As a result, the cost to manufacture this design would be extremely large, for the tooling and heating devices required. 4.6 Design #6: Magnetic Clamp with Springs Design #6 utilizes the attractive forces provided by reversible electromagnets to secure the payload to the rocket (Figure 16). The magnetic connection is turned off by an electrical pulse. Once this occurs, the payload is decoupled from the rocket, and springs then separate the payload from the rocket. Figure 16: Magnetic Clamp with Springs This system will provide a high force to secure the payload via magnets, while also providing a low shock separation from the springs. Magnets provide reliability in the locking of the payload because no external force or electronic connection is required once they are connected. They may be configured to only separate with the electronic pulse. While the magnets may be reliable for the application, they introduce electromagnetic fields to the system Without shielding, these fields can potentially damage the sensitive electronics within the payload. Depending on the mass of the magnets, there is potential for an increased mass in the system. The corrosive properties of magnets could limit the lifetime and durability of the system. 21

25 4.7 Design #7: Magnetic Locking & Separation Similar to Design #6, Design #7 utilizes the attractive forces provided by reversible electromagnets to secure the payload to the rocket (Figure 17). However, the polarity of the magnets are reversed by a provided electrical pulse, to push the payload away from the rocket. Figure 17: Magnetic Locking and Separation This system will provide low shock while separating. The tip-off angle could be an issue depending on the specific magnetic fields supplied by the magnets. This system contains all other advantages and disadvantages associated with magnets in Design # Design #8: Pneumatic Seal & Release with Springs Design #8 utilizes the compressive force of a pneumatic tube to seal the payload and rocket together (Figure 18). Figure 18: Pneumatic Seal and Release with Springs 22

26 After the gas in the compressive tube is released, the two components are then separated using springs. This design provides multiple benefits to the separation process. By utilizing a hollow tube filled with lightweight gasses, this device should prove to be a low mass separation solution. Also, the sealing of the payload without mechanical devices helps with low shock separation. While this design provides a state of the art solution, there are some concerns with using pneumatics for locking and release. Since the locking mechanism contains compressed gasses, there are concerns with safety while containing all of the compressed energy. If there were to be a leak or a problem, injury could occur if the seal explodes. Additionally, manufacturing the sealing mechanism could prove difficult, based on the forces required to maintain a seal and grip. 4.9 Design #9: Pneumatic Seal & Release with Jets Similar to Design #8, Design #9 utilizes the compressive force of a pneumatic tube to seal the payload and rocket together (Figure 19). After the gas in the compressive tube is released, the two components are then separated using pneumatic jets, where either the gasses from the tube or an external source push the payload away. Figure 19: Pneumatic Seal and Release with Magnets This design provides multiple benefits to the separation process. By utilizing a hollow tube filled with lightweight gasses, this device should prove to be a low mass release solution. Also, the sealing of the payload without mechanical devices helps with low shock separation. The forces generated by the pneumatic jets also aide in imparting low shock to the payload. Similarly to previous design iterations, incorporating a pneumatic seal system introduces a safety hazard due to a high-pressure vessel. If a leak, rupture, or catastrophic material failure occurs, the effects could be similar to that of a small bomb. Manufacturing of such a device may be difficult with the high forces required to seal and maintain a frictional grip on the payload. The tip off angle will have inherent problems due to the uneven release of gas during separation. 23

27 4.10 Design #10: Pneumatic Seal & Release with Balloon Similar to Design #9, Design #10 utilizes the compressive force of a pneumatic tube to seal the payload the rocket together (Figure 20). After the gas in the compressive tube is released, the energy stored from the gas is transferred to an inflatable balloon-like device that forces the payload to separate from the rocket as it inflates. Figure 20: Pneumatic Seal with Balloon This design provides multiple benefits to the separation process. By utilizing a hollow tube filled with lightweight gasses, this device should prove to be a low mass separation solution. Also, the sealing of the payload without mechanical devices helps with low shock separation. The forces generated by the balloon can be controllable by the rate that it is filled with the gas from the tube. As with the other pneumatic seal systems, high pressure vessels create a safety hazard for manufacturing and testing of the tube. Manufacturing of a seal device can prove to be difficult with a limited amount of resources and materials available. Using a transfer of energy from one vessel to another creates variability. More valves and air control components will be put in place to ensure the flow rate and tip off angle is sufficient. Incorporating system controls on the pneumatics is not an option, as the size of the controls system requires more space than we have available. 24

28 5 DESIGN SELECTED Due to feedback from Orbital ATK, all the designs that were selected from the team s pugh chart were very appealing, and Orbital ATK requested more research on the down selected designs. After research on the positive and negative features of the designs, our team performed more down selection through a decision matrix to select a final design. 5.1 Rationale for Design Selection From the concept generation mentioned above, our team began to down select the ideas based on their ability to meet the customer requirements. This was accomplished using a Pugh chart, which allowed our team to compare our newly generated designs to an existing with the customer requirements. The chart used can be seen in Table 6 below. Table 6: Pugh Chart For the Pugh chart above, our team selected the RUAG 381S to act as the datum. Being that Orbital ATK currently uses this product and enjoys its simplicity, the RUAG separation system acts as a strong datum. After comparing the potential designs to the existing product, the shape memory alloy clamp band with spring separation, magnetic clamps with spring separation, pneumatic seal with spring separation, and pneumatic seal with jet separation were selected as final designs. Notable trends in the evaluation based on the customer requirements are seen in the temperature resistance, stability, shock, and manufacturability. For example, temperature resistance negatively affected the shape memory bands, due to their effects relying on temperature change. Similarly, manufacturability affected the pneumatic designs due to the difficulty of finding materials that could fulfill the role of the sealing mechanism. Additionally, stability negatively affected designs that utilize magnets or pneumatic jets for separation due to the unreliable tip off velocities and angles they produce. For positive trends, low shock positively affected designs that did not use as many mechanical components. Based on these trends, the four highlighted designs were selected for further research and down selection. The decision matrix used to down select can be seen in Table 7 below. 25

29 Table 7: Decision Matrix Customer Requirement Weight SM Weighted score M Weighted Score P Weighted Score PS Weighted Score 1.Low Shock Stability/Durability Manufacturable Cost Reliability Low Mass Temperature Resistant Safety Repeatability Low EMI/EMF Total Score Percent Score Based on the ratings given, the decision matrix selected the magnetic design as the final design for the project. This was determined based on the research conducted on each design. After researching reliability of pneumatic designs, the pneumatic reliability proved to be too low for aerospace standards. Additionally, the pressurized gas would prove difficult to release at equal rates, thus affecting stability and manufacturability. The shape memory alloy design became infeasible due to the amount of current draw required to release a reliable ring. The ring required kiloamps in current, compared to milliamps for other actuators, and as a result, the design received low scores in reliability. Additionally, the manufacturing process for heat treating shape memory alloy can be very difficult due to the equipment and accuracy in the temperature required, thus the design received low scores in manufacturability. Based on these downfalls, the magnetic design proved to be the best option for the project, receiving a top score of 818 out of The magnets are very reliable because they are permanent magnets and do not release hold until a current is sent to them. Additionally, the spring separation mechanism proved much more manufacturable and stable compared to the jet propulsion, due to the pipe tolerances and consistent release rates. Furthermore, the design showed no major downfalls with exception to mass, due to their slightly higher weight compared to other metals. 5.2 Design Description After careful consideration and analytical analysis Team 7 is pursuing the magnetic clamp with spring separation. The magnetic clamping system was selected due to its simplistic design and ease of manufacturing. Magnets are also a passive system that revert to a locked state. The use of a passive system enhances the overall system reliability which Orbital ATK holds paramount. The magnetic clamp is paired with springs to supply the separation energy the system requires. Springs are a reliable, simple, 26

30 and lightweight separation mechanism that allows the system to stay compact. The following sections further describe the notable features of this design, and how they relate to each engineering requirement. An image of this design can be seen in Figure 21 below. Figure 21: Magnetic Separation System Two dimensional drawings of the system can be further viewed in Appendix B Magnets Magnets were selected after further feasibility of the pneumatic seal was analyzed and proved infeasible. Magnets have proved to be a reliable and simple method of attachment that require no moving components to activate. Permanent electromagnets were selected, which have a magnetic field constantly on until a current is applied to shut them off the magnetic field. This is ideal for the proposed separation system since the system will be locked together more than 50% of the time [8]. The permanent electromagnets have the capability to far exceed the temperature range the system will be exposed to, while also being shock resistant. Based on analysis of the strength to weight ratio of 14 different permanent electromagnets a final magnet was selected from APW Electromagnets. The system will utilize 4, 1.37-inch diameter magnets having a total weight of 1.45 pounds. The most critical factor of the magnet is the strength to weight ratio because the weight must be kept to a minimum while also providing adequate holding force. The 1.37-inch magnet had the second-best strength to weight ratio, but required 4 magnets. The extra.3 pounds added by the 1.37-inch magnet is justified because it will significantly reduce manufacturing costs by installing 61 less magnets. Lastly the total power needs to be analyzed in order to determine the size battery required. The battery adds weight to the rocket and must be able to handle 112 watts Springs Springs will be used to separate the two rings and release the payload from the rocket due to their ability to release with minimal shock. The engineering requirements provided to the team supply an energy that 27

31 the springs must create in order to release the payload. The energy ranged from 4.5 ft-lbf to 18 ft-lbf. Using values imputed based on the structure, magnets, number of springs to be used, energy required, and arbitrary spring values the spring wire diameter was calculated along with the number of coils and the spring constant. The energy provided needed to be converted to a force that can be distributed equally to each spring. The number of springs will be selected based on the number needed to keep the tip off rate within 1 /s and to minimize the vibration effects. The spring s free and compressed length will be selected based on the depth and size of the magnets and ring. The spring diameter will be selected based on the area of the ring. Three different wire materials were selected to take into consideration; stainless steel, chrome-vanadium, chrome-silicon. Chrome-silicon will be used after considering the properties and reliability needed from the spring. The potential energy equation and the spring constant equation were combined and used to solve for the diameter of the wire. With the wire diameter selected the number of coils and the spring constant were calculated. With that information, a spring can be selected from Lee springs [9]. See Appendix C for the equations and variables that were used in the calculation Structure The structure of the separation system was designed to contain all components and withstand all inertial loads. The structure consists mainly of two concentric rings with tabs on the inside to mount magnets and an outer flange to support inertial loads. The flange contains holes to interface with the required bolt pattern and recesses to mount spring guides in. The spring guides will be attached using an epoxy. Bolt holes will be drilled in the center of the tabs to mount the magnets. The critical dimension of the structure is the distance traveled by the upper spring to disconnect. This flange length of one inch is the primary design element to prevent deflection due to the moment loading. All other dimensions adequately withstand the inertial loads, but may be subject to change in order to reduce weight. After completion of the structural force analysis seen in Appendix D, the material selected is 7075-T6 aluminum. This alloy has a high strength to weight ratio, and is used in other aerospace applications making it a suitable choice Material Coating After performing friction calculations for the contact surfaces of the top and bottom ring of our selected design it was determined that system performance will be improved by applying a Teflon coating on the contact surfaces (see Table E1 Appendix E). With a Teflon coating the coefficient of friction can drop from 1.2 (aluminum on aluminum) to the range of 0.05 to 0.2 (Teflon on Teflon), a maximum reduction of 2,300% [10] [11]. The force required to overcome the opposing frictional force is linearly related to the frictional coefficient, so the spring system used to achieve that force does not need to be as strong. Because of this, lighter and less expensive springs can be used. For the purposes of this project, the team may not send the components into a professional Teflon coating vendor. A Teflon dry lubricant spray can be used with the prototype. If the customer proceeds with the design in the future, then the coating will be done professionally. 28

32 6 PROPOSED DESIGN A sequence of tasks will be completed for successful implementation of the payload separation system. The first step will be to acquire all of the necessary materials, followed by manufacturing and tooling materials, assembling prototype, systems testing at NAU and Orbital ATK, redesign and repeat, and lastly the team will present the working design. Materials will be provided by the vendors listed in the bill of materials table below. Table 8: Bill of Materials Material/Part Vender Cost Quantity Total Cost per item Source 7075 Aluminum block (38x17x3) Inches Midwest Steel and Aluminum $ $ [12] Springs Lee Springs $ $ [9] Spring Guides 3D print $ $12.00 Electromagnets APW $ $ [13] M5 Screws McMaster Carr $12.45 package of 100 $12.45 [14] CRS 1215 Steel Plate (D=1.5 inch L=12inches) Speedy Metals $ $15.00 [15] Wire (26 ga) Amazon $ ft $5.00 Teflon Dry Lubricant Amazon $ $9.99 Total Shipping $550 All $550 Total Cost * $ *Total cost doesn t include machining cost As materials are received the team will work with the machine shop located on NAU campus in building 98c to determine what parts can be made in house. Team members will fabricate parts that do not require machining expertise. Work orders will be made for any part that the team members are not qualified to fabricate. If the machine shop does not have the capability to manufacture any components the production will be outsourced to a different machine shop facility. Upon completion of tooling materials, the components will be assembled. If any size or fitting issues arise during assembly, the components will be retooled and reassembled as necessary. When the prototype is fully assembled and in a functioning state, testing procedures and design of experiments will be written. Testing will be conducted partially on NAU campus and partially at the Orbital ATK facility. The team will conduct structural and EMI testing at NAU campus. An EMI tester from the electrical engineering department will be procured and used for the EMI test. For structural testing the team will obtain weights, a long shaft, and a hammer to test the axial, moment, shear, and shock requirements. For vibration and thermal testing, vibration tables and ovens at the Orbital ATK facility will be used. When the design has been fully tested, the results will be 29

33 presented to Orbital ATK and Sarah Oman. The expected design can be viewed in Figure 21 above, and an exploded view of the assembly can be viewed in Figure 22 below. Figure 22: Exploded View This explode view shows the assembly of major components with exception to components that can be added in excess, such as extra springs, spring supports, screws, etc. 30

34 References [1] Orbital ATK, "Company Overview," [Online]. Available: [Accessed 28 September 2016]. [2] Orbital ATK, "Minotaur I User's Guide," September [Online]. Available: [Accessed 29 September 2016]. [3] Planetary Systems Corporation, " F MkII MLB User Manual," 30 July [Online]. Available: Available: [Accessed 20 September 2016].. [Accessed 20 September 2016]. [4] RUAG, "PAS 381S (15") Separation System Data Sheet," [Online]. Available: aration_system.indd.pdf. [Accessed 21 September 2016]. [5] Sierra Nevada Corporation, "Sierra Nevada Corporation's Space Systems: Space Technologies Product Catologue," [Online]. Available: [Accessed 25 September 2016]. [6] Ensign-Bickford Aerospace & Defense, "Frangible Joint," [Online]. Available: [Accessed 21 September 2016]. [7] James E. Fritz, "Separation Joint Technology," in AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Huntsville, Alabama, [8] Magma Magnetic Technologies, "Permanent Electromagnets," Magma Magnetic Technologies, [Online]. Available: [Accessed 19 November 2016]. [9] Lee Spring Company, "Lee Spring," Lee Spring Company, [Online]. Available: [Accessed 19 November 2016]. [10 ] [11 ] [12 ] [13 ] [14 ] [15 ] T. E. Toolbox, "Friction and Friction Coefficients," T. E. Toolbox, [Online]. Available: [Accessed 13 November 2016]. I. Donwell Company, "Properties of DuPont Teflon industrial coatings," I. Donwell Company, [Online]. Available: [Accessed 17 November 2016]. Midwest Steel and Aluminum, "7075 Aluminum Plate," Midwest Steel and Aluminum, [Online]. Available: [Accessed 15 November 2016]. APW Company, "Permanent Electromagnets," APW Company, [Online]. Available: [Accessed 12 November 2016]. McMaster-Carr, "Screws," McMaster-Carr, [Online]. Available: [Accessed 19 November 2016]. Speedy Metals, "1-1/2" {A} Rd Cold Finished 1215," Speedy Metals, [Online]. Available: [Accessed 20 November 2016]. 31

35 APPENDICES Appendix A Removed for client confidentiality Appendix B Removed for client confidentiality Appendix C Appendix D Table B1: Structural Analysis Variables and Definitions Variables: Definitions: 32

36 σσ ττ FF FF AA FF SS mm LL Compressive Stress Shear Stress Force Caused by Moment Load Axial Force Shear Force Moment force Length of Flange The following equations were used to evaluate the loading conditions: σσ = FF AA AA CC ττ = FF SS AA SS FF = 2mm LL Table B2: Structural Analysis Results Removed for client confidentiality Appendix E Table E1: Friction Calculation Tables [10] [11] 33

37 Appendix F Table F1: Analysis Assumptions Number: Assumption: Result: 1 Payload center of mass is centralized at the center of its dimensions. Symmetry simplification for free body diagrams. 2 Separation structure guides the payload during separation. Makes response only a function of displacement (tipoff angle removed) 3 All springs have same stiffness Makes response only a function of displacement (tipoff angle removed) Geometry of ring does not matter in analysis. 4 Response relative to the rocket frame. Inert frame for equations of 34

38 motion. 5 Vibration during launch is random Only separation phase response needs analyzed. 6 Negligible friction damping No external forces in response. 7 Six Springs on system Table F2: List of Variables and values Variable: Description: Given Value: m Mass of the payload 250 [lbm] k Spring stiffness 480 [lbf/ft] X 0 Initial displacement -1/12 [ft] t time NA [s] X(t) Displacement as a function of NA [ft] time X(s) Laplace Displacement Transfer NA Function ω n Natural frequency [rad/s] ω Forcing Frequency [rad/s] a Mass acceleration NA [ft/s 2 ] The following Equations were used to derive a response to the system: mmmm 6kkkk = 0 XX(ss) = xx 0ss ss 2 6ωω nn 2 ωω nn = kk mm xx(tt) = cos ( tt 805) 12 35

39 Figure F1: Payload Separation Response 36