Documenting Rocket Science: Cardinal Heavy Design Overview

Cassandra Gearhart Iowa State University—Ames, Iowa 50011 Cyclone Student Launch Initiative April 17, 2017

Cardinal Heavy Design Overview Cassandra Gearhart

Contents

Contents ...... i Figures...... ii Tables ...... ii Table of Acronyms ...... ii Abstract ...... iii 1 Introduction ...... 1 2 NASA’s Centennial Challenge Requirements ...... 1 3 Cardinal Heavy’s Design ...... 2 3.1 Basic Material Overview ...... 2 3.2 Rocket Overview ...... 2 3.3 Nose Cone Overview ...... 3 3.4 Camera Bay Overview ...... 3 3.5 Parachute Bay Overview ...... 3 3.5.1 Parachute Bay 1 ...... 4 3.5.2 Parachute Bay 2 ...... 4 3.6 Recovery Overview ...... 4 3.7 Flight Computer Bay Overview ...... 5 3.8 Roll Control System Overview ...... 5 3.9 Air Brake Overview ...... 6 3.10 Motor Mount Overview ...... 6 3.11 Split Fin Overview ...... 7 4 Conclusion ...... 7 References ...... 7 Appendix A ...... A Table of Technical Terms ...... A Appendix B ...... B Technical Document Style Sheet ...... B Bibliography ...... D

Iowa State CySLI i

Cardinal Heavy Design Overview Cassandra Gearhart Figures

Figure 1: M:2:I Program Logo ...... 1 Figure 2: OpenRocket Diagram of Cardinal Heavy’s Seven Main Body Sections ...... 2 Figure 3: SolidWorks Rendering of Nose Cone ...... 3 Figure 4: Recovery Configurations of First and Second Recovery Events ...... 4 Figure 5: SolidWorks Rendering of Flight Computer Bay Components ...... 5 Figure 6: SolidWorks Rendering of Roll Control System ...... 5 Figure 7: Diagram of Air Brake Set-up ...... 6

Tables Table of Acronyms………………………………………………………………………………. ii Table of Technical Terms……………………………………………………………………….. A

Table of Acronyms

Above Ground Level AGL Critical Design Review CDR Cyclone Student Launch Initiative CySLI Flight Readiness Review FRR High-definition HD Inertial Measurement Unit IMU Launch Readiness Review LRR Make-to-Innovate M:2:I Mars Ascent Vehicle MAV Preliminary Design Review PDR Roll Control System RCS

Iowa State CySLI ii

Cardinal Heavy Design Overview Cassandra Gearhart

Abstract Aerospace engineering, or rocket science, is just one of many engineering disciplines that make use of collaboration with technical communicators to provide a comprehensive overview of any engineering project, old or new. For my honors project, I explored multiple aspects of being a technical communicator that collaborates with an all-engineer team to produce effective technical communication. The Cyclone Student Launch Initiative (CySLI) gladly accepted my offer to assist them with their NASA competition documents while I worked on my project. In exchange, I gained the technical background required to produce three forms of technical communication about rocket science at Iowa State: a brochure, a newsletter, and a technical description. The brochure is designed to reach out to middle school students who may be interested in model or high-powered rocketry. The newsletter is meant to inform CySLI team sponsors and program coordinators of events that occurred during CySLI’s competition year. Finally, the technical description (this report) provides a condensed design overview of the 2016–2017 rocket and provides information about NASA’s Student Launch challenge. Through working with these engineers, I gained a better understanding of how collaborative processes function in technical communication and had the experience of a lifetime building a true rocket.

Iowa State CySLI iii

Cardinal Heavy Design Overview Cassandra Gearhart

1 Introduction Iowa State University’s Department of Aerospace Engineering is a place where students work with technology and each other to develop skills needed in aerospace careers. One way in which the department helps students develop their abilities is through the Make-to-Innovate (M:2:I) program (Figure 1), where they gain hands-on experience in implementing classroom knowledge by designing, building, and operating functional Figure 1: M:2:I Program Logo aerospace systems. In M:2:I, there are 13 operational projects, out of which one deals with high-powered rocketry. The Cyclone Student Launch Initiative (CySLI) is a team that designs and builds a rocket meant to compete in one of NASA’s Centennial Challenges. For the 2016–2017 school year, CySLI has set out to fulfil the design and experiment requirements in NASA’s Student Launch Handbook. CySLI will meet these requirements by producing multiple design-related documents to be submitted to NASA officials for review. This document briefly overviews the competition and rocket design for the 2016–2017 year. Appendices A and B hold supplemental materials about technical terms and document design processes.

2 NASA’s Centennial Challenge Requirements Every year, NASA’s Centennial Challenges partner with NASA’s Student Launch Initiative to produce what is termed the NASA Mars Ascent Vehicle (MAV) Challenge. Teams from universities across the United States participate in this challenge, which brings “a broad audience of colleges and universities across the nation in an eight-month commitment to design, build, and fly payloads or vehicle components that support [the] SLS” (May 2017). CySLI has entered this competition—which takes place at NASA’s Huntsville—Alabama location, for three consecutive years. CySLI must meet a certain set of requirements that NASA’s Student Launch sets forth in its annual handbook. A proposal is necessary to enter the competition, as it outlines a basic new design and plans for implementing the rocket design. The other 2017 requirements include successfully completing a “Preliminary Design Review (PDR), Critical Design Review (CDR), Flight Readiness Review (FRR), [and] Launch Readiness Review (LRR)” (NASA SL Handbook 2017, 4). These documents must include basic vehicle and recovery system requirements that present safety concerns if improperly implemented. Other requirement examples include “deliver[ing] the science or engineering payload to an apogee altitude of 5,280 feet above ground level (AGL)” (NASA SL Handbook 2016, 4) and “design[ing] [the vehicle] to be recoverable

Iowa State CySLI 1

Cardinal Heavy Design Overview Cassandra Gearhart and reusable” (NASA SL Handbook 2016, 5). There are also requirements for a chosen experiment, safety during construction and launch, and general regulations. Technical requirements such as these allow NASA to weed out potentially unsafe rockets from the competition, in addition to testing students’ ability to design a vehicle with certain restrictions.

3 Cardinal Heavy’s Design CySLI’s rocket for the 2017 launch in Huntsville, Alabama, is designed with many specifications in mind. Due to the unusually heavy approximated weight of the rocket, CySLI has christened the 2017 rocket “Cardinal Heavy.” The information in this section is up-to-date as presented to NASA through CySLI’s CDR, posted online on January 13, 2017.

3.1 Basic Material Overview CySLI, having dealt with high-powered rockets before, has selected its materials to be of the lighter weight and more durable quality to ensure maximum rocket performance upon launch. The main airframe will be constructed of Blue Tube, a cylindrical tube that is more durable than fiberglass or phenolic and is commonly used in high-powered rocketry. Fiberglass—G-10 sheet and filament wound—will be used for the main fins and the nose cone as it is a lightweight and durable material that is a better alternative to metal or plastic. Carbon fiber will comprise the roll control system (RCS) and air brake fins. Any 3D printed components will consist of white ABS plastic, which is amorphous and easily formed into various shapes by a 3D printer. It is also durable in comparison to other available plastics for 3D printing. Internal structural components such as bulkheads and bay sleds will be comprised of birch plywood cut and sanded to fit the airframe. Threaded steel rods, washers, nuts, and U-bolts, will be used to hold together bay components and rocket sections.

3.2 Rocket Overview The basic design for the rocket body includes seven main body sections (Figure 2) held together with securing rivets or shear pins and three Blue Tube couplers. Our seven main

Figure 2: OpenRocket Diagram of Cardinal Heavy’s Seven Main Body Sections sections include the nose cone, camera bay, parachute bay one, altimeter bay, parachute bay two,

Iowa State CySLI 2

Cardinal Heavy Design Overview Cassandra Gearhart flight computer bay, and motor mount. “The dimensions of the rocket body were determined by the space needed to comfortably house all of the necessary components” (Kaiser 2017, 15). The airframe will have a 6-inch diameter to accommodate the camera bay and air brake assemblies and will be 132 inches long.

3.3 Nose Cone Overview CySLI selected a 5:1 Ogive nose cone for Cardinal Heavy, rather than a 4:1 Ogive like in years’ past. This lengthens the rocket to improve the stability margin to NASA’s 2.0 requirement. The nose cone is 30 inches long, is 6 inches in diameter, and has a 6-inch shoulder for easy coupling with Figure 3: SolidWorks Rendering of Nose Cone the rocket (Figure 3). The aluminum tip is an added precaution against fracturing. The cone is constructed of filament wound fiberglass. This fiberglass was selected as an alternative to regular fiberglass nose cones, primarily because “fiberglass nose cones have cracked or fractured near the tip” (Kaiser 2017, 15) as a result of typical force exerted on the rocket. Filament wound fiberglass prevents this fracturing from occurring.

3.4 Camera Bay Overview The camera bay consists of seven Mobius high-definition (HD) cameras mounted into an ABS plastic, 3D-printed case. Two cameras are pointed out static portholes at 45-degree angle mirrors “epoxied to the outside of the rocket” (Kaiser 2017, 17), which capture a view along the rocket airframe and ensure the visibility of our RCS fins and air brake systems to prove actuation. The other Mobius HD cameras lenses are arrayed so that their main body fits within the 3D printed housing and a cable connects the lens back to the body. The lenses are pointed through five equally spaced static portholes in order to capture a 360-degree view of the rocket launch. The footage taken from these five cameras will be stitched together to form panoramic video.

3.5 Parachute Bay Overview One of the most important aspects of a successful launch is that of the recovery system. The parachute bays house the materials that enable the rocket’s safe return to the launch field after its flight.

Iowa State CySLI 3

Cardinal Heavy Design Overview Cassandra Gearhart

3.5.1 Parachute Bay 1 This bay is situated between the fore avionics bay coupler and the aft flight computer bay. To accommodate the recovery system components, the bay is 8.5 inches long and 6-inches in diameter. There are 12 yards of nylon shock cord attached to two U-bolts and an 18-inch-diameter drogue parachute. The U-bolts are screwed into birch plywood bulkheads, one attached to the avionics bay and the other to the flight computer bay, which distributes the recovery forces evenly across the airframe.

3.5.2 Parachute Bay 2 Parachute bay 2 is located between the fore camera bay and the aft avionics bay. The bay is 28.25 inches long and 6 inches in diameter to accommodate the larger portion of Cardinal Heavy’s recovery system. This bay contains the main 120-inch-diameter parachute as well as the 24-inch pilot parachute. A Nomex heat shield is fastened to 12 yards of nylon shock cord, which protects the parachutes from the black powder ejection charges.

3.6 Recovery Overview Cardinal Heavy’s recovery system consists of multiple parts. The avionics bay houses two altimeters to ensure parachute deployment. The altimeters are wired to black powder charges on the bulkheads on either side of the coupler, which connects the two parachute bays together using shear pins. With the charges and bays packed in place, the system has a series of two events that allow for the safe recovery of the rocket. Figure 4: Recovery Configurations of First and Second Recovery Events The first recovery event (Configuration 1 in Figure 4) occurs when the rocket has achieved apogee. A 3.7-gram black powder charge ejects the 18-inch drogue parachute from parachute bay 1, which unfolds and slows the rocket’s descent to about 119 feet per second. Recovery event 2 (Configuration 2 in Figure 4) occurs once the altimeters register 800 feet AGL. A 4.1-gram black powder ejection charge blows the avionics bay coupler away from parachute bay 2, deploying the 24-inch pilot parachute, which aids in the deployment of the 96-inch main parachute. “As to minimize the potential interference between the two sections of the rocket, the shock cords connecting each section of the rocket will be different” (Kaiser 2017, 41). Shock cord lengths of 200-inches between the camera bay and avionics bay, and 110-inches between the avionics bay and flight computer bay will minimize the interference between rocket sections while descent is occurring. Iowa State CySLI 4

Cardinal Heavy Design Overview Cassandra Gearhart Each tubing section of the recovery system is held together with four 2-56 shear pins, which will break upon black powder charge ignition, allowing for in-flight separation and parachute deployment.

3.7 Flight Computer Bay Overview The flight computer bay is inside the coupler between the motor mount and parachute bay 1 on the aft end of the rocket. Figure 5 demonstrates “the individual components [that] consist of the following items: two end cap plates to contain the bay within the coupler, three inner rings for structural stability, one rectangular sled to hold the electronics, and two threaded rods to secure the bay inside the coupler” (Kaiser 2017, 19). These components hold the wiring and servo for the air brake, roll control, and flight computer assemblies. The main flight computer is housed on a sled within the bay. The flight computer is a Nucleo STM32 and runs the Kalman filtering program that cleans the data of noise created by the rocket. In the bay, there is an inertial measurement unit (IMU) and barometric pressure senor that feed the flight computer data. The Kalman filter, using a recursive system, predicts the rocket’s apogee using the current provided data and the previous data point. If the rocket is projected to go above the target apogee programmed into the rocket, the air brakes are actuated to achieve exactly a mile. Figure 5: SolidWorks Rendering of Flight Computer Bay Components

3.8 Roll Control System Overview The RCS is also housed within the flight computer bay with the air brake and flight computer components. This system is designed to induce a controlled roll in the rocket. There

Figure 6: SolidWorks Rendering of Roll Control System

Iowa State CySLI 5

Cardinal Heavy Design Overview Cassandra Gearhart are two, 3-inch by 1-inch by 2-inch carbon fiber fins attached to two aluminum dowel rods that are inserted through the outer airframe of the rocket. Each axel is locked into an aluminum cylinder within a ball-bearing housing that allows for the turning of the fin set-up by a servo (Figure 6). The flight computer and IMU control the RCS fin deflection after motor burnout. An accelerometer picks up a spike in action when the motor ignites and the rocket launches. The RCS is designed to actuate after motor burnout. As a result, a preset timer within the flight computer will use manufacturer’s information about the motor to determine when burnout occurs and, after it has run out, will initiate the roll. The roll will occur twice, then the fins will reverse actuate, stopping the roll and holding the remainder of the flight constant.

3.9 Air Brake Overview The air brakes are the other subsystem managed by the flight computer. The assembly runs from the flight computer bay into the motor mount. The motor mount houses four tubes, which connect to four pulleys and the bottom servo in the flight computer bay, hold the cables that run to the air brake assembly at the base of the rocket. The air brakes themselves are carbon fiber and formed to the shape of the rocket airframe for aerodynamic purposes. Team members dremeled holes into the motor mount in order to epoxy the hinges to a centering ring and create room for the spring assembly that prevents the air brakes from remaining open. The hinges are held onto the air brake with screws, washers, and nuts. The cables are attached to the exterior housing of the rocket via pulleys made aerodynamic with 3D- printed fins. The cables are then strung from the servo, through the tubes, out the airframe, through the fin pulleys, and into the air brake fins (Figure 7). This assembly controls apogee control based off the flight computer Kalman filter system. Figure 7: Diagram of Air Brake Set-up

3.10 Motor Mount Overview In addition to housing the air brake assembly, the motor mount is designed to hold the rocket motor. Within the 6-inch Blue Tube airframe, there is a 75-millimeter Blue Tube airframe Iowa State CySLI 6

Cardinal Heavy Design Overview Cassandra Gearhart centered in outer airframe with 5 birch wood centering rings. An Aero Pack flanged retainer ring screw into the rear centering ring, allowing a way to secure the motor in the rocket. The retainer ring is attached to a force plate that screws into the rear centering ring to assist with transferring forces from the rocket to the airframe.

3.11 Split Fin Overview CySLI selected a split fin design for reasons that extend beyond aesthetics alone. The fins are constructed of G-10 sheet fiberglass as it is strong and highly recommended for use as a material for rocket fins. The split fins allow for different flutter velocities that exceed a single fin design. This allows for a larger safety margin between the expected flutter velocity (587 feet/second) and the maximum for each fin (1,022 feet/second on the fore fins, 1,182 feet/second on the aft fins).

4 Conclusion CySLI has worked diligently over the course of the year to refine this design and ensure its readiness to present to NASA in multiple reviews. This design has passed each NASA review with minimal changes between presentation dates. The information in this document is subject to change due to NASA recommendations and other minor issues that typically arise between test and competition launches. As always, CySLI is excited to compete in Alabama. It is the high point of the year when the team member’s hard work comes together at NASA’s Student Launch event.

References Kaiser, Austin. “NASA Student Launch Initiative Critical Design Review 2016–2017.” CySLI Website [Online PDF]. Ames, IA.: Iowa State University’s M:2:I Program, 2017 [Cited April 16, 2017]. URL: http://M:2:I.aere.iastate.edu/cysli/files/2016/10/Iowa_State_2016- 2017_NASA_SL_CDR_Final.compressed.pdf. [Pages 15–41]. May, Sandra and Brian Dunbar. “About Student Launch.” NASA Student Launch Website [HTML Page]. Huntsville, AL.: National Aeronautics and Space Administration, 2017 [Cited April 16, 2017]. URL: https://www.nasa.gov/audience/forstudents/studentlaunch/ about/index.html “NASA Student Launch College and University Handbook.” NASA Student Launch Website [Online PDF]. Huntsville, AL.: National Aeronautics and Space Administration, 2016 [Cited April 16, 2017]. URL: https://www.nasa.gov/sites/default/files/atoms/files/ nsl_un_2017_web.pdf. [Pages 4–5].

Iowa State CySLI 7

Cardinal Heavy Design Overview Cassandra Gearhart

Appendix A Table of Technical Terms Aft In back, in this case referring to the part(s) placement in relation to one another and between the front tip and back end of the rocket. Airframe The outer housing/main rocket body that houses internal components. Generally referring to the Blue Tube shell or nose cone. Apogee The highest point, in this case, the highest point of the rocket’s flight arc. Fore In front, in this case referring to the part(s) placement in relation to one another and between the front tip and back end of the rocket. Kalman Filter Program that removes the noise of the rocket motor from data so it is easier to read for the computer. Ogive Common nose or tail cone shape. Rather than flat sides like a true cone, sides are rounded to give it a certain shape. Stability Margin The measure in caliber of a rocket’s ability to move in a straight line from the direction it is pointed at launch Note: The term definitions in this table were developed based off my personal rocketry experience and two dictionary-type resources, which are cited below. Table References The Gage Canadian Dictionary. Revised and Expanded. Toronto: Gage Educational Publishing Company, 1997. “Rocketry Glossary.” EMRR Rocket Reviews [Online Glossary]. Essence’s Model Rocketry Reviews, 2017 [Cited April 16, 2017]. URL: https://www.rocketreviews.com/ glossary.html

Iowa State CySLI A

Cardinal Heavy Design Overview Cassandra Gearhart

Appendix B This document, in addition to demonstrating CySLI’s 2016–2017 rocket design, was also created with the intention of demonstrating technical writing and document design processes. In this Appendix, I present the compiled document style sheet that lists the dictionary, style guide, and other editorial references and decisions that were used in this document’s production.

Technical Document Style Sheet Style Guide: The Canadian Style The Canadian Style: A Guide to Writing and Editing. Revised and Expanded. Toronto: Dundurn Press Limited in co-operation with Public Works and Government Services Canada Translation Bureau, 1997. Dictionary: Gage Canadian Dictionary The Gage Canadian Dictionary. Revised and Expanded. Toronto: Gage Educational Publishing Company, 1997.

Numbers Rule 5.01 in Canadian Style: “Numerals are preferred to spelled-out forms in technical writing. Except in certain adjectival expressions (see 5.05) and in technical writing, write out one-digit numbers and use numerals for the rest. Ordinals should be treated in the same way as cardinal numbers, e.g. seven and seventh, 101and 101st.”

Except: When used in conjunction with units of measurement or ratios e.g. 6-inch, 6 inches long, or 5:1

Captions Rule 4.30 in Canadian Style: “(a) Capitalize references to specific parts of a document. These include certain common nouns in the singular when they are used in text references with numbers or letters indicating place, position or major division in a sequence. Capitalize a letter following such a term: Act II or Figure 7.”

Caption Text (Set ulc)

Note: Captions should be a noun phrase of some sort.

Terms Cardinal Heavy (set roman, ulc) Rocket components or parts e.g. parachute bay or carbon fiber (set lc) Ogive (set ulc) Blue Tube (set open, ulc) U-bolt (set hyphenated, ulc) Mobius (set ulc) Air brakes (set open) Airframe (set closed) Iowa State CySLI B

Cardinal Heavy Design Overview Cassandra Gearhart Spell out unit measurements (inch, millimeter, etc.) 3D (Set numeral, capital D) Set-up (set hyphenated) Burnout (set closed) Aero Pack (Set open, ulc)

Other Editorial References: Kostelnick, Charles and David D. Roberts. Designing Visual Language: Strategies for Professional Communicators. 2nd Edition. Boston: Pearson Education, Inc., 2011. Rude, Carolyn D. and Angela Eaton. Technical Editing. 5th Edition. Boston: Pearson Education, Inc., 2011. Van Buren, Robert and Mary Fran Buehler. “The Levels of Edit.” NASA Technical Reports Server (NTRS) [Online Database]. Pasadena, CA.: Jet Propulsion Laboratory California Institute of Technology, 1976 [Cited April 16, 2017]. URL: https://ntrs.nasa.gov/archive/ nasa/casi.ntrs.nasa.gov/19760015018.pdf. [Page 16].

Iowa State CySLI C

Cardinal Heavy Design Overview Cassandra Gearhart

Bibliography Kaiser, Austin. “NASA Student Launch Initiative Critical Design Review 2016–2017.” CySLI Website [Online PDF]. Ames, IA.: Iowa State University’s M:2:I Program, 2017 [Cited April 16, 2017]. URL: http://M:2:I.aere.iastate.edu/cysli/files/2016/10/Iowa_State_2016- 2017_NASA_SL_CDR_Final.compressed.pdf. [Pages 15–41]. Kostelnick, Charles and David D. Roberts. Designing Visual Language: Strategies for Professional Communicators. 2nd Edition. Boston: Pearson Education, Inc., 2011. May, Sandra and Brian Dunbar. “About Student Launch.” NASA Student Launch Website [HTML Page]. Huntsville, AL.: National Aeronautics and Space Administration, 2017 [Cited April 16, 2017]. URL: https://www.nasa.gov/audience/forstudents/studentlaunch/ about/index.html. “NASA Student Launch College and University Handbook.” NASA Student Launch Website [Online PDF]. Huntsville, AL.: National Aeronautics and Space Administration, 2016 [Cited April 16, 2017]. URL: https://www.nasa.gov/sites/default/files/atoms/files/ nsl_un_2017_web.pdf. [Pages 4–5]. “Rocketry Glossary.” EMRR Rocket Reviews [Online Glossary]. Essence’s Model Rocketry Reviews, 2017 [Cited April 16, 2017]. URL: https://www.rocketreviews.com/ glossary.html. Rude, Carolyn D. and Angela Eaton. Technical Editing. 5th Edition. Boston: Pearson Education, Inc., 2011. The Canadian Style: A Guide to Writing and Editing. Revised and Expanded. Toronto: Dundurn Press Limited in co-operation with Public Works and Government Services Canada Translation Bureau, 1997. The Gage Canadian Dictionary. Revised and Expanded. Toronto: Gage Educational Publishing Company, 1997. Van Buren, Robert and Mary Fran Buehler. “The Levels of Edit.” NASA Technical Reports Server (NTRS) [Online Database]. Pasadena, CA.: Jet Propulsion Laboratory California Institute of Technology, 1976 [Cited April 16, 2017]. URL: https://ntrs.nasa.gov/archive/ nasa/casi.ntrs.nasa.gov/19760015018.pdf. [Page 16].

Iowa State CySLI D