Further improvements will be made relating to the holders to secure them to the bulkhead instead of having them unrestrained during launch

The goals of the redesign of the avionics sled for the IREC 2020 rocket were the following:

1. Optimize the avionics bay for a 6" rocket

2. Address wiring concerns from AirBears to improve ease-of-use during launch

The new chosen design was an I-beam model, in which the batteries were placed in a center section of the sled and one altimeter was mounted to each side, as shown below. This design somewhat improved the space usage in the vertical direction, but there was significant unused horizontal space. The Recovery subteam selected this design because they felt it was more important to be able to wire the altimeters efficiently at launch than to use the least possible space.

Avionics Sled as viewed from back. Batteries are placed in middle centrals and the second altimeter is in the corresponding position on the other side of the sled.

2020 Sounding Rocket Design Challenge Website

Report

This report is intended to be used as a reference for all IREC 2020 payloads, as a preliminary description of all projects.

Excerpt (Abstract):

The Payload subteam of Space Technologies And Rocketry (STAR) at the University of California, Berkeley focuses on launching scientific instruments and experiments to high altitude: we are what makes rockets worth flying. This academic year, the payload projects, all integrated into a 5U CubeSat payload structure, include: onboard cameras, a dual sensor suite and cosmic particle detector, a microbial fuel cell, and an active stabilization system. The overarching mission objective is to record data and test experimental systems in-flight.

Primary changes to Airbears designs include improved wiring and accommodations for fiberglass tubing. This project also is significantly heavier, has twice the target apogee (10k ft), and has a much larger diameter (6") than Airbears.

Some info:

We have a base containing large electronics supporting our servos and arms. Each servo provides rotational motion to one axis with range of +-90 degrees (180 total), with an initial configuration of all axes being orthonormal to each other. The first servo is attached to our base, which controls an arm that our next servo is mounted to. This second servo controls the next arm that our third servo is mounted to. Our last servo, however, does not control an arm, instead it controls a platform, the platform which we would like to stabilize.

Inventory:

Electrical Components

All electrical components below, unless otherwise specified, we have in inventory. For everything without a number or description, assume we have one part in inventory.

• Arduino Nano

  • Connects all components together and provides communications/calculations between components.

• 1S 3.7V Lipo Battery

  • Power source for stabilization.

• Booster Converter (many extra)

  • Need 5V for most (all?) components, and the lipo only provides 3.7V, so we use this to step it up.

• Photo-relay (still needs to be ordered)

  • We don't want to waste any power before launch, so we can use a photo-relay to only allow current to the servos once the MPU's detect launch.

• Resistor (330 Ohms, have extras)

  • We need one resistor to connect to the photo-relay to have it perform to expectations (ideally it would be 336 Ohms).

• MPU's (x2)

  • One MPU is attached to the base of our stabilization unit, this gives us gyroscopic and acceleration data of how the rocket moves through time. This MPU also provides data so that we can provide the adequate torque to our servos to stabilize the platform. Our second MPU is mounted on our platform, this will provide data for how well our platform is being stabilized. We can take both our MPU's data and record it to the SD Card.

• Servos (x3)

  • Provides mechanical control of the three arms (be wary of Gimbal Lock problem).

• MicroSD Card

  • Provides storage for sensor data, which we can analyze after launch.

• MicroSD Card Breakout Board

  • A board which provides us the ability to write to the MicroSD card using the arduino.

• Protoboards (many extra)

  • A board so we can solder some of our components (like the Arduino Nano and Photo-relay) and keep them reasonably secure during launch.

• Wires (stranded, 26 gauge, 50 feet)

  • Electrons

• Servo Extensions (many)

  • The most convenient way to connect our servos to the power and arduino.

• Lipo Connectors (many)

  • The most convenient way to connect our lipo to the converter.

• 1S Lipo USB Charger

  • A convenient way to charge our lipo (before testing and launch, not during).

Mechanical Components

• Servo Bolts

• Servo Nuts

• Sensor Bolts

• Sensor Nuts

• Arduino Bolts

• Arduino Nuts

• Arduino Spacers

• MicroSD Card Breakout Board Bolts

• MicroSD Card Breakout Board Nuts

• Booster Converter Fasteners

Harness Components

1. Quick Links- metal rings that connect the shock cord to the u-bolts and also connect the parachutes to the shock cord.

2. Shock Cord- durable kevlar rope that holds all of the rocket together when parachutes are deployed.

3. Bulkheads- metal cylinders that are important for structural integrity. The u-bolts thread through the bulkheads.

4. U-Bolts- Are connected to the shock chord by a quick link.

5. Swivel?

Fold the Parachutes (Ideally a two person job)

1. Dedicate a 10 by 10 foot area to fold the main chute.

2. Lay out the parachute on its side and gather the shroud lines (the string coming from the edge of the parachute). This means that if the parachute was fully open with the inside facing up and you were standing at the center of the parachute holding all the shroud lines, that you move to the side folding it in half.

3. Make sure the shroud lines are untangled.

4. Examine each section and patch holes

5. Examine each colored section and patch holes.

6. For each section on one half of the parachute, fold the colored section in half do the edges of each section meet.

7. Have the folded half of the parachute on one side and the unfolded half of the parachute other on the other side.

8. Before continuing, only two sections of the parachute should be visible, with half of it folded under one color and the other half unfolded under the other color.

9. Fold the edge of the unfolded half of parachute to the middle and the the other edge to the newly created edge.

10. From the resulting rectangle, bundle the short edge four times until you have a resulting almost square parachute.

If confused watch the video attached.

Introduction

Main Contributors and General Progress

The IRIS project combines two originally separate projects (IRIS Legacy and Muons) into a 1U CubeSat unit to conserve space in the payload structure.

Rajiv Govindjee, Jason Xu, Bryant La and Ocean Zhou are the main contributors to this project. Rajiv and Jason worked on the first iteration of IRIS while Jason and Ocean worked on the first iteration of Muons. It was decided for the sake of efficiency and adventure that the two detectors should be combined into one complete detector. Jason was heavily responsible for the electrical design of IRIS, in particular the printed circuit boards (PCBs). Bryant and Ocean worked on the mechanical integration of IRIS to the rocket. IRIS is currently in its assembly phase, although with the impacts of the COVID-19 pandemic, the assembly phase has faced delays.

IRIS Overview

IRIS Records Information via Sensors (IRIS) is a sensor suite printed circuit board (PCB), outfitted with an accelerometer, a gyroscope, a magnetometer, a barometric pressure sensor, and a High-G accelerometer. Its function is to record various flight data (acceleration, angular velocity, absolute orientation, barometric pressure/altitude) to assist in developing flight-critical avionics and validating current and future simulation work with respect to flight dynamics.

The IRIS assembly consists of three main PCBs. In order, from bottom to top, the three main PCBs are:

1. a power distribution board (IRIS-Power) connected to a two-cell (2S) 8.4V lithium polymer (LiPo) battery

2. a primary IRIS board (IRIS-Core)

3. an auxillary IRIS board (IRIS-Core)

Inspiration

The first iteration of Muons was based heavily off of Spencer Axani's project. He is a current particle physics PhD student at MIT! This is the website that contains all the info about his project. The GitHub page that includes all the software, details, PCB soldering guidelines for this project can be found here. Our first detector was basically following his step by step instructions and recreating his detector. So to Spencer, a massive massive thank you!

Optional Sensors (Reserved for Future Use)

In addition to the motion sensors, there are two optional components on IRIS that are currently unpopulated but can be implemented in the future.

GPS

IRIS supports the addition of a GPS module (uBlox cam-m8) in the future.

Pitot Tube Sensor

IRIS supports the addition of a differential pressure sensor, for implementing an external pitot tube in the future.

Electrical Hardware Design Overview

The electrical hardware (PCBs) are avaliable on our cadlab:

• IRIS-Core PCB

• IRIS-Power PCB

IRIS-Power

IRIS-Power occupies the bottom most board of the 3 board stack. The primary purpose of IRIS power is to output regulated power from the 2S LiPo, gauge the LiPo's charge with a battery fuel gauge IC, and provide a backup source of power in case the battery fails or is suddenly disconnected. The backup is provided through 2 supercapacitors that can provide several minutes of backup power.

Additonally, the power board has the ability to automatically switch to a connected USB-C power delivery adapter in order to save battery charge during bench-top testing and programming.

IRIS-Power provides 5V for the Teensy 4.1 MCU on IRIS-Core, 3.3V for other extra ICs, and 29.5V for the photo-multipler Muon sensor.

IRIS-Core

IRIS-Core is the primary module of the 3 layer stack. The middle board of the 3-layer stack is a full-fledged IRIS-Core board, while the top board of the 3-layer stack is a partially populated IRIS-Core board.

The main MCU of IRIS-Core is a Teensy 4.1, an Arduino compatible board.

The full-fledged middle module contains a Teensy 4.1, IMU breakout board, High-G accelerometer breakout board, and a muon sensor.

The partially-populated top module contains a Teensy 4.1 and a muon sensor.

Very Useful Diagrams

For some very useful diagrams detailing the pinouts, peripherals, and power flow connections, see the following pages:

Design Log and Updates

Mechanical Design

(12/06/20): There is no way to fasten a nut on a screw from inside the enclosure. The enclosure will be secured to the T-slotted rails with eight screws going through eight brackets, held in place by having the screws serving as pegs into slots. The screws are at different heights, so interference is not an issue.

Electrical Design

(12/06/20): The backboard support PCB has been replaced with the stack connectors (pin headers) pictured below. This was done for simplicity of design, to reduce the space taken up by the PCBs, and to prevent interference between the vertical threaded rods and the fasteners attaching the enclosure to the T-slotted rails. The enclosure and spacers have been updated to accommodate this change.

Manufacturing

Engineering Drawings

Prototyping Processes

The enclosure measures 7.9 cm x 7.9 cm x 10.635 cm, and can be manufactured via 3D printing with PLA material.

Progress

(12/06/20): The PCBs were ordered and arrived. Bryant La will solder the components on campus with a reflow oven over winter break, with Jason Xu's remote assistance. Boards will be shipped to Jason Xu for him to attempt soldering without a reflow oven, though he does not need to succeed for the project to progress.

The BOM is being finalized and the parts will be ordered soon. Once fully manufactured, the code will be rewritten to interface with the combined IRIS/Muons.

(01/25/21): Both Jason Xu and Bryant La are near campus and will work together to finish manufacturing for this project.

(02/14/21): The power board and one of the sensor boards have been soldered. Jason Xu and Bryant La will need to procure the existing completed Muons boards from the Supernode locker to move their scintillators onto the new IRIS/Muons boards. After soldering of the final board is complete, efforts will be focused on writing the board firmware.

Launch Results

At the time of writing (May 2020), due to power and launch issues, IRIS has been unable to record data during flight for any launch. Data obtained so far has been limited to what IRIS senses during assembly on the ground, which showed little variability as expected; however, the values IRIS reports are accurate (e.g., the barometer shows atmospheric pressure near sea level), which is evidence that the sensor suite functions as it should.

Muons has been launched like IRIS and was able to record data during flight. However, due to the minor detector malfunction, relating to multiple data files being saved for unknown reasons, the data obtained was unable to offer much use; besides total muon count, it was impossible to pinpoint which files corresponded to different points during the flight. Nonetheless, the fact that the detector was able to record muon count and that the muon counts increased over time indicate that the detector is able to function properly during flight.

The previously assembled detectors have been tested twice. The first test was to ensure that the measured voltage signals matched the expected values, in which the detector succeeded. The second test measured how the angle of the scintillator (with θ = 0° being the horizontal orientation) affected muon count measured within an interval of 1 minute. This was done to decide the orientation the detector was to be at inside the rocket. Having the scintillator at a horizontal orientation yields the most counts.

References

1. https://www.space.com/32644-cosmic-rays.html

2. https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-20693.pdf

3. https://www.radioactivity.eu.com/site/pages/Cosmic_Muons.ht

Overview

Many systems within a rocket are controlled by electronics, such as the parachute deployment systems, the motor ignition systems, and with our latest SSEP project, the stage separation mechanisms. These electronic controls are known as avionics, and they are essential to the function of the rocket, but they can be quite delicate and must be in proximity to the systems they are controlling so they can be wired effectively. The avionics bay houses these avionics in a relatively central location in the rocket and in such a way that the avionics are kept safe throughout the rocket's flight.

Types

We use two main types of avionics bays: axial designs and radial designs. These names refer to how each design is installed into the rocket. Axial av-bays are inserted through the airframe tube along the tube's long axis, and radial av-bays are inserted radially through the side of the airframe tube, through a door in the tube. All radial av-bays have a sled, which houses the avionics and is the actual component to slide in and out of the airframe tube. Some axial av-bays have a sled design so that the avionics can be accessed radially as well, but this is not the case for all axial av-bays.

Full avionics bay for Bear Force One with the radially installed sled highlighted in blue (Right), and sled from avionics bay for Bear Force One with altimeters to control the parachute deployment (Left):

Components

There are two main types of components discussed here: structural components and electronic components. The structural components serve to house the avionics (the sled) and to connect the inner structure to the rocket’s frame (bulkheads, u-bolts, etc.). The electronic components are the avionics themselves, notably the altimeters and CAS, along with their power supplies.

Structural Components

The following outer structural components are found in practically every av-bay, no matter the design:

• Bulkheads: These usually metal plates connect the rest of the avionics bay assembly to the frame of the rocket.

• U-bolts: These u-shaped bolts are fastened to bulkheads and connect the bulkhead, and therefore the avionics bay assembly, to a parachute assembly. Typically there is a fore u-bolt that connects to the drogue chute assembly forward of the av-bay and an aft u-bolt that connects to the main chute assembly aft of the av-bay. However, if there is only one chute assembly connected to the av-bay, as is the case with the lower stage of the SSEP rocket, only one u-bolt is needed.

• Av-bay rods: These rods provide additional structural support for the av-bay and are fastened with wingnuts. They can be seen in the av-bay for Bear Force One as the two vertical rods, shown at the bottom of this section.

Bulkhead + u-bolt assembly from Jay’s CAS-compatible 5.5” av-bay:

Additional outer structural components can be found on some av-bays, depending on their design:

• Additional outer bulkheads: Some av-bays, like the one in Bear Force One, have an additional set of outer bulkheads so that the rods and the u-bolts have four connection points instead of two. These additional outer bulkheads are depicted in the image below of the av-bay in Bear Force One with a slightly blue hue.

• Av-bay door: Any av-bay with a sled needs to have a door to access the sled. By default, any radial av-bay will have an av-bay door. This is one of the drawbacks to a radial av-bay design, as any hole in the airframe, such as an av-bay door, could potentially negatively impact the stability of the airframe.

Av-bay airframe tubes for Bear Force One with cutout for av-bay door:

The following are the main inner structural components of a radial av-bay or an axial av-bay with a sled:

• Sled: This structure houses all the avionics in a radial av-bay and some axial av-bays, and is designed to slide in and out of the av-bay assembly through the av-bay door for easy access to the electronics. It is convenient, but requires an av-bay door.

• Sled housing: This structure houses the sled and essentially gives the sled something to slide into. There are channels cut into the inner edges of the housing that the sled can slide into so that it is held firmly in place.

• Inner bulkheads/sled housing bulkheads: These bulkheads have a large section cut out and the edges of the cutout grooved so that a sled can slide directly into the bulkheads instead of sliding into a housing. These are used in the av-bay for Bear Force One, shown below highlighted in blue.

Sled from Jay’s 5.5” CAS compatible av-bay (Left), and corresponding sled housing from Jay’s av-bay (Right). One can see how the sled could slide into the housing and be held still by the grooves cut into the housing that match the rails on the sled:

Avionics bay for Bear Force One with upper inner bulkheads highlighted blue:

Avionics Components

The following components are the avionics in a typical av-bay along with their associated components:

• Altimeters: These measure the altitude of the rocket during its flight and are used to trigger the parachute deployment.

• 9V batteries: These are used to power the altimeters in flight. They are encased in a housing we have designed.

• 9V battery cases: These cases keep the 9V batteries safe and allow them so be more easily secured to the avionics bay.

• CAS: Our very own modular avionics unit designed by the avionics subteam. It usually has four layers of adaptable circuitry, and is roughly 2”x2”x2” in size. It will hopefully be used in the SSEP rocket to trigger the stage separation mechanism, but for right now we’re just including it in all of our new av-bay designs, as our goal is for it to become a standard part of our avionics system.

• LiPo batteries: These are used to power CAS, and they also have housing units that have been designed for them.

• CAS antenna: This antenna would allow CAS to talk to instruments on the ground, but it still needs to be integrated into the avionics system.

PerfectFlite Stratologger altimeter (first), LiPo battery for CAS (second), and 9V battery inside custom-made casing (with cover removed to view the battery) (third):

CAS stack put together (without antenna):

Other Av-bay Designs

Some av-bays are designed with a specific, unique purpose in mind, so they may have different designs to fit their specifications. For instance, an additional av-bay aft of the main parachute assembly was needed on the SSEP rocket in order to trigger the stage separation system and to ignite the upper stage motors. However, there was not much space to fit this av-bay. So, a small axial av-bay was designed by Hadar to meet these requirements, shown below. Note that it does not have a sled and an access door but instead splits into two accessible parts that are then clamped together when installed into the rocket.

Description

The Cameras project uses the Mobius Maxi camera mounted on a custom base plate that is epoxyed on the airframe's exterior with a custom shroud.

Two shrouds shall be mounted. The camera shrouds have been optimized to maximize field of view while minimizing impact to the aerodynamics of the airframe, allowing the cameras to record the flight with as much detail as possible without being a detriment to vehicle performance. The recorded results are retrieved from an in-camera SD card post-landing. The captured footage should theoretically document the rocket in flight even after it escapes visual range from the ground.

System Weights, Measures, and Test Reports

Each Mobius Maxi measures 7.1 cm x 3.5 cm x 1.8 cm and weighs 52 g. Each shroud measures approximately 13.2 cm x 4.1 cm x 3.8 cm and will be manufactured from PLA material using 3D printing.

At the time of writing, no in-air flight recordings have yet been captured. Recording testing has been performed, but the full extent of camera capabilities have not yet been documented. A battery life test has been completed along with a shake test to mimic the turbulance he camera would experience while on the rocket. The Camera was able to record for over 2 continuous hours with minimal quality degrigation as a result of shaking. Worst-case test is planned in the future, with active external heating to mimic launchpad conditions.

CADS

CADs are for the camera's custom shroud.

Hazard Analysis and Risk Assessment

The primary risks and failure modes associated with Cameras are depletion of the battery and structural failure of the shroud during flight. The camera shroud could sheer off from the baseplate, take damage from shaking from not being properly secure in the shroud. Test on different epoxies are being conducted to determine which would best minimize the risk of the camera seperating from the body of the rocket, with the possibility of grooves being put in place to increase surface area contact.

Without power, the Mobius Maxi camera cannot record data. Mitigation strategies include fully charging the camera the night before and setting the video recording settings to their lowest power consumption setting.

Structural failure of the camera shroud would cause parts of the shroud or the entire shroud to shear off of the launch vehicle, potentially even changing the vehicle's trajectory. Mitigation strategies include printing the shroud at higher densities and out of stronger materials, and checking again that the shroud is properly mounted before launch.

Assembly, Pre-flight, and Launch Checklists

Pre-Flight

1. Charge both Mobius Maxi cameras with MicroUSB cable.

2. Place one MicroSD card into each camera.

3. Configure settings on both cameras to be appropriate to flight mission and launch conditions, including recording automatically when power is turned on.

4. Turn cameras off.

5. Place shroud onto the baseplate with lens oriface towards fins and align the two holes on the shroud with the corresponding two holes on the airframe.

6. Secure the lower, fin-most hole with the nut plate on the other side of the airframe wall.

7. Place camera into shroud so the lens faces the fins.

8. Secure the upper hole with the nut plate on the other side of the airframe wall.

9. Secure the shroud cap onto the shroud, ensuring that the locks snap fast onto the side of the shroud. If uncertain, apply adhesive.

10. Remove lens cap from camera.

11. Turn on camera and start recording.

12. Repeat steps 5–11 with second camera on opposite side of launch vehicle.

Post-Launch

1. Retrieve all payload components from the downed rocket.

2. Turn cameras off and stop recording.

3. Disassemble camera assemblies.

4. Read and analyze data from the SD card.

Background

The IRIS journey started in 2018; IRIS v1 was conceived of as a project for the. The board was assembled in Fall 2018 and found to be relatively functional, with difficulties arising mostly due to lack of software libraries for the ICM 20948. IRIS v2 was designed and assembled in early 2019, adding rounded corners, more sensors, options for breakout boards, test points, improved power electronics, and more. IRIS v2 was also more successful on the software front; all sensors tested worked nominally, including the ICM 20948. Code for IRIS v2 can be found at . While IRIS v2 was intended to fly on Spectre, STAR's ambitious entry for IREC 2019, Spectre was never constructed due to significant engineering challenges.

For a more detailed look at requirements and progression of IRIS v1 and v2, see the IREC 2019 documentation:

AirBears Test Flight

IRIS v2 was flown on . To prepare for this flight, the casing was significantly re-designed to integrate with the other payload (Muons) on the test flight. Software was completed to allow for continuous recording of IMU data to the on-board SD card on the Teensy.

Unfortunately, as a result of non-comprehensive assembly procedures and some time pressure to assemble the payloads, IRIS was flown while not in a recording state.

The following recommendations were made following this test flight:

• Implement some method for back-up power (capacitor, coin cell battery, etc.). This ensures writes to non-volatile memory have time to safely complete.

• Create robust procedures and test them entirely before launch. This includes all integration needed with other payloads. Add special notes if power may not be disconnected from the payload after a certain point.

• Perform as much assembly as possible beforehand. Ensure that no more than 30 minutes are needed at launch for assembly; time someone actually completing this assembly beforehand.

Current Work

The team is currently working on physical design and manufacturing for IRIS to fly in the IREC 2020 payload suite as one of 5U worth of CubeSats. Work is also underway on a potential IRIS v4 board, although not required for competition readiness. Software is the largest hurdle for the competition; some development may be required to communicate with all sensors on multiple SPI buses at once (effectively).

• PLEASE learn how to solder printed circuit boards. Though it is not hard to pick up, learning understandably still takes time. At Cal, you can either practice soldering in the Chen-Ming Hu Lab in Cory Hall Second Floor (aka SuperNode), or in the Electronics Lab in Jacobs Hall. Here's a tutorial to get you started: https://www.youtube.com/watch?v=Qps9woUGkvI

• Find a way to machine the scintillator if the one you bought is not already machined. The manufacturing drawing is attached below: https://github.com/spenceraxani/CosmicWatch-Desktop-Muon-Detector-v2/blob/master/CAD/Scintillator%20CAD%20file.pdf

• After you purchase the SiPM and it arrives, PLEASE place it somewhere safe and load-free. Do NOT crush the SiPM as it is very delicate (and expensive!)

Assembly Instructions

1. Buy all required electrical components

2. For the Arduino Nano, be sure to upload the coincidence.ino code to it, as this ensures a muon will be counted! Refer to pdf attached below for specific detail.

3. Solder the electrical components onto the 3 PCBs (Main Board, SiPM Board, SD Card Board). Use this as the guide to know where to solder the components: https://github.com/spenceraxani/CosmicWatch-Desktop-Muon-Detector-v2/blob/master/PCB_Files/SMT_reference.pdf

4. Drill 4 mounting holes into SiPM PCB. Polish it afterwards.

5. Wrap the scintillator in reflective foil.

6. Put optical gel on SiPM board and mount it to scintillator using the mounting holes on the SiPM board.

7. Wrap both with electrical tape to make light tight. Important! Carefully wrap or else "light-leak" will occur. This will distort your results!

8. Plug the SiPM PCB into the Main PCB through the header pins.

9. Finally, upload the SDCard.ino code to the Arduino Nano.

10. Plug in a 5V power bank to the detector and make sure that the HV pin on the Main Board delivers 29.5 V.

For greater detail, read the entire instruction manual: https://github.com/spenceraxani/CosmicWatch-Desktop-Muon-Detector-v2/blob/master/Instructions.pdf

(Please Read!) Miscellaneous Files/Instructions

• Please make sure you have access to the STAR GrabCAD! If you do not, you will be unable to locate any of these files*

• Also make sure you have SolidWorks 2019 and Ultimaker Cura 4.4.1!*

• Please also purchase a Makerpass for Jacobs Hall Access. It will make your life so much easier for assembly*

• After you obtain your Makerpass, get training on the Wood Laser Cutters, Ultimaker 3D Printers, Electronics Lab, and FabLight metal laser cutter (this last one isn't really necessary but it's so fun that I think you should still do it!).

• The detector CAD is located in the IREC 2020 GrabCAD under:

  • Upper_Section -> Payload -> Muons_IRIS -> Detector_CADs -> IREC20_PAY_MuonDetector.

• Under the Muons_IRIS folder, the other folder called "STL Files". These are the CAD files in the Detector_CADs folder but translated into .stl files which can be passed in Ultimaker Cura and in turn be 3D printed.

Plan for IREC 2020

While we did collect data from our AirBears launch, it correlated only time with muon count. Furthermore, 4 separate SD files were created, meaning we had no idea at which height did the counts correspond to, making the data not as useful.

To combat this, our beloved payload lead Jason Xu (Woo!) is working to merge IRIS and Muons together as IRIS records height (through pressure) which allows us to see how muon count correlates with other parameters besides time. Excited events to come!

Sources

1. https://www.space.com/32644-cosmic-rays.html

2. https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-20693.pdf

3. https://www.radioactivity.eu.com/site/pages/Cosmic_Muons.ht

• Sand Paper

• Filers

• Phillips screw driver

• Drill and drill bits

• Respirators (when filing fiberglass)

• Epoxy (JB Weld ColdWeld ™️ Steel Reinforced Epoxy)

• bulkhead jig (designed to correctly place bulkhead and keep level

Procedure

Unfortunately for this assembly/manufacturing process to epoxy the avionics bay into the airframe became more inconvenient due to the need to epoxy the door nuts to the airframe. As a result, we must assemble the av bay in the airframe tube layer by layer. The components once within the av bay will no longer be accessible, apart from the sled and electronics mounted on it.

Prep work

• Confirm you have all required materials including tools

• Sand down the PLA and Wooden bulkheads to allow the them to more easily slide into the tube

• Sand down sled to allow for it to more easily slide into the bulkheads

  • you want only enough clearance to allow for easy removal, while still maintaining enough friction to hold the sled in place securely during flight.

• File down aluminum bulkheads to ensure they can slide down the tube

  • NOTE: Make sure the bulkheads are properly dimensioned before attempting to assemble, or you run the risk of getting them stuck even with filing for 4+ hours

• Sand down the inside of the airframe tube that you will be epoxying to

  • NOTE: sand down enough to remove the first layer but not enough to break down the fibers of the fiberglass

  • Make sure you are wearing a respirator, gloves, and long sleeves

• Using a handsaw or sharp dremel bit, cut the threaded rods to length

  • Note: if using a dremel be aware that the rod can heat up, wear thick gloves on the hand holding down the rod

• Using 5 minute epoxy, glue the PLA bulkhead and wooden bulkhead together for the top and bottom sections of the av bay

  • Allow this to set for at least 10 minutes, you can place a weight on top to hold each subassembly together while it cures.

  • Be sure to prevent any excess epoxy from pooling out from the sides of the seam (this will change the physical outer diameter and make it more difficult to slide into the airframe tubes)

• Drill out the holes of the PLA and Wooden bulkheads once the epoxy has cured to ensure the wires can pass through them easily

• Align the Aluminum Bulkheads with the PLA bulkheads and drill out the holes once again to ensure wires can pass through the assembly easily

Aluminum Bulkhead Manufacturing

• Insert the U Bolts into the Aluminum Bulkhead and attach the nuts on the other side

  • take care to make sure the nuts are level

• Add epoxy to the underside of the bulkhead between the nuts, ubolt, and bulkhead

• Add epoxy to the top of the bulkhead at the interface of the ubolt and the holes

  • allow that to cure

Assemble the AvBay for Test Fit

This is done so that we can be assured of the fit of all components before we assemble the av bay within the tube

• Begin first with the sled and work from the "inside" outwards

• PLA bulkheads around the sled on the top and bottom

  • this is a great time for any final filing to ensure the slide can slide in and out smoothly

• Slide the threaded rod past the first bulkhead, and add 2 nuts

• run the threaded rod past the second bulkhead and add an additional nut on the exterior side of each bulkhead

• adjust the nuts so that the assembly is secure against the surface of each side of the bulkhead (the nuts serve as placeholders)

  • check that you can slide the sled in and out easily and tighten or loosen the nuts as needed

• add an additional nut ~1 inch away from each of the most exterior nuts on the threaded rod

• repeat for the second threaded rod

• add the aluminum bulkheads to each side

• adjust the outer most nuts as needed to ensure the aluminum bulkhead is level! and the ubolt is gently touching the wooden bulkhead

• add the wingnuts to the exterior of the aluminum bulkheads to hold them in place

• make a final check that the sled is still able to slide in and out of the assembly and that all the nuts are properly tightened

  • then you take off the wingnuts and the aluminum bulkhead

  • leave the rest of the assembly together

• Test that you can slide the assembly into the tube and file as needed

• Place the assembly into the tube and mark where the epoxy for the first bulkhead will be placed

Assembly of AvBay within the Tube

Note that this is especially difficult and limited for BFO specifically because of the accessibility and mounting requirements of the av bay

1. Epoxy in the first bulkhead

• The procedure for the first bulkhead is the airframe standard for epoxying bulkheads into the airframe tube

• The first bulkhead (put in place prior to the sled) can be done normally, with two precise fillets on either side done by hand.

  • The specific epoxy will depend on the material of the bulkhead and the material of the airframe.

  • in this case we have a fiberglass airframe and an aluminum bulkhead and are using JB Weld Epoxy

• INSERT SLED INSERTION PROCEDURE

• For the second bulkhead, Make a ring of epoxy on the inside of the airframe, pull the bulkhead past the ring of epoxy to create a fillet on the inaccessible side (recall we are assembling this av-bay layer by layer)

  • After the first fillet has set, on the remaining exposed side make a standard epoxy fillet

  • let set

Background

The Microbial Fuel Cell (MFC) was inspired by NASA Micro-12 studying MFCs for the purpose of wastewater treatment and electricity production. The purpose of our MFC payload is to determine the effects of rocket launch and flight on the performance and health of the MFC.

The first iteration of MFC was designed to to use wild-type Shewanella oneidensis bacteria in a LB broth with platinum electrodes. The bacteria were sourced from Adam Deutschbauer's Lab at LBL. However, due to the difficulty of the project and a fungal infection that wiped out the bacterial culture, we decided to pivot to a more robust and simpler design.

The second iteration of the MFC was designed to use electrogenic soil bacteria from locally sourced soil, mixed with distilled water with graphite electrodes. The maintenance of this iteration of the MFC was much easier and a control MFC of this design was manufactured to gather voltage data over the course of 2 weeks.

Ballast

Primary Payload Structure

Tie-down rods

Purpose: To constrain the payload structure along the long axis of the rocket

Important design considerations:

• We used flight data and openrocket simulations to estimate maximum acceleration loads at 16 g's

• Two #4 threaded rods are spec'ed to a FOS of ?????

• @Ritvik something about having two possible orientations to minimize issues in assembly

What we have one:

• Complete test fit of design

What is left to be done:

• Add to launch-day parts list

Lateral support system (i.e. leaf springs)

GPS Mounting

GPS mounting is designed to attach the GPS module on the inside of the nosecone. In the designing process, two important factors were considered, stability, and suitability. Also, there were restrictions which are the GPS mounting can't touch the top metal plate of the structure and the GPS antenna should be mounted straight.

For higher stability of the GPS module, mounting has 6 zip tie holes on the front. There are two ways to fix the battery and GPS module into the mounting. 1) Using zip tie, combine together battery and GPS module. 2) Or, insert the battery and the GPS module into the mounting and tied them up together. The GPS mounting and holes are small, so a tweezer is needed to assemble it.

For the suitability of the mounting, the rear side of the mounting is designed with the same curvature as the inside of the nosecone. Also, the curvature was measured at 10.5 inch far from the top plate of the primary payload structure.

• Payload Structure :

  • 1/16” Steel ballast plates (32)

  • 9” Miniature T-slot rails (8)

  • 4 1/2” Miniature T-slot rails (4)

  • Aluminum leaf springs (4)

  • Top base plate (1)

  • Center base plates (2)

  • Top aluminum bulkhead (1)

  • Bottom aluminum bulkhead

  • Wooden bulkhead spacer (1)

  • Tie down rods (2)

  • M3x35 button head screws (4) (Needs purchasing)

  • M3 hex nuts (44)

  • L brackets (64)

  • MX10101 nut plates (64)

  • MX10101 button head cap screws (64)

  • M3x10 button head screws (24)

  • M3x20 button head screws (8)

  • Adjustable wrench

  • 5/64” allen key

ASSEMBLY

1. Place 4 long t-slot rails on each corner of the top base plate.

2. Attach rails to base plate through 2 L brackets on each corner of base plate.

3. Using 2 M3x10 screws and 2 hex nuts on each corner, fasten each screw with all screw heads facing out of the opposite side of the t-slot rails.

4. Using 2 nut plates and 2 cap screws on each corner, attach other end of L bracket to t-slot rails by connecting nut plate through t-slot rail and screwing through the hole of the L bracket with cap screw.

5. Attach MFC payload in payload structure.

6. Push 4 cap screws through each leaf spring and screw on nut plate to each side of leaf spring.

7. Slide leaf spring through t-slot rails until top of leafspring is 0.9” from top of t-slot rail.

8. Repeat step 7 for each side of structure (4 total).

9. Repeat step 3 and 4 on other end of t-slot rails.

10. Attach center base plate to the top of t-slot rails by placing M3x10 screw through L bracket hole with screw head on same side of t-slot rails and hold.

11. Place L bracket through end of screw with tall end facing corner and tighten with hex nut.

12. Repeat steps 10 and 11 for each L bracket.

13. Repeat steps 1, 2, 3, and 4 with each corner of center base plate.

14. Repeat steps 3 and 4 on top of t-slot rails, instead letting drop to bottom of t-slot rails.

15. Hang 32 ballast plates on the bottom brackets.

16. Push the M3x35 screw through slots of ballast, ensuring the screw heads point towards open end of structure.

17. Secure the ballast by tightening hex nuts on opposite end of each M3x35 screw.

18. Attach Stabilization payload to structure.

19. Repeat steps 3 and 4 on top of t-slot rails.

20. Repeat steps 10, 11, 12, and 13, instead using the shorter t-slot rails.

21. Attach IRIS/Muons payload to structure.

22. Repeat steps 3 and 4 on top t-slot rails.

23. Place top bulkhead on top of t-slot rails.

24. Push M3x20 screws through L brackets with screw heads facing opposite the t-slot rails and fasten with M3 hex nuts.

25. Place wooden spacer on top of top bulkhead.

26. Place bottom bulkhead on top of wooden spacer.

27. Turn entire structure on its side so that t-slot rails are horizontal.

28. Push tie down rod through slit on the top base plate, through entire structure, and stopping once it is through the bottom bulkhead.

29. Repeat step 28 with the other side of the structure.

30. Screw hex nuts onto each end of tie down rods, tightening until the structure has tension.

31. Flip structure so that it is resting on the bottom bulkhead.