My Second Internship — STAR a space startup (space technology and aeronautical rocketry)

Recently I participated in my second internship, a virtual, 30 day structured course and student project organised by STAR Labs at Surat. Was focused on teaching us about rocket subsystems, designing small rockets, and the avionics and circuits involved in the launch pad infrastructure.

At the end of two weeks, a student design project was introduced and we had to form small teams with each member taking over a designated role. I was one of only two two high school students in this batch, and my team mates were a mix of university students and one working professional. Our project was titled DESIGN STATIC TEST PAD FOR ROCKET MOTOR.

PROBLEM STATEMENT:

To design a Rocket Motor Static Test Pad for testing and acquiring the required data for the performance analysis of the high powered rocket motors.

To work on the given statement, we were assigned into groups, with each group having two departments- Avionics and Designing. I was assigned to the Avionics department, but was also assigned as Systems Engineer of the group, to function as a link between both departments.

Being assigned as a Systems Engineer gave me a good chance to display and develop my leadership and communication skills.Avionics:

· To design a system to acquire and process the data

· To design the electrical power system

· To build a test control system

· To acquire and store the required data for further analysis

· To design the systems for real-time data transmission and reception

Designing:

· To design the static test pad (STP) mechanism with a good strength/weight ratio

· To design a STP with a good aesthetics and ergonomics

· To design a STP which can be assembled and dissembled easily

· To design a structure to install all electronics and power system conveniently

· To perform the required simulations to minimise the errors while operating

Below is a highlight and overview. The report compiles all of our work and the final model.

Product Overview/ Product Developed by us (Group F)

The above picture is the CAD model of the Static Test Pad model that we were assigned to create.

Design Team

The goal of the design team was to develop, create and simulate the 3D models and the visual representation of our STP that we were assigned to develop. They had to graphically create and develop the different parts our STP model, their individual working, and how they combined collectively.

Preliminary Design Stages

Our design team first worked on the basic sketch and the outline of our STP model. They collected and interpreted the basic requirements from the problem statements, and developed this model.

After reconsidering and considering the model, they developed another model for the same design of the STP.

On further analysis and working with each other and the shapers from STAR, our design team developed several more models and arrived at the blueprint of the model that would provide them with the necessary requirements, and also fulfil the requirements given in Problem Statement.

The design team first created the individual components of the entire CAD model, then assembled them together to create the final model of the STP. They went through several experimental stages, and many trial and error phases before arriving at the final model. They first chose the base ( as shown below)

Then moved on to the adjustable clamps, the stands, the load cell placement, avionics bay placement. The materials of the STP were also chosen by them based on several tests that they conducted with different materials.

Design- Process & Analysis

Design Objectives:- Highest Factor of Safety, Lowest amount of stress.

Static stress acting due to clamp

Thermally induced stress

We went through several stages of testing and inquiry for the design aspect of our project until we finally arrived at the final STP model that we would be presenting. As system engineer, I was fortunate enough to interact with a brilliant group of highly dedicated Design interns, who analysed the design aspect of the problem statement with accuracy and precision, and arrived at an excellent model for our final STP.

Avionics Team [Primarily the work I did in Avionics]

The primary goal of the Avionics team was to design a system to acquire and process the data

Preliminary Avionics Stages

For our preliminary Avionics, I worked on the flow of events of our presentation and our solution for Problem Statement 1. I did a good amount of research on the working of STPs and Rocket Launchers, Ignition relays and warning systems. After analysing them I decided to create a flowchart that we would be following for the Avionics portion of this project. The first two presentations of the Avionics systems were also given by me as I had created the flowchart and had to explain it to our shapers.

We would refer to this flowchart and proceed accordingly with the remainder of our Avionics, which included the Circuit designing, coding, relays and the PCB designing.

Our team then decided the components that we would require for our Avionics Bay. Using our flowchart, we decided all the components that we would need.

Compressive Load Cell, HX711, Arduino UNO, Bluetooth Module (HC-05), SD Card Module, ESP266–01, LED, Buzzer, LCD, Relay Module, Nichrome Wire, 12 V Battery, Push Button.

Our design team also needed the dimensions of our Avionics Bay. For this, I researched the dimensions of all components that would need to be put in the bay. The dimensions of the Avionics Bay, which came to be 135mm* 95mm (Length * Breadth).

After obtaining this information, we proceeded to build the individual circuits for the different components of our Avionics final circuit, along with the code required for each component. Since I was unable to download Proteus in my computer, I was not able to help a lot in this part of the project. Below are the different Avionics circuit and its respective code.

Ignition

The initial part, shown in fig 1, was designed and simulated to execute ignition. It is made up of a Relay and a 10 volt battery. There’s also an ignitor. To start the ignition, first turn off the safety switch, and then press the ignition button. Wait approximately 10 seconds after pressing the button for the relay to switch on and activate the motor. If the safety switch is turned on, the LED D1 will illuminate. In the virtual terminal, the output can be viewed.

Ignition Code

Thrust Measurement

Thrust measurement code was lengthy and required several efforts from our side to complete

SD Card and Temperature

Complete Avionics Circuit [All subsystems combined together]

After creating all of our separate circuits for our Avionics subsystems, we had to combine everything into one circuit, which would be in our Avionics Bay.

While doing this, we did run into several problems with the connections of the different parts of the circuit. Some of the wires were still not attached/ connected properly. Thankfully, Sanjay came to our rescue. He had an immense amount of experience when it came to circuit building and coding. He managed to compile all the different parts together into one final circuit, which looked like this.

Now, our final plan of action was to work on the PCB model design of the final circuit in the Proteus App. The PCB would be the actual physical component that would be inserted inside the Avionics Bay, and would be the main brains of the STP as a whole. I was assigned the task of making the PCB.

Designing the PCB for me was one of the hardest tasks that I was assigned in the entire portion for the Avionics design.

I had to first learn the software where the PCB could be created, which was Eagle EDA. I sat through several lectures on the usage of Eagle EDA and how to use its several tools in the main application. After this, I also had to install several libraries which had our components, since Eagle software itself did not offer some components that we required, such as HX711 and Arduino Uno M3.

After completing all the preliminary work for our PCB design, I had to remake the entire circuit of the complete Avionics in the Eagle Schematics software itself. This also took a large chunk of time, and also took a large amount of trial and error from my side as well.

I also consulted Sanjay from my team and Harsh sir from the shapers team. I gained some amount of knowledge about electronic circuits and components from both of them, which was a great learning experience for me.

After completing the circuit schematic, I had to create the PCB board and drag the components into the board. I again ran into more problems in this phase as well, as several of my wires were overlapping the components, which was the wrong configuration for the PCB. I consulted Sanjay and Harsh sir and they told me about what sort of improvements I could make in the PCB. Harsh sir suggested that I should autoroute the wires instead of wiring and separating each wire by myself. This made the process of routing and designing the PCB easier for me.

There were also some SMD components that Harsh sir said that I should replace, but as I lacked prior experience in PCB designing, I decided to not touch them in the case that they interfere with the entire circuit, which was very sensitive to any sort of change and would lead to an error in the Eagle PCB software.

For our final PCB diagram, I made this board and presented it. Although it had errors in it , I made my best attempt at it. I am still trying to resolve the issue of the overlapping wires, but as of yet haven’t found a fix.

With the completion of our PCB board, it marked the end of our Avionics systems and as our Design team had finished before us, it marked the end of work for the Problem Statement One.

All in all, it was a great learning experience for me in all spheres. I learned leadership skills as I was assigned as the Systems engineer, which would be the main link between the Avionics and the Design team. I also got to improve my presentation and speaking skills, as several of our team’s presentations were given partly by me. I was also blessed to have such humble, kind, experienced and skilled teammates, all of whom contributed immensely to our solution for the Problem Statement One.

I would like to thank all of them, and was a pleasure for me to have the opportunity to work with all of them.

I was also lucky enough to receive a letter of recommendation from their team.