How do you keep all the systems on a launch pad active and running from setup all the way to the launch of a rocket? The answer – electronic control.
Click here to read about the launch pad I’m designing this for!
Why does a launch pad need electronics?
1 – Electric ignition
When you first start up a typical solid rocket motor, you need some sort of spark to start the chain reaction. Typically, model rocket engine starters are used. These necessitate a high-current source to heat them up enough to begin the chain reaction of a solid rocket motor. While this hardware can be kept on the model rocket’s electronics, it adds extra weight. You can easily make this weight unnecessary if the launch pad has an integrated high-current source for launch.
2 – Safety features
Having electronics on the launch pad allows for a “smarter” launch pad. With electronics, it’s much easier to make sure the rocket is in place and ready to launch before the launch pad ignites the motor. Furthermore, with an articulating launch pad like the one I’m building, having electronics is a huge help. Not only can I use the electronics to automatically articulate the launch pad, I can also use them to detect what angle the launch pad is at. This makes it impossible to launch the rocket while its not pointing straight up, further adding to safety and reliability.
3 – Ease of use
Having all the electronics bundled onto a tiny flight computer is exhausting to work on once the rocket is assembled. Each time you want to interact with the electronics, you need to take the rocket apart. Having electronics on the launch pad allows for an articulating launch tower, and easy access to launch electronics. Having this easy access to launch electronics and the articulating launch tower is a huge help. It makes loading the rocket onto the pad and making sure its perfectly level so much easier.
Ascent: The electronics behind it all
Ascent has all the features necessary to launch a rocket safely with the launch pad I’m designing. It’s features include:
- Voltage regulator for servos and high voltage GPIO
- Logic GPIO for simple communication
- Six servo ports for launch tower articulation and rocket clamps
- On-board IMU for determining how straight the launch pad is
- I2C exposed pins for connecting another IMU to be mounted to the articulating part of the launch pad
Through all of these features, Ascent is able to determine what to do and when to do it, allowing much safer and easier rocket launches.
Design Decisions & Risk Mitigation
Unfortunately, when it comes to designing circuit board and having them manufactured on the other side of the planet, risk mitigation can be difficult. I try to review every part of my schematic and layout before the board files are sent for production. Many of the design decisions I made with this board were made because of possible failures during assembly. Traces are significantly bigger than is necessary to prevent possible imperfections from compromising the board. Parts are run way under their rated specifications in order to extend longevity and lower heat dissipation.
What’s next?
Designing a launch pad from scratch, electronics and all, is a daunting task. I’ve been working on this project and the HORIZON line of model rockets for a year now. Each time I share a new advancement or project with you guys, I feel like I get one step closer to having a rocket truly fly.
This launch pad is the next step to launching HORIZON II. I would say it’s a pretty big step, too. All that’s left for the launch pad is ordering the parts, assembly, and programming. Then, all eyes are on HORIZON II and refining it to perfection.
Until next time.
