General

Version: 0.1.0
Date: 19 October 2019
Status: Draft
Type: System Specification

Overview

Propulsion Avionics shall be avionics systems that control and instrument the BJ-01 rocket engine during test runs (CFTs and hot fires) and full flights. This system is safety critical, and any changes shall be integration tested with propulsion components before flying.

Goals

1. Minimize risk to anyone involved in propulsion system operations
2. Ensure reliable ignition and operation of the BJ-01 rocket engine
3. Collect propulsion system metrics for analysis

Requirements

1. Accept and log instrumentation data
2. Initiate and monitor ignition process for the rocket engine
3. Monitor instrumentation and alert operator(s) in case of malfunction and/or automatically act to minimize safety risk.
4. Respond automatically to failures to minimize safety risk

Out of scope

1. Rocket operations after engine burn has completed (this is the domain of recovery avionics)
2. Rocket operations before oxidizer fueling (this is the domain of the ground support hardware)

Components:

• Data Acquisition Plane (DAP): Tasked with receiving and logging data from engine instrumentation
• Command & Control Plane (C2P): Tasked with receiving operator commands and sending the appropriate control signals to the engine (oxidizer valve and fueling solenoids). Also tasked with automatically responding to real-time data received from the DAQ.
• Data Transmission and Visualization plane (DTP): Tasked with transmitting data to the operator console. Must also visualize telemetry data easing identification of error conditions.

Data Acquisition Plane

The data acquisition plane shall read and track the state of the following engine components:

1. Thermocouples (TCs)
2. Pressure transducers (PTs)
3. Load cells (LCs)
4. Solenoids
5. Motorized valve

and log the output to a csv log at a sample rate of __ seconds. The log shall consist of one line per sample and E_[sensor] for any data collection errors. The log for each run shall be called log_[time] where [time] is the Unix timestamp. The DAQ shall also provide the DTP and C2P with updated data in every sample interval.

Command and Control Plane

See the specification for a detailed treatment of this component.