Popularize science about the circumstances under which the rocket test run (ignition experiment) will fly out

This article has nothing to do with the incident that happened today but fortunately there were no casualties but seemed outrageous, I just asked Azure OpenAI-GPT4o to write an article to popularize science.

Rocket Engine Test Firing or Static Fire Test refers to the ground ignition test of the rocket engine or the entire rocket before the rocket is launched to verify its performance and reliability. This is a crucial part of the rocket launch preparation process, and through test tests, potential problems can be identified and solved in advance, ensuring that the rocket can work properly during the actual launch. The following is the main content and purpose of the rocket test test:

1. The type of test experiment

1.1 Engine commissioning

• Single-stage engine commissioning: A single rocket engine is tested, usually on a dedicated test bench.
• Multi-stage engine commissioning: Independent testing of each stage engine of a multi-stage rocket.

1.2 Test run of the whole rocket

• Static commissioning: The entire rocket is installed on the launch pad for a full-scale ignition test. This type of testing usually includes all engines and subsystems.

2. The purpose of the test experiment

2.1 Performance Verification

• Thrust Measurement: Measure the thrust of an engine to ensure it meets design specifications.
• Combustion efficiency: Check the combustion efficiency to ensure that the mixing and combustion process of fuel and oxidizer is normal.

2.2 Reliability and durability testing

• Material and Structural Strength: Verify the strength and durability of rocket engines and related structures under high temperature and pressure conditions.
• Vibration and Noise Testing: Evaluates the effects of vibration and noise generated during engine operation on the overall structure and electronics of the rocket.

2.3 System Integration Testing

• Subsystem coordination: Ensure that the various subsystems such as the fuel supply system, ignition system, cooling system, and control system work in harmony.
• Data acquisition and analysis: Engine operating data is collected through sensors and monitoring devices for real-time analysis and subsequent evaluation.

2.4 Security Testing

• Emergency abort system: Test the effectiveness of the emergency abort system to ensure that the engine can be quickly shut down in the event of an abnormality.
• Leak and Fault Detection: Detect leaks or faults in fuel systems and other critical areas.

3. The steps of the test experiment

3.1 Preparation

• Equipment installation: Install the rocket engine or the entire rocket on the test or launch pad, connecting all the necessary pipes and cables.
• Inspection and calibration: All sensors and monitoring equipment are inspected and calibrated to ensure that they are working properly.

3.2 Pre-commissioning inspection

• System Inspection: Perform a comprehensive inspection of the fuel system, ignition system, control system, cooling system and fixtures, etc.
• Security Check: Confirm that all security measures and emergency abort systems are activated.

3.3 Ignition test

• Ignition start: start the engine according to the predetermined procedure and carry out the ignition test.
• Data monitoring: real-time monitoring of various performance parameters and operating status of the engine.
• Emergency abort: When an abnormal situation is found, the emergency abort system is immediately activated and the test run is terminated.

3.4 Follow-up Analysis

• Data analysis: Detailed analysis of the data collected during the commissioning process to evaluate the performance and reliability of the engine.
• Troubleshooting: If a problem is found, conduct detailed troubleshooting and analysis to find out the root cause and develop an improvement plan. Some parts may need to be redesigned, manufactured, or adjusted.
• Validation and adjustments: Based on the results of the data analysis, the necessary adjustments and optimizations are made to the engine or rocket system, and retests may be carried out to verify the improvements.

4. Key elements of the test test

4.1 Security Measures

• Delineation of safety areas: During the commissioning experiment, delineate and clear the surrounding area to ensure that irrelevant personnel and equipment are kept away from the commissioning site.
• Emergency Abort System: Ensures that the emergency abort system is functioning properly and can quickly terminate engine combustion when an anomaly is detected.
• Emergency response plan: Develop a detailed emergency response plan, including response measures for emergencies such as fire and explosion.

4.2 Data collection and monitoring

• Sensor arrangement: Arrange various sensors in key parts of the engine and related systems, such as pressure sensors, temperature sensors, accelerometers, etc.
• Real-time monitoring system: Record and analyze engine operation data in real time using a high-performance data acquisition and monitoring system.
• Data redundancy: Multiple independent data acquisition systems are used to ensure the reliability and integrity of data.

4.3 Control Systems

• Automatic control system: The advanced automatic control system is used to realize engine ignition, combustion, thrust adjustment and other operations.
• Manual backup: In the event of an automated control system failure, ensure that a reliable manual backup system can take over control.

5. Challenges and risks of commissioning experiments

• High temperature and high pressure environments: Rocket engines operate at extremely high temperatures and pressures, and materials and structures must be able to withstand these extreme conditions.
• Vibration and shock: Severe vibrations and shocks are generated during engine ignition and combustion, which may affect the rocket structure and electronics.
• Fuel and oxidizer management: The storage, delivery, and combustion processes of fuels and oxidizers require a high degree of precision management, and any leakage or misoperation can lead to serious accidents.
• Complexity of data analysis: There is a large amount of data involved in a test run, and how to effectively collect, store, analyze, and interpret this data is a complex process.

At this time, you may have to ask: Is there a safety buckle on the launch base to prevent the rocket from flying out accidentally in the general rocket ignition test?

Yes, during the rocket ignition test run and launch, a structure called a "launch stand" or "launch fixture" is usually used to ensure that the rocket does not accidentally fly off the launch pad during ignition. Here are some common fixtures and methods:

1. Launch Bracket: A launch bracket is a structure used to support a rocket and typically includes fixtures and guide rails to ensure that the rocket remains stable during the ignition and initial ascent phases.
2. Fixing fixtures: Some launch pads use mechanical clamps or locking devices to secure the rocket to the launch pad. These clamps are automatically released at a specific point in time after ignition, allowing the rocket to lift off smoothly.

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4. Hydraulic or pneumatic locking device: Some launch systems use hydraulic or pneumatic means to hold the rocket in place and release it at the right moment. These systems are generally quick to respond and are able to withstand large forces.

5. Combustion chamber pressure sensors: Some launchers are also equipped with combustion chamber pressure sensors, which can trigger the release of the fixture when the rocket engine reaches a predetermined thrust level.

   The purpose of these fixtures is to ensure that the rocket does not have an uncontrolled situation during the ignition phase due to any unexpected factors such as engine instability or insufficient thrust. In addition, they ensure that the rocket is lifted off along the correct trajectory at the initial stage, avoiding potential danger to ground facilities and personnel.

You may also ask, I don't understand the others, but I know the fixed fixture, I want to ask, what is the general structure of the fixed fixture, how many are needed, and how much force will it withstand to prevent the rocket from flying out during the test phase?

The structure and number of fixing fixtures will vary depending on the type of rocket, size, and the design of the launch pad. Here are some common fixing fixture structures and design principles:

1. The structure of the fixed fixture

Fixed fixtures are usually made of high-strength materials that are able to withstand the enormous thrust generated by rocket engines. Common structures include:

• Mechanical pliers: Similar to a giant manipulator, capable of grasping a specific part of the rocket (such as the tail or fuel tank).
• Locking pins and latches: High-strength latches are used to secure the rocket to the bracket of the launch pad.
• Hydraulic or pneumatic grips: Grippers controlled by hydraulic or pneumatic systems that can be quickly released when needed.

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2. Number of fixing fixtures

• Small rockets: 2 to 4 fixed clamps are usually required.
• Medium to large rockets: 4 to 8 or even more fixtures may be required to ensure that the rocket does not move when ignited.

3. Withstand force

The force that the fixing fixture needs to withstand depends mainly on the thrust of the rocket engine. Here are some examples:

• Small rockets: Engine thrust can range from a few thousand newtons (kN) to tens of thousands of newtons.

• Medium and large rockets: The engine thrust may reach hundreds of thousands of newtons or even more.

  For example, SpaceX's Falcon 9 rocket has a total thrust of about 7,600 kilonewtons (kN) at the time of ignition, and each fixed fixture needs to withstand a portion of the total thrust and ensure that the rocket does not accidentally fly off the launch pad when it ignites.

4. Release mechanism

Fixed fixtures are usually equipped with automatic release mechanisms that are automatically activated after the rocket engine reaches a predetermined thrust. Common release mechanisms include:

• Mechanical release: The mechanism is triggered by the control system to release the fixed fixture.
• Hydraulic/pneumatic release: Quick release of the clamp by hydraulic or pneumatic system.

5. Security redundancy

To ensure safety, fixed fixture systems are often designed with redundancy. Even if one fixture fails, the others will continue to stabilize the rocket.

You may be curious to see this, if there is really a rocket that takes off in the test stage, what will be the reason?

If a rocket takes off unexpectedly during the test phase, this is usually a very serious accident that can be caused by a number of reasons. Here are some possible reasons and their explanations:

1. Failure of the fixed fixture

Mechanical or control system failures: Fixed fixtures can fail due to mechanical failures, material fatigue, design flaws, or manufacturing process issues.

Control System Error: The automatic release mechanism may be triggered prematurely due to a control system error or sensor failure, resulting in an early release of the fixing fixture.

2. Engine thrust exceeds expectations