Elon Musk on Twitter Spaces on SpaceX’s Starship 4/20 launch & my speculations and learnings

"On April 29, SpaceX founder Chief Engineer Elon Musk hosted a live ‘Twitter Spaces’ call with his ‘Subscribers’ during which he discussed what happened during SpaceX’s Starship 4/20 (April 20) launch and provided a brief glimpse of future improvements for the next test flight."

Here is the TESMANIAN's article of the ‘Twitter Spaces’ call:

https://www.tesmanian.com/blogs/tesmanian-blog/spaces-2

Note: The intention of this blog post is purely interest and curiosity to know about Starship, and the time spent on this blog is very very very tiny (no extensive research, at all).

The purpose of this blog post is only truly interest but nothing else. The purpose of this blog post is only to talk about any spacecraft, in general. The main purpose of this blog post is to learn #rocketscience.

The information in this blog that I collected from ChatGPT may not be accurate.

Rapid Unscheduled Disassembly (RUD) can occur due to a variety of reasons, including design flaws, manufacturing defects, or operational errors.

Question for Elon: What are the primary and secondary reasons, that SpaceX have categorized, for RUD on the 4/20 launch?

SpaceX, one of the leading companies in the commercial space industry, has experienced several RUD events in the past during their rocket landing attempts. However, they have learned from these incidents and made improvements to their designs and procedures to reduce the likelihood of future RUD events.

Here are some notable examples:

1. CRS-7 Mission (June 2015) - The Falcon 9 rocket carrying the Dragon cargo spacecraft to the International Space Station exploded shortly after liftoff. The cause of the explosion was traced back to a faulty strut in the rocket's upper stage.

2. AMOS-6 Mission (September 2016) - The Falcon 9 rocket exploded during a pre-flight test, destroying the satellite payload it was scheduled to launch. The cause of the explosion was traced back to a failure in the rocket's helium pressurization system.

3. Landing Attempts - SpaceX has also experienced several RUD events during their attempts to land the first stage of their Falcon 9 rocket back on Earth. These events include:

• CRS-5 Mission (January 2015) - The first attempt to land the Falcon 9 first stage on a drone ship in the ocean failed when the rocket tipped over and exploded upon landing.

• CRS-6 Mission (April 2015) - The second attempt to land the Falcon 9 first stage on a drone ship in the ocean failed when the rocket crashed into the ship and exploded.

• CRS-16 Mission (December 2018) - The Falcon 9 first stage made a successful landing back on Earth, but then toppled over and exploded due to a failure in one of its grid fins.

Despite these setbacks, SpaceX has continued to make significant progress in the commercial space industry, and they have successfully completed many missions and achieved many milestones, including launching astronauts to the International Space Station and developing the world's most powerful operational rocket, the Falcon Heavy.

SpaceX has not officially released a statement categorizing the primary and secondary reasons for the RUD that occurred during the SN11 test flight on April 20, 2021. However, based on available information and observations, here are some possible factors that may have contributed to the incident:

Primary reasons:

• Loss of thrust vector control (TVC) in one of the Raptor engines

• Possible structural failure or explosion of the same engine

Secondary reasons:

• Loss of control due to the failure of the TVC system

• Debris from the engine failure causing damage to other systems or components

It's important to note that the above factors are based on observations and speculations from the media and public, as SpaceX has not released an official statement on the incident. SpaceX conducts a thorough investigation of any incident or failure and releases a report on the findings, which helps to identify the root cause(s) and preventive measures.

Thrust vector control (TVC) is a technology used in rockets to adjust the direction of the thrust produced by the rocket engine. It is used to control the attitude and trajectory of the rocket during flight.

If a rocket were to lose thrust vector control during flight, it could result in a loss of stability and control, potentially leading to a catastrophic failure. The rocket could start to spin out of control or deviate from its intended flight path, making it difficult or impossible to recover.

To prevent the loss of thrust vector control, rockets are typically equipped with redundant systems and safety measures to ensure that the engine nozzles remain pointed in the correct direction. For example, the Space Shuttle had two independent TVC systems, and SpaceX's Falcon 9 rocket has a backup TVC system that can take over in the event of a failure in the primary system.

The cause of a loss of thrust vector control can vary, and may be due to a range of factors such as mechanical failure, electrical failure, or a software error. It's also possible that the loss of thrust vector control could be caused by external factors such as wind shear or turbulence.

In the event of a loss of thrust vector control, the rocket's onboard guidance and control systems would likely attempt to correct the deviation using other control surfaces, such as fins or reaction control thrusters. However, if the deviation is too large or the rocket is too far off course, it may not be possible to recover, and the flight termination system may need to be activated to prevent a more serious accident.

He said that at T+ 27 seconds into the flight SpaceX lost communications due to “some kind of energy event” and “some kind of explosion happened to knock out the heat shields of [Raptor] engines 17, 18, 19, or 20.” Musk said that the Super Heavy rocket kept going through T+62 seconds with the engines continuing to run then lost thrust vector control at T+85 seconds.

What energy event could cause the rocket to loose communications?

A wide range of energy events can cause a rocket to lose communications, depending on the specifics of the event and the systems being used to communicate. Some examples of energy events that could cause a loss of communications in a rocket include:

1. Electromagnetic interference (EMI): This occurs when electromagnetic waves generated by one electronic device interfere with the operation of another electronic device. EMI can be caused by a variety of sources, including power lines, lightning strikes, and other electronic equipment.

2. Solar storms: Large solar storms can release massive amounts of charged particles into space, which can cause disruptions in satellite and spacecraft communications. These disruptions are known as "space weather."

3. Radio frequency (RF) interference: RF interference can occur when multiple electronic devices are operating on the same frequency or when signals are being jammed intentionally.

4. Power surges or outages: Sudden changes in electrical power can cause electronic devices to malfunction or shut down completely, leading to a loss of communications.

5. Physical damage: Physical damage to a rocket or its communication systems, such as from impact with debris or extreme weather conditions, can also cause a loss of communications.

Musk said that Engine Isolation is very important.

Engine isolation refers to the process of separating a malfunctioning or damaged engine from the rest of the propulsion system in order to prevent the failure from affecting the other engines and the overall mission. This is a critical safety measure in rocket systems, where the failure of even a single engine can have catastrophic consequences.

In a multi-engine rocket, such as SpaceX's Falcon 9 or Falcon Heavy, engine isolation can be achieved by shutting down or throttling back the malfunctioning engine while allowing the remaining engines to continue firing at full thrust. This helps to maintain the overall thrust and stability of the rocket while minimizing the risk of further damage or failure.

Another approach to engine isolation is to physically separate the malfunctioning engine from the rest of the propulsion system. For example, in some rocket designs, the engines are mounted on separate stages, and each stage can be jettisoned if a problem occurs with one of the engines. This allows the malfunctioning engine to be safely separated from the rest of the rocket, which can then continue the mission using the remaining engines.

Overall, engine isolation is an important safety measure in rocket systems and is used to prevent the failure of a single engine from affecting the performance and safety of the entire rocket.

Note: I have spent just a few seconds to put together this incomplete note of learnings, just out of my inquisitive nature and some unexplainable interest in 🚀

I am hoping Elon Musk & SpaceX would be interested in hiring me after reading this.