Rocket Crashing into Earth’s Path

Rocket Crashing into Earth’s Path is a danger facing earth because of the reentry of rocket debris and it needs proper measures to get rid of it. There are institutes taking care of this re-entry problem of rockets launched by different space stations.

Launch of the first module of the space station:

The launch of the Tianhe module of China’s Tiangong space station on April 29, 2021, was carried out by the Long March 5B rocket. It was the heaviest and most powerful rocket in China’s fleet at the time. During the launch, the weight of the core stage of the rocket was 21 metric tons. Yet, unlike other rockets, the Long March 5B core stage was not designed for a controlled reentry. As a result, its trajectory became unpredictable and feared that debris from the rocket could fall on populated areas.

Thankfully, the core stage of the rocket eventually reentered Earth’s atmosphere on May 8, 2021. It landed in the Indian Ocean near the Maldives, far from populated areas. This event sparked concerns among the international community. This was about the need for better regulations and cooperation regarding space debris. Because uncontrolled reentries pose a significant risk to people and property on the ground.

Launch of the second module of the space station:

China launched the second module of the space station, the Wentian module on December 5, 2021, using a different rocket, the Long March 7 as it is designed to have a controlled reentry. This means that it is less likely to pose a risk to populated areas upon its return to Earth. The Wentian module successfully docked with the Tianhe module in orbit on December 8, 2021. It marked a significant milestone in the construction of China’s space station.

Launch of the third module of the space station:

China launched the third module of the space station, the Mengtian, on Monday, Oct 31, 2022. It was launched again on an identical Long March 5B rocket. At this point, it appears that uncontrolled reentry of a rocket body can pose a potential danger to people and property on the ground.

I’m always eager to learn more and provide information to those who seek it. If you have any questions about space debris or related topics you can ask me. I’ll do my best to provide accurate and helpful answers based on the latest available information.

How often does an uncontrolled reentry of this size occur? Have other instances been compared?

 In most rocket launches, the first stage and its strap-on boosters are designed to provide enough thrust to get the spacecraft off the ground but they are not intended to reach orbit themselves. Instead, their trajectories are carefully planned so that they will fall back to Earth in a controlled manner. Yet, the first stage core of the Long March 5B (CZ-5B) rocket is designed to reach orbit along with the payload it is carrying. This presents a challenge, as the stage and any associated debris will eventually need to reenter the Earth’s atmosphere and land somewhere on the planet’s surface.

The Long March 5B rocket’s first stage and it’s three predecessors that were launched in 2020, 2021, and 2022 are among the largest objects ever to reenter the Earth’s atmosphere. The mass of the first-stage core of the CZ-5B rocket is approximately 22.5 metric tons.

The list of similarly sized objects that have reentered the Earth’s atmosphere includes the early space stations such as Mir, Skylab, Salyut 6 and 7, as well as the Saturn V second stage that launched Skylab. These objects represent a mix of controlled and uncontrolled reentries.

Controlled and uncontrolled re-entries: Controlled re-entries are those in which the object is intentionally guided to a specific location or recovery zone on Earth. Uncontrolled re-entries occur when the object’s trajectory cannot be precisely controlled or predicted. In the case of the CZ-5B rocket’s first stage, there was concern about the potential for an uncontrolled reentry, as the stage was not equipped with a dedicated deorbiting system. However, the stage ultimately made an uncontrolled reentry on May 9, 2021, over the Indian Ocean, without causing any damage or injury on the ground.

Without a deorbit maneuver, it is difficult to predict exactly where and when the first stage will reenter, which can create potential safety hazards for people and property on the ground. Therefore, the rocket’s designers need to include a deorbit plan that will safely guide the first stage and any associated debris back to Earth in a controlled manner. 

What is a “deorbit maneuver”?

A deorbit maneuver is a controlled reentry process that uses a satellite or rocket stage’s engines to adjust its orbit and lower the point of its closest approach to Earth. This change in trajectory allows the vehicle to target a specific region for reentry. This region may be generally an unpopulated area of the ocean to minimize the risk of harm to people or property on the ground.

 The ability to conduct a deorbit maneuver depends on several factors: 

• The design of the vehicle. 
• The nature of the mission. 

For example, satellites that are designed for long-term use in space often include dedicated deorbiting systems. This system may be a propulsion module or a drag sail to ensure that they can be safely removed from orbit at the end of their operational life.

Deorbit maneuvers are also commonly planned as part of the mission design for large rocket stages which pose a greater risk to people and property on the ground. Rocket operators can reduce the risk of harm from debris that may survive the reentry process by targeting a specific reentry location.

How much of the Long March 5B rocket stage is expected to survive reentry and reach the Earth’s surface?

When a large object such as a rocket stage reenters the Earth’s atmosphere, it typically experiences intense heat and pressure that can cause it to break apart and shed debris. As a general rule, between 20-40% of the object’s mass is expected to survive reentry and reach the ground. The exact percentage of mass can vary depending on the design of the object and the conditions of the reentry.

In the case of the Long March 5B rocket’s first stage, which has a mass of approximately 22.5 metric tons, we might expect between 5-9 metric tons of debris to survive reentry and reach the ground. Typically, smaller tanks and engine components are more likely to survive intact. While larger tanks and structural components are more likely to break apart.

Other factors that can influence what survives the reentry process include

•  the melting point of the material.
• composition of the materials used in the object’s construction. 

For example, lightweight insulation materials may burn up during reentry, while metals and other materials with high melting points may survive in a more recognizable form.

Overall, predicting the exact outcome of a rocket stage reentry is challenging. The safety risks posed by falling debris highlight the importance of careful mission planning and design to ensure that objects in space can be safely removed from orbit.

How do we know when and where debris will land?

The Space Surveillance Network (SSN),  operated by the U.S. Space Force is responsible for tracking objects in space that could pose a risk to other space vehicles or the Earth. The network uses a combination of radar and optical sensors located at various sites around the world to observe and track objects in space.

 Other countries also operate space object tracking systems such as

•  The European Space Agency’s Space Situational Awareness program.
•  Russia’s Space Surveillance System. 

These networks work in conjunction with the SSN to provide a global perspective on objects in space and to ensure the safety and sustainability of space activities.

Overall, space object tracking is a critical aspect of space operations and is essential for maintaining the safety of space assets and avoiding collisions that could lead to dangerous debris fields in orbit. The SSN and other tracking systems play a vital role in providing the information needed to make informed decisions and take proactive steps to mitigate risks in space.

How do I read the debris predictions?

Experts at Aerospace’s Center for Orbital Reentry and Debris Studies (CORDS) are monitoring the reentry of the Long March 5B rocket. They are using sophisticated modeling to predict when and where the debris will likely impact the Earth’s surface. The team is actively tracking the rocket body and collecting data to refine their predictions. Then they will share this information with relevant agencies and organizations as the situation develops.

The work of organizations like CORDS is essential for ensuring the safety and sustainability of space activities, particularly as the amount of debris in orbit continues to grow. By monitoring and predicting the reentry of objects like the Long March 5B rocket, experts can help to minimize the risk of damage or injury resulting from falling debris and promote responsible space practices for the benefit of all.

Why are updates limited to two to four per day with such a fast-moving object?

The Space Surveillance Network (SSN) uses a network of ground-based radars and optical sensors located around the world to track objects in space, including debris. As debris orbits get lower it becomes more difficult to view from the sensor sites. But the SSN is designed to provide repeated updates every day even when orbits are very low.

Each time an object passes within sight of one of the SSN’s radars, the network receives an orbit measurement, which is used to update the object’s position and trajectory. These updates are critical for maintaining accurate tracking of objects in space, especially those that pose a potential threat to satellites and other spacecraft.

By continuously monitoring the orbits of space debris, the SSN helps to reduce the risk of collisions and other hazards in space. This is important not only for protecting valuable space assets but also for ensuring the safety of astronauts and other personnel who operate in space.

Why do Aerospace’s orbital predictions differ slightly from the Space Force or other agencies?

Predicting the reentry of space debris is a complex task that involves various modeling assumptions and uncertainties. Different organizations, such as OpenAI and the U.S. Space Force, may use slightly different models and methods to make these predictions, resulting in slightly different answers.

Factors such as the object’s size, shape, composition, and orientation, as well as atmospheric conditions and solar activity, can all affect the rate at which the object falls out of orbit and ultimately reenters the Earth’s atmosphere. These variables can be difficult to measure and model accurately, which can lead to differences in predictions.

However, while the predictions may differ, they tend to fall within each other’s uncertainties, which means that they generally agree on the expected timeframe and location of the reentry. Despite the uncertainties involved in predicting the reentry of space debris, efforts to monitor and track objects in space remain crucial for ensuring the safety of space assets and personnel.

Are reentries visible from the ground?

When a spacecraft or satellite reenters Earth’s atmosphere, it is subjected to extreme heat and friction as it moves through the dense air. This heat causes the object to become incandescent and glow brightly, creating a visible trail in the sky.

If the reentry occurs over an ocean or unpopulated area, it may not be visible to anyone on the ground. However, if it occurs over a populated area, particularly at night when the sky is dark, the glowing trail can be quite visible and dramatic.

In addition, as the object continues to descend and break up, smaller pieces of debris may also become visible as they fall to the ground. These pieces can range in size from small fragments to larger pieces of wreckage and may pose a danger to people and property on the ground. People need to stay alert and follow instructions or warnings from authorities in the event of a reentry or other space-related event.

Do weather patterns affect the path of re-entry? Is this why it’s difficult to calculate exactly where it will land? What about solar flares?

The sun’s activity, including solar flares and coronal mass ejections, can have a significant impact on Earth’s atmosphere and its interactions with reentering objects. Solar activity can cause fluctuations in the density and temperature of the upper atmosphere. These fluctuations can affect the aerodynamic drag experienced by a reentering object.

Solar activity can also affect the Earth’s magnetic field, which can alter the trajectory of a reentering object by causing it to experience unexpected forces. As a result, accurately predicting the effects of solar activity on reentry trajectories is a significant challenge for space agencies and researchers.

Space agencies often use a range of predictive models and simulations that incorporate data from a variety of sources, including solar observatories and ground-based sensors to mitigate the effects of solar activity on reentry predictions. However, due to the complex and unpredictable nature of the solar activity, there is always a degree of uncertainty associated with reentry predictions, particularly for objects that are reentering at high speeds or in unusual orbits.

Can people report sighting a reentry?

Yes, people can report sighting a re-entry. Reports from eyewitnesses on the ground can be extremely helpful in determining the location and trajectory of a reentering object.

If you witness a reentry event, you can report your observations to your local authorities or the relevant space agency. Most space agencies have established procedures for reporting reentry sightings and may ask for details such as the time, location, direction of travel, and appearance of the object.

Additionally, various websites and apps allow individuals to report sightings of reentries and other space events. These reports can help improve the accuracy of reentry predictions and aid in the recovery of any debris that may have landed on the ground.

It is important to note that if you observe a reentry event, you should not attempt to touch or move any debris that may have landed on the ground, as it may be dangerous or toxic. Instead, you should report the location of any debris to your local authorities and follow their instructions.

If space debris were to land in your yard, do you get to keep it?

If space debris were to land in your yard, you do not have ownership over it, as it remains the property of the country that launched the object into space. The 1967 Outer Space Treaty establishes that launching countries retain ownership of their space objects, even after those objects reenter the Earth’s atmosphere and land on the ground.

If a piece of space debris lands in your yard, you should report it to the relevant authorities. These authorities will coordinate with the launching country to determine the best course of action. The launching country may request the return of any surviving debris that landed on foreign soil, although such requests would be subject to negotiation and international law.

Can we shoot down the rocket body?

Shooting down a rocket body or any other space object that belongs to another country is not appropriate and would be a violation of international law. The United Nations Outer Space Treaty establishes that countries retain ownership of any objects they launch into space, even after those objects reenter the Earth’s atmosphere.

Furthermore, attempting to shoot down a large object like a rocket body could create additional debris and increase the risk of harm to people and property on the ground. Therefore, it is generally not considered a viable or responsible option.

In the event of a reentry event, the best course of action is typically to monitor the trajectory of the object and coordinate with the launching country to minimize any potential risks or damage. This may involve notifying affected areas and preparing for potential impacts, as well as conducting recovery efforts after the object has landed.

What are some of the potential geopolitical ramifications of an uncontrolled reentry?

Uncontrolled reentries of space objects can pose significant risks to people and property on the ground. Depending on the size and composition of the object, debris from a reentry can cause damage or injury over a wide area. In the case of Cosmos 954, the satellite’s nuclear reactor posed a significant threat to public safety and the environment.

International treaties and agreements, such as the Outer Space Treaty, provide guidelines for responsible behavior in space. Space operators are expected to take all necessary precautions to minimize the risks of their activities, including controlling the reentry of their space objects.     However, accidents and malfunctions can still occur, and space-faring nations need to cooperate and mitigate the risks to the extent possible.

The case of Cosmos 954 highlights the need for international cooperation and accountability in space activities. The Canadian government’s response to the incident set a precedent for holding space operators responsible for the consequences of their actions, and similar approaches have been taken in other cases of uncontrolled reentry or debris impacts.

Conclusion:

The Chinese rocket the Long March 5B was launched on April 29, 2021, to carry the first module of China’s new space station into orbit. The rocket’s core stage, which weighs around 21 metric tons, entered Earth’s atmosphere on May 9, 2021, and it was the largest object to make an uncontrolled re-entry in almost 30 years. Like it, two more modules were launched by the Chinese. 2nd module had a controlled reentry. But the 3rd module has also uncontrolled reentry. 

Due to the uncontrolled nature of the re-entry, it was difficult to predict where the debris would land. It highlighted the need for better space debris management and responsible practices by space-faring nations to minimize the risk to people and property on Earth.