Traffic Lights in Space? How to Craft Rules of the Road for a Growing Industry

Massive commercial and government investment in space has created a gap between individual participant decision-making and best practices for the space ecosystem.

The Aerospace Corporation
Aerospace TechBlog
Published in
5 min readNov 3, 2022


The cadence of space launch has increased exponentially in the past decade. Photos by SpaceX (left, center) and NASA (right) on Unsplash

Over the past three years, China has launched four Long March 5B rockets— resulting in four uncontrolled reentries that have captured global attention. Two of the first three occurrences resulted in large debris being scattered near populated areas without warning.

Safe Space Operations are based on international cooperation and partnerships. In order to manage the space domain and address growing challenges, the space sector requires a holistic approach. Each segment must be properly managed to work together correctly.

We asked Dr. Josef Koller, one of the authors of the 2022 Space Safety Compendium, and Dr. William Ailor, Technical Fellow with Aerospace CORDS, about what can be done to improve space safety for everyone as the pace of space development increases.

What are some of the risks or safety hazards uncontrolled deorbit activity presents?

The final reentry breakup process, showing that debris surviving reentry would fall through airspace potentially occupied by aircraft (commercial airspace extends to 18 km above ground) and could spread over a long, narrow path as it impacts the ground, possibly causing human casualty.

For uncontrolled reentry, a rule of thumb is that anywhere between 10% and 40% of the dry mass of a reentering object will survive reentry and impact the Earth’s surface. While some fragments could be large enough to injure a person, the small fragments also pose a threat to commercial aircraft in the air.Why is a consideration for space safety important? What are the potential ramifications of pushing the risk threshold too far?

While the risks are low when following the general guidelines, large debris could seriously harm individuals or damage aircraft in the air. A larger accident would likely lead to public pressure to impose more stringent rules to minimize future hazards. Instead, the goal should be for any space operator to follow internationally adopted best practices and guidelines and to act responsibly.

Have space safety measures kept up with the massive growth of the space industry over the past decade?

The current state of space safety. Image from the 2022 Space Safety Compendium.

The safety measures for minimizing reentry hazards are continuously evolving. Usually, this is accomplished by direct and controlled reentry into the ocean. International guidelines call for directing rocket stages and objects whose casualty expectations for a random reentry exceed 1 in 10,000 (i.e., one person on earth might be injured or killed for 10,000 reentries of that object) into a safe area such as a large ocean area.

Research on spacecraft designs that would reduce reentry hazards, or so-called “Design for Demise” is ongoing, but more research needs to be done.

Generally, space debris is deorbited into the Earth’s atmosphere to burn up on reentry. Are there any drawbacks to this method from a safety perspective?

The primary safety drawbacks of disposal by reentry is the potential injury or death to people on the ground or causing serious damage to aircraft. A related long-term hazard may be the effects of the materials used in the spacecraft—long-lived clouds of very small particles could accumulate in the atmosphere which might affect the environment.

Image of an ATV-1 Reentry from February 2015. Image courtesy European Space Agency.

There are other methods to further limit hazards to people or aircraft. Satellite and launch stages can be controlled and directed to reenter in a safe ocean area. In addition, satellites and launch stages could be fabricated to reduce the number of hazardous fragments surviving reentry.

Interested in the climate impact of rocket launch? Read What’s the Impact of the Space Industry on Climate Change?

Launch and reentry isn’t the only segment of space operations. What other areas are important for space safety?

The space domain is international and predicated on cooperation and partnerships enabled by safe space operations. In order to manage this domain and address growing challenges, the space sector requires a holistic approach to include how we operate in space without generating debris, how we assure human spaceflight safety while in orbit, and how we measure and analyze situational awareness data. All those areas are connected and a safety incident in one area can easily affect other areas of operations.

Does the space industry recognize the need for better safety practices?

The industry recognizes the need for integrated safety and is addressing these issues with the development of best practices and standards. Aerospace has established a Space Safety Institute to facilitate the process by leveraging our technical expertise and analysis.

Incorporating a holistic approach to space safety would further enable the space economy while protecting the long-term sustainability of outer space. Space is inherently a multi-actor, international domain and Safety should be a collaborative, not a competitive, endeavor. For example, a safety mishap that generates debris will quickly affect a series of operators — domestic, international, government and commercial. A holistic approach can also enable new scientific developments.

The complexity of systems is the biggest challenge. The space sector is undergoing an unprecedented period of growth that expands the scope of what is possible in space and who is involved. We see a number of new space actors with varying degrees of prior safety experience. It’s important to support new actors and provide them with safety solutions that are well established while allowing the freedom to innovate new ideas.

Interested in learning more? Visit the Aerospace Space Safety Institute online.



The Aerospace Corporation
Aerospace TechBlog