How Do Rocket Launches Avoid Collisions With Satellites and Space Junk in Earth’s Crowded Orbit?

The Gauntlet

This article explores the intricate, high-stakes process of launching a rocket through the increasingly dense field of satellites and debris surrounding our planet. It is a story of physics, data, and global coordination, where a simple launch is now a complex act of threading a needle in a high-speed orbital environment. This article examines the scale of the debris problem, the surveillance systems that track it, the pre-launch analysis that dictates “when” to fly, the physical constraints that prevent a rocket from swerving, and the future of automated “space traffic control” needed to keep orbit usable for generations to come.

The Void Isn’t Empty

When we look up at the night sky, space appears as a vast, black, and empty void. This perception is a powerful illusion. The region just above Earth’s atmosphere, particularly Low Earth Orbit (LEO), is now a bustling, crowded, and hazardous environment. Decades of space activity have populated this finite resource with thousands of active satellites, thousands more defunct ones, and millions of pieces of high-velocity shrapnel. For any new rocket attempting to ascend from Earth, this orbital region is a gauntlet.

A Sky Full of Objects

The sheer number of objects is difficult to comprehend. Since the first launch in 1957, humanity has attempted about 7,070 rocket launches. These missions have successfully placed approximately 23,770 satellites into orbit. While many of these have naturally fallen back to Earth and burned up in the atmosphere, about 15,860 remain in space. Of those, only about 12,900 are still functioning. This leaves thousands of large, uncontrolled, and “dead” satellites tumbling through the most valuable orbital paths.

The population of objects is not static; it’s growing at an accelerating rate. This is driven by two main factors: the continuous launch of new satellites for communications, navigation, and science, and the fragmentation of old objects. More than 650 break-ups, explosions, collisions, and other fragmentation events have been recorded since the space age began. Each event creates a cloud of new, smaller pieces of debris, each on its own orbital path and each a new collision threat.

The Tracked vs. The Untrackable

The most significant danger of the orbital environment isn’t just what we know is there; it’s what we don’t know. The difference between what global surveillance systems can track and what they can’t is the single greatest risk in spaceflight.

Global Space Surveillance Networks (which will be discussed in detail) actively track and maintain a catalog of about 43,510 space objects. These are, generally, objects larger than 10 centimeters (about 4 inches, or the size of a softball) in Low Earth Orbit. This catalog is the “phonebook” of space, and it’s the basis for all collision avoidance.

The real problem lies in the untracked population. Based on statistical models and radar sampling, it’s estimated there are 1.2 million debris objects in orbit that are between 1 cm and 10 cm. These objects are too small to be reliably tracked and cataloged but are large enough to be mission-ending. Furthermore, the models estimate there are 140 million objects between 1 mm and 1 cm.

To put this in perspective, the orbital environment, as of late 2024 and 2025, can be summarized as follows.

The primary hazard of this “space junk” isn’t its size; it’s its speed. Objects in LEO travel at enormous velocities, often exceeding 25,000 km/hr (about 7 km/s). At these speeds, kinetic energy is immense. A collision is not a “fender bender”; it’s an explosion.

A 1 cm paint fleck, too small to be tracked, can strike a satellite with enough energy to disable a critical subsystem or shatter a solar panel. The windows on the Space Shuttle frequently had to be replaced due to impacts from particles of this size. An object 10 cm or larger, like a defunct satellite or an old rocket body, would be catastrophic. A collision with an object that size would completely destroy a satellite and generate thousands of new pieces of debris, exacerbating the problem. The total mass of all this material orbiting Earth is estimated to be more than 15,100 tonnes.

The Kessler Syndrome

This scenario – a collision creating more debris, which in turn increases the probability of more collisions – is the foundation of a theory known as the “Kessler Syndrome.” This concept describes a potential tipping point, a critical density of objects in orbit where the chain reaction of collisions becomes self-sustaining.

If this point is reached, one collision can set off a cascading effect that rapidly pollutes an entire orbital band with so much shrapnel that it becomes unusable for exploration or satellite operations for decades, or even centuries. It would effectively create an impassable barrier, trapping us on Earth.

Mathematical modeling has repeatedly shown this is a real possibility. It’s not an instant disaster but a “slow-motion disaster” that plays out over decades. The concern is that for some of the most populated orbits, this tipping point may have already been passed.

The Changing Face of Risk

The nature of this risk is undergoing a fundamental shift. Historically, the primary source of new space debris was accidental explosions. Spent rocket upper stages, left in orbit with residual fuel, would break apart years later, creating thousands of fragments.

Two specific events in the last two decades dramatically worsened the environment. In 2007, a Chinese anti-satellite test intentionally destroyed a weather satellite, creating one of the largest and most dangerous debris clouds in history. In 2009, an active Iridium communications satellite accidentally collided with a defunct Russian Cosmos satellite. This single event generated thousands of new cataloged fragments.

Today, a new factor is accelerating the risk: the sheer number of active satellites. With the deployment of “megaconstellations” for global internet, tens of thousands of new satellites are being launched into LEO. The 2025 European Space Agency (ESA) Space Environment Report noted that within certain heavily populated altitude bands, the density of active satellites is now on the same order of magnitude as space debris.

This changes everything. The problem is no longer a passive, long-term environmental one, like a junkyard slowly decaying. It has become an active, real-time traffic management problem. A new launch isn’t just dodging a static field of old junk; it’s trying to cross a multi-lane, high-speed highway with thousands of active, maneuvering vehicles.

The Planet’s Watchtowers: Knowing What Is Where

Before a rocket can be cleared for launch, operators must have a precise map of the orbital highway. The entire system of collision avoidance is built upon a single foundation: a constantly updated catalog of objects in orbit. This is the mission of Space Domain Awareness (SDA), a discipline that has evolved from a niche military function into a global public safety necessity.

The 18th Space Defense Squadron

The primary “keeper of the catalog” for the non-classified world is the United States Space Force’s 18th Space Defense Squadron (18 SDS), based at Vandenberg Space Force Base, California. The 18 SDS is the U.S. Space Force’s premier squadron for Space Domain Awareness. Its mission is to maintain a continuous and comprehensive understanding of the space situation to defend U.S. and allied interests.

A critical part of this defense mission is a non-military, global safety function: the 18 SDS provides Space Situational Awareness (SSA) data and services to the entire planet. They detect launches, track objects, identify breakups, and predict reentries. Most importantly, they maintain the high-accuracy catalog of all trackable man-made objects. This data is shared with other governments, academic institutions, and commercial satellite operators around the world via the website space-track.org. This data-sharing program is essential for promoting the responsible and peaceful use of space.

The Space Surveillance Network (SSN)

The 18 SDS doesn’t operate in a vacuum. It is the command-and-control center for the U.S. Space Surveillance Network (SSN), a global web of ground- and space-based sensors. This network is the “eyes” that feed the catalog. The SSN has its roots in the 1950s, pieced together from early warning systems designed to track Soviet missiles and satellites. Today, it’s a sophisticated system using two primary types of sensors.

First are the radars. These ground-based systems are the workhorses for tracking objects in Low Earth Orbit. They function by sending out a powerful pulse of radio-frequency energy and then “listening” for the faint echo that bounces off an object. By measuring the timing and direction of this echo, they can pinpoint an object’s position, velocity, and trajectory. The advantage of radar is that it can “see” objects day or night and through cloud cover.

Second are the optical telescopes. Systems like the Ground-Based Electro-Optical Deep Space Surveillance (GEODSS) are essentially a network of powerful, automated telescopes. They are used to track objects in higher orbits, such as Medium Earth Orbit (MEO) and Geostationary Earth Orbit (GEO), which are 36,000 kilometers away. These telescopes don’t send out a signal; they are passive. They work by detecting the faint glint of sunlight reflecting off an object. This means they can only be used at night, when the sensor on the ground is in darkness, but the object in high orbit is still illuminated by the sun. These telescopes can see objects 10,000 times dimmer than the human eye can detect.

The 10-Centimeter Limit

The SSN is a marvel of engineering, but it has a fundamental limitation: it cannot see everything. The public catalog is reliably limited to objects larger than 10 centimeters (about 4 inches) in LEO.

This 10-cm limit isn’t an arbitrary choice; it’s a limit of physics. For a radar, an object smaller than 10 cm simply doesn’t return a strong enough “echo” to be reliably detected, tracked, and distinguished from background noise. For an optical telescope, an object that small at 36,000 km altitude is too dim to be consistently seen from the ground.

This is the central paradox of space safety. The entire, sophisticated, global collision avoidance system – from pre-launch planning to on-orbit maneuvers – is based on tracking the ~43,510 objects in the catalog. But we know, from statistical sampling, that there are 1.2 million untrackable objects in the 1-cm to 10-cm range.

An impact with a 10-cm object is catastrophic. The avoidance system is built to prevent this. An impact with a 1-cm object is mission-ending. The avoidance system can do nothing about this. This means that every satellite, and every astronaut on the International Space Station, is “flying blind” against a swarm of 1.2 million lethal-but-invisible projectiles. The only defense against this untracked risk is physical shielding (like the multi-layered Whipple shields on the ISS) or, for the most part, statistical luck.

The Rise of Commercial Watchmen

For decades, this government-run, military-operated SSN was the only “phonebook” in town. That reality is now changing. A new ecosystem of commercial Space Situational Awareness (SSA) providers is emerging, building and deploying its own sensor networks.

Companies like ExoAnalytic Solutions have built a private network of over 350 ground-based optical telescopes worldwide. They specialize in tracking the high-altitude GEO belt, providing persistent, real-time data on satellites and debris. Their network is so sensitive it can also detect and track objects as small as 10 cm in that distant orbit. Other companies, like LeoLabs, are building and operating networks of advanced ground-based radars, providing high-fidelity tracking in LEO, independent of the government.

This marks a significant shift in the business and geopolitical model of space awareness. The U.S. Space Force isn’t competing with these companies; it’s partnering with them. The military’s sensor network has known limitations, including geographical gaps in coverage. Commercial companies are filling those gaps.

The Space Force now has programs to actively purchase commercial SSA data and feed it into its own systems, like the Unified Data Library. This creates a richer, more resilient, and more accurate hybrid catalog. The 18th SDS is evolving from being the sole producer of SSA data to being the primary integrator and validator of data from a multitude of government and commercial sources. This public-private partnership means more sensors are watching the sky, which ultimately leads to fewer blind spots and better safety for the entire global space community.

Designing a Safe Trajectory

Collision avoidance for a new launch doesn’t start on launch day. It starts months or even years earlier, on the computers of mission designers. The international community and national regulators now require that “end-of-life” is one of the first things a satellite operator must plan for.

Filing the Flight Plan

Just as an airline must file a flight plan, a satellite operator can’t simply buy a rocket and launch. In the United States, the process is heavily regulated. An operator must apply for and receive licenses from multiple federal agencies.

The Federal Communications Commission (FCC) is one. Every satellite uses radio frequencies to communicate, and the FCC must grant a license to ensure its transmissions don’t interfere with other operators. The Federal Aviation Administration (FAA) is another. The FAA’s Office of Commercial Space Transportation licenses the launch itself, with a mandate to protect the safety of the “uninvolved public” on the ground from a launch or reentry accident.

The Orbital Debris Mitigation (ODM) Plan

A core part of this licensing process, for both the FCC and the FAA, is the submission of a detailed Orbital Debris Mitigation (ODM) Plan. This is a document that effectively forces the operator to answer the question: “How will you ensure your mission does not make the space junk problem worse?”

This plan must address several key points. Operators must prove they have minimized the release of any “mission-related debris,” such as lens caps or adapters. They must prove they have a plan to “passivate” their spacecraft and rocket body at the end of its life – venting any leftover fuel or discharging batteries to prevent an accidental explosion years later. NASA provides tools, like its Debris Assessment Software (DAS), that allow operators to model these risks and demonstrate compliance.

The “25-Year Rule” and Beyond

The most significant part of the ODM plan is the disposal strategy. For decades, the internationally accepted guideline has been the “25-Year Rule.” This standard, established by the Inter-Agency Space Debris Coordination Committee (IADC) in 2002, states that operators should ensure their spacecraft are removed from LEO within 25 years of their mission’s end. U.S. government regulations, and now FAA and FCC rules, have codified this guideline into a hard requirement and have reduced the timeline to 5 years.

This disposal is accomplished in one of two ways.

1. Atmospheric Reentry: For satellites in LEO, the most common method is to use the spacecraft’s last bit of fuel to perform a “de-orbit burn.” This fires its thruster to slow down, lowering the lowest point of its orbit (its perigee) deep into Earth’s atmosphere. Once this is done, atmospheric drag takes over, pulling the satellite down until it reenters and burns up.
2. Graveyard Orbit: For satellites in the very high Geostationary Orbit (GEO), reentry is not practical; it would take far too much fuel. Instead, these satellites are required to push up, maneuvering several hundred kilometers above the active GEO belt into a permanent “graveyard orbit.” This acts as a junkyard where they will not interfere with active, operational satellites.

Stricter Rules for a Crowded Sky

This 25-year-old rule is increasingly seen as dangerously insufficient. It was created in 2002, long before the advent of megaconstellations that plan to launch tens of thousands of satellites into the same orbital shells. Allowing thousands of defunct satellites to linger for 25 years in an already-crowded highway is a recipe for a Kessler-style chain reaction.

In response, regulatory bodies are tightening the rules. The European Space Agency (ESA) has adopted a “Zero Debris approach” for its own missions. This new, aggressive policy requires new ESA missions to de-orbit from LEO within just five years of mission completion, not 25. This reflects a clear scientific understanding that LEO must be cleared much faster to remain stable. This creates a regulatory friction: the old, globally-accepted guideline is now in direct conflict with the new, urgent scientific necessity.

This entire pre-launch planning process rests on a critical assumption: that the satellite doesn’t fail. The entire mitigation strategy – the 25-year rule, the 5-year rule, the de-orbit burn – is a gamble on future reliability. It assumes the satellite’s propulsion system and flight computer will still be working 10 or 15 years after launch. But satellites fail. Solar flares, micrometeorite impacts, or simple component failure can leave a satellite “dead in the water” and unable to perform its disposal maneuver.

ESA’s new guidelines acknowledge this, requiring missions to have a greater than 90% probability of a successful disposal. They even suggest that future satellites include standard interfaces that would allow them to be captured and removed by an “active debris removal” mission, implying they know that self-disposal will, in some cases, fail. A single, large satellite that dies in a high-density orbit and cannot be de-orbited instantly becomes one of the most dangerous pieces of debris in the sky for decades, and no pre-launch mitigation plan can do anything about it.

Threading the Needle: The Launch Window

After months of planning and regulatory approval, the rocket is finally on the pad. The mission is defined, the trajectory is designed, and the satellite is built. Now, the operator faces the most complex, high-stakes, and time-sensitive part of the process: finding a safe moment to launch. This is where collision avoidance transitions from long-term planning to a real-time, second-by-second operation.

The COLA Process

This operation is centered on the Collision on Launch Assessment (COLA), also known as Launch Conjunction Assessment (LCA). This is a free service provided by the U.S. Space Force’s 18th and 19th Space Defense Squadrons (18/19 SDS) to any organization launching from a U.S. range. This includes commercial companies like SpaceX and ULA, as well as allied foreign space agencies. It’s a cornerstone of the U.S. commitment to global spaceflight safety.

The process is a tight, real-time collaboration between the launch provider, the 18/19 SDS (as the catalog keeper), and the FAA (as the public safety regulator).

Running the Numbers

Days, and then hours, before the launch, the provider electronically submits its precise, second-by-second trajectory file to the 18/19 SDS. This file is the rocket’s exact flight plan, mapping its predicted position and velocity from the moment of liftoff, through its various stage separations, and all the way to its final orbital insertion.

The computers at the 18/19 SDS take this trajectory and perform a massive screening calculation. They digitally “fly” this planned path through the entire space catalog of 43,510+ objects. This check isn’t static. The system propagates the orbits of all cataloged objects forward in time, predicting where each one will be at every second of the rocket’s flight.

This “conjunction assessment” process flags any object whose predicted path comes “too close” to the rocket’s predicted path.

The Go/No-Go Metric: Probability of Collision

“Too close” is a surprisingly complex concept in orbit. A rocket’s trajectory is not known with perfect precision; it’s affected by winds, tiny variations in engine performance, and other factors. Likewise, a satellite’s position in the catalog also has a small amount of uncertainty.

Because of this, the COLA process doesn’t return a simple “hit” or “miss.” It returns a statistical value: the Probability of Collision (Pc). This complex calculation compares the “uncertainty box” of the rocket’s position with the “uncertainty box” of the satellite’s position. It calculates the statistical likelihood that these two boxes will overlap, resulting in a collision.

This probability is then compared to a pre-determined risk threshold. For NASA’s robotic (unmanned) missions, that threshold is typically 1 in 10,000 (or 1.0E-04). If the Pc for any of the 43,510 objects at any point during the rocket’s ascent is calculated to be greater than this threshold, it’s a “red light” for that specific launch time.

“Blackout Periods”: The Red Lights on the Orbital Highway

This statistical analysis is the key outcome of the COLA. The launch provider doesn’t just ask, “Is 10:00 AM safe?” They provide their entire launch window, which might be one or two hours long. The 18/19 SDS then runs the Pc analysis for every single second within that window.

The result is a “green light / red light” timeline for the launch director.

• Green Window: A period where the Pc for all 43,510+ objects is below the 1-in-10,000 risk threshold.
• Blackout Period: A period where the Pc for at least one object is above the threshold.

If the analysis finds that launching at 10:01:30 would result in a 1-in-9,000 chance of colliding with a 30-year-old defunct rocket body, then the time interval from 10:01:00 to 10:02:00 (for example) is declared a “COLA blackout period.”

The launch team in the control room will literally be watching the clock, knowing they must not press the “launch” button during these blackout intervals. They must wait for the window to turn “green” again. A multi-billion dollar launch, the culmination of years of work, is held hostage by this statistical forecast.

This system relies entirely on the 18th SDS catalog as the single source of truth. This creates a “data dictatorship” that is also a systemic weakness. The 18th SDS’s own handbook states that it does not currently screen launches against other launches that may be happening at the same time. It also screens against so-called “analyst objects” that are not in the public catalog, meaning a launch provider may be told “no-go” for a reason they cannot see or verify. If an object is missing from the catalog, or its orbital data is stale, the COLA process provides a false “all-clear.” This is a systemic risk that reinforces the need for the new, hybrid public-private tracking model.

Why Can’t a Rocket Just Swerve?

This entire, complex system of pre-calculating “blackout periods” often leads to a simple question: If a radar sees a piece of debris coming, why can’t the rocket just steer around it?

The answer lies in the fundamental difference between a rocket on ascent and a satellite in orbit. A satellite, already in the vacuum of space, is a precision instrument. It can fire a tiny thruster for a few seconds and, with no air resistance, that small push will change its orbit by kilometers over the next few hours. It can, and does, “swerve” all the time.

A launch vehicle, by contrast, is a creature of brute force. It is not “flying” in the traditional sense; it is engaged in a desperate, controlled battle against Earth’s gravity and atmosphere. Its engines are pointed in one direction and are focused on a single goal: generating enough forward-and-upward velocity to reach orbit.

The “Gravity Turn”: A Precision Fall

The trajectory a rocket follows is a delicate and highly optimized path called a “gravity turn.” It’s the most efficient way to get to orbit without wasting fuel or breaking the vehicle.

The rocket lifts off vertically. As soon as it clears the launch tower, it performs a tiny “pitchover maneuver,”tilting its nose just a few degrees in the direction it wants to go. From that point on, it stops actively steering. It just pushes forward. As it gains altitude, Earth’s gravity, which is now pulling at a slight angle to the rocket, naturally and passively bends the rocket’s trajectory from vertical to horizontal. The rocket is essentially “falling” into orbit.

The Angle of Attack

Any attempt to “swerve” or deviate from this pre-planned gravity turn would be instantly catastrophic. To swerve, the rocket’s engines or fins would have to force its nose to point in a different direction than it’s actually moving. This difference is called the “angle of attack.”

At the hypersonic speeds a rocket reaches while still in the atmosphere, flying at any significant angle of attack would create immense, transverse (sideways) aerodynamic stresses on the vehicle’s structure. The air resistance would be hitting the rocket “side-on,” and the vehicle, which is only designed to handle forces along its long axis, would break apart in mid-air.

This means a rocket on ascent has zero spatial maneuverability. It is a bullet fired from a gun, and its path is set.

This physical limitation is what makes the COLA process so important. Because a rocket cannot dodge, its only collision avoidance tool is temporal. The launch director cannot choose a new path to avoid an object; they can only choose when to start on their single, pre-determined path, timing the “shot” to pass through the gaps in the orbital traffic.

This lack of precision is a double-edged sword. The rocket’s own trajectory has a high degree of uncertainty, as it’s buffeted by winds and engine fluctuations. This “fuzziness” is a primary limiting factor in the COLA analysis. The Probability of Collision (Pc) calculation must account for the rocket’s large “error box.” Because this error box is so wide, it is statistically more likely to overlap with something in the catalog, which in turn creates more blackout periods. In a very real sense, the rocket’s own inability to fly a perfect path is its worst enemy in clearing the orbital highway.

The “COLA Gap”: A 56-Hour Vulnerability

The rocket’s engine cuts off. The payload – a new, multi-ton satellite – separates from the spent upper stage. By the rules of the pre-launch COLA, the mission has been a success. But for the astronauts on the International Space Station (ISS) and for every other satellite operator, the danger is just beginning.

This is because the launch has just introduced two new, large, and untracked objects into the orbital environment. This begins a critical, high-risk vulnerability period known as the “COLA Gap.”

Flying Blind

The “COLA Gap” is the seam, or handoff failure, between two different safety systems.

1. It begins when the pre-launch COLA screening ends (which is typically about 100 minutes after liftoff, once the rocket has achieved orbit).
2. It ends only when the new objects (the satellite and the rocket body) are found by the Space Surveillance Network, tracked long enough to determine their precise orbit, and officially entered into the 18th SDS catalog.

This cataloging process is not instant. For a high-priority asset like the International Space Station, this “vulnerability period” is 56 hours long. This time is required to allow 24 hours for the 18/19 SDS to track the new objects, and then 12-36 hours for the ISS to assess the risk and, if needed, plan and execute a collision avoidance maneuver.

During this 56-hour gap, the new, multi-ton objects are flying “dark.” They are untracked and uncataloged. This means the automated, on-orbit collision assessment systems – like NASA’s Conjunction Assessment Risk Analysis (CARA) team that protects the ISS and all other NASA satellites – cannot see the new objects coming. The ISS, which is heavily shielded against 1-cm debris, has no protection against these new, untracked, 10-ton rocket bodies. It is a sitting duck.

The 2009 GPS IIR-20 Incident

This risk is not theoretical. The “COLA Gap” was identified as a serious safety risk as early as 2006, but awareness was heightened by a near-miss in 2009.

On March 24, 2009, a rocket launched a GPS IIR-20 satellite. During the 56-hour COLA gap, the spent upper stage of that launch vehicle unexpectedly crossed inside the ISS’s safety notification box. No one on the ground saw it coming, and the ISS had no time to react. Had the timing been slightly different, the event could have been one of the worst disasters in space history. This incident proved the vulnerability was real and highlighted the urgent need to protect human spaceflight from this “blind spot.”

Bridging the Gap

Because of this risk, an additional layer of pre-launch analysis is now performed for any launch that couldcome near a crewed asset. NASA’s Launch Services Program and other organizations now perform a special “COLA gap analysis.”

This involves “nodal separation analysis,” which checks if the launch’s orbital plane (its “hoop” around the Earth) will ever cross the ISS’s orbital plane. If it does, they run “Monte Carlo” simulations, running thousands of launch variations to see if any of them could result in a close approach during that 56-hour blind period. If the analysis shows the rocket body could come near the ISS before it can be tracked, that launch window is closed.

This vulnerability has also created a new business opportunity. The “COLA Gap” is a problem of time – the time it takes the military’s tracking network to find and catalog a new object. Today, the government’s Office of Space Commerce has announced a “Commercial COLA Gap Pathfinder” program. It is actively seeking help from the new commercial SSA companies, asking if their agile, autonomous sensor networks can find and catalog new launches faster than the government’s current system. The new, competitive metric in space awareness is “speed-to-catalog.” Shrinking that 56-hour gap to just 6 hours is a multi-million dollar value proposition for orbital safety.

The New Space Age: Megaconstellations Change the Game

The entire system described so far – a rocket launch deconflicting with a static field of debris – is the “classic” model of collision avoidance. That model is now being rendered obsolete. The explosive growth of satellite megaconstellations, primarily for global internet, has fundamentally changed the physics, economics, and statistics of the problem.

Creating an Orbital “Shell”

Megaconstellations like SpaceX’s Starlink and Eutelsat OneWeb are not just large collections of satellites. They are integrated systems designed to form a “high-density ‘space grid'” that wraps the entire planet in multiple layers of coverage.

The scale is unprecedented. A decade ago, a large constellation might have consisted of 60 or 70 satellites. As of late 2025, Starlink alone has over 8,800 active, maneuvering satellites in orbit, with plans to launch tens of thousands more.

This new, extreme density has a direct and immediate impact on the launch process. The LEO altitudes that every new rocket must pass through are now dramatically more crowded. This means the probability of a COLA conflict is much higher. A launch trajectory that might have had to deconflict with 50 cataloged objects a decade ago might now have to deconflict with 500.

The immediate result for all launch providers is more “COLA blackout periods.” This, in turn, means fewer available “green” launch windows. It makes launching anything – a new science telescope, a national security satellite, or even a competing internet satellite – more difficult, more expensive, and more constrained by time.

The Unprecedented Burden of Avoidance

While the impact on launch is significant, the primary risk has shifted to on-orbit operations. A company like SpaceX, which operates Starlink, is now the world’s largest satellite operator. They are not just causing the traffic problem; they are also the ones most affected by it.

In a six-month period from December 2023 to May 2024, Starlink satellites had to perform nearly 50,000collision avoidance maneuvers. This number was roughly double the number from the previous six-month period, showing a clear and accelerating trend. This scales to an average of 14 separate maneuvers per satellite in just six months.

This volume of alerts has made the old way of doing business impossible. The traditional method of collision avoidance involved an operator on the ground at one company receiving a “conjunction alert,” analyzing it, and then sending an “ad-hoc… email exchange” to the operator at the other company to coordinate who would move.

With 50,000 alerts in six months, that human-in-the-loop system is broken. SpaceX’s only solution was to take the human out of the loop. They have implemented a fully autonomous collision avoidance system. Their satellites receive alerts from the 18th SDS and other sources, analyze the risk, and then automatically fire their thrusters to move out of the way, all without a human command.

This vertical integration – where SpaceX is the launch provider, the satellite builder, and the autonomous avoidance operator – gives them a powerful advantage. But it also creates a massive new challenge for the entire launch avoidance system.

The COLA process, which determines the “blackout periods,” works by predicting the future path of a cataloged object. But a Starlink satellite’s path is no longer predictable; it might change its own orbit autonomously to dodge a different piece of debris after the 18th SDS has already run its COLA prediction.

This means the COLA report a launch provider receives is now inherently less reliable. It’s screening against a dynamic and unpredictable environment. This new reality necessitates a move away from a static catalog and toward a live, real-time data-sharing system where operators broadcast their intentions, which is the foundation of Space Traffic Management.

The Future: From Collision Avoidance to Traffic Management

The system that has kept space safe for 60 years is breaking under the strain. The current model – a static, military-run catalog, ad-hoc email coordination, and non-binding international guidelines – is purely reactive. The explosive growth of megaconstellations, with their 50,000+ annual maneuvers, proves that this reactive model is unsustainable. The future of launch avoidance, and all space safety, is a proactive, coordinated, and automated system known as Space Traffic Management (STM).

A New U.S. Philosophy: Civil STM

One of the most important developments in this new era is a philosophical and bureaucratic shift in the United States. In 2018, Space Policy Directive-3 ordered that the responsibility for civil space traffic management – providing collision alerts to commercial and international operators – be moved from the military (the Department of Defense) to a civilian agency.

That agency is the Department of Commerce’s Office of Space Commerce (OSC). This is not just a bureaucratic shuffle; it’s a fundamental change in philosophy. The DOD’s primary mission is national security; its best tracking data is often classified and cannot be shared. This creates an inherent “data asymmetry” and distrust. The OSC’s primary mission, by contrast, is to foster the economic growth and technological advancement of the U.S. commercial space industry.

This move decouples the public safety mission from the military secrecy mission. It aims to create a neutral, trusted data layer that can serve as the “public good” for the entire globe, building the international trust necessary for a true STM system to work.

TraCSS: The Future U.S. System

The OSC is now building this new system, called the Traffic Coordination System for Space (TraCSS). TraCSS is not a new set of government radars and telescopes. It is a modern, cloud-based, data-driven platform.

It is being designed to ingest and fuse data from all available sources to create a single, authoritative catalog for safety. It will take the foundational data from the DOD’s SSN, augment it with data purchased from commercial SSA providers (like ExoAnalytic), and – most importantly – it will also directly ingest predictive data from satellite operators themselves. For example, the OSC has entered into an agreement with SpaceX to study and evaluate its automated avoidance software.

Automation is Key

This is the key to the future. The sheer volume of data and the number of required maneuvers are already far beyond human scale. Future systems, like ESA’s developing CREAM (Collision Risk Estimation and Automated Mitigation) project and the OSC’s TraCSS, are not being built for humans to use. They are being built for machines to use.

These systems are being designed around Application Programming Interfaces (APIs), a standard way for computer programs to “talk” to each other. The old model of “air traffic control,” with a human controller ordering a pilot to change altitude, is a poor analogy for space. Sovereignty issues and physics make that impossible.

A better analogy is the internet. The future of STM will be a federated protocol. TraCSS will act as the neutral “server,” providing the “best-known-truth” map of where everyone is. It will also provide the standardized language (the API) for operators to “talk” to each other.

In this future, a new rocket’s launch trajectory will be uploaded to this system. SpaceX’s autonomous system will see it, automatically deconflict, and broadcast its planned maneuver. OneWeb’s autonomous system will see that broadcast and adjust its own plan in turn. All of this will happen machine-to-machine, in seconds, without a single email being sent. This bottom-up, decentralized, and automated ecosystem is the only viable path forward.

Summary

Launching a rocket safely through Earth’s orbit has evolved from a brute-force physics problem into one of the most complex data-management and logistical challenges of our time. The “void” of space is a high-speed “space grid,” a gauntlet cluttered with not only 1.2 million lethal, untrackable objects but also tens of thousands of active, maneuvering satellites.

For a new launch, the physics are unforgiving. A rocket cannot swerve. Its only tool for collision avoidance is timing. This timing is dictated by the “blackout periods” generated by the U.S. Space Force’s meticulous, pre-launch COLA screening, a process that “flies” the rocket’s path against a catalog of 43,510 known objects.

This system, while effective, is strained. It is plagued by a 56-hour “COLA Gap,” a critical blind spot after launch that leaves even the International Space Station vulnerable to newly deployed, untracked rocket bodies. The new era of megaconstellations, with their autonomous, high-frequency maneuvers, has finally broken this old, reactive model.

The world is now in a race to build a new system. The solution is no longer passive collision avoidance; it’s active, automated Space Traffic Management. The U.S. shift to a civilian-led OSC, the development of the data-fusing TraCSS platform, and the global push for machine-to-machine coordination are no longer optional upgrades. They are the only way to ensure the gauntlet can still be run, keeping space – our planet’s most valuable resource – usable for generations to come.