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As a SciShow viewer, you can keep building  your STEM skills with a 30 day free trial and 20% off an annual premium  subscription at Brilliant.org/SciShow. When you’re on a flight to Florida, you’re  probably thinking about which book you should read on the beach…not about the  chances your plane will collide with a rocket launching from Cape Canaveral!

You might assume that the  professionals tracking your plane also know when and where rockets are in the air. But you’d be wrong. And we’re living in the age  of commercial space flight.

In 2022 alone, there were a record-setting 180  successful rocket launches around the world! The off chance that something goes wrong between  a plane and a rocket is higher than ever. So to keep us safe in this rocket-filled world, engineers and air traffic controllers have  to reinvent the way we keep track of rockets. [♪ INTRO] Let’s start with why rockets are effectively  invisible to air traffic controllers.

It’s all because of space history. When humans started going to space, each launch was a massive undertaking  run by federal agencies like NASA. And to keep commercial airplanes from hitting  those rockets, air traffic controllers borrowed the technique that the military used  to clear airspace for practice exercises.

They declared a temporary no-fly zone  known as a Special Activities Airspace. For several hours, airplanes had  to detour around these areas, which could range anywhere from 90 to 4400  square kilometers surrounding the launch pad. With such large empty swaths of airspace around  a rocket, the Federal Aviation Administration, or FAA, didn’t need to know where  that rocket was at all times.

Strategically speaking, having to clear out  such a large airspace wasn’t that big of a deal when NASA was launching one or two rockets a year. But now that there are nearly  200 launches a year worldwide, including ones run by private companies,  the technique is pretty inefficient. It’s wasteful, too.

Planes fly longer routes around rocket  launches and use a lot more fuel. For just one rocket launch in  2018, 563 flights were delayed, and those planes flew an extra  64,500 kilometers in total. But the system also needs  a revamp because of safety.

Now, even if there weren’t any airspace  restrictions to separate planes and rockets, there’s still not a huge chance a rocket  would actually hit a plane, or vice versa. Rockets have to be pretty  zippy to get up into space, so they leave the airspace that commercial  planes fly through pretty quickly. The real concern is damage from  the debris that rockets drop.

Two types of rocket debris exist:  pieces that are intentionally ejected, and pieces that fall back to Earth  due to any number of accidents. The stuff that engineers plan to eject is made  from materials with low melting temperatures. So, after it’s ejected, it burns up in  the atmosphere at way higher altitudes than commercial planes fly.

Meanwhile, debris from accidents can  fall through commercial airspace. And what’s worse, it often ends up  spreading out over a pretty wide area. For example, when the space  shuttle Columbia disaster happened, it generated 38,000 kilograms of debris that ended up covering an area 1000  kilometers long by 40 kilometers wide.

But NASA had only planned to close  airspace in a 48 kilometer circle around an emergency shuttle landing. It’s incredibly fortunate that no  commercial aircraft was struck by anything. Nine planes flew through the debris zone during  the 40 minute period when pieces were falling, and no system was in place to warn them.

And if you’re wondering if a plane ever  has had the misfortune of getting struck, the answer is yes. In 1996, space debris hit a Chinese plane,  cracking its windshield and forcing it to land, although no one knows exactly what the debris was. And an emergency landing is the best  case scenario in accidents like these.

So air traffic controllers  want to avoid collisions   while keeping no-fly zones as small as possible. Currently, if anything goes wrong,  someone at NASA or the rocket company has to email or call the FAA  to let another person know. It’s a time-consuming process that needs double  checking to avoid introducing any human error.

All in all, it would take around 13 minutes  for a plane to maneuver away from an accident. Which is not nearly fast enough, because large debris could fall through  commercial space in as little as four minutes. So the FAA is developing a new system that  should allow planes to adjust their route within the first minute and a  half of an accident occurring.

It’s called the Space Data  Integration system, or SDI for short, and it will finally let the FAA  track rocket launches in real time. Knowing a rocket’s actual location will let air   traffic controllers treat  them more like airplanes. Currently, the FAA gives each commercial  plane its own personal bubble of space that’s about 16.7 kilometers wide.

With the SDI, rockets…or at least the  ones that can prove they’re reliable… could be upgraded and  assigned bubbles of their own. The exact size of these bubbles  would vary on a case-by-case basis, but they’d be a much smaller, no-fly zone  compared to what we’re working with, now. But if we’re actually going to feel comfortable transitioning to these bubbles  of restricted rocket airspace, the SDI will need to do more than track  where rockets are at any given moment.

It’ll also need to help the FAA protect  planes from flying through debris fields… predicting where high-risk debris areas  will be as soon as an accident happens, and suggesting the fastest detours. Computer scientists are hard  at work developing algorithms that are up to such a complicated task. One group uses a famous statistical  method called a Markov Decision Process.

This model estimates the outcome of a  particular decision at a point in time… say to reroute a plane to the left…based  on the current position of the plane. For example, 90% of the time the decision  to bank left at a specific moment will result in a safe flight and 10% of  the time it will result in collision. Then the algorithm estimates other rerouting  choices, say to banking right instead of left.

Once the safest choice is  identified for one point in time, the model estimates all the safe rerouting  choices for the next chunk of time. Another group of researchers  updated this decision-making tool using a related statistical method  called the Monte Carlo Simulation. This method randomly samples the  possible movements of both airplanes and debris to calculate the best,  most efficient route to fly to safety.

Random sampling works better when addressing  the uncertainty of where debris pieces will be, but Monte Carlo simulations are slow and  require a lot of computational power. Fine tuning these algorithms and connecting them  to all the data they need for their calculations is a big process, so the FAA doesn’t have the  Space Data Integrator up and running just yet. Once they do, maybe we’ll all  get to see some rocket launches pass our plane as we fly into Florida!

Or you can just go back to  second-guessing your beach read. Thank you for watching this SciShow video  and thanks to Brilliant for supporting it! If you could use a little more background  and explanation for all of that Markov and Monte Carlo talk just  now, Brilliant’s got your back.

There could be entire courses about that stuff. And in fact, Brilliant has made them! Brilliant is an online learning platform  with thousands of lessons in science, computer science, and math,  including statistics and probability.

To learn way more about Markov chains  and other probability fundamentals, immerse yourself in Brilliant’s 23  lesson Applied Probability course. You can understand Markov with a 30 day free trial and 20% off an annual premium  Brilliant subscription. And you get that special deal  because you’re watching SciShow!

Find those savings at the link in the description  down below or at Brilliant.org/SciShow. [♪ OUTRO]