Amid the backdrop of rapid advancements in space exploration, exemplified by SpaceX's recent successful launch and return of its reusable Starship booster, a study led by Bucknell University Professor Greg O'Neill, mechanical engineering, reveals the complex tradeoffs between increasing rocket launches and the ripple effects on commercial air traffic. Published by the American Institute of Aeronautics and Astronautics, the study underscores the need to carefully balance airspace sharing between space launch providers and airline operators as the frequency of launches continues to rise.

With SpaceX taking a staggering lead in the space sector — now accounting for over 90% of all U.S. rocket launches — the landscape has shifted significantly from the days when government-funded launches dominated. Today, private entities like SpaceX and Blue Origin, owned by Jeff Bezos, are the primary drivers of space exploration. As Professor O'Neill points out, "The paradigm of the government-funded launch has shifted to private entities, and that's not only changing how space missions are funded but how frequently they occur."

The study dives into Special Use Airspace (SUA), designated areas that are restricted during rocket launches to protect the public and air traffic from potential launch failures or malfunctions. However, creating SUAs for launches requires temporarily rerouting commercial flights, leading to increased travel time and substantial costs for airlines. As rocket launches become more frequent, airlines face mounting financial impacts due to these reroutes.

The research analyzed 381 U.S. space launches from 2001 and 2023 to find a more equitable balance between restricted airspace usage and aircraft rerouting costs. The results showed that SUAs are very often underutilized, finding that 70% of the launches have SUAs that are open for about an hour, if not more, after the launch has occurred.

"One of the things I look at in research is whenever a rocket launches, they have to clear out airspace or, alternatively, airlines have to wait on the ground until the launch is over, which makes airlines unhappy," says O'Neill, whose research provides quantitative data on the interaction of aircraft and spacecraft in shared airspace, helping stakeholders make informed decisions about the amount of time and space that should be designated for rocket launches.

In recent years, the frequency of rocket launches has soared from around 20 to 30 annually to almost 100 in 2023, and the number is projected to continue rising.

"We're not quite at a rocket launch a day, but we’re getting close," O'Neill says. "That's drawn a number of complaints from the airlines. It costs the airlines money, and they don’t like it. When they have to reroute space launches, they incur thousands of dollars, and they won’t get reimbursed."

The analysis from O'Neill's study explores a potential solution: shorter and more precisely timed SUAs. By limiting the duration and size of SUAs, airlines could reduce rerouting costs, but there's a tradeoff. If SUA restrictions are too narrow or brief, the risk of delaying a launch due to unforeseen issues increases, increasing costs for space companies.

"The research shows that there may be opportunities to reduce the impact of space launches on air traffic in the future by changing the timing and length of Special Use Airspaces," O'Neill says. "Balancing the costs of rerouting aircraft with the potential delay costs for launch providers may be key to minimizing overall impacts."

The study holds significant implications for policymakers, particularly in Washington, D.C., where discussions about airspace usage are heating up. Airlines and space companies are actively lobbying for adjustments to SUA policies, hoping to find a middle ground that allows for more efficient launches while minimizing disruption to air travel.

"If Elon Musk has anything to say, rocket launches will continue to grow," says O'Neill. "We've almost hit a point where we’re looking at a launch every day. I track launch progress and data in the U.S. going back to the 1990s. Within the next five years, I expect there to be a rocket event per day."

O'Neill's background in space traffic management, developed during his postdoctoral work at MIT, fuels his current research at Bucknell. His analysis of rocket launch vehicles and air traffic interactions offers invaluable insights, helping stakeholders understand the performance metrics and costs associated with rerouting flights around SUA zones.

As space launches approach daily frequencies, O'Neill's study could play a pivotal role in the future of airspace sharing, guiding decisions that will shape both industries for years to come.