SpaceX, Blue Origin and a host of other private companies helped make 2021 the year with the most space launches in history, but scientists say this mad dash to space could cause further damage to our atmosphere.
The number of launch attempts has double in the last decade. And after counting all the launches scheduled for 2022, it looks like the current year is Position break last year’s record. But the rocket launches are coming with big showswhose atmospheric impact is not fully understood.
Now two scientists have added to the growing body of acquaintance suggesting that the race to leave Earth could harm our planet and our health. The researchers referenced a web-streamed video to model a SpaceX launch in great detail. Their simulation showed that the rocket’s exhaust dumped a startling amount of climate-altering carbon dioxide, as well as harmful nitrogen oxides, at multiple levels of the atmosphere.
“Rocket pollution should not be underestimated as future frequent rocket launches could have a significant cumulative effect on climate,” the researchers wrote in their paper, published Tuesday in the journal Physics of Fluids. They also mentioned the possibility of rocket launches becoming a future hazard to human health.
“Currently, the risk is low because a small number of launches are taking place”, Dimitris Drikakis, a physicist and engineer from the University of Nicosia in Cyprus and co-author of the new study, explained in an email to Gizmodo. “The issue can become significant when frequent launches occur.”
Drikakis and his colleague from the University of Nicosia Ioannis Kokkinakis specifically looked at the exhaust emissions of a computer model they built, one intended to closely match the 2016 Launch of Thaicom-8 of SpaceX’s Falcon 9 rocket, which drew its energy from fuel RP-1, or Rocket Propellant-1, which is similar to jet fuel. Researchers took into account the role of heat, pressure, gas mixture, dispersion patterns and other factors to estimate rocket emissions at different heights and up to a maximum of 41.6 miles. (67 kilometers) above the surface.
Earth’s atmosphere has several levels based on altitude, each presenting its own unique set of conditions. Drikakis and Kokkinakis tracked their modeled rocket launch from the near-Earth troposphere up into the stratosphere and into the mesosphere.
Based on their models, the researchers estimated that the Falcon 9 rocket alone produced about 116 metric tons of carbon dioxide in the first 165 seconds of its journey. “This quantity is equivalent to that emitted by approximately 69 cars over an entire year. [in the United Kingdom]Drikakis wrote to Gizmodo. To repeat: 69 years of driving in a car against 165 seconds of rocket flight.
Carbon dioxide builds up in the lower atmosphere when we burn fossil fuels and is the greenhouse gas largely responsible for human-induced climate change. But much of the emissions produced in the model’s study appeared in the higher-altitude mesosphere, where the climate impacts of C02 are less well understood than they are closer to Earth. For every kilometer climbed by the rocket at the highest altitudes examined, the simulated Falcon 9 emitted a mass of carbon dioxide equal to 26 times the amount already present in a cubic kilometer of the mesosphere.
At the same time, the rocket also emitted similar amounts of carbon monoxide and water vapor, which are usually only present in the mesosphere in trace amounts. This now adds to the list of poorly understood atmospheric changes that rocket launches could create.
And then there are the dreaded nitrogen oxides (NOx) to consider. In addition to being harmful pollutants to breathe which can trigger respiratory diseases, these gases also degrade our atmosphere critical ozone layer. During the first 70 seconds of the studied launch, the SpaceX rocket produced about one metric ton of NOx, which equates to about 1,400 cars of annual emissions, according to Drikakis. Nitrogen oxides form best in high heat, so most of this release occurred in the lower atmosphere, especially at altitudes below 10 km.
“CO2 and other greenhouse gases [types] emitted into the mesosphere can affect the climate, if emitted in sufficient quantities,” said Erik Larson, a Harvard University geoscientist who was not involved in the new research, in an email to Gizmodo. But he added that this document does not actually assess the climate impacts of the rocket launch.
Instead, Larson said the value of the study lies in its estimates of emission quantities. The study “fills in some gaps,” he explained. In particular, Larson believed that the “most important contribution” of the new research was to the production of nitrogen oxide and the potential risk of ozone, as opposed to assessments of direct impacts on air quality. “It destroys the beneficial ozone layer,” he said. “I think the significant global impacts of rocket NOx emissions are likely to be stratospheric ozone destruction as opposed to air quality.”
The ozone layer protects the surface of our planet from the sun’s most harmful rays. Without this, a big part of life on Earth would die. And we almost lost him once before due to chemical emissions. After the offending and harmful compounds were banned, the ozone layer recovered, but it has remained a constant concern ever since.
A UN Report 2018 concluded that rocket launches have a miniscule impact (less than 0.1%) on ozone. But the loss of ozone due to rocket launches could be more than 10 times higher than expected due to lack of research on the subject, according to the new study. And, again, there are many more rockets going into space today than four years ago.
It’s important to remember that the new study depends on estimates and models, which means it has major limitations. “The atmosphere is a very complex system,” Drikakis said. He pointed out that his team had to reckon with a great deal of uncertainty when obtaining these results due to the lack of clear information about the physical and chemical processes occurring at higher altitudes in the atmosphere.
In addition to reducing these uncertainties, scientists plan to further explore the link between ozone depletion and space launches in future research. They also hope that more studies will examine the impact of changes in the mesosphere on Earth’s climate.
But for now, even knowing all of the above, Drikakis and Kokkinakis are still pro-space exploration. “We are rocket enthusiasts and believe the commercial sector has made incredible strides in the field,” Drikakis told me. “We are at the start of a fantastic journey” which we must continue, he added.
He hopes their research and studies like this will help the burgeoning space industry “design solutions that will improve rocket design and mitigate the effects of exhaust.” For Earth’s sake, let’s all hope innovation happens at lightning speed.