Scientists warn of air pollution with every launch into space

With every rocket we celebrate for launching a satellite, humans to the space station or to the moon, as happened last year with the mission Artemis I, our atmosphere feels it.

The space junk It’s a growing problem every day with pieces of rockets, space stations and broken satellites which burn up on re-entry into the atmosphere, leaving permanent traces of metal in the thin layer that shields us from space and provides us with oxygen.

In last years, rocket launches increased exponentially, while our atmosphere is increasingly contaminated by the amount of metal vapors present in the stratosphere.

It’s a recent study by a team of researchers led by a physicist Daniel Murphy of United States National Oceanic and Atmospheric Administration (NOAA), It not only points to the pollution of the space environment due to the number of satellites and parts of rockets orbiting the Earth, but also warns of the effects of metal vapors in the atmosphere as they lose height and eventually fall to our planet.

“Measurements show that about 10% of aerosol particles in the stratosphere they contain aluminum and other metals which They were caused by the “burning” of satellites and rocket stages during re-entry. Although direct health or environmental impacts are unlikely at ground level, these measurements have broad implications for the stratosphere and higher altitudes. With many more launches planned in the coming decades, metals from spacecraft re-entry could trigger changes in the stratospheric aerosol layer,” the experts said in a scientific paper published in Proceedings of the National Academy of Sciences (PNAS).

“Currently, the refractory material is mainly stratospheric particles iron, silicon and magnesium of natural meteoric origin” write the scientists in their new article.

“However, the amount of material from return rockets and upper-stage satellites is expected to increase dramatically.” in the next 10 to 30 years. Consequently, the abundance of aluminum in stratospheric sulfuric acid particles is expected to be comparable to or even higher than that of meteoric iron, with unknown implications for ice inclusions and nucleation,” Murphy and colleagues.

Although there is much debris in Earth orbit from the early years of the human space age, more recent launches have been made with the limited lifetime of launched objects in mind. And that’s why engineers design rockets or satellites that eventually leave orbit and return to Earth after completing their mission. the use of materials that will burn in the upper atmosphere, instead of crashing to the surface.

This raises the concern of experts, who are unclear as to what is happening in our atmosphere with the vaporized by-products of re-entry. Murphy and his colleagues wanted to find out if Vapors from these deorbits persisted in the stratosphere. To do so, they took samples of stratospheric aerosols and analyzed them using the Particle Analysis Laser Mass Spectrometer (PALMS) instrument aboard NASA’s WB-57 high-altitude aircraft.

Aerosols in the stratosphere, consisting mainly of sulfuric acid droplets resulting from the oxidation of gaseous carbonyl sulfide, which occurs both naturally and as a pollutant in the atmosphere, may contain trace metals and silicon obtained from the entry atmosphere of meteors whose surfaces evaporate. they fall

The experts analyzed about 500,000 individual aerosol droplets they were looking for traces of metals used in the manufacture of spacecraft. They detected about 20 metals. Some of these metals were in proportions consistent with meteorite vaporization, but others, such as lithium, aluminum, copper, and lead, exceeded the amounts expected from meteorite ablation. The team found that the excess was consistent with the proportions expected from spacecraft production.

Other metals they found, such as niobium and hafnium, are common in spacecraft but not common in meteors. In general, The team found that about 10 percent of stratospheric aerosols exceed a certain size They held the vaporized particles of spaceships.

There are several effects this could have on Earth and the atmosphere. The presence of these particles could affect the way water freezes to form ice in the stratosphere and affect the size of stratospheric aerosol particles. They could also induce salt deposition on aerosol particles and alter the stratospheric refraction of light.

These may seem like subtle changes, but they could have unintended consequences that we should really investigate, the researchers say. “The space industry has entered an era of rapid growth. With tens of thousands of small satellites planned for low Earth orbit, this larger mass will be broken up into many more return events,” they noted.

“Given that 10 percent of stratospheric particles now contain enhanced aluminum, with many more return events, it is likely that in the coming decades the percentage of stratospheric sulfuric acid particles containing aluminum and other metals from satellite returns will be comparable to about 50 percent.” it now contains meteoric metals,” the experts concluded.