More space junk, nothing to celebrate

Space debris is growing exponentially. Humanity celebrates each launch of a satellite, such as those sent to the space station or the Moon, as happened last year with the Artemis I mission. But this generates large amounts of air pollution.

Space debris is becoming a bigger problem every day: pieces of damaged rockets, space stations and satellites burn up when they re-enter the atmosphere, leaving permanent traces of metal in the thin layer that protects us from space and provides us with oxygen. .

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

This latest study, carried out by a team of scientists led by physicist Daniel Murphy of the US National Oceanic and Atmospheric Administration (NOAA), shows that it is not just contamination from space debris due to the large number of satellites and rocket parts orbiting the Earth. The problem also lies in the pollution of the atmosphere due to the effects of metal vapor that, as they lose altitude and eventually fall on our planet.

New space junk: metal vapors

"Measurements show that about 10% of aerosol particles in the stratosphere contain aluminum and other metals that originated from the “burning” of satellites and rocket stages during reentry. 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 reentry could induce changes in the stratospheric aerosol layer.a," the scientists write in their new paper.

"Currently, the refractory material of stratospheric particles is mainly iron, silicon and magnesium of natural meteoric origin"clarify the authors of the study.

"However, the amount of material from re-entry rockets and upper-stage satellites is expected to increase dramatically over the next 10 to 30 years. As a result, the amount of aluminum in stratospheric sulfuric acid particles is expected to be comparable to or even exceed the amount of meteoric iron, with unknown consequences for ice inclusions and nucleation.”, Murphy and his collaborators.

They are looking for new materials for rockets or satellites

Although there is a lot of new special garbage and debris in Earth orbit From the early years of the human space age, many recent launches have been carried out with the limited lifespan of launch objects in mind. That is why engineers design rockets or satellites that, after completing their mission, will leave orbit and return to Earth, using materials that, instead of falling to the surface, will burn in the upper layer of the atmosphere.

As a result, experts aren't sure what is happening in our atmosphere with the vaporized byproducts of the reentry process. Murphy and his colleagues wanted to discover if water vapor from these orbits existed in the stratosphere.

space junk

To do this, they collected stratospheric aerosol samples and analyzed them using the Particle Analysis Laser Mass Spectrometer (PALMS) on NASA's WB-57 high-altitude aircraft.

Stratospheric aerosols, consisting primarily of sulfuric acid droplets resulting from the oxidation of carbonyl sulfide gas, are produced both naturally and by atmospheric pollutants, which may contain traces of metals and silicon from the atmospheres of meteorites whose surfaces They evaporate when they fall.

Experts analyzed around 500.000 individual aerosol droplets for traces of metals used in the manufacture of spacecraft. They discovered about 20 metals. Some of these metals were present in proportions consistent with meteorite evaporation, but others, such as lithium, aluminum, copper, and lead, were in excess of quantities expected from meteorite ablation. The team found that the surplus was consistent with the expected pace of spacecraft production.

Other discovered metals, such as niobium and hafnium, are commonly found in spacecraft, but not in meteorites. Overall, the team found that about 10% of stratospheric aerosols of a certain size contained particles evaporated from spacecraft.

Consequences for the Earth and the atmosphere

The presence of these particles can affect how water freezes to form ice in the stratosphere and influence the particle size of stratospheric aerosols. They can also cause salt to deposit on aerosol particles and alter stratospheric refraction.

Scientists say these changes may seem small, but they could have unintended consequences that we should consider carefully. “The space industry has entered an era of rapid growth. With tens of thousands of small satellites planned for low-Earth orbit, that increased mass will be divided into many more reentry events"they warned.

“Given that 10 percent of stratospheric particles now contain enhanced aluminum, with many more reentry events, it is likely that in the coming decades, the percentage of stratospheric sulfuric acid particles containing aluminum and other metals from reentry of approximately 50 percent now contains meteoric metals," the experts concluded.

With information of: