Space debris, even if designed for quick disposal, still pollutes the Earth, report scientists from the American NOAA institution. Pieces of rockets, space stations and defunct satellites that burn up during re-entry leave small traces of metals in the atmosphere.
There is a lot of debris in Earth’s orbit dating back to the early years of the space age. However, the newly designed spacecraft that deorbit and ultimately return to Earth also use materials that burn in the upper atmosphere.
What was found
Daniel Murphy, a physicist at the National Oceanic and Atmospheric Administration and the lead author of the study published on Monday in PNAS, wanted to find out whether vapors from deorbitation remain in the stratosphere. For this purpose, he collected samples of stratospheric aerosols and analyzed them using the Particle Analysis by Laser Mass Spectrometer (PALMS) instrument on board the NASA WB-57 aircraft.
Aerosols occurring in the stratosphere are mainly sulfuric acid droplets formed as a result of the oxidation of carbonyl sulfide gas. These droplets may contain trace amounts of metals from space rocks that enter the atmosphere and burn up there.
Murphy’s team analyzed about 500,000 individual aerosol droplets, looking for traces of metals used to make spacecraft. The paper found that about 10 percent of the stratospheric aerosols contained spacecraft particles, and this was shown by excess traces of lithium, aluminum, copper and lead, and traces of niobium and hafnium, which are not found in meteors.
Consequences? To explore
As researchers note, such a situation may have several effects on the Earth and the atmosphere. Metal vapors can affect the way water freezes in the stratosphere and determine the particle size of stratospheric aerosol. They can also cause salt to deposit on aerosol particles and change the refraction of light in the stratosphere. Scientists say these changes may seem subtle, but they could have consequences that we really should explore. Especially since “the amount of material from re-entry rockets and satellites is expected to increase dramatically over the next 10-30 years.”
– This discovery forces us to conduct further research and check the impact of metal vapors on the atmosphere. It is also worth starting to forecast how they will change over time, Murphy said.
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