Falling SpaceX Satellites Are Turning Into Fireballs Every Day And More Are Coming

If you didn't already know, the vast orbital constellation that is Elon Musk's Starlink satellites has been providing a spectacular, if concerning, daily light show as an increasing number of them fall back to Earth. Experts estimate that one to two of the SpaceX-operated satellites are de-orbiting and burning up in the atmosphere every single day, with that rate projected to rise to four or five per day as the fleet expands.

Indeed, Starlink satellites are designed to have a lifespan of about five years before they are serially decommissioned. No big deal, but what's drawing attention here are the sheer volume of the constellation and resulting re-entry rate. Prior to the first Starlink launch in 2019, only about 40 to 50 satellites total would re-enter the atmosphere globally per year. SpaceX is now bringing down a number equivalent to a decade’s worth of old satellites in just a matter of months.

SpaceX stresses that its satellites are designed to demise completely upon re-entry, with over 95% of the material vaporizing before reaching the ground. However, during the burn/re-entry process, the satellites release byproducts, most notably aluminum oxide particles. One study found that Starlink’s de-orbiting process is adding an estimated 15,000 kilograms of aluminum oxide to the upper atmosphere over a six-month period, potentially increasing the daily load of cosmic dust by about 10%. The key concern is whether this aerosolized aluminum oxide could contribute to the depletion of the ozone layer or have an unintended atmospheric warming effect by altering the reflectivity of the atmosphere.

As SpaceX and other companies continue to launch more and/or even larger next-generation satellites (or orbital shipping warehouses), the daily amount of material being vaporized will only increase. (As if humans don't already have their hands full grappling with the effects of atmospheric pollution from terrestrial sources.) Now might be the best time for space companies and regulators to discuss and address the issue before things get out of hand.