Some things to think about from Spaceweather.com
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PUTTING THE "MEGA" IN MEGACONSTELLATION: Two months ago, headlines
announced a Space Age milestone: SpaceX now has more than 10,000 active
Starlink satellites circling Earth--two-thirds of all the working
satellites in the sky. Analysts were gobsmacked by the pace of change.
Turns out, that's nothing. Back in January, SpaceX had already filed
paperwork asking the FCC for permission to launch a million. The
proposed megaconstellation would become a solar-powered AI data center,
requiring hourly rocket launches carrying a million tons of satellites
per year.
Above: Starship, the launch vehicle for the proposed AI data center
Condemnation was swift. Critics pointed out that the new satellites
could outnumber visible stars, altering the appearance of the night sky.
Moreover, the traffic jam could bring Earth orbit to the doorstep of
"the Kessler Syndrome" -- a dangerous cascade of satellite collisions.
"The industrial scale of this is staggering," satellite expert Jonathan
McDowell (recently retired from the Harvard-Smithsonian Center for
Astrophysics) told Sky&Telescope, adding that it might even be a
publicity stunt.
While much criticism has focused on night-sky light pollution and
orbital safety, there's an even bigger issue: The effect on Earth's
atmosphere. Satellites change the atmosphere twice: On the way up (via
rocket exhaust) and again on the way down (via reentry debris).
Researchers are only beginning to understand what happens at scale.
The "black carbon problem" is a good example. Almost every rocket
deposits black carbon (residue left over when carbon-based fuels do not
burn completely) into the upper atmosphere. It's like the black soot
inside a chimney. Black carbon can be tricky. By absorbing sunlight, it
heats the atmosphere. By shading sunlight, it cools the atmosphere. So,
while researchers are sure that black carbon will tip the atmosphere's
thermal balance--they don't know which way (Maloney et al. 2022; Barker
et al. 2026).
Reentries are just as bad. Consider this: For millions of years, natural
meteoroids have been adding about 10,000 to 20,000 tons/year of material
into Earth's atmosphere. Humanity is about to match that total. No later
than 2040, disintegrating satellites will put as much material into the
atmosphere as meteoroids do (Maloney et al. 2025; Sharma 2024). Unlike
meteoroids, however, satellites are rich in industrial alloys. A million
years of meteor bombardment doesn't tell us what a million satellite
reentries might do.
NOAA has already detected the first signs of change. About 10% of
sulfuric-acid droplets in the stratosphere contain metals from
disintegrating spacecraft (Murphy et al. 2023). Aluminum oxides found in
these droplets are a concern because they help destroy ozone, our
planet's sunscreen.
Studies attempting to predict the effects of megaconstellations have
proliferated since the Starlink program began in 2019. The catch is that
nearly all of the forecasts assume Starlink-sized swarms of a few tens
of thousands of satellites. A million satellites is another problem
entirely.
Let the launches begin. But, first, could we do a little research?
--
W7RH DM35OJ
If it's true that our species is alone in the universe, then I'd have to say
the universe aimed rather low and settled for very little. George Carlin
βIt is not that I'm so smart. But I stay with the questions much longer.β
β Albert Einstein
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