#satellites

Over the past few years, the number of #satellite launches has skyrocketed. There are now nearly 15 000 active #satellites in orbit around the Earth, most of them part of mega-constellations in which each satellite has a service life of only a few years. New satellites must be quickly launched as replacements. To avoid leaving old, dead satellites in Earth’s already-crowded low orbits, most satellite operators deliberately de-orbit them into Earth’s upper atmosphere. That approach is now being taken to a vastly larger scale and there are implications for Earth’s #climate and #atmosphere. Rocket launches already contribute to climate change and #ozone depletion. Scaling them up to deploy a million aircraft-sized satellites would push upper-atmosphere heating and ozone loss far beyond previous estimates, with the steady burn-up of dead satellites compounding the impacts. This is just a fraction of what is to come if planned mega-constellations go ahead. Operators worldwide have already asked for a combined total of over one million satellites. The very smallest particles, finer than a human hair, can stay suspended in the atmosphere for years, contributing to ozone depletion and climate change. A million satellites could mean that a teragram of alumina accumulates in the upper atmosphere – enough, alongside launch emissions, to significantly alter atmospheric chemistry and heating in dramatic ways we do not yet understand. There is no public mandate for a single company in one country to make changes on that scale to the planet’s atmosphere. #space #astronomy https://theconversation.com/a-new-space-race-could-turn-our-atmosphere-into-a-crematorium-for-satellites-276366

@sundogplanets@mastodon.social probably you already knew this but i just came across this thanks to a colleague of mine that sent me tho link. Amazon satellites are pretty bright --> https://arxiv.org/pdf/2601.07708 Abstract: "The mean apparent magnitude of Amazon Leo satellites is 6.28 based on 1,938 observations. For spacecraft in their operational mode, 92% exceeded the brightness limit recommended by the IAU for interference with research, while 25% distract from aesthetic appreciation of the night sky. The reflective characteristics are similar to Version 1 Starlink spacecraft." #satellites #amazon #megaconstellations #skypollution #satellitepollution #lightpollution #space #astronomy

Yes, you may be killed by falling human made space junk, but the odds remain small(ish) that will occur. The (almost inevitable) #KesslerSyndrome may also prevent future #space flights if all those #satellites in Low Earth Orbit start colliding, creating countless debris. However, we *ALL* have to worry about the ‘chemical problem’ being created by SpaceX et al in the upper atmosphere. I have been banging on about this for a while and the attached article summarises the science in an easy to understand way - I have pasted the bit about the ‘chemical problem’ below because we *ALL* need to understand what the billionaires are doing to the planet while we are watching. ————— Quote: Debris on the ground attracts immediate attention, but atmospheric scientists are tracking a slower process with potentially larger consequences. When satellites vaporize in the mesosphere, 50 to 80 kilometers above Earth, they release clouds of vaporized metals that condense into aerosol particles. Those particles descend into the stratosphere, where Earth’s protective ozone layer resides. Aluminum is the element of greatest concern. Upon reentry, aluminum oxidizes into aluminum oxide nanoparticles. A single 250 kilogram satellite generates roughly 30 kilograms of these particles. Unlike chlorofluorocarbons, which directly destroy ozone, aluminum oxide acts as a catalyst. One particle can facilitate chemical reactions that destroy thousands of ozone molecules over decades without being consumed. Researchers from the University of Southern California’s Department of Astronautical Engineering documented an eightfold increase in atmospheric aluminum oxides between 2016 and 2022, directly correlating with the proliferation of satellite constellations, a finding reported in detail by CNET. In 2022 alone, reentering satellites released an estimated 41.7 metric tons of aluminum, approximately 30 percent more than the natural input from micrometeoroids. Projections based on current deployment schedules suggest annual aluminum oxide emissions could reach 360 metric tons, a 646 percent increase over natural background levels, according to research highlighted by Popular Mechanics. Because these particles take 20 to 30 years to descend into the ozone layer, the atmospheric chemistry of today’s satellite fleet will not manifest as measurable ozone loss until the 2040s. By then, the upper atmosphere could already be saturated with catalysts. NASA high altitude sampling flights over Alaska in 2023 detected the signature of this process. At approximately 60,000 feet, instruments found that 10 percent of stratospheric sulfuric acid particles larger than 120 nanometers contained aluminum and other metals traceable to spacecraft reentries, according to data presented at the American Astronomical Society meeting that year. The atmosphere now bears a permanent chemical marker of human activity in space. ————— #space #science #TheBillionairesAreKillingUsAll https://indiandefencereview.com/starlink-satellites-falling-nonstop-to-earth-risk/

From @Techcrunch@flipboard.com: SpaceX has filed a request with the Federal Communications Commission to launch a constellation of up to 1 million solar-powered satellites that it said will serve as data centers for artificial intelligence. https://flip.it/ERl.g6 #Tech #SpaceX #Satellites #Technology