We bury the Earth in an impenetrable shell of dead satellites
The successful launch of Sputnik in 1957 marked a milestone in human history, as it was the first time that a man-made object orbit the Earth. But we didn’t understand much of the space SNAFU we were courting with the advent of satellite technology. Over the next 64 years, our planet’s night sky has grown increasingly crowded. Today more than 3000 satellites circle the Earth and they’re joined by millions of pieces of space debris – such as pieces of broken satellite, discarded rocket parts, and stains of spaceship paint. NASA estimates that there are around 6,000 tonnes of debris in low Earth orbit alone.
“Astronomers – and casual viewers of the night sky – should expect a future in which the population in low Earth orbit includes tens of thousands of relatively large satellites,” warned Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics in a statement. Study 2020. “The impacts will be significant for certain types of observations, certain observatories and at certain times of the year.”
Until a few years ago, humanity had launched less than 10,000 objects into orbit since the start of the space age. However, with the advent of low-cost commercial rocket launch technology – which has seen the price of the cargo launch pound drop from $ 24,800 in the shuttle age to just $ 1,240 today – the The rate at which we put satellites into orbit is expected to increase exponentially. .
In total, more than 18,000 satellites expected to be launched in LEO by 2025 – about ten times the total number of active satellites in 2018. SpaceX alone has clearance from the US government to launch 12,000 Starlinks into orbit (with plans to have up to 42,000), while Project Kuiper Amazon is authorized to send 3,236 to its own satellites in the coming years. These two programs aim to create an orbital low-earth orbit network capable of providing high-bandwidth, low-latency Internet connectivity accessible from anywhere on the planet. While their intentions are noble, the unintended consequences of packing many spaceships into our skies could fundamentally change our view of the surrounding solar system.
“If the 100,000 or more LEOsats offered by many companies and governments are deployed, no combination of mitigation measures can completely avoid the impacts of satellite trails on the science programs of optical-NIR-based astronomy facilities. current and planned ground, ” a 2020 report from the American Astronomical Society Noted.
When the first 360 Starlinks launched in May 2019, for example, their presence in the night sky was immediately noticeable. Their highly reflective design made each mini-satellite about 99% brighter than surrounding objects during the five months it took them to reach their operating altitude of 550 km. This effect was particularly pronounced at sunrise and sunset when the sun’s rays reflected off solar panels from satellites. SpaceX’s attempt to reduce this reflectivity by using “darkening processing” in early 2020 was only partially successful.
“We are detecting an approximately 55% reduction in the reflective brightness of DarkSat compared to other Starlink satellites,” noted Jeremy Tregloan-Reed of the University of Antofagasta in Chile, in a report. Study 2020.
The luminosity of a celestial object is measured on the scale of stellar magnitude – that is, the brighter an object, the larger and negative its corresponding rating. For example, the Sun is rated at -26.7 magnitude while the North Star is rated at +2. Any object noted above +6 is effectively invisible to the human eye, although probing telescopes and other sensitive observing systems can spot objects as faint as +8. According to the Treglon-Reed study, the treated Starlink satellite had a magnitude of +5.33 at its operating altitude, compared to +6.21 for an untreated satellite.
The overall impact of these satellites will depend on a number of factors, including the type of telescope used, the time and season of observations, and the height of the constellation of satellites. Large-scale surveys in the visible and infrared spectra (such as those conducted by the Vera C. Rubin Observatory in Chile) are particularly vulnerable to this interference, as are those conducted at dusk. And while constellations orbiting in LEO typically darken once they pass into Earth’s shadow, those in geosynchronous orbit 750 miles and above – such as the OneWeb short-term program – would be “visible all night long in summer and during significant fractions of the night in winter, autumn and spring, and will have negative impacts on almost all observation programs”, according to the AAS.
“High altitude satellites must be inherently less reflective than low altitude satellites to leave a comparable track. [in professional detectors]. This is due to two factors: orbital speed (lower altitude satellites move faster so spend less time on each pixel) and focus (lower altitude satellites are less sharp, so the streak is more wide but has a lower peak brightness, ”University of Washington Astronomer Dr. Meredith Rawls said Forbes.
In response to the growing problem, astronomers around the world, as part of the National Science Foundation’s SATCON-1 workshop last July, put together a list of potential corrective actions and policies. These include limiting constellations to a maximum altitude of 550-600 km, requiring individual satellites to have a stellar magnitude of +7 or greater, and sharing orbital information regarding these constellations with the research community. so that astronomers can avoid these areas of the sky.
“SpaceX has shown that operators can reduce reflected sunlight through the orientation of the satellite’s body, sun protection and darkening of the surface.” SATCON-1 workshop found. “A joint effort to obtain more accurate public data on the predicted locations of individual satellites (or ephemerides) could allow some pointing avoidance and mid-exposure shuttering during the satellite pass.” Alternatively, operators could design their satellites to actively deorbit when they reach the end of their lifespan – as Starlink’s satellites do – or they could simply launch fewer constellations in general. It remains to be seen whether national or international regulators will actually adopt these recommendations.
But even if satellite operators manage to reduce the brightness of their constellations, we still face an increasingly dense orbital “graveyard” of broken satellites and air space debris. NASA Orbital Space Debris Office estimates there’s half a million marble-sized junk zipping around LEO at 22,300mph – fast enough to chip even heavily reinforced ISS windows upon impact – and up to 100 million parts measuring one millimeter or less.
NASA became the first national space agency to develop a comprehensive space debris mitigation plan in 1995. These guidelines were subsequently adapted by the Inter-Agency Space Debris Coordination Committee (IADC) of 10 countries and ultimately adopted by the United Nations General Assembly in 2007. The US government also established its Orbital Debris Mitigation Standard Practices (ODMSP) in 2001, in a renewed effort to “limit the generation of new long-lived debris by controlling debris released during normal operations, minimizing debris generated by accidental explosions, selecting a safe flight profile and operational configuration to minimize accidental collisions, and the elimination of space structures after the mission. In addition, the Ministry of Defense manages the Space surveillance network, which is responsible for cataloging and tracking objects between 0.12 and 4 inches in diameter using a combination of ground-based visual telescopes and radar arrays.
Tracking this debris is only the first step. A number of space agencies are developing systems to actively capture and dispose of orbital waste. JAXA, for example, envisages an “electrodynamic cable” 2300 meters long which, once deployed, would break up debris passing through to the planet where it would burn on reentry. In 2018, a consortium led by the Surrey Space Center of the United Kingdom successfully demonstrated its RemoveDebris device – essentially a huge space array designed to capture dead satellites and rogue space debris up to 10 meters in length.
In 2025, ESA hopes to launch its ClearSpace-1 mission in which a four-pronged capture device will attempt to capture space debris. like an oversized claw set prize, then get rid of himself and his generosity abandoned in the earth’s atmosphere.
“Space debris is a global problem because it affects all nations,” said Xander Hall, Airbus mission systems engineer. CNN in 2018. “Every piece of junk in space belongs to the original operators and orbital debris is not explicitly addressed in current international law. An international effort must be made to claim ownership of the debris and help finance its safe removal. “