Astronomers stand up to satellite mega-constellations

Continuing the discussion from Energy sources of the future:

Starlink satellite train in the night sky.

Huge networks of spacecraft are being launched that are making it harder to get a clear view of the cosmos. These low-orbiting, fast-moving satellites leave bright streaks across telescope images. The International Astronomical Union is establishing a new centre to focus the community’s response. Its work will be led by the US National Optical-Infrared Astronomy Research Laboratory (NOIRLab) in Tucson, Arizona; and by the Square Kilometre Array Organisation (SKAO) in Manchester, UK. The latter is most concerned with the satellites’ effects on radio astronomy.

The new Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference will try to act as a single voice for astronomy. It will engage with, and encourage, satellite companies to make every effort to minimise the light pollution they are creating. But it will also pursue policymakers around the world to tighten the regulations on what is acceptable behaviour in orbit.

The dramatic reduction in the cost of rocket launches, linked to a similar reduction in the cost of building satellites, has led to a rush to place new infrastructure in the sky. Of immediate concern are the constellations designed to deliver broadband internet connections from space. These involve placing many hundreds to many thousands of satellites just a few hundred kilometres above the Earth. At this altitude, they move quickly across the sky, and at dawn and dusk when the Sun is low on the horizon will catch the light and trace a bright line through a telescope’s exposure.

Starlink satellites cross over Venus and the Pleiades (“Seven Sisters”) group of stars

The satellites’ transmissions can also, if not tightly constrained, bleed across the frequencies used by astronomy’s radio antennas.

Two broadband projects - US entrepreneur Elon Musk’s Starlink network and the UK-headquartered OneWeb initiative - are leading the new wave of constellations, and have between them launched over 2,000 satellites, but both have plans for many, many more.

Connie Walker from NOIRLab and the other co-director of the new centre said: “As the number of satellites continues to grow, astronomy is facing a watershed moment of increasing interference with observations and loss of science. By the end of a decade, more than 5,000 satellites will be above the horizon at any given time at a typical dark-sky observatory location. A few 100 to several 1,000 of these satellites will be illuminated by the Sun. These satellites will be detectable by even the smallest optical or infrared telescopes, depending on the hour of the night and the season.”

2020 - For illustrative purposes only - not to scale.

It’s hard to believe that there’s no control on satellite launches and placement … :astonished:

After the Soviet Union launched Sputnik, the world’s first human-made satellite, in 1957, a slow but steady stream of satellites entered Low Earth Orbit (LEO), with between 10 and 60 launched annually until the 2010s, Supriya Chakrabarti, a professor of physics at the University of Massachusetts Lowell, wrote in an article published on, a Live Science sister site. Since then, that rate has skyrocketed, with more than 1,300 new satellites launched into LEO in 2020 and more than 1,400 satellites launched in 2021, Chakrabarti wrote. In total, there were around 7,500 satellites in LEO as of September 2021, according to the United Nations’ Outer Space Objects Index.

The number of satellites in LEO, a region that spans up to 1,424 miles (2,000 kilometers) from Earth, will continue to increase at an exponential rate in the coming decades. That’s because private companies are setting up their own megaconstellations, each containing thousands of individual satellites, which will be used to develop faster online networks and deliver a range of other services, such as monitoring climate change.

This increased activity is happening now largely because of dropping costs, said Aaron Boley, an astronomer at The University of British Columbia. “We know SpaceX, OneWeb, Amazon and StarNet/GW [China’s satellite network] have proposed a combined satellite total of 65,000 when including all phases” of their satellite programs, Boley told Live Science. And “well over 100,000 satellites have been proposed” in total, he added.

@Omah , Commerce will always win over science Omah !
Unless politics intervenes, which will only happen once the
general public becomes concerned unfortunately !
Donkeyman! :-1::frowning::-1:

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Indeed … sad but true … :090:

Until they make Alchemy work. Then they own the game! :smiley: :grin:


The satellite people will win.

@swimfeeders , Yeah, you are right!
I seems that space is the new real estate?
Shame only the multi-billionares can afford it at the moment
By the time we get up there it will all be gone !!
Donkeyman! :frowning::frowning:

Ever heard of Fulcanelli? He was more a spiritual alchemist than anything & wrote an amazing treatise about the design & construction of cathedrals. And one of Fulcanelli’s students, Eugène Canseliet is said to have transformed a small amount of lead into gold in front of witnesses.

Fulcanelli may or may not have been a real person, he may or may not have been able to transform lead into gold. But we do know that both British & American intelligence spent a reasonable level of time & energy looking for Fulcanelli at the start of WW2.

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I would dispute any lead-to-gold claims as ridiculous and falls into the same bracket as flat-earth conspiracies, aliens building pyramids and other such nonsense. Given its not possible to turn lead to gold - unless you happen to have a high energy particle accelerator - alchemy is at best regarded as pseudoscience and those claims to have actually achieved lead transmutation have been exposed as fraudulent.

@Graham , But we have high energy particle accelerators?
Do you think they are making gold with them?
And uranium ends up as lead without the use of one ??
Donkeyman! :thinking::thinking:

  1. Yes we do.
  2. No. It’s not viable because of the high energy levels involved and the resultant gold is radioactive and basically useless.
  3. Uranium will naturally decay to Lead 204, due to alpha and beta decay. Nothing to do with any alchemical process.

@Graham Thanks for confirming my thoughts Graham?
You sound like a bit of a fundi on this subject ??
Donkeyman! :+1::roll_eyes::+1:

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On February 4, a geomagnetic storm caused by the sun knocked up to 40 new SpaceX Starlink satellites out of orbit. Now experts are worried about whether mega-constellations planned by Elon Musk, Jeff Bezos, and others will be resilient to such events in the future.

SpaceX had launched its latest batch of Starlink satellites on a Falcon 9 rocket from Cape Canaveral in Florida on Thursday, February 3. This was SpaceX’s 38th Starlink launch; in all, the company has launched more than 1,900 of the car-size satellites, and eventually it wants to have up to 42,000 of them in low Earth orbit to deliver the internet to all corners of the globe.

The day after the launch, however, disaster struck. An eruption of plasma from the sun sent charged particles streaming into Earth’s atmosphere, sending the planet’s magnetic field haywire and increasing the density of its atmosphere. That increase in density meant there were more particles to push against satellites in Earth’s orbit. This phenomenon, known as atmospheric drag, can pull them out of their orbital paths.

As a result of the storm, as many as 40 of the new satellites “will reenter or already have reentered the Earth’s atmosphere,” SpaceX said in a statement, describing it as a “unique situation.” These satellites were vulnerable because they are launched into a low orbit, between 210 and 240 kilometers, where the atmosphere is denser, making the effects of the storm worse. The satellites are meant to use onboard ion thrusters to slowly raise their orbits to 550 kilometers over several weeks. Those already in these higher orbits were less affected because the atmosphere is much thinner at that altitude, so drag is reduced.

SpaceX noted that the satellites were designed to completely burn up in the atmosphere, “meaning no orbital debris is created and no satellite parts hit the ground.” A handful of the satellites have already reentered, and the rest are expected to do so within a week. But the financial cost of the botched launch is estimated to be between $50 millionand $100 million.

While we have experienced solar maximum with satellites in orbit before, the number orbiting now is unprecedented. By 2025, there could be more than 10,000, not only from SpaceX but from other ventures such as Amazon’s Project Kuiper and the UK’s OneWeb. Future storms could frequently push and pull these satellites, changing their positions and putting them at risk of colliding.

This latest event highlights how carefully all mega-constellation operators will need to plan for the effects of solar activity, since any collisions could add thousands more pieces of space debris that could affect our ability to use Earth’s orbit safely.

As of 2021, the United States Space Surveillance Network was tracking more than 15,000 pieces of space debris larger than 10 cm (4 inches) across. It is estimated that there are about 200,000 pieces between 1 and 10 cm (0.4 and 4 inches) across and that there could be 1,000,000’s of pieces smaller than 1 cm. How long a piece of space debris takes to fall back to Earth depends on its altitude. Objects below 600 km (375 miles) orbit several years before reentering Earth’s atmosphere. Objects above 1,000 km (600 miles) will orbit for centuries.

With the increasing amount of space debris and the advent of mega-constellations of thousands of satellites, there are fears that collisions such as that between Iridium 33 and Cosmos 2251 could set off a chain reaction (called the Kessler syndrome after American scientist Donald Kessler) in which the resulting space debris would destroy other satellites and so on, with low Earth orbit eventually becoming unusable.

It’s a free-for-all in space … :scream:

@Omah , So it looks like all that space junk wil end up in the
same place as all the plastic then ??
In the ocean !!
What a disgusting species we are ?
Donkeyman! :-1::frowning::-1: