Apr 9, 2021 06:16 AM
(This post was last modified: Apr 9, 2021 08:23 PM by C C.)
OneWeb, SpaceX satellites dodged a potential collision in orbit
https://www.theverge.com/2021/4/9/223742...pace-force
INTRO: Two satellites from the fast-growing constellations of OneWeb and SpaceX’s Starlink dodged a dangerously close approach with one another in orbit last weekend, representatives from the US Space Force and OneWeb said. It’s the first known collision avoidance event for the two rival companies as they race to expand their new broadband-beaming networks in space.
On March 30th, five days after OneWeb launched its latest batch of 36 satellites from Russia, the company received several “red alerts” from the US Space Force’s 18th Space Control Squadron warning of a possible collision with a Starlink satellite. Because OneWeb’s constellation operates in higher orbits around Earth, the company’s satellites must pass through SpaceX’s mesh of Starlink satellites, which orbit at an altitude of roughly 550 km.
One Space Force alert indicated a collision probability of 1.3 percent, with the two satellites coming as close as 190 feet — a dangerously close proximity for satellites in orbit. If satellites collide in orbit, it could cause a cascading disaster that could generate hundreds of pieces of debris and send them on crash courses with other satellites nearby.
Currently, there’s no national or global authority that would force satellite operators to take action on predicted collisions. Space Force’s urgent alerts sent OneWeb engineers scrambling to email SpaceX’s Starlink team to coordinate maneuvers that would put the two satellites at safer distances from one another.
"“Coordination is the issue. It is not sufficient to say ‘I’ve got an automated system.’”"
While coordinating with OneWeb, SpaceX disabled its automated AI-powered collision avoidance system and manually steered its Starlink satellite out of the way... (MORE)
We're entombing the Earth in an impenetrable shell of dead satellites
https://www.engadget.com/were-entombing-...02560.html
EXCERPTS: Today more than 3,000 satellites circle the Earth and they are joined by millions of pieces of space debris — such as bits of broken satellite, discarded rocket parts and flecks of spacecraft paint. NASA estimates that there’s around 6,000 tonnes of debris in Low Earth Orbit alone.
This orbital refuse doesn’t just create navigation hazards for astronauts, it also reflects sunlight down to the surface, interfering with ground-based telescope observations. A study recently accepted by Monthly Notices of the Royal Astronomical Society: Letters suggests that there is now nowhere on Earth free from the light pollution produced by overhead debris and satellites. Even more concerning, researchers expect the amount of debris in orbit to increase by an order of magnitude over the next decade as mega-constellations of internet-beaming mini-satellites, like SpaceX’s Starlink program, take off.
“Astronomers – and casual viewers of the night sky – must expect a future in which the low Earth orbit population includes tens of thousands of relatively large satellites,” Jonathan McDowell at the Harvard-Smithsonian Center for Astrophysics warned in a 2020 study. “The impacts will be significant for certain types of observation, certain observatories and at certain times of year.”
Until a couple years ago, humanity had launched fewer 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 per pound of launching cargo fall from $24,800 during the Shuttle era to just $1,240 today — the rate at which we put satellites into orbit is set to increase exponentially.
[...] In response to the growing problem, astronomers from around the world, as part of the National Science Foundation’s SATCON-1 workshop last July, have assembled 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 higher, and sharing orbital information regarding these constellations with the research community so that astronomers can avoid those areas of the sky.
“SpaceX has shown that operators can reduce reflected sunlight through satellite body orientation, Sun shielding and surface darkening,” the SATCON-1 workshop found. “A joint effort to obtain higher accuracy public data on predicted locations of individual satellites (or ephemerides) could enable some pointing avoidance and mid-exposure shuttering during satellite passage.” Alternatively, operators could design their satellites to actively deorbit when they reach the end of their service life span — as Starlink’s satellites do — or they could just launch fewer constellations in general. Whether national or international regulators will actually adopt these recommendations remains to be seen.
But even if satellite operators do manage to turn down the brightness of their constellations, we are still faced with an increasingly dense orbital “graveyard” of broken satellites and overhead space junk. NASA’s Orbital Space Debris Office estimates that there are half a million marble-sized bits of junk zipping around LEO at 22,300 mph — fast enough to chip even the ISS’s heavily reinforced windows upon impact — and as many as 100 million pieces measuring a millimeter or less.
NASA became the first national space agency to develop a comprehensive space debris mitigation plan in 1995. Those guidelines were later adapted by the 10-nation Inter-Agency Space Debris Coordination Committee (IADC) and eventually adopted by the UN 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 the control of debris released during normal operations, minimizing debris generated by accidental explosions, the selection of safe flight profile and operational configuration to minimize accidental collisions, and post-mission disposal of space structures.” Additionally, the Department of Defense operates the Space Surveillance Network, which is charged with 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 in the process of developing systems to actively capture and dispose of orbital refuse... (MORE - details)
https://www.theverge.com/2021/4/9/223742...pace-force
INTRO: Two satellites from the fast-growing constellations of OneWeb and SpaceX’s Starlink dodged a dangerously close approach with one another in orbit last weekend, representatives from the US Space Force and OneWeb said. It’s the first known collision avoidance event for the two rival companies as they race to expand their new broadband-beaming networks in space.
On March 30th, five days after OneWeb launched its latest batch of 36 satellites from Russia, the company received several “red alerts” from the US Space Force’s 18th Space Control Squadron warning of a possible collision with a Starlink satellite. Because OneWeb’s constellation operates in higher orbits around Earth, the company’s satellites must pass through SpaceX’s mesh of Starlink satellites, which orbit at an altitude of roughly 550 km.
One Space Force alert indicated a collision probability of 1.3 percent, with the two satellites coming as close as 190 feet — a dangerously close proximity for satellites in orbit. If satellites collide in orbit, it could cause a cascading disaster that could generate hundreds of pieces of debris and send them on crash courses with other satellites nearby.
Currently, there’s no national or global authority that would force satellite operators to take action on predicted collisions. Space Force’s urgent alerts sent OneWeb engineers scrambling to email SpaceX’s Starlink team to coordinate maneuvers that would put the two satellites at safer distances from one another.
"“Coordination is the issue. It is not sufficient to say ‘I’ve got an automated system.’”"
While coordinating with OneWeb, SpaceX disabled its automated AI-powered collision avoidance system and manually steered its Starlink satellite out of the way... (MORE)
We're entombing the Earth in an impenetrable shell of dead satellites
https://www.engadget.com/were-entombing-...02560.html
EXCERPTS: Today more than 3,000 satellites circle the Earth and they are joined by millions of pieces of space debris — such as bits of broken satellite, discarded rocket parts and flecks of spacecraft paint. NASA estimates that there’s around 6,000 tonnes of debris in Low Earth Orbit alone.
This orbital refuse doesn’t just create navigation hazards for astronauts, it also reflects sunlight down to the surface, interfering with ground-based telescope observations. A study recently accepted by Monthly Notices of the Royal Astronomical Society: Letters suggests that there is now nowhere on Earth free from the light pollution produced by overhead debris and satellites. Even more concerning, researchers expect the amount of debris in orbit to increase by an order of magnitude over the next decade as mega-constellations of internet-beaming mini-satellites, like SpaceX’s Starlink program, take off.
“Astronomers – and casual viewers of the night sky – must expect a future in which the low Earth orbit population includes tens of thousands of relatively large satellites,” Jonathan McDowell at the Harvard-Smithsonian Center for Astrophysics warned in a 2020 study. “The impacts will be significant for certain types of observation, certain observatories and at certain times of year.”
Until a couple years ago, humanity had launched fewer 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 per pound of launching cargo fall from $24,800 during the Shuttle era to just $1,240 today — the rate at which we put satellites into orbit is set to increase exponentially.
[...] In response to the growing problem, astronomers from around the world, as part of the National Science Foundation’s SATCON-1 workshop last July, have assembled 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 higher, and sharing orbital information regarding these constellations with the research community so that astronomers can avoid those areas of the sky.
“SpaceX has shown that operators can reduce reflected sunlight through satellite body orientation, Sun shielding and surface darkening,” the SATCON-1 workshop found. “A joint effort to obtain higher accuracy public data on predicted locations of individual satellites (or ephemerides) could enable some pointing avoidance and mid-exposure shuttering during satellite passage.” Alternatively, operators could design their satellites to actively deorbit when they reach the end of their service life span — as Starlink’s satellites do — or they could just launch fewer constellations in general. Whether national or international regulators will actually adopt these recommendations remains to be seen.
But even if satellite operators do manage to turn down the brightness of their constellations, we are still faced with an increasingly dense orbital “graveyard” of broken satellites and overhead space junk. NASA’s Orbital Space Debris Office estimates that there are half a million marble-sized bits of junk zipping around LEO at 22,300 mph — fast enough to chip even the ISS’s heavily reinforced windows upon impact — and as many as 100 million pieces measuring a millimeter or less.
NASA became the first national space agency to develop a comprehensive space debris mitigation plan in 1995. Those guidelines were later adapted by the 10-nation Inter-Agency Space Debris Coordination Committee (IADC) and eventually adopted by the UN 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 the control of debris released during normal operations, minimizing debris generated by accidental explosions, the selection of safe flight profile and operational configuration to minimize accidental collisions, and post-mission disposal of space structures.” Additionally, the Department of Defense operates the Space Surveillance Network, which is charged with 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 in the process of developing systems to actively capture and dispose of orbital refuse... (MORE - details)