There is good reason for a neutral party to be a clearinghouse for global collision data. Think it's in everyone's interest. I really doubt this is anything about Musk or SpaceX or whatever, just the issue in general. China is definitely quite proud of their space station, and the US is definitely worried about their space ambitions and any potentially aggressive moves.
Quote from: thirtyone on 12/31/2021 11:13 am There is good reason for a neutral party to be a clearinghouse for global collision data. Think it's in everyone's interest. I really doubt this is anything about Musk or SpaceX or whatever, just the issue in general. China is definitely quite proud of their space station, and the US is definitely worried about their space ambitions and any potentially aggressive moves.The main thing is that this neutral monitoring center has data on all satellites.But now most countries, including the United States, consider the orbits of their military satellites to be secret and do not report them to anyone ....
Per this SpaceNews article, the head of the India division also resigned, effective December 31, 2021. https://spacenews.com/starlinks-head-of-india-resigns-as-spacex-refunds-preorders/From talking to people who have tried to do business there, India is not particularly welcoming to outside companies coming in and selling products without "local partners" owning majority shares and greasing the right palms in the process, so I do not predict that license will be forthcoming any time sooon.
The rapid proliferation of low-Earth orbit satellite constellations came into full-force in 2020. The primary difference in these launches compared to historical launches involved the number of simultaneous deployments, the frequency of deployments, and the scaled use of electronic propulsion for orbit-raising. We examine the impacts of this emerging methodology on the space surveillance mission and the improvements made to date to meet the challenges of this new environment. Starting with pre-launch conjunction assessment, new techniques have been adopted to blend risk mitigation practices, system capabilities, and screening responsiveness. During the launch phase, existing sensor management and tasking processes have evolved to ensure custody of all newly launched objects as well as the existing space catalog. This also drove changes during the object separation phase which required new orbital modeling techniques and analyst expertise to distinguish the clustered objects in a short period of time. Novel approaches towards satellite operator-provided ephemerides, in addition to rapid software upgrades, enabled a new field of orbital analysis which will soon dominate the efforts of resident space object custody. The increase of payloads and data also increased the volume of orbital conjunction assessment data, which drove the need for increased collaboration between data providers and satellite operators to ensure safety of operations in the space domain. Finally, the increase in satellites has resulted in an increase in reporting as satellites re-enter the atmosphere prompting a more efficient approach on how these events are managed and reported.
McKnight said commercial mega-constellations like SpaceX’s Starlink or OneWeb are criticized for compounding the congestion in LEO but these companies should be seen as victims that are increasingly at risk. “Old abandoned massive objects pose greater risk than smaller, more agile constellations,” he added. “Many of these satellite operators are working with mitigation guidelines and operational procedures that are much more stringent than any government guidelines. They’re being safer than what the government’s asking them to do. But they are going to likely have some difficult times in the near future because of debris objects.”
Because there is only a finite amount of spectrum available to LEO broadband systems such as Starlink (which must be shared with other LEO systems within the U.S., according to FCC rules), only a limited amount of capacity can be delivered to users in a given area, regardless of the number of Starlink satellites in the sky.It is therefore far from clear that Starlink will be capable of serving a comparable number of customers to Viasat and Hughes (i.e. in excess of 500K subscribers), let alone a significant proportion of the millions of homes in the U.S. that currently lack terrestrial broadband, in the medium term.Overall, while Starlink represents an admirable first attempt to develop a LEO broadband system and bring more choices to rural U.S. consumers, it cannot and will not become the only option for satellite broadband in the U.S. or around the world, because in many areas at least some potential customers will be unable to access Starlink, due to capacity limitations and/or the difficulty of securing a reliable line-of-sight to the constellation.
Tim Farrar is at it again: Starlink's reach won’t be enough to solve rural broadband dilemma — FarrarQuote from: fiercewireless.comBecause there is only a finite amount of spectrum available to LEO broadband systems such as Starlink (which must be shared with other LEO systems within the U.S., according to FCC rules), only a limited amount of capacity can be delivered to users in a given area, regardless of the number of Starlink satellites in the sky.It is therefore far from clear that Starlink will be capable of serving a comparable number of customers to Viasat and Hughes (i.e. in excess of 500K subscribers), let alone a significant proportion of the millions of homes in the U.S. that currently lack terrestrial broadband, in the medium term.Overall, while Starlink represents an admirable first attempt to develop a LEO broadband system and bring more choices to rural U.S. consumers, it cannot and will not become the only option for satellite broadband in the U.S. or around the world, because in many areas at least some potential customers will be unable to access Starlink, due to capacity limitations and/or the difficulty of securing a reliable line-of-sight to the constellation.Starlink will have less than 500K subscribers? We'll see...
Quote from: su27k on 01/14/2022 04:23 amTim Farrar is at it again: Starlink's reach won’t be enough to solve rural broadband dilemma — FarrarQuote from: fiercewireless.comBecause there is only a finite amount of spectrum available to LEO broadband systems such as Starlink (which must be shared with other LEO systems within the U.S., according to FCC rules), only a limited amount of capacity can be delivered to users in a given area, regardless of the number of Starlink satellites in the sky.It is therefore far from clear that Starlink will be capable of serving a comparable number of customers to Viasat and Hughes (i.e. in excess of 500K subscribers), let alone a significant proportion of the millions of homes in the U.S. that currently lack terrestrial broadband, in the medium term.Overall, while Starlink represents an admirable first attempt to develop a LEO broadband system and bring more choices to rural U.S. consumers, it cannot and will not become the only option for satellite broadband in the U.S. or around the world, because in many areas at least some potential customers will be unable to access Starlink, due to capacity limitations and/or the difficulty of securing a reliable line-of-sight to the constellation.Starlink will have less than 500K subscribers? We'll see...It will be interesting to see what kind of response he will have if Starlink gets anywhere close to their long term goal of 10gb connections to its users.
Quote from: DigitalMan on 01/14/2022 06:08 amQuote from: su27k on 01/14/2022 04:23 amTim Farrar is at it again: Starlink's reach won’t be enough to solve rural broadband dilemma — FarrarQuote from: fiercewireless.comBecause there is only a finite amount of spectrum available to LEO broadband systems such as Starlink (which must be shared with other LEO systems within the U.S., according to FCC rules), only a limited amount of capacity can be delivered to users in a given area, regardless of the number of Starlink satellites in the sky.It is therefore far from clear that Starlink will be capable of serving a comparable number of customers to Viasat and Hughes (i.e. in excess of 500K subscribers), let alone a significant proportion of the millions of homes in the U.S. that currently lack terrestrial broadband, in the medium term.Overall, while Starlink represents an admirable first attempt to develop a LEO broadband system and bring more choices to rural U.S. consumers, it cannot and will not become the only option for satellite broadband in the U.S. or around the world, because in many areas at least some potential customers will be unable to access Starlink, due to capacity limitations and/or the difficulty of securing a reliable line-of-sight to the constellation.Starlink will have less than 500K subscribers? We'll see...It will be interesting to see what kind of response he will have if Starlink gets anywhere close to their long term goal of 10gb connections to its users."Finite amount of spectrum" is very nearly meaningless, due to spectral reuse. When transmitters are in different locations and the receivers use sufficiently narrow beams, the same frequencies can be reused. Simple example: GEO satellites are at 2-degree longitude separation. Two GEO satellites in adjacent slots can use the same frequencies. The receiver chooses a satellite to use by pointing at it. Same thing happens with the LEO constellations, but it's more complicated because the satellites move with respect to the receivers. At the limit, the number of satellites that can transmit to one spot on the earth depends on how well the receiver can discriminate (how tightly the receiver can focus on the satellite) which is a function of the receiver's antenna size. The GEO arc is fairly full, but we are nowhere near saturating LEO. The earliest LEO constellations concentrated on making sure each spot on the Earth's surface could see at least one satellite, but the laws of physics would let a spot on Earth discriminate more than 100 satellites. As a practical matter there is a huge amount of complexity involved if you try to reach this level, but it's feasible."line of sight" is another non-problem, given enough satellites. With a minimum constellation designed only to guarantee one satellite in view, then yes, a subscriber needs to see the whole sky. But with lots more satellites, a given user will have at least one satellite visible even if the whole sky is not visible. On average the users will end up seeing the whole sky, so it all works out.Please note: this is a theoretical analysis. I do not know how it relates to today's Starlink constellation.
Overall, while Starlink represents an admirable first attempt to develop a LEO broadband system and bring more choices to rural U.S. consumers, it cannot and will not become the only option for satellite broadband in the U.S. or around the world, because in many areas at least some potential customers will be unable to access Starlink, due to capacity limitations and/or the difficulty of securing a reliable line-of-sight to the constellation.
The 140,000 number is from November 2021, I believe. They’re likely approaching 200,000 now.I agree 500,000 by end 2024 is a pretty safe assumption. Could easily get there by the end of this year if they can launch at a similar or better rate as last year and terminal deployment overcomes component shortage issues.
Tim Farrar is at it again: Starlink's reach won’t be enough to solve rural broadband dilemma — FarrarQuote from: fiercewireless.comBecause there is only a finite amount of spectrum available to LEO broadband systems such as Starlink (which must be shared with other LEO systems within the U.S., according to FCC rules), only a limited amount of capacity can be delivered to users in a given area, regardless of the number of Starlink satellites in the sky.It is therefore far from clear that Starlink will be capable of serving a comparable number of customers to Viasat and Hughes (i.e. in excess of 500K subscribers), let alone a significant proportion of the millions of homes in the U.S. that currently lack terrestrial broadband, in the medium term.Overall, while Starlink represents an admirable first attempt to develop a LEO broadband system and bring more choices to rural U.S. consumers, it cannot and will not become the only option for satellite broadband in the U.S. or around the world, because in many areas at least some potential customers will be unable to access Starlink, due to capacity limitations and/or the difficulty of securing a reliable line-of-sight to the constellation.
Quote from: DanClemmensen on 01/14/2022 06:58 amQuote from: DigitalMan on 01/14/2022 06:08 amQuote from: su27k on 01/14/2022 04:23 amTim Farrar is at it again: Starlink's reach won’t be enough to solve rural broadband dilemma — FarrarQuote from: fiercewireless.comBecause there is only a finite amount of spectrum available to LEO broadband systems such as Starlink (which must be shared with other LEO systems within the U.S., according to FCC rules), only a limited amount of capacity can be delivered to users in a given area, regardless of the number of Starlink satellites in the sky.It is therefore far from clear that Starlink will be capable of serving a comparable number of customers to Viasat and Hughes (i.e. in excess of 500K subscribers), let alone a significant proportion of the millions of homes in the U.S. that currently lack terrestrial broadband, in the medium term.Overall, while Starlink represents an admirable first attempt to develop a LEO broadband system and bring more choices to rural U.S. consumers, it cannot and will not become the only option for satellite broadband in the U.S. or around the world, because in many areas at least some potential customers will be unable to access Starlink, due to capacity limitations and/or the difficulty of securing a reliable line-of-sight to the constellation.Starlink will have less than 500K subscribers? We'll see...It will be interesting to see what kind of response he will have if Starlink gets anywhere close to their long term goal of 10gb connections to its users."Finite amount of spectrum" is very nearly meaningless, due to spectral reuse. When transmitters are in different locations and the receivers use sufficiently narrow beams, the same frequencies can be reused. Simple example: GEO satellites are at 2-degree longitude separation. Two GEO satellites in adjacent slots can use the same frequencies. The receiver chooses a satellite to use by pointing at it. Same thing happens with the LEO constellations, but it's more complicated because the satellites move with respect to the receivers. At the limit, the number of satellites that can transmit to one spot on the earth depends on how well the receiver can discriminate (how tightly the receiver can focus on the satellite) which is a function of the receiver's antenna size. The GEO arc is fairly full, but we are nowhere near saturating LEO. The earliest LEO constellations concentrated on making sure each spot on the Earth's surface could see at least one satellite, but the laws of physics would let a spot on Earth discriminate more than 100 satellites. As a practical matter there is a huge amount of complexity involved if you try to reach this level, but it's feasible."line of sight" is another non-problem, given enough satellites. With a minimum constellation designed only to guarantee one satellite in view, then yes, a subscriber needs to see the whole sky. But with lots more satellites, a given user will have at least one satellite visible even if the whole sky is not visible. On average the users will end up seeing the whole sky, so it all works out.Please note: this is a theoretical analysis. I do not know how it relates to today's Starlink constellation.Spectrum reuse is limited by the allowable power flux at the Earth's surface. Yes, making the receiver bigger helps. So does making it more efficient. But the biggest opportunity IMO is to make the spot beam tighter, by a combination of lower satellites and larger satellite-side transmitter antennas. This keeps the power flux constant, but means that the area that was formerly served by 1 beam is now served by 2, or 3 or more... each of which can reuse the same spectrum and thus serve 2x, or 3x, or more users.The V-band VLEO constellation is already using smaller cell sizes than the Ka/Ku band constellation. So with the same efficiencies to can serve more customers per hertz of spectrum used.
