Quote from: Robotbeat on 05/25/2021 01:02 amI like how the Twitter astro community's hyperbolic concern-trolling is now being weaponized by companies just for protecting their profits.Worse, the higher orbit is much more damaging to astronomy than lower orbit, by preventing Starlink to lower its orbit, they're shooting themselves in the foot.
I like how the Twitter astro community's hyperbolic concern-trolling is now being weaponized by companies just for protecting their profits.
Quote from: su27k on 05/25/2021 02:51 amQuote from: Robotbeat on 05/25/2021 01:02 amI like how the Twitter astro community's hyperbolic concern-trolling is now being weaponized by companies just for protecting their profits.Worse, the higher orbit is much more damaging to astronomy than lower orbit, by preventing Starlink to lower its orbit, they're shooting themselves in the foot.It's not the astronomy community that opposed lowering the orbits.
“Astronomers are having these issues [and think] there’s nothing they can do legally,” says the paper’s author Ramon Ryan, a second-year law student at Vanderbilt University. “[But] there is this law, the National Environmental Policy Act [NEPA, pronounced ‘Nee-pah’], which requires federal agencies to take a hard look at their actions. The FCC’s lack of review of these commercial satellite projects violates [NEPA], so in the most basic sense, it would be unlawful.”
Quote from: rsdavis9 on 05/21/2021 11:42 amQuote from: su27k on 05/21/2021 05:53 amJust putting this Nature article here because I suspect some talking heads will try to use this to attack Starlink, even though Starlink comes through looking pretty good: Satellite mega‑constellations create risks in Low Earth Orbit, the atmosphere and on EarthQuoteThe rapid development of mega-constellations risks multiple tragedies of the commons, including tragedies to ground-based astronomy, Earth orbit, and Earth’s upper atmosphere. Moreover, the connections between the Earth and space environments are inadequately taken into account by the adoption of a consumer electronic model applied to space assets. For example, we point out that satellite re-entries from the Starlink mega-constellation alone could deposit more aluminum into Earth’s upper atmosphere than what is done through meteoroids; they could thus become the dominant source of high-altitude alumina. Using simple models, we also show that untracked debris will lead to potentially dangerous on-orbit collisions on a regular basis due to the large number of satellites within mega-constellation orbital shells. The total cross-section of satellites in these constellations also greatly increases the risk of impacts due to meteoroids. De facto orbit occupation by single actors, inadequate regulatory frameworks, and the possibility of free-riding exacerbate these risks. International cooperation is urgently needed, along with a regulatory system that takes into account the effects of tens of thousands of satellites.QuoteThere are reasons for hope. SpaceX is showing some leadership with rapid end-of-life deorbiting, automatic collision avoidance, and visors to reduce light pollution, even if these are not yet sufficient. Spacefaring countries, moreover, recognize that debris threatens all satellites, including military satellites. Some are strengthening their national regulations, including by incorporating non-binding international guidelines into binding national laws. However, there is little recognition that Earth’s orbit is a finite resource, the space and Earth environments are connected, and the actions of one actor can affect everyone. Until that changes, we risk multiple tragedies of the commons in space.Don't solid rocket boosters deposit mega tonnes of Al in the upper atmosphere?Short answer: no. Off my orders of magnitude (around a kiloton, i.e. one thousandth a megaton, is estimated to have *ever* been ejected, and a few tons remain).Long answer: check Section 3.5 here: https://link.springer.com/content/pdf/10.1007%2F3-540-37674-7_3.pdf . Not sure what the relevance is: if SRMs are bad for the environment, other problems are not worth addressing?
Quote from: su27k on 05/21/2021 05:53 amJust putting this Nature article here because I suspect some talking heads will try to use this to attack Starlink, even though Starlink comes through looking pretty good: Satellite mega‑constellations create risks in Low Earth Orbit, the atmosphere and on EarthQuoteThe rapid development of mega-constellations risks multiple tragedies of the commons, including tragedies to ground-based astronomy, Earth orbit, and Earth’s upper atmosphere. Moreover, the connections between the Earth and space environments are inadequately taken into account by the adoption of a consumer electronic model applied to space assets. For example, we point out that satellite re-entries from the Starlink mega-constellation alone could deposit more aluminum into Earth’s upper atmosphere than what is done through meteoroids; they could thus become the dominant source of high-altitude alumina. Using simple models, we also show that untracked debris will lead to potentially dangerous on-orbit collisions on a regular basis due to the large number of satellites within mega-constellation orbital shells. The total cross-section of satellites in these constellations also greatly increases the risk of impacts due to meteoroids. De facto orbit occupation by single actors, inadequate regulatory frameworks, and the possibility of free-riding exacerbate these risks. International cooperation is urgently needed, along with a regulatory system that takes into account the effects of tens of thousands of satellites.QuoteThere are reasons for hope. SpaceX is showing some leadership with rapid end-of-life deorbiting, automatic collision avoidance, and visors to reduce light pollution, even if these are not yet sufficient. Spacefaring countries, moreover, recognize that debris threatens all satellites, including military satellites. Some are strengthening their national regulations, including by incorporating non-binding international guidelines into binding national laws. However, there is little recognition that Earth’s orbit is a finite resource, the space and Earth environments are connected, and the actions of one actor can affect everyone. Until that changes, we risk multiple tragedies of the commons in space.Don't solid rocket boosters deposit mega tonnes of Al in the upper atmosphere?
Just putting this Nature article here because I suspect some talking heads will try to use this to attack Starlink, even though Starlink comes through looking pretty good: Satellite mega‑constellations create risks in Low Earth Orbit, the atmosphere and on EarthQuoteThe rapid development of mega-constellations risks multiple tragedies of the commons, including tragedies to ground-based astronomy, Earth orbit, and Earth’s upper atmosphere. Moreover, the connections between the Earth and space environments are inadequately taken into account by the adoption of a consumer electronic model applied to space assets. For example, we point out that satellite re-entries from the Starlink mega-constellation alone could deposit more aluminum into Earth’s upper atmosphere than what is done through meteoroids; they could thus become the dominant source of high-altitude alumina. Using simple models, we also show that untracked debris will lead to potentially dangerous on-orbit collisions on a regular basis due to the large number of satellites within mega-constellation orbital shells. The total cross-section of satellites in these constellations also greatly increases the risk of impacts due to meteoroids. De facto orbit occupation by single actors, inadequate regulatory frameworks, and the possibility of free-riding exacerbate these risks. International cooperation is urgently needed, along with a regulatory system that takes into account the effects of tens of thousands of satellites.QuoteThere are reasons for hope. SpaceX is showing some leadership with rapid end-of-life deorbiting, automatic collision avoidance, and visors to reduce light pollution, even if these are not yet sufficient. Spacefaring countries, moreover, recognize that debris threatens all satellites, including military satellites. Some are strengthening their national regulations, including by incorporating non-binding international guidelines into binding national laws. However, there is little recognition that Earth’s orbit is a finite resource, the space and Earth environments are connected, and the actions of one actor can affect everyone. Until that changes, we risk multiple tragedies of the commons in space.
The rapid development of mega-constellations risks multiple tragedies of the commons, including tragedies to ground-based astronomy, Earth orbit, and Earth’s upper atmosphere. Moreover, the connections between the Earth and space environments are inadequately taken into account by the adoption of a consumer electronic model applied to space assets. For example, we point out that satellite re-entries from the Starlink mega-constellation alone could deposit more aluminum into Earth’s upper atmosphere than what is done through meteoroids; they could thus become the dominant source of high-altitude alumina. Using simple models, we also show that untracked debris will lead to potentially dangerous on-orbit collisions on a regular basis due to the large number of satellites within mega-constellation orbital shells. The total cross-section of satellites in these constellations also greatly increases the risk of impacts due to meteoroids. De facto orbit occupation by single actors, inadequate regulatory frameworks, and the possibility of free-riding exacerbate these risks. International cooperation is urgently needed, along with a regulatory system that takes into account the effects of tens of thousands of satellites.
There are reasons for hope. SpaceX is showing some leadership with rapid end-of-life deorbiting, automatic collision avoidance, and visors to reduce light pollution, even if these are not yet sufficient. Spacefaring countries, moreover, recognize that debris threatens all satellites, including military satellites. Some are strengthening their national regulations, including by incorporating non-binding international guidelines into binding national laws. However, there is little recognition that Earth’s orbit is a finite resource, the space and Earth environments are connected, and the actions of one actor can affect everyone. Until that changes, we risk multiple tragedies of the commons in space.
Quote from: eeergo on 05/21/2021 01:07 pmQuote from: rsdavis9 on 05/21/2021 11:42 amQuote from: su27k on 05/21/2021 05:53 amJust putting this Nature article here because I suspect some talking heads will try to use this to attack Starlink, even though Starlink comes through looking pretty good: Satellite mega‑constellations create risks in Low Earth Orbit, the atmosphere and on EarthQuoteThe rapid development of mega-constellations risks multiple tragedies of the commons, including tragedies to ground-based astronomy, Earth orbit, and Earth’s upper atmosphere. Moreover, the connections between the Earth and space environments are inadequately taken into account by the adoption of a consumer electronic model applied to space assets. For example, we point out that satellite re-entries from the Starlink mega-constellation alone could deposit more aluminum into Earth’s upper atmosphere than what is done through meteoroids; they could thus become the dominant source of high-altitude alumina. Using simple models, we also show that untracked debris will lead to potentially dangerous on-orbit collisions on a regular basis due to the large number of satellites within mega-constellation orbital shells. The total cross-section of satellites in these constellations also greatly increases the risk of impacts due to meteoroids. De facto orbit occupation by single actors, inadequate regulatory frameworks, and the possibility of free-riding exacerbate these risks. International cooperation is urgently needed, along with a regulatory system that takes into account the effects of tens of thousands of satellites.QuoteThere are reasons for hope. SpaceX is showing some leadership with rapid end-of-life deorbiting, automatic collision avoidance, and visors to reduce light pollution, even if these are not yet sufficient. Spacefaring countries, moreover, recognize that debris threatens all satellites, including military satellites. Some are strengthening their national regulations, including by incorporating non-binding international guidelines into binding national laws. However, there is little recognition that Earth’s orbit is a finite resource, the space and Earth environments are connected, and the actions of one actor can affect everyone. Until that changes, we risk multiple tragedies of the commons in space.Don't solid rocket boosters deposit mega tonnes of Al in the upper atmosphere?Short answer: no. Off my orders of magnitude (around a kiloton, i.e. one thousandth a megaton, is estimated to have *ever* been ejected, and a few tons remain).Long answer: check Section 3.5 here: https://link.springer.com/content/pdf/10.1007%2F3-540-37674-7_3.pdf . Not sure what the relevance is: if SRMs are bad for the environment, other problems are not worth addressing?you have extreme reading comprehension problem.He is talking about alumina in high atmosphere (risk to ozon and blah, as usually in itself quite a subj to discuss), you are talking about alumina in free space.Apples and carots.
ViaSat asks FCC to halt SpaceX Starlink launches because it can’t compete AvatarBy Eric RalphPosted on May 25, 2021Under the hollow pretense of concern for the environment, Starlink satellite internet competitor ViaSat has asked the Federal Communication Commission (FCC) to force SpaceX to stop Starlink launches and threatened to take the matter to court if it doesn’t get its way.
Exactly 🤣🤣
The 70 degree shell will provide outstanding coverage at 70 degrees North, as all the 70 degree orbits overlap somewhat there. (And this effect will still be relevant down towards the 53 degree parallel.)I think the minimum elevation allowed is 22 25degrees, giving an extra 13.5 degrees of coverage about 890 miles, and of course more risk of obstruction etc. reaching to 6.5 degrees from the poles! Therefore Alaska will be perfectly covered. Prudhoe Bay on the North coast, is 70 degrees N.This will meet and exceed the intention to provide broadband to remote communities ... in this case to so many places which cannot be reached by road, let alone fibre!!!! In the South it will give outstanding coverage to all the Antarctic research stations, and also southern Chile and Argentina. How wonderful to be able to live in the Chilean archipelago and have outstanding internet! Edit 22 degrees - the other figures are based on this.
Edit 22 degrees - the other figures are based on this.
The massive launch of satellites into low orbit by the American SpaceX for its Starlink constellation created a "risk of de facto monopolization" of space which undermines the sustainability of its operation, denounced the head of Arianespace Stéphane Israël....
Quote from: DistantTemple on 05/29/2021 01:21 pmEdit 22 degrees - the other figures are based on this.Where did you get 22 degrees? The FCC authorization is for 25 degrees, and the corresponding ITU filing has 25 as well as 18.
I think the minimum elevation allowed is 22 25 (final) CORRECTION it IS 25 degrees, giving an extra 13.5 degrees of coverage about 890 miles, and of course more risk of obstruction etc. reaching to 6.5 degrees from the poles!
Quote from: DistantTemple on 05/29/2021 01:21 pmI think the minimum elevation allowed is 22 25 (final) CORRECTION it IS 25 degrees, giving an extra 13.5 degrees of coverage about 890 miles, and of course more risk of obstruction etc. reaching to 6.5 degrees from the poles!I get a coverage area with a 8.7 degree radius or 968 km (~605 miles) radius. That's at 570 km altitude. So a satellite in a 70 degree inclination orbit would be usable at a 25 degree elevation at a maximum latitude of 78.7 degrees north/south.But it's a bit of an open question exactly how usable it would be at that latitude. You would really only see at most one satellite at a time, peaking at 25.X degrees elevation before going back down again. To consistently see multiple satellites, you would need to be a bit closer to 70 degrees.
