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“Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

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Re: “Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

#121
post #96

Earlier quoted context omitted.

No they don't. It's more of an issue for long-exposure galaxies and nebula. And asteroids are an extremely rare threat in the first place. It's literally a once-in-a-million-years kind of event.

Dinosaur killers? Yes. City killers? That size hits more often > Asteroids with a diameter more than 30–50 metres (100–150ft) are large enough to make it through our atmosphere intact, however, and the chance of this happening is estimated to be around once in every 100 years. > The damage from an impact of this size would be wide-ranging, and could wipe out an entire city if they were to impact a heavily populated a…

We lack the technology to detect this size of asteroid with enough time to do anything about it.

Luckily, the majority of the earth's surface is unpopulated. Most of these rocks hit the ocean or Siberia and cause few or no casualties. The odds of it hitting a major city are quite low.

Re: “Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

#122
post #40

Earlier quoted context omitted.

Not to mention starlink is not a solution for internet for everyone on the planet: it cannot serve everyone in a densely populated area, no matter how many satellites they have in their constellation. It's a useful piece of infrastructure, but it's far from the panacea people seem to think it is.

> it cannot serve everyone in a densely populated area, I also suspect that to be the case but in order to be more objective I wonder. What's the theoretical maximum bandwidth per square meter (or other unit area) that it can deliver?

Starlink is useful, but people often confuse coverage with capacity density.

The rough hierarchy is: fixed fiber/cable > Wi-Fi > cellular > LEO satellite > traditional GEO satellite. Starlink is a huge improvement over old satellite internet, but it is still fundamentally a satellite system, not dense terrestrial infrastructure.

As a rough illustration, suppose one Starlink beam covers about 63 square miles and has 6 Gbps of usable downlink. At New York City density, that footprint contains about 1.85 million people. That works out to roughly 3 kbps per person. For comparison, network planners typically budget on the order of Mbps per person to comfortably support peak demand in dense urban environments.

You can improve that with more satellites, more beams, more spectrum, and better hardware. But even a 100x improvement only gets you to about 300 kbps/person. Additionally, this all adds cost... that isn't needed for the vast majority of time or space that the sattelites will be over. If the sattelites orbiting over New York also orbit over the Sahara Desert - every $ spent improving NY capacity is also improving the Sahara... but with no return.

The reason fiber, cable, Wi-Fi, and cellular work so well in cities is spatial reuse. Capacity can be reused block by block, building by building, apartment by apartment, tower by tower, and access point by access point. A beam from hundreds of kilometers overhead covers a much larger area.

So Starlink is excellent for rural areas, ships, aircraft, remote sites, disaster recovery, and backup connectivity. But it is not a replacement for terrestrial broadband in dense cities. It solves coverage much better than it solves urban capacity.

Re: “Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

#123

Earlier quoted context omitted.

> Why don’t “we” just build more cell towers? Why is littering our landscape with cell towers and power and fiber lines inherently better than putting this stuff in space?

Google “Kessler syndrome”.

I am aware of no orbital solutions for a catastrophic Kessler cascade in LEO. The only place you could engineer one is in GEO, because that’s a singular orbit, not a plane much less a volume.

Re: “Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

#124
post #13

These kinds of caps have for years been a dampener on human flourishing. My observation has been that those in stagnation or decline tend to attach themselves to these desires to hold the status quo. Anti-energy, anti-housing, anti-industry and so on because they've reached a local maxima in their ability to live and have chosen to spend their life in leisure. But there is the rest of the world, and if I'm told that…

This is a good point.

A similar thread that links your examples together is how we all want to be the last person up the ladder. The last person to move into some neighborhood or into the last apartment complex. Or into a country. The last person to have internet access. Now we want to freeze how it is. Everyone after us threatens our experience.

An American with access to good internet for decades is annoyed that their stargazing session isn't what it used to be now that the city is growing and creating more light or that other people are getting to tech up.

Re: “Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

#125
post #12

Should it be possible to coordinate orbits to create permanent clear spots on the sky where observatories are? A LEO no flight zone of sorts.

It’s not just about where the observatories are. It’s where they want to point to. Good luck figuring out which part of the night sky isn’t important for astronomy.

Re: “Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

#127

Earlier quoted context omitted.

As a literal leftist by any reasonable metric, the recent trend towards “I wish it was 1995” and “AI is the worst” and “tech sucks now” from people I agree with on many other points frustrates me to no end. “You guys know we could basically live in a Star Trek style utopia if we get this right, right?” “The DATA cenTERS are STEALING the water and breaking Taleckshual ProPerty LERRS!” Like, I thought we were for pirac…

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I think we'd be better off limiting whom to kill to one person only.

Re: “Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

#128

Earlier quoted context omitted.

Google says that James Webb telescope cost a total of $10bn. That's not a lot of money in the grand scheme of things. Private citizens could afford to put similar things into space if they chose to. We don't need them to be cheaper.

> James Webb telescope cost a total of $10bn I’d love to see an estimate of what a JWST-class telescope would cost to design, build and launch in a world maintaining a million-satellite fleet. My guess is less than $2bn.

A big part of the complexity of JWST was the way everything had to fold and fit into a small launch vehicle. With larger vehicles (e.g. Starship) the JWST mirror could have been built in one piece, which is much simpler. The whole thing was engineered to the max to fit within tight constraints, which is very expensive.

Re: “Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

#129

How much CO2 does launching a million satellites produce? Is is significant compared to other sources of CO2?

Compare it to air planes, which are already at a much more significant scale. Accounting for fuel type and combustion efficiency seems relevant. I recall around SpaceX 100th landing, that a day of just transatlantic flights was more than everything SpaceX had done to that point

Exactly, they don't matter when compared to general aviation or even just consumer shipping.

And in all cases, if you produce the fuel using renewables then the CO2 output is trivially brought near zero.

Re: “Beyond the limit”: Satellites and mirrors in space pose threat to the night sky

#130

Earlier quoted context omitted.

“if we get this right” is doing a whole lot of heavy lifting here.

But that’s the thing! We could and we can!

“We” can’t even effectively distribute food, healthcare and housing yet but yeah I’m sure capital will totally figure it out if we build enough machines that just accumulate more wealth to the richest people in history. I love cool new tech but I’m perfectly aware it will not do shit to solve any problem other than “eliminate or make labor cheaper”
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