Amazon and Spacex plan to launch thousands of satellites - sane or reckless?

[Rerouter]

We already launch our trust in politicians in to the sun on a weekly basis. An try to prevent cetain groups from trying to fire a preserved cat on a ballistic trajectory at the curiousity rover.

So global communications empire. Seems easy enough.

[BrianHG]

I wonder if someday it will become so crowded up there that they will actually partly shield us from sunlight.

dyson swarm

It would help with global warming...

[edy]

How about just putting a huge transmitting station on the moon.... As long as you can see the moon, you have "Moonternet".   

This way you also build in automatic "offline" time so the kids don't use the internet 24 hours a day... They only get access while their half of the Earth is facing the moon! 

All kidding aside, it seems that nobody is yet worried because space is so huge that the chances of collisions between satellites is extremely small. However, you never know what will happen and eventually this could put astronauts in danger if they are trying to leave the planet for various missions. I hope the satellites have some fuel left so when it's time to decommission them, we can point them back down to Earth and have them activate their rockets and so enter the atmosphere to burn them up.

[rdl]

It's funny all the people worrying about 50,000 satellites. Imagine the Superbowl, or World Cup. Think of how many people are crowded in that stadium. Now spread them out around the Earth. How crowded is it now?

[coppercone2]

how about a big thruster with magnets on it that accumulates satellites and flies into the moon?

nuclear powered. or are they not magnetic enough?

[digsys]

It's funny all the people worrying about 50,000 satellites. Imagine the Superbowl, or World Cup. Think of how many people are crowded in that stadium. Now spread them out around the Earth. How crowded is it now?

errrrrr not quite - constant explosions / collisions generate MILLIONS of tiny dust sized (plus larger) debris and they can still (and DO) a heck of a lot of damage !!
https://aerospace.org/article/danger-orbital-debris
And the more crap they put up there, the chances of failure / collisions increases dramatically !

[Nusa]

From what I've read, there are already 500K pieces of debris larger than a marble in LEO. 20K of which are larger than a softball. And millions of stuff that is too small to track. So from the debris point of view, I suspect it won't have much of an impact either way.

Latency is far less important than bandwidth and availability when you're talking about areas that have little to no infrastructure for telephones, never mind internet. Much of the interior of Africa comes to mind. Or Antarctica (limited satellite service currently, as there are no cables to the continent). Even some of the very rural areas in more developed countries. The existing satellite network only has so much bandwidth.

The other issue that comes to mind for some is that of information control. How can a government practically exercise control over the internet if the communications are simple, relatively cheap, localized transmitters directly to space?

And, of course, this could result in satellite phone service becoming cheap enough for the masses to use. Good for us. Maybe bad for the existing services reclaiming their investment.

[GeorgeOfTheJungle]

We'll have planes colliding with satellite rubbish?

[Nusa]

We'll have planes colliding with satellite rubbish?

Only a problem in your mind, as there is no satellite rubbish orbiting within the atmosphere. Commercial flights cruise less than 12 km up. LEO is from about 300 km to 2000 km.

[tautech]

What if China decides to launch 10,000/20,000/50,000+? I doubt India or Russia could afford to unless, perhaps, there were a strategic military objective rather than pure commercial reasons. Europe could also decide to get in on the act. And S. Korea, Brazil etc? The Middle East could see space as a new

Sorry, forgot the Aussies and NZ - I'm sure they have ambitions in space too...

Already doing it for the Aussies and the US.

Then seven with one blow ! 
https://www.rocketlabusa.com/news/updates/rocket-lab-successfully-launches-seventh-electron-mission-deploys-seven-satellites-to-orbit/

[madires]

Radio waves propagate in the air faster than the light inside a fiber optic, right?

Yep, light travels with 2/3c in glass fiber.

And a submarine cable can have tens or hundreds of fibers, how many radio links with a decent bandwidth can be had simultaneously between a satellite and the ground station? There's a physical limit to that, isn't it? I mean the EM spectrum is what it is and only so many channels can fit, so to upgrade you can't just put 1000 fibers more in parallel and be done, right?

Most submarine cables have 8 fibers. Maybe we'll see some with 12 or little bit more but this is the current limit of what's feasible. The high data rates of many Tbps are achieved by DWDM, i.e. running several light colors each carrying 100 or 400Gbps. 20 years ago it was just 10Gbps per color. With radio links you have a limited frequency range assigned by some authority.

[madires]

It's funny all the people worrying about 50,000 satellites. Imagine the Superbowl, or World Cup. Think of how many people are crowded in that stadium. Now spread them out around the Earth. How crowded is it now?

Try tracking all those people running around after the Superbowl. You don't want to hit a LEO satellite when launching a rocket.

[GeorgeOfTheJungle]

We'll have planes colliding with satellite rubbish?

Only a problem in your mind, as there is no satellite rubbish orbiting within the atmosphere. Commercial flights cruise less than 12 km up. LEO is from about 300 km to 2000 km.

But sooner or later they'll fall out of orbit and disintegrate into pieces, then what?

[madires]

An LEO satellite at 350km altidute will be visible for maybe 6 minutes when tracked with an Yagi antenna, or say 1/2 minute flying  over your head inside your fixed antenna main lobe.

That's the reason why they need data links between the satellites or a second layer of satellites linking the lower layer. And that will increase the overall latency.

[GeorgeOfTheJungle]

From NYC to London there are 5565 km (according to google maps), at the speed of light that's 5565/300e3= 18.55 ms, in a fiber 5565/(2*300e3/3) = 27.82 ms. The difference is 9.27 ms. But the path of the RF link isn't a straight line, so it'll be a smidge less than that.

[rdl]

If there actually were 50,000 satellites and assuming a size of one square meter, and if they were all in the same orbit, and if there was no idea exactly where each one was but they are evenly spaced, there would be roughly one satellite every 42,000 meters.

Change any one of those conditions to something closer to what the likely scenario will be and I think the odds of an accidental collision will be close to zero.

[bd139]

That's not how it works though.

One bit of space crap hits one of them at 20,000mph and it's now 12 bits of satellite. Then one of those bits hits another one ...

Next thing you know there's a debris cloud which stops all space launches. Any system on the verge of chaos only takes one stimulative event to set it off.

[Nusa]

We'll have planes colliding with satellite rubbish?

Only a problem in your mind, as there is no satellite rubbish orbiting within the atmosphere. Commercial flights cruise less than 12 km up. LEO is from about 300 km to 2000 km.

But sooner or later they'll fall out of orbit and disintegrate into pieces, then what?

Most will disintegrate into dust and vapor before getting down to flying levels. The few larger items will make a single pass through airspace and impact the earth. Which can kill you, even on the ground, but its not very likely. You're more likely to get hit by a stray bullet coming back down after being fired into the air by someone a mile away. In any event, it stops being a piece of debris.

[GeorgeOfTheJungle]

If there actually were 50,000 satellites and assuming a size of one square meter, and if they were all in the same orbit, and if there was no idea exactly where each one was but they are evenly spaced, there would be roughly one satellite every 42,000 meters.

But if it takes 6 minutes to cross the sky, and you need to always have one visible/in range, you'd need a pile of them in line in series in the same orbit, spaced less than 6 minutes one from another, no? A belt of satellites so to speak...

[tautech]

What's all this talk of moving satellites, won't they be geostationary like sat TV ones ? 

[GeorgeOfTheJungle]

No, can't be geostationary because they want/need them to be much closer to ground.

[tautech]

No, can't be geostationary because they want/need them to be much closer to ground.

Existing data providers ones are stationary.....why can't land based connections just use greater RF power and sensitivity ?

[GeorgeOfTheJungle]

Because Elon is a Think Different®™ guy? 

[Nusa]

If there actually were 50,000 satellites and assuming a size of one square meter, and if they were all in the same orbit, and if there was no idea exactly where each one was but they are evenly spaced, there would be roughly one satellite every 42,000 meters.

But if it takes 6 minutes to cross the sky, and you need to always have one visible/in range, you'd need a pile of them in line in series in the same orbit, spaced less than 6 minutes one from another, no? A belt of satellites so to speak...

It's not how fast they move, but how much of the orbital arc a single satellite can cover that determines the count. I could probably do the math with some assumptions, but I'm not going to put that much effort into it. Also it's a lot more complicated since a single orbit cannot provide coverage of the entire earth. Ideally there should be at least two satellites in view most of the time anywhere on earth if fully implemented.

[bd139]

No, can't be geostationary because they want/need them to be much closer to ground.

Existing data providers ones are stationary.....why can't land based connections just use greater RF power and sensitivity ?

Actually they did that in the UK. We had a massive microwave backbone run by BT from the 1960s-1990s. This is mostly been supplanted by DWDM fibre.