This was a big concern for NASA though. Their typical guidelines were that commercial satellites have to have >90% reliability to deorbit the satellite. But they want to increase this for the SpaceX satellites because if 10% (~400) of the satellites end up failing then they are effectively up there forever.
Edit: Their most recent application only moved the Phase 1 satellites in to the lower orbit. In later phases they are still planning on having more than 1000 satellites at the higher orbital altitude.
So it wouldn't stop progress for a century, but might it put a damper on things on the same scale as the Great Depression?
Plus, in the ~1100 km orbit you are getting in to the lower Van Allen belt where the radiation will degrade electronics much more quickly. This can be mitigated with radiation-resistant parts and more shielding, but it adds a lot more cost.
https://mobile.twitter.com/TMFAssociates/status/106076080100...
An example of how long shit can stay in space: A Saturn V booster rocket is still out there, slowly orbiting the planet: https://en.wikipedia.org/wiki/J002E3
https://licensing.fcc.gov/myibfs/download.do?attachment_key=...
Part of the problem, though, is that said Xerox machine is traveling at 17,000 miles per hour.
We've already had a collision (https://en.wikipedia.org/wiki/2009_satellite_collision) between two of the ~3-4k satellites in orbit. SpaceX's constellation is planned to be double that number.
That single collision turned two satellites into two thousand high-velocity projectiles, too.
Just to add to that point: https://en.wikipedia.org/wiki/Envisat#Space_safety
A single 10kg. chunk of debris could result in over 8 tonnes of additional debris, triggering a rather nasty chain reaction.
The idea of satellite collisions and space junk is an actual concern https://en.wikipedia.org/wiki/Kessler_syndrome .
Sure a few washing machines in space isn't a big concern. Now imagine a few collide, hundreds of bits and bolts flying around earth, at unknown trajetories, at thousands of miles per hour.
1. Satellites can kill themselves by dropping back into the atmosphere by their own propulsion system
2. Even if they fail, most of these are low enough that the time until they fall is reasonable short.
3. The objects are known and tracked so even if they are out of control, the others will avoid them.
4. We are moving into a world with cheap access to space and lots of satellites we need service satellites anyway and multiple are in development. This could be a legal requirement but even without it will develop because SpaceX doesn't want to have debris flying around on 'their' plane.
https://www.quora.com/Why-dont-satellites-crash-into-each-ot...
Doing some quick math, the shell in which they'll be orbiting has a surface area of 373,367,808km. With ~7000 satellites, an even distribution would leave them 533,382 km between satellites. All the satellites have station keeping thrusters to keep them in LEO with drag. Keeping them from running into each other is probably pretty simple, in comparison to the other challenges they'll need to solve.
There is just far too much space for 100k objects, let alone 10k to ever run the risk of collission. These satellites are all meant to be in line-of-sight. They will communicate with optics as opposed or in conjunction to radio.
You fear unforseen space particles destroying one and causing a chain reaction. Why don't you hold that same fear for existing satelittes which typically operate at an orbit with far lower decay rate? The orbit for StarLink is very low, small particles would not sustain their energy long enough to be a risk factor. The StarLink sats maintain orbit with fuel, everything else without fuel in that orbit will fall. The chance that a particle will end up in the same orbit, on the same plane, at the same time is astronomically low.
Your comments just echo the same type of delusions of people who think in their brillance they've found problems others have not foreseen. SpaceX is really just full of amateurs you ought to submit your findings.
No, there isn't. Satellites can and do collide despite the vast amount of space in a given orbit. It is improbable, but likely enough to warrant at least some concern.
> Why don't you hold that same fear for existing satelittes which typically operate at an orbit with far lower decay rate?
I do, as does the FCC. This is evident in the fact that they now require any body wishing to launch a spacecraft guarantee that the craft can be put into a graveyard orbit.
> Your comments just echo the same type of delusions of people who think in their brillance they've found problems others have not foreseen. SpaceX is really just full of amateurs you ought to submit your findings.
I'm genuinely sorry this post made you feel this way. If I already had the brilliance to answer this question as I'm sure many bright minds at SpaceX do, I would not have asked the question and rebutted the responses to begin with.
Excluding planned collisions, or collisions during failed docking, I found 4 instances of collisions between satellites and space debris. Ever. Now, a couple of things:
* Yes this larger constellation will increase those odds in the future.
* No, a catastrophic doomsday scenario did not occur when those happened.
* SpaceX will have complete control of these satellites through their operational lifespan (excluding collisions or malfunctions).
* Orbital decay for debris at the altitude they're operating at is ~10 years.
Also, have to ask... is all this concern a result of reading Seveneves? :)
My concern is just from a general interest in spaceflight. More of a wish to protect a resource rather than a Chicken Little fear of the sky literally falling out.
Satellites do collide with debris, but that's a different issue. Furthermore, they don't need a guarantee that they can be put into a graveyard orbit - the proposed satellites (and even any debris, if they'd explode for whatever reason) will be in a graveyard orbit from day one until they stop being pushed up and deorbit.
Actually, they do, and it has indeed happened before (https://en.wikipedia.org/wiki/2009_satellite_collision). Far from a Kessler syndrome scenario, but certainly something that should be examined.
It could make orbital planes unusable, but is generally thought not to pose a substantial problem for launching through them, so worst case we just have to start putting satellites a bit higher.
The article mentions the movie Gravity, which is a bit unrealistic as it portrays multiple large bodies in orbit all being at about the same altitude (which isn't the case in reality). That is not the case with this web of satellites. If a chain reaction of collisions does occur, it would cause a field of tiny, fast, deadly debris all orbiting on a similar orbital "plane". It would pretty much blanket the planet. Wouldn't this cause a large issue for anything attempting to reach orbit? What am I missing here?
EDIT: A lot of replies here mentioning the fact that LEO spacecraft decay more quickly than higher orbits. Please note that not all LEO orbits are low enough to guarantee a quick decay without powered retrograde thrust. Stuff can hang up there in LEO a long, long time depending on the actual altitude.