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Comment by eddieh | Hacker News Reader

So there are ~1,459 artificial satellites orbiting the Earth right now. Am I the only one that thinks adding 4,425 is a bit much? Certainly there is a way to do this with less space junk?

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Maybe your sense of "much" is thrown off by not-to-scale visualizations. Space is big, even near-earth space is bigger than the entire surface Earth.

These 1500 satellites are probably, on average, the size of a van. Is 1500 vans distributed on surface of the earth "much"? These SpaceX / Starlink satellites are considerably smaller - about the size of an oven or washing machine. What does it mean for 4500 ovens spread out over the surface of the earth to be "much"?

> These SpaceX / Starlink satellites are considerably smaller - about the size of an oven or washing machine.

The dimensions that appear in the FCC application[1] are 4.0 x 1.8 x 1.2 meters. About size of a small passenger van actually. Doubtless that will not be the launch size, but they will have these dimensions while in operation.

[1] http://licensing.fcc.gov/myibfs/download.do?attachment_key=1...

Yes, space is, like, infinitely bigger than people imagine it to be. However your analogy is incomplete unless those 4500 ovens are wandering the surface of the Earth at mach 25.

Well, we do have thousands of airplane-sizes airplanes wandering the atmosphere at mach speeds. And we wouldn’t consider the airspace "full".

It's full enough that it requires continuous guidance and collision avoidance measures. And the majority of those planes are not going even close to as fast as satellites in LEO/MEO move.

That has a lot to do with human lives being within those objects and gravity pulling them down to earth potentially being a danger to more human lives. All that versus floating space junk and dollars down the drain for the engineering, development, launch, and ongoing functionality of those satellites.

There is a team at NASA tracking all that stuff though

>NASA and the DoD cooperate and share responsibilities for characterizing the satellite (including orbital debris) environment. DoD’s Space Surveillance Network tracks discrete objects as small as 2 inches (5 centimeters) in diameter in low Earth orbit and about 1 yard (1 meter) in geosynchronous orbit. Currently, about 15,000 officially cataloged objects are still in orbit. The total number of tracked objects exceeds 21,000. Using special ground-based sensors and inspections of returned satellite surfaces, NASA statistically determines the extent of the population for objects less than 4 inches (10 centimeters) in diameter.

https://www.nasa.gov/mission_pages/station/news/orbital_debr...

Sure, that's pretty common knowledge isn't it?

GGP was trying to make the point that airplanes don't collide and that they travel fast but that's not the whole story, there are a lot of people working hard to keep it that way.

Also, even though NASA is tracking stuff there isn't much they can do about it, it's mostly to help determine new orbits and to make sure that launches do not accidentally intersect with some chunk of space debris.

My point was that we can apply the same technological solutions we’ve found for aerospace also to spaceflight.

We can use tracking and modern software solutions to plan where to put new satellites.

4500 is far from the maximum possible.

> We can use tracking and modern software solutions to plan where to put new satellites.

And of course they will do just that.

But satellites carry only relatively little propellant and the bulk of it is used to maintain altitude, especially for LEO/MEO satellites. Serious course changes are going to be pretty rare whereas they are the norm for anything with wings.

On another note, airtravel (not general aviation) tends to happen in 'corridors' with traffic control handing over at the borders of control zones. For satellites the situation is vastly different.

The same technological solutions that we've found for aerospace have almost no application in satellite orbital computations and the management of fleets of satellites.

I would not describe any commercial aviation operation as "wandering". The rules are very clearly defined and very strict about where and when a plane is allowed to be. It's very much actively managed.

Take a look at the airspace around a major airport when a storm system moves in. Airspace is absolutely congested.

“Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.”

This quote sounds familiar, but can't pinpoint who said it. It almost feels like I should know even...

Any pointers? :)

Hitchhikers Guide to The Galaxy, Douglas Adams. Everyone here knows that but the real world is different.

Douglas Adams

This is a great analogy! To add a little color, all of those satellites that are geostationary (most of them used for communications to date, with the exceptions of Iridium and o3b) are like vans laid out along the equator. Starlink's satellites (in addition to being at a much, much lower altitude) are in different planes - for even more separation from existing satellites.

The available volume out at geostationary orbit absolutely dwarfs low earth orbit or the Earth's surface.

Unless I'm mistaken, isn't geostationary orbit essentially a single circle? So it technically has zero volume. Individual satellites are assigned constant locations in longitude.

https://www.n2yo.com/satellites/?c=10

I think that's correct, but since they're stationary (relative to each other) perhaps they can be packed more densely without risk of collision?

Geostationary orbit is just really really far away.

Before they push that much extra stuff into orbit, they really should be required to demonstrate a working way to clean up space junk. If they aren't required to, then these 4500 ovens will be left for a very long time after they are no longer in use, until their orbits decay...

The plan submitted to the FCC includes descriptions of the plans for deorbiting the satellites when they have completed their useful life.

SpaceX proposes to deorbiting the satellites much faster then international regulations require.

If 4,425 low orbit satellites which are responsibly recovered can subsume the function of some large chunk of the ~1,459 currently existing, then this will actually substantively reduce the amount of space junk being introduced to Earth orbit. This is assuming that the launches and satellites create zero debris, which is in line with SpaceX's goal of total reusability. (Harder to reuse a vehicle that has things falling off of it.)

Low orbit satellites will fall back to earth much sooner than ones in higher orbit. I would also expect SpaceX to responsibly de-orbit and scuttle their satellites, if for no other reason than to make their own lives easier.

> Am I the only one that thinks adding 4,425 is a bit much?

Probably not; all such endeavours are met by fear. Allow me to further unnerve you; this is just the first phase. The complete system, should it ever be realized, will have more than 8,000 satellites. And that's just SpaceX. There are competitors planning to launch systems of similar scale.

My wife called it the 'Cambrian explosion of space.' Effective, if not entirely correct, analogy.

The article mentions 12,000 total final satellites, but the other 8,000 operate at different altitudes/frequencies so they will need to be approved separately.

The other 8000 are going to be orbiting so low that they'll have to constantly raise their orbit to avoid re-entry.

There's only ~1459 satellites in orbit and already someone wants to prevent more building. What's the reason for this? Preserve neighborhood character? too much noise? are you worried about the traffic?

If you arbitrarily regulate everything before you even begin to innovate, you'll never know what inventions could have been created: that's why there hasn't been hardly any innovation in housing construction over the last 20 years.

In New Zealand, if you installed certain new fangled plastic plumbing a few decades ago, you house may now be unmortgagable for a new buyer because it's been silently spraying water inside your walls for years. 20 years ago there was also a rush of monolithic cladding, now many of those houses are silently rotting due to invisible leaks into the walls. Fun new construction does reduce costs but can ruin people many years later if it's too wild west.

For this to be a good argument you have to assume that the regulater understands all of these things and makes systematically better choices then the people who build the houses.

Or it would require qualifing all materials before being uses. That would increase time before deployment massivly, making new devlopment less attractive. Economist talk about 'permissionless innovation' being incredible important for progress.

These satellites are in MEO (1150km) which is relatively sparsely trafficked. Here is a good visualization http://stuffin.space/ . If you zoom out MEO would be just above the dense sphere of space stuff in LEO.

And if you think 4.5k is a lot wait until you hear about phase 2. Thankfully that is in close LEO and without constant propulsion things would deorbit in a matter of weeks. See https://www.cnbc.com/2018/02/17/spacex-testing-its-own-satel...

yeah, from what I've read they will have enough fuel to stay aloft for ~5 years. They won't be a source of permanent space debris.

Isn't space debris more about collisions which spew out thousands of tiny bits which are hard to track and may have a ludicrous velocity relative to things they run into? AIUI, large objects a relatively easy to track and avoid if you have the gas and are on a collision course.

Every satellite floating around without maneuvering capabilities is one more chance for that existing tiny debris to hit something and cause a chain reaction.

The worst kind of space debris sits in orbits outside of the atmosphere where there is negligible drag. Since these satellites will be in very low orbits that require propulsion to stay aloft, any potential debris from collisions or inoperable satellites will fall back to Earth relatively quickly.

https://www.nasa.gov/news/debris_faq.html

The majority of currently tracked space debris is the result of a single anti-satellite missile test China conducted. So less collisions more weapon based destruction. And any future conflict (between nation's reliant upon gps guided weapons)will likely start with anti-satellite warfare. This worries me greatly.

https://en.wikipedia.org/wiki/2007_Chinese_anti-satellite_mi...

That stuffin.space link is very cool. I'm a little disappointed I couldn't find the moon though. ;)

Depends on what you mean by "doing this." Having them in a lower orbit means smaller equipment required to connect, lower latency compared to connecting to satellites in GEO, and smaller lower power satellites. To get those benefits they have to be close which means more satellites for full coverage.

Also it's not like even this particular orbit will be full when SpaceX is done at 1150 km orbit the 4425 satellites would each have a bit over 80,000 km^2 to themselves on average if they're spread out evenly.

Space is big, we won't be running into any issues with satellite collisions since they can be positioned in three-dimensions and there is a lot of space.

Operational satellites are not considered space-junk since they typically have predictable or fixed orbits which can be avoided. Space junk is non-operational stuff, with potentially unpredictable orbits.

so long as it has a sufficient radar cross section, the orbits of non-operational stuff can be predicted just fine.

NORAD tracks the location of everything big enough to track, and makes it all available.

> and makes it all available

Well not 'all'; naturally the published elements omit objects related to 'national security' and objects which weren't announced as space vehicles e.g. debris.

They are also published under a very restrictive license; I can't forward the elements to you, nor publish anything derived from them, such as predictions for a pass. End-user eyes only.

All satellites will eventually be non-operational, so the question is: do they have a plan for picking up these 4500 pieces of future space junk once they are no longer in use?

Low orbit junk quickly falls back onto earth if not supported by engines.

"quickly" can still be several years, or more.

The industry standard is deorbit within 25 years after end of mission. The SpaceX proposal (1) plans for deorbiting of every satellite within one year after the end of their mission.

(1) http://licensing.fcc.gov/cgi-bin/ws.exe/prod/ib/forms/report...

They're in LOE, so they just go into atmosphere and burn.

How are SpaceX going to monitor and maintain TT&C on 3x the number of satellites that are currently orbiting the planet? That seems like a bigger question in my mind.

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