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Comment by martythemaniak | Hacker News Reader

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"?

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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.

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

> 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...

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.

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