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Comment by carlsborg | Hacker News Reader

> "Earth has 4550 satellites in orbit"

Rapidly obsoleted information. SpaceX alone has > 7500 satellites in orbit. It added 2,300+ satellites in the one year period ending Jun 2025.

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> It added 2,300+ satellites in the one year period ending Jun 2025.

Take in account, that a lot of those are replacement sats for the first generations that they are deorbiting already. Do not quote me on this, but its a insane amount (i though it was around 2k) of the first generation that they are deorbiting. If there is a issue, its not the amount of sats in space, but more the insane amount of deorbiting StarLink is doing.

Starlink wanted to put up insane numbers, but a lot of their fights contain a large percentage of replacement sats.

And they are getting bigger ... v1.5 is like 300kg, the v2.0 mini (ironic as its far from mini compared to its predecessors) are 800kg.

So before StarLink launched 60x v1.5's but now they are doing 21x v2.0 Mini's per launch.

The technology has been improving a lot, allowing for a lot more capacity per satellite. Not sure when they start launching v3's but those have like 3x the capacity for inner connects/ground stations and can go up to 1Gbit speeds (compared to the v2's who are again much more capable then multiple v1.5s).

So what we are seeing is less satellites per launch but more capacity per sat. This year is the last year that they are doing mass 1.5 launches, its all now going to the v2.0 "mini" (so 3x less sats).

Satellite constellations in LEO tend to have short design lives of 5 years or so, but the net change in operating satellites since that 2021 graphic is huge: Starlink alone has over 8000 in orbit now (plus another 1200 deorbited). The later generations of Starlink are bigger, but the launch cadence increases...

I love checking out the Starlink launches wikipedia page every so often [1], which is regularly updated. Here's stats as of today:

"As of 31 July 2025:

Satellites launched: 9,314

Satellites failed or deorbited: 1,237

Satellites in orbit: 8,096

Satellites working: 8,077

Satellites operational: 7,040"

1. https://en.wikipedia.org/wiki/List_of_Starlink_and_Starshiel...

The next line after the text you quote reads "(as of 9/1/2021)".

Which was a very outdated number even back when this article was published two years ago

I'm not sure what the exact number was in 2023, but according to [1] it was 6718 at the end of 2022. With that kind of growth, quoting two year old numbers isn't all that helpful

1: https://blog.ucs.org/syoung/how-many-satellites-are-in-space...

Not sure if number of satellites matters so much at this point. As India has already demonstrated that they can launch 100s of them on one rocket. Which means they can very cheaply put them into space as needed.

https://www.dailymail.co.uk/sciencetech/article-4226900/Indi...

If you are trying to create satellite internet in low earth orbit (for reduced ping/latency) the satellite moves faster than the earth spins, and the user on the ground loses point to point contact. So there has to be another satellite already over the horizon before the first one goes out of view. Wiki says Starlink sats travel at about 340 miles above the ground.

The easiest alternative to implement is having the satellites in a geostationary orbit so that they are always above a single spot. The altitude necessary for this is higher than 20k miles, and results in very bad ping/latency. Inmarsat is one of these, and I had a chance to use it in the past. It was slow and laggy, as the realities of physics would suggest.

So more satellites means more potential coverage of the globe, or increased capacity over existing coverage regions, or both. It seems very important.

The Indian satellites in the article weighed on average around 6 kilograms. A starlink satellite weighs 227 kg. You can put more telecom equipment in 227 kg than in 6kg. A better metric than #of satellites is probably total mass of satellites, to make broad comparisons more meaningful.

This really isn't all that much if you pause to consider it. For example. Lets take the larger possible number of 7500 plus 2,300 plus the 4,550 satellites noted up to 2021. That's a total of just under 15,000 satellites. Most of those are fairly small objects, at the most about the size of a typical mini-van, with most being quite a bit smaller than that.

Now, all of this is spread over a three-dimensional topography that's much larger than the total surface area of the Earth, and because their orbits are, as mentioned, three-dimensionally occupying various altitudes, the size of the total topography they move through is enormously larger than just one single surface area in square kilometers of a single hypothetical sphere X km above the Earth's surface. In the least case, even if all existing orbital satellites were stationed at the lowest possible orbital altitude, that's still quite a bit bigger than the 509 600 000 square km of the Earth's total surface. (too lazy to calculate the specific increment in this moment)

Across all of that, just 15,000 objects that are individually smaller than your average family sedan.

For comparison, the island of Manhattan has approximately 116,000 buildings crammed into it. If you spread those more or less equi-distantly from each other across the whole of the Earth's surface, water or air, there'd still be a tremendous amount of empty space between them. That's nearly 10 times as many objects individually much larger than any human satellite, across a much smaller surface area than what's occupied by our orbital satellites.

(Yes, I know we also have a shit-load of other inert junk zipping around up there at tens of thousands of KM per hour, but even if that stuff, most of which is very tiny, were included, we're still talking about an enormous amount of empty space between objects)

But apart from all the other stuff you mention, you’re missing an important point: these things move. And unless all objects are synchronized (which they are not) they occupy a whole orbit, not only their actual volume. If two orbits intersect, the objects occupying those will eventually collide.

Therefore, they occupy much more volume.

Yes. This is the idea behind Kessler Syndrome - that the accumulation of clutter in Earth orbit could lead to an "ablation cascade" as more and more things collide and more and more debris is created from those collisions leading to Earth orbit becoming too hazardous to traverse.

"A 1 kg object impacting at 10 km/s, for example, is probably capable of catastrophically breaking up a 1,000 kg spacecraft if it strikes a high-density element in the spacecraft. In such a breakup, numerous fragments larger than 1 kg would be created." https://orbitaldebris.jsc.nasa.gov/library/a-technical-asses...

The dimensionality of usable orbits is much less than 3.

For example all the GEO satellites are positioned along a 1D line.

I believe I described it badly or you misunderstood me then. What I was referring to in my mention of three-dimensionality is that the area in which all of them orbit isn't a single flat plane over a sphere shape. It's actually several flat planes layered on top of each other, with an obviously ever greater surface area the higher you go. Thus you have LEO, MEO and GEO satellites all sharing orbital space but at different heights so to speak. I'm aware that any given satellite generally flies along a fixed altitude (though as far as I know their latitude along that altitude can shift enormously)

I suppose each satellite has its orbit defined by the elliptical path (4 parameters). Like for GEO you can have many satellites in a single elliptical path.

You can also probably have different satellites on different ellipses whose paths intersect with each other, but the timing is such that they never collide.

I suppose it's quite complex in reality!

What you say is important of course, and it's what makes me less than sure in my assessment. It was after all more of a mental exercise in appreciating just how vast an area of space this relatively tiny quantity of objects is spread across.

To give one further perspective example here: a single large bulk container ship can carry up to 8,500 car-sized units.

This means that even if every single one of the maybe 15,000 satellites in orbit were the size of a car (most of them are much smaller actually), all together, they'd fill no more than the storage spaces of two bulk container ships with lots of room to spare at that.

This, spread over a multi-layered area as vast as our orbital space, means that even with their constantly moving at incredible speeds, and all the junk out there scattered between the satellites themselves, there's an enormous amount of emptiness between it all mitigating against impacts being very likely or frequent at all.

After all, of the 8,070 or so Starlink satellites in orbit right now, there's little mention of more than a few having been knocked out by debris in orbit. It seems that solar storms are their much bigger worry and cause of mishaps.

As the saying goes, space is huge, sometimes more than our brains can easily comprehend. This applies even in the comparatively tiny orbital regions of it that we use daily.

The mental exercise is fine for realising that satellites don't look as big as pictures of satellites in graphics, it's just missing the point that if you don't want to hit a 20cm x 20cm x 20cm cube that moves at 17,500 mph and has slow and limited capability to adjust that movement you need to allow it quite a bit more space, and be able to predict its movement accurately relative to yours. Especially if any collision means thousands of pieces of shrapnel that continue to move at 17500mph for decades or more, whilst potentially being too small to track but large enough to do a lot of damage.

Trains take up a negligible fraction of the mileage of the lines they operate on and rarely cross other lines, but signalling is still critical.

All of these are useful things to keep in mind of course, and they're why I put forth my consideration as a thought experiment for perspective, not so much as an absolute assertion. Orbital space is complicated, and the the ramifications of accidents are extremely unique compared to those that apply in a terrestrial context, but I still stand by my point about it being absurdly big enough that a sense of proportion is needed in worrying about something like Kessler syndrome.

To those downvoting a completely innocuous comment like this and my other replies below, which simply put forth a thought experiment for the sake of debate, without asserting anything at all controversial: Grow an adult brain, no? idiotic as the downvote feature is in general, one would at least assume that the self-professed "intellectually above-average" readers of a site like this would use it better than 12-year-old rage-lords on a 4chan thread.

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