
The Kessler Syndrome Explained (2014) - pmoriarty
http://www.spacesafetymagazine.com/space-debris/kessler-syndrome/
======
alex_duf
>prepare to spend a few years without cell phone reception, Internet, and a
five-day weather forecast.

Aside from the weather forecast the rest doesn't need any sort of satellite.

It's incredible how many people still think mobile phones are using
satellites! It's a ground antenna, connected via copper or fiber to a wider
network of... antennas. If you call abroad, 99% chances your call goes through
a submarine cable which is again copper or fiber.

Same with Internet, unless you really are in the middle of the Amazon forest,
or (live in country side in the states)

~~~
TeMPOraL
I still think there's lots of benefits to be had (and lots of money to be
made) from replacing many of current satellites with high-altitude solar-
powered UAVs. They'll be much cheaper to design and manufacture (no need for
satellite-grade sterility, or engineering for microgravity environment), much
easier to service and replace, and they'd offer some capabilities impossible
for satellites (like _not_ flying around the globe).

I've said that before, and got plenty of skeptical looks. I recently learned,
however, that I'm not the only one thinking this - in fact the concept has
been dubbed "atmosats", "pseudosats", or "HAPS". ESA seems to be into it now:

[http://www.esa.int/Our_Activities/Navigation/Crossing_drones...](http://www.esa.int/Our_Activities/Navigation/Crossing_drones_with_satellites_ESA_eyes_high-
altitude_aerial_platforms)

~~~
flashmob
Have you heard of Facebook's Aquila drone? Sounds like something you are
describing.
[https://en.m.wikipedia.org/wiki/Facebook_Aquila](https://en.m.wikipedia.org/wiki/Facebook_Aquila)
Also, Google's project loon comes to mind.

~~~
TeMPOraL
Yeah, they would both be good examples qualify.

------
alkonaut
So a tragedy of the commons, like any other.

The best way to solve it would probably be to have all actors agree on some
rules (no rocket bodies left in orbit etc) and some economic incentives such
as "for every kg put in orbit you have to pay $X to a fund for the cleanup".

And just like with CO2, the countries responsible for the last 50 years of
launches should prime this fund with money for past launches, because the
countries that just started launching won't agree to the scheme otherwise.

So basically: US, EU and Russia pay billions to a fund in exchange for India
and China agreeing to _start_ paying for future launches.

~~~
Already__Taken
There are rules for satellite designs in place and evolving to address this.
You can't just leave things in GEO they must have been launched with a
lifecycle plan and suitable fuel/propulsion to move to a dead parking orbit.

~~~
SilasX
Enforced by what bodies?

(Not trying to be cheeky, I really want to know. The primary problem here
isn’t specifying rules but enforcing them among superpowers.)

~~~
jerf
At the moment, common consensus is strong enough. There isn't anyone who has
the precise combination of the discipline and foresight necessary to have a
functioning space program at all, and the lack of discipline and foresight to
not care at all about Kessler syndrome, and/or not be directly impacted by it.
It would seem to me to require a contradictory level of long-term thinking and
lack of long-term thinking.

If a rogue actor (in the parlance of the age) managed to put together enough
of a space program that they could make a few launches, but felt they
personally had no stake beyond that, they could try to deliberately trigger
the Kessler catastrophe, but at the moment I'm not aware of anyone who is
there. (Even the gulf between suborbital missiles and true orbit is fairly
large.) And it would have to be a _truly_ rogue actor, not merely one
sponsored by a superpower who does have an interest in the orbital space
staying useful, e.g., North Korea and their complicated relationship with
China, so not a puppet of the US, China, Russia, the EU, etc.

------
chillydawg
I wonder if there's a bit of a land grab going on right now to claim as much
LEO and geosync spots as possible before they dry up and become too crowded to
operate in safely. Maybe a secondary market of orbital slots will open up
where current operators sell their huge chunks to new entrants. Just like good
old ipv4.

~~~
diamondo25
There's not really a land grab, and you better be sure to have propulsion on
board in the coming years, as youll most likely have to evade other defunct
satellites.

The ISS is actually in a bad position, as satellites tend to go to earth, and
the ISS is between earth and most LEO sats (400km vs 600-800km).

~~~
snrplfth
The ISS is in a great position, because it's in an altitude with such high
drag that small objects and uncontrolled fragments deorbit very quickly. Even
the ISS loses 50 - 90 m of altitude a day.

Satellites passing through the ISS's orbit do not tend to spend that many
orbits there.

------
jandrese
This is something I've wondered about when people start talking about
capturing asteroids in Earth orbit and mining them. Mining is typically a
dirty activity and most asteroids are more like a loose collection of gravel
to begin with, and have such pitiful escape velocity that keeping them
together is going to be a significant challenge. One high energy impact from
an errant asteroid could make a tremendous mess in whatever orbit they are
using, and to the extent that orbital mining makes sense at all it almost has
to happen in LEO if you want to use the products on Earth or benefit from
labor/equipment being launched from Earth.

~~~
Symmetry
You could plausibly get a nearby asteroid into a wide orbit of the Earth for
500 m/s of delta v. But getting it from there all the way down to LEO would
take 3 km/s. So I expect most asteroid mining would take place fairly far out
as a practical matter since the products of mining would be lighter and easier
to move. The main downside would be days of travel time to and from the mining
site. And there is a market for the products of asteroid mining in GEO in the
form of commsats who might want to be refueled or someday maybe even have some
parts make from asteroid stuff.

~~~
jandrese
Refueling GEOs will probably never be profitable. They already last for 15+
years and are replaced by much improved satellites when they are retired.
Keeping an old one running isn't worth it because the orbital slots they are
in are too expensive.

IMHO, asteroid mining only makes sense if you are also manufacturing things in
orbit (like spaceships and orbital colonies). All of these plans to deorbit
the mined materials are crazy talk IMHO. Even if you find some amazing near
solid platinum asteroid nearly in orbit already the costs of mining it and
bringing the material back to Earth make it extremely difficult to compete
against terrestrial mining.

If you are actually manufacturing stuff, then you are much more free to choose
your orbit. You can even choose to orbit the moon instead to reduce the
possibility of disaster.

------
farseer
So if North Korea launches one of their ICBMs into LEO with a billion metal
pellets, would it be the end of the space age?

~~~
mnw21cam
It takes more rocket to launch into LEO than it does to get a ballistic
trajectory to your nearest enemy. Your average ICBM doesn't have the oomph to
do it. If it did, then it could target any point on the planet, and we are
fairly sure the North Korea ICBMs can't do that. Yet.

Also, once you have got your pellets into LEO, you need a way to spread them
with a variety of relative velocity. A satellite-satellite collision or a
rocket explosion does this very well - the models give the individual
fragments 1km/s relative outward velocity from the incident, so you basically
need to make a nail bomb. Some of the fragments will be blown in the backwards
direction, and may re-enter the atmosphere on the first orbit. Interestingly,
because reasons, fragments that are blown upwards and downwards may also re-
enter on the first orbit too.

~~~
TeMPOraL
Launch retrograde (in the direction opposite to the spin of the Earth) with
low inclination, and spread the pellets around just a little; should be enough
to deny everyone their typical launch trajectories and would also remove the
need to shoot those pellets very hard - everything else will be running into
them at 2x the orbital speed.

~~~
mnw21cam
Launching retrograde means you have to make your rocket bigger. And once you
are travelling at orbital velocities, a glancing blow is quite enough to cause
catastrophic damage anyway.

~~~
TeMPOraL
A bigger rocket or a smaller payload, yes. Higher-energy collisions should
produce more and higher-energy shrapnel, through, leading to even less
predictable mess. Also, Inescapable Hypervelocity Shredder™ has a nice ring to
it, and it would be giant "fuck you" to the rest of the world; precisely
something you'd want to do if you were crazy and hated the West.

~~~
vidarh
> precisely something you'd want to do if you were crazy and hated the West.

That assume the leadership is actually crazy and hating the west, though,
rather than a mix of in a bind because their own propaganda has made a lot of
their population expect a hard line against the west, and genuinely believing
they are facing a threat.

To dig into history, Reagan by most reports reacted to the indications of the
Soviet fear over Able Archer 83 [1] (where the Soviets may have come
dangerously close to thinking the NATO exercise was a smoke screen for an
intended first strike) with shock that they might have actually seen America
that way. He later wrote in his autobiography (copied from Wikipedia):

> "Three years had taught me something surprising about the Russians: Many
> people at the top of the Soviet hierarchy were genuinely afraid of America
> and Americans. Perhaps this shouldn't have surprised me, but it did...During
> my first years in Washington, I think many of us in the administration took
> it for granted that the Russians, like ourselves, considered it unthinkable
> that the United States would launch a first strike against them. But the
> more experience I had with Soviet leaders and other heads of state who knew
> them, the more I began to realize that many Soviet officials feared us not
> only as adversaries but as potential aggressors who might hurl nuclear
> weapons at them in a first strike...Well, if that was the case, I was even
> more anxious to get a top Soviet leader in a room alone and try to convince
> him we had no designs on the Soviet Union and Russians had nothing to fear
> from us."

In other words: if your opponents seems to act irrational, it's worth
considering that maybe it is because you don't understand their world view. If
someone is threatening to nuke you left right and center, is it more likely
they are crazy, or that their starting worldview has led them to a conclusion
that they are under such dire threat that they have no other choice than to
play up their capabilities as deterrence?

It is worth considering because the avenues to defend against a madman vs. a
scared but mostly rational person are potentially very different. E.g. the
latter is more likely to respond well to attempts at giving them reasons to
feel safer.

(and as much as I dislike a lot of Reagans legacy, the above realisation was a
large part of him changing tack on foreign policy towards actually talking to
the Soviet leadership, and it made a huge difference, and he deserved praise
for doing so instead of just blindly continuing to push the same aggressive
line he started out with)

[1]
[https://en.wikipedia.org/wiki/Able_Archer_83](https://en.wikipedia.org/wiki/Able_Archer_83)

------
kitbrennan
How long would it take for orbit decay to bring these objects back into the
atmosphere?

~~~
danielvf
That’s one of the key factors. It depends on the how high the orbit of the
satellite is. For ones in LEO

\- below 350 km, months

\- 400km a year

\- 500km five years

\- 600km ten years

\- 700km twenty five years

Etc.

However, when a satellite breaks up, the small pieces are much more affected
by drag. Another is effect is that an explosion results in approximately 50%
of the pieces having a lower orbit. So even though the Cosmos-Irdium collision
happened at 700km, which would take about twenty five years to deorbit, in
just five years, more than a quarter of the debris had deorbited.

~~~
Cthulhu_
When you put it like that, it doesn't sound as bad as, say, nuclear winter.
25-50 years of high debris, then slowly reducing remains. It's weird to
imagine that if humanity would die out suddenly, our satellites and orbital
space waste would only stay up there for what, 100 - 200 years more?

~~~
danielvf
You are right - it's not apocalyptic.

Particularly, since satellites in general are getting much lighter than they
used to be (faster decay times, less mass in case of a collision, smaller
target), as well as targeting lower orbits than we used to (most go to
400km-500km now).

Also, even in the event of everything in LEO blowing up, we can still launch
to farther orbits / other planets.

~~~
TeMPOraL
> _Also, even in the event of everything in LEO blowing up, we can still
> launch to farther orbits / other planets._

It'd be risky though, since you have to cross LEO to get there (unless you're
willing to pay the extra cost of launching to absurd inclinations and
correcting in space).

~~~
jandrese
It would take an unbelievably catastrophic Kessler syndrome to make it too
dangerous to boost through LEO. It's not a game of Asteroids, we're talking
about collisions on a yearly or possibly monthly timeframe. Bad enough to ruin
LEO for satellites, but not so bad that it blocks you from space entirely.

~~~
TeMPOraL
I still think a _believably_ catastrophic Kessler syndrome would be risky
enough that NASA and others would refrain from sending _manned_ missions
through LEO at low inclinations.

It's not a game of Asteroids, but it's also not as thin as the asteroid belt.

------
breakyerself
How long can something stay in low earth orbit without propulsion?

------
venning
Needs a (2014) tag.

