Unexpected solar weather is accelerating satellites' orbital decay

120 points17
FunnyBadger14 hours ago

This is simply part of the solar cycle. And it's a standard part of satellite planning when it comes to operational quality and reliability to account for solar cycle radiation effects.

This is an ignorant fear article and/or an article written by someone who knows NOTHING about space launch and design.

(I used to be a military rocket scientist specializing in radiation effects on space electronics many moons ago).

pdabbadabba11 hours ago

The article could be much clearer about this but no, this isn’t just about the standard solar cycle. The issue is that the sun has been more active in this portion of the solar cycle than predicted, resulting in greater atmospheric mass in LEO than anticipated. Planners knew that the cycle was ramping up, but may have underestimated its intensity.

Check out the NOAA solar cycle data:

You are right that operators plan for variations in solar activity. But it remains to be seen how many can cope with a significantly more active cycle than predicted.

walrus0112 hours ago

I concur with this, and also, one possible solution to this from a technical perspective is to increase the amount of fuel carried for ion/hall effect and similar thrusters (high specific impulse, low thrust) for periodic orbit raising maneuvers to extend lifetime.

Theoretically, as $ per kg launch costs come down with things like reusable falcon 9, it makes it much less costly to equip medium sized LEO satellite with more fuel than it might have costed 10 or 15 years ago.

Or if you have something that needs to orbit really low and minimize drag/maximize lifespan, you could design it to be particularly aerodynamic and shaped like this:

dylan60411 hours ago

>(I used to be a military rocket scientist specializing in radiation effects on space electronics many moons ago).

Great, and I'm sure literal rocket scientists are not's target audience.

I read the article, and I didn't receive it as fear mongering at all. You might not be aware that people outside of rocket science are probably pretty ignorant of space weather and its direct affect on the Earth and its inhabitants. Putting a bit of explanation out there in a fairly easy way to understand is not a bad thing. As easy as this was to grasp, there will still be people that are confused after reading.

kmbfjr13 hours ago

>By coincidence (or beginner's luck), the onset of the new space revolution came during that sleepy solar cycle.

Apparently not simply part of the solar cycle when new types of spacecraft (lacking typical propulsion systems) haven’t been in orbit during a high activity solar peak.

There are some points that are alarmist. “Plummet” isn’t something that seems to happen.

KennyBlanken11 hours ago

The article at length describes how this solar cycle is different from prior cycles and forecasts.

> This drag also helps clean up the near-Earth environment from space junk. Scientists know that the intensity of this drag depends on solar activity — the amount of solar wind spewed by the sun, which varies depending on the 11-year solar cycle. The last cycle, which officially ended in December 2019, was rather sleepy, with a below-average number of monthly sunspots and a prolonged minimum of barely any activity. But since last fall, the star has been waking up, spewing more and more solar wind and generating sunspots, solar flares and coronal mass ejections at a growing rate. And the Earth's upper atmosphere has felt the effects.

> In late 2021, operators of the European Space Agency's (ESA) Swarm constellation noticed something worrying: The satellites, which measure the magnetic field around Earth, started sinking toward the atmosphere at an unusually fast rate — up to 10 times faster than before.

> By coincidence (or beginner's luck), the onset of the new space revolution came during that sleepy solar cycle. These new operators are now facing their first solar maximum. But not only that. The sun's activity in the past year turned out to be much more intense than solar weather forecasters predicted, with more sunspots, more coronal mass ejections and more solar wind hitting our planet.

> "The solar activity is a lot higher than the official forecast suggested," Hugh Lewis, a professor of engineering and physical sciences at the University of Southampton in the U.K. who studies the behavior of satellites in low Earth orbit, told "In fact, the current activity is already quite close to the peak level that was forecasted for this solar cycle, and we are still two to three years away from the solar maximum."

> Stromme confirmed those observations. "The solar cycle 25 that we are entering now is currently increasing very steeply," she said. "We do not know if this means that it will be a very tough solar cycle. It could slow down, and it could become a very weak solar cycle. But right now, it's increasing fast."

ngcc_hk9 hours ago

Exactly. The issue is you cannot easy say “unexpected”. Whilst we cannot account for everything and there could be something new like mercury orbit is “unexpected” and not due to Vulcan (as suspected in one stage there is another planet inside its orbit).

Really what is unexpected.

mturmon13 hours ago

As people are pointing out, the rate of orbital decay does matter (even if it's not a "plummet"!) -- because everyone concerned knows that solar activity should be increasing to some extent in 2022 as a new solar cycle takes hold.

This plot of sunspot activity, and the (highly correlated) 10.7cm radio flux, indicates that the current cycle (cycle #25) is rising much faster than typical:

As you can see, cycle #24, which ended in 2019, was quieter than expected (annoying to solar physicists who only see a few cycles within their whole career) -- so it's actually very interesting that Cycle #25 is starting out with a bang.

NOAA is the main US government agency tasked with monitoring/predicting solar activity for the protection of ground and space systems. The main facility is the Space Weather Prediction Center which is in Boulder, CO -- that's the data source of the above plots. The SWPC centerpiece used to be a control room with a bunch of people looking at computer monitors filled with various real-time and historical time series.

We don't know why some cycles are less intense, and the last few cycles have generally been on a downward trend (e.g., So again, it is indeed quite interesting to see this high activity - if it holds up.

Treblemaker13 hours ago

(December 19, 2020) "The consensus view of an international panel of 12 scientists calls for the new cycle, Solar Cycle 25, to be small to average, much like its predecessor, Solar Cycle 24.

But a prominent astrophysicist at the National Center for Atmospheric Research, Scott McIntosh, foresees the sun going gangbusters. The cycle is already off to a fast start, coinciding with the recent publication of McIntosh’s paper in Solar Physics. The study, with contributions from several of his colleagues, forecasts the nascent sunspot cycle to become one of the strongest ever recorded."


Treblemaker13 hours ago

Update on the prediction:

(Feb. 26, 2022) "“We have finalized our forecast of SC25’s amplitude,” says McIntosh. “It will be just above the historical average with a monthly smoothed sunspot number of 190 ± 20.”

"“Above average” may not sound exciting, but this is in fact a sharp departure from NOAA’s official forecast of a weak solar cycle"


mah4k4l5 hours ago

Sure hope that Jello Biafra doesn't have his facts straight in his 1991 song The Sky Is Falling And I Want My Mummy (Falling Space Junk) with NoMeansNo. The part of the song about US orbital satellites carrrying plutonium waste with them. Please be just a little bidenism from this also so priestly character that JB is. The pitfall of the priestly archetypical character so many a time is just being out to to get the good old Holy Spirit emotional response from the churchgoers and not so much alawys concerned with getting the facts straight.

Increased solar flare EMP risk during the next years ain't a picnic either. Yo this all sucks. Bummer vibes. But don't shoot the messenger.

The song:

zoomablemind16 hours ago

There were some space tech startups planning to provide a kind of tug-service to satellites on the low orbit. Not sure if any viability for this is on the near-future horizon.

Space tugs as a service:

Konohamaru1 hour ago

"[Solar] climate is what you expect, [solar] weather is what you get." - Mark Twain

vsllc16 hours ago

I am thinking about a commercial data product to address the situational awareness need here. It feels daunting though, because customers would be the likes of SpaceX and other intimidating entities. If anyone has thoughts, or is interested, please send me an email. (Contact info in profile!) Thanks.

visviva15 hours ago

Commercial SSA is getting to be a busy... space. Have you seen what others are doing in that area? How does your idea differ?

colechristensen15 hours ago

With NASA and related space weather data products and internal tracking of satellites being a core competence of companies like SpaceX, I don't necessarily see where a commercial data product would fit or provide value. Unless you're actually going to launch orbital assets and have some significant scientific work, I'm just not sure.

Some competition:

palisade10 hours ago

I wonder what this means for Starlink. I know that Elon put them into a slightly lower orbit accidentally than what they originally intended. Which probably had the positive side effect of better latency. But, now that solar weather is accelerating orbital decay, this perhaps affects Starlink more adversely than it would have otherwise.

alar449 hours ago

That wouldn't affect latency in any noticable way.

yabones11 hours ago

Maybe this will help clean up the debris from Russia's ASAT missile test last year?

jaywalk17 hours ago

Is the word "plummet" really appropriate here? They're talking about falling at a rate of 0.001mph, which is much faster than expected but hardly a "plummet."

colechristensen16 hours ago

Yes, orbit decay having gone up by a factor of ~10 is indeed plummeting.

You park things in low earth orbit so that they don't stay up forever and indeed come down in reasonably small human-scale timeframes. Usually on the time scale of decades, sometimes more, sometimes less.

If you designed a satellite to stay up for 10 years, it'll suddenly only be able to stay up a year, that's the scale of these things.

Again it's an exponential thing, a seemingly small scale change in the slow part makes the fast part come quite a lot sooner.

BitwiseFool15 hours ago

I think the primary objection is that to the vast majority of people 'plummet' implies the satellite is suddenly and violently falling from the sky - it's the kind of word people would describe an airplane crash with.

However unless the author happens to know a lot about orbital mechanics (or they've played Kerbal Space Program) they probably just picked an expressive word for the sake of a compelling article rather than something that would give a better picture to the layperson.

orbital-decay14 hours ago

Sidenote: KSP is the worst way to build intuition in this particular case as it doesn't have any drag model in orbit, or even n-body simulation, so no orbital decay is possible there. Playing around with NASA's GMAT [0] or similar more comprehensive software is much more helpful to understand real-world orbital mechanics.


ericbarrett13 hours ago

There is a high-quality mod which adds n-body gravity:

It will also add orbital perturbations/frozen orbits if you use Real Solar System:

That said, to my knowledge there isn't yet a mod that adds high-altitude drag.

colechristensen15 hours ago

It's a dumb objection. A mission manager was quoted using the word "diving".

It isn't the journalist but the nitpicking commentors who are clueless. The headline accurately enough conveys what is happening and the article articulates it well. Orbital mechanics isn't intuitive enough for there to be perfect fit words given human experience, human timescales, "plummet" is fine.

corrral14 hours ago

Plummet implies a straight-line dead fall, or close to it. It derives from lead weights (hence the similarity to "plumber") attached to a line, used for sounding depth of water or for marking a straight vertical line. The "verbing" of that noun and its figurative use to describe falling appear to be quite recent developments—Webster's 1913 only lists a noun. I'd say it's the wrong word for this case, but then I'm an opponent of using slightly-similar words interchangeably, such that we effectively have fewer words to work with. However, I'm losing that fight anyway, so who cares I guess.

[EDIT] On reflection, this is even goofier than I thought at first, since the choice of lead for those applications is precisely because it's little affected by wind, and even fares better than most things against moving water, while this is entirely about something falling faster because of its interaction with air.

BitwiseFool15 hours ago
nomel12 hours ago

The definition of the word, that everyone is probably familiar with, strongly disagrees:

    1. to fall perpendicularly
    2. to drop sharply and abruptly
Or, Google's scraped definition from Oxford dictionary:

    fall or drop straight down at high speed.

If you google "satellite plummeting", you'll notice that almost all of the results also include "fireball", "burning up" and/or "reentry".
GekkePrutser14 hours ago

But this space 'weather' won't last forever right? Won't it go back to the old decay rate after this?

So if it lasts a week, the lifetime will be reduced by 10 weeks? Still a lot but something you can cope with.

colechristensen12 hours ago

There are events measured in minutes, hours, and years (or decades).

We’re ramping up to a maximum which should happen in a few years but activity has been above predictions. We don’t understand the Sun dynamics all that well, but what’s happening now is a little weird beyond expectations and might be something that continues for years.

dylan60417 hours ago

Just finished reading the article with the exact same question in mind.

Plummet gets the clicks though, so to the website, it is appropriate.

It could also be argued it's a sense of perspective. Something that falls at the rate of 2km per year suddenly in a matter of months starts to fall at a rate of 20km per year could seem like plummeting when you're the one tasked with keeping it alive or the person that paid for it to be there for 10 years to see it suddenly shortened to 2 years. It's a stretch, but we all love hyperbole

uranium16 hours ago

This. To space folks, that is plummeting. It's enough of a difference, and a surprise, to have a significant effect on business models.

Aachen16 hours ago

It's a significant difference that has a real impact on the satellites. But we also don't say that airplanes plummet when landing or elevators when going down.

To me at least, plummet signals it's a matter of seconds or, perhaps from great altitude, minutes until it hits the bottom. So to me, and that's knowing a thing or two about space, this title is just clickbait and not a good description of the phenomenon observed even for a techy public like HN.

dylan60416 hours ago
dang14 hours ago

Alright you guys, they are no longer plummeting in the title above. Let's talk about the interesting bits now!

cperciva14 hours ago

I would have said "... is accelerating satellites' orbital decay".

dang13 hours ago

Ok, it's up there now. Thanks!

B1FF_PSUVM10 hours ago


(pet peeve, sorry)

mc3217 hours ago

Yeah, plummet is like straight down till it hits something. Given it's root is in "plumbum" it's not surprising and yes, this is used incorrectly. Not being prescriptive, but this usage is pretty misleading.

pempem16 hours ago

Well now that we've determined that plummet maybe isn't the right word to use, shall we discuss the fact that satellites are unexpectedly falling from the sky in yet another climate change that we had not predicted?

mc3216 hours ago

While solar phenomena influences climate, this aspect is not human induced. We have put artificial satellites up there, in earth orbit, but they are not causing solar eruptions or solar flares. We don't understand solar "climate" enough to say that it's changing (cycle frequency, amplitude, etc).

bityard15 hours ago

> We don't understand solar "climate" enough to say that it's changing (cycle frequency, amplitude, etc).

We certainly do know a fair amount about the sun's "climate":

The sun has an 11-year solar cycle where each cycle has a period of low and high sunspot activity and currently we are just starting Cycle 25 with a corresponding uptick of solar flare activity.

zoomablemind16 hours ago

> ...shall we discuss the fact that satellites are unexpectedly falling from the sky

Well, the falling is rather expected, it's just the rate of it is faster, than we hoped for.

Maybe in a couple of years, once at max, the rate will start decreasing, but for some cubesats this may be terminal by then.

anigbrowl16 hours ago

I think this is widely predicted actually

jtbayly16 hours ago

If only we hadn't been burning fossil fuels, the sun wouldn't be punishing us like this!

pempem16 hours ago

Climate of the sun. ugh. climate of the sun obviously.

furyofantares15 hours ago

That's what's happening, right? It's just that space is curved by the earth

mc3214 hours ago

A meteor/meteorite plunges to earth. Something that lowers its altitude so very slightly is not “plummet”. Skylab yes plummeted back to earth.

jcims17 hours ago

I don’t really pay attention that closely, but is a common theme when i see hacky stories about space/astronomy.

Eddy_Viscosity217 hours ago

I'm surprised they didn't go all out and call 'solar weather' 'extreme nuclear explosion activity on the sun'. I'm mean, if its for the clicks, why not.

perihelions16 hours ago

They also say Starlink fully lost 40 satellites to solar weather (were decelerated rapidly enough to burn up in the atmosphere, before their orbits could be rescued). There's a range of outcomes.

Thread about that: (488 comments)

mirashii15 hours ago

For those who don’t click through to the other thread, I’d say that solar weather contributed, but the root cause was more an overzealous safe mode induced by the operations team that didn’t leave time to recover. A better operations plan would’ve shortened the safe mode duration to ensure that they attempted to raise their orbit even if it meant deploying during the solar event. Letting safe mode destroy the satellite to mitigate a probabilistic risk is just bad planning. Take the chance and deploy anyways and hope you get lucky.

adolph12 hours ago

> Take the chance and deploy anyways and hope you get lucky.

If they got unlucky they might have spiked a space in which another satellite could have orbited (no pun intended).

mirashii4 hours ago

There’s not really a shortage of space, even in LEO. This isn’t a place where Kessler syndrome or orbital slots are really a concern.

daniel-cussen11 hours ago

Come on, 40 satellites is not all that much for Spacex.

mirashii3 hours ago

Even on the cheap end of estimates at 250k/each, that's still 10 million in hardware alone, not to mention launch costs, opportunity cost of delaying operations, etc.

But really, that's neither here nor there, the point of the comment is that a combination of an unexpected solar storm and the operations procedures followed for dealing with them lead to a possibly unnecessary loss of satellites. Just because they have more doesn't mean they're happy about losing out on millions of dollars of hardware.

izzydata16 hours ago

Wow, so you are telling me satellites are falling to earth and burning up in the atmosphere? No? Oh.. ok.

kzrdude15 hours ago

No? Yes. They always do this. The only question is how fast. They'll fall and burn eventually.

martinky2417 hours ago

Pop-sci articles... Always disappointing

nomel17 hours ago

But dang, they sure made me fall in love with science, as a kid.

dylan60417 hours ago

Was this one disappointing? Maybe if you're going by the title alone, which granted was the original question. However, it was a decent enough explanation for the target audience of the site.

CodeWriter2317 hours ago

Well at that rate, it will crash into the Earth in…never

dr_orpheus16 hours ago

But it will though. The lowest satellites are at an altitude of 460 km above the Earth. And the decay of the satellite in to the Earth is exponential [0] so the unexpected drop is a significant impact on the lifetime of the spacecraft. You can see from the plot in that Orbital Decay that there is an altitude that it starts dropping very rapidly. So they may have expected it de-orbit in approximately 10 years, but now the de-orbit could be something like 5 years.

CodeWriter2310 hours ago

You don’t think it will burn to ashes during re-entry?

stjohnswarts12 hours ago

I mean wouldn't they account for this and add thrusters and fuel to put it back where they want it?

ngcc_hk9 hours ago

Unexpected or failed theory or failed engineering or … . What is expected in the real world? Or just an excuse.

You always have unknown unknown but is this sort of expected as the sun is not yours. The solar wind model is the problem?

zackees13 hours ago

So this effect is caused by more solar wind slamming into the atmosphere at 100’s of km/hr and is so powerful that it’s CAUSING THE ATMOSPHERE TO HEAT UP AND EXPAND?

Does the global warming models take this into effect? This seems like an unfathomable amount of energy.

mturmon13 hours ago

Solar irradiance variations amount to a bit less than 0.1% over the solar cycle. It used to be thought solar-cycle variations (the 11-year period) could be a significant contributor to climate change.

This turned out not to be the case...that was pretty much known by the early 2000s.

Other irradiance variations, due to orbital variations called Milankovich cycles, happening in the 10,000's of year range, do appear to influence climate. Of course, the extremes we're seeing now are not on the 10,000-year time scale.

jhgb11 hours ago

It's causing the uppermost layers of atmosphere to expand. That's less than an unfathomable amount of energy because the uppermost layers of atmosphere are extremely rarefied, to the extent they don't even behave like gases.

not2b16 hours ago

Too many HN threads just seem to be people arguing about the appropriateness of the title. The article addresses a significant and interesting issue that's going to have major negative effects on business models, as well as some positive effect on space junk. I think they did a decent job, at least for an article intended for the general public, and I'm glad I read it. And yes, the word "plummet" is an exaggeration. But that isn't a big deal.

andrewflnr16 hours ago

Misleading headlines are a constant act of sabotage on our ability to prioritize our information intake. I don't know if it really needs to be discussed every single time, but it is important enough to be recognized and discussed, and until we decide to get serious about rebelling or whatever, well, who's going to decide where the exact appropriate place is to discuss it? So basically as long as it keeps hurting, were going to keep talking about it whenever and wherever it hurts.

topspin16 hours ago

"But that isn't a big deal."

It's clickbait. I appreciate people pointing out clickbait. I think a lot of others do as well; it's why they read the comments on an article before the look at the article.

Had the story been titled "Solar Weather Causes Unexpected Satellite Orbit Decay" or some other non-clickbait thing I'd have read it without looking at comments first. I'm actually interested in solar weather due to its impact on radio. Too bad publishers don't understand that clickbait titles are a serious turn off. Apparently everything must be TMZ.

not2b15 hours ago

I don't appreciate it when the whole comment section of a substantive article is complaints about the headline. Maybe we should just have a way for people to privately message the moderators proposing a headline change to correct a misleading headine, and do that instead. Then the comment section could talk about the article instead of the headline.

kzrdude15 hours ago

I think HN's current title policy is exactly right, for this reason: submissions need "neutral" titles so that we can discuss the content instead.

In this case, the discussion of the word plummet is halfway topical: it's about understanding the severity and going more into detail of what's actually happening, putting it in context. The equivalent discussion would happen regardless of word choice.

corrral14 hours ago

> Too many HN threads just seem to be people arguing about the appropriateness of the title

Too many writers—including of headlines—are so sloppy with language that it's misleading, or even incorrect.

Perhaps when GPT-4 or whatever takes over those jobs, it will be better at it. Provided we don't train it on anything written after 2000 or so, when all headlines became tabloid headlines and margins got tight enough that no-one had time for careful editing anymore.

colechristensen15 hours ago

And most aerospace threads are a shitshow, people who have no idea what they are talking about getting uppity about words which are basically appropriate in this circumstance. Going from 2 km/year to 20 km/year orbit decay is indeed quite significant and could cause a satellite to be lost many years early, the last stage of which is burning up in the atmosphere which is quite plummetous.

anigbrowl16 hours ago

This can bel alleviated by choosing better sources or relaxing the objections to editing titles. I agree that there are lots of useful and informative stories with shitty headlines. I personally don't mind title edits as long as they aim to be less rather than more sensational, and OP briefly notes the reason for the change.

dang14 hours ago

Never underestimate the passion users feel about titles:

jandrese16 hours ago

Writing a good title is as hard as naming things in code. It's a much harder problem than it seems like it should be, with mutually exclusive interests often creating impossible situations.

But also, people just kind of suck at it.

dang14 hours ago

With media publications, at least, it's more that they have specialists dedicated to slathering bait on the titles. That's their job and they're perfectly good at it—they just don't produce what people here would call a good title. This is an example of what Eric Evans called a "bounded context". The way I look at it, it's their job to sex up the headlines and our job (community as well as moderators!) to deflate them again. "Not in this context."

(I suppose this is what you meant by "mutually exclusive interests".)

birdyrooster16 hours ago

Bike shedding at work

brazzledazzle16 hours ago

I like to take a break from bike shedding at work with some bike shedding on HN. Has a different flavor.

RosanaAnaDana16 hours ago

HN: come for the pedentry, stay for the pedentry on pedentry.

jtbayly16 hours ago

It's spelled "pedantry." :)

a9h74j16 hours ago

An MP-complete post is one in which the meta-pedantry completes in polynominal time.

dang14 hours ago

That has to have been a trap.

jtbayly11 hours ago

Lol. That was certainly on my mind. And then I decided it was such a lovely trap that I wanted to be the one that fell in it.

formerkrogemp10 hours ago

Pedantry for the peasantry. And pleasantly peering for pedantry on HN.

kgc15 hours ago

I wish we could go back to the days of non-clickbait headlines.

dragontamer14 hours ago

When exactly did those days exist?

* "Destruction of the Warship Maine was the work of an Enemy. $50,000 Reward~"

* There's also the fake propaganda Ben Franklin pushed so that the 1776 revolution would have the moral high ground. (Ben Franklin fabricated the "Scalping" of USA's early citizens to fake a war-crime, to make the British look more monstrous).

I'm not sure if there ever was non-clickbait headlines. In fact, the further back in history you go, the more clickbait, and even fully fake, information seems to exist.

daltont16 hours ago

Hyperbolic headlines plus the fact the people tend to not read anything except the headline (a form Lem's law IMO) is part of the disinformation problem.

rcardo1116 hours ago

I'm wondering if this solar cycle can be a reason for the recent wild summer temperatures? Anyone here can confirm?