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Unexpected solar weather is accelerating satellites' orbital decay

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Re: Unexpected solar weather is accelerating satellites' orbital decay

#71

Post by dragontamer »

kgc wrote: post #50

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

When exactly did those days exist?

* "Destruction of the Warship Maine was the work of an Enemy. $50,000 Reward~" https://sophia.smith.edu/fys169-f19/wp-content/uploads/sites...

* 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). https://founders.archives.gov/documents/Franklin/01-37-02-01...

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.

Re: Unexpected solar weather is accelerating satellites' orbital decay

#72

Post by cardiffspaceman »

BitwiseFool wrote: post #67
colechristensen wrote: post #52

Earlier quoted context omitted.

It’s dumb because it is based on the objector imagining what an uninformed reader would imagine and thinking that anything unlike mighty Thor smiting satellites out of the sky with lightning bolts would make the word “plummet” inappropriate. Satellites are falling relatively very fast compared to usual and some of them have or soon will burn up in atmosphere as a result, it’s a headline, not a half sentence expected…

Likewise, why would you imagine that an uninformed reader would see the word "plummet" and understand that none of these satellites are in immediate danger of re-entry, that they will in-fact continue to stay aloft for several more months, and that in this context plummet means an orbit decaying an order of magnitude faster than expected? You are correct, one of the meanings of plummet is a rapid descent. These satel…

Remember that Star Trek movie trailer wherein the Enterprise (or a similar) spacecraft seemed to drop like the string had been cut? That's what I picture with "plummet".

Re: Unexpected solar weather is accelerating satellites' orbital decay

#73

Post by mturmon »

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:

https://www.swpc.noaa.gov/products/solar-cycle-progression

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., https://en.wikipedia.org/wiki/Solar_cycle#Sunspots). So again, it is indeed quite interesting to see this high activity - if it holds up.

Re: Unexpected solar weather is accelerating satellites' orbital decay

#74

Post by zackees »

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.

Re: Unexpected solar weather is accelerating satellites' orbital decay

#75

Post by dang »

cperciva wrote: post #69
dang wrote: post #60

Earlier quoted context omitted.

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

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

Ok, it's up there now. Thanks!

Re: Unexpected solar weather is accelerating satellites' orbital decay

#76

Post by Treblemaker »

(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."

[0] https://www.washingtonpost.com/weather/2020/12/19/solar-cycl...

Re: Unexpected solar weather is accelerating satellites' orbital decay

#77

Post by mturmon »

zackees wrote: post #74

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.

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.

Re: Unexpected solar weather is accelerating satellites' orbital decay

#78

Post by ericbarrett »

orbital-decay wrote: post #58
BitwiseFool wrote: post #46

Earlier quoted context omitted.

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…

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. [0] https://sourceforge.net/projects/gmat/

There is a high-quality mod which adds n-body gravity: https://github.com/mockingbirdnest/Principia

It will also add orbital perturbations/frozen orbits if you use Real Solar System: https://github.com/mockingbirdnest/Principia/blob/master/ast...

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

Re: Unexpected solar weather is accelerating satellites' orbital decay

#79

Post by Treblemaker »

Treblemaker wrote: post #76

(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 pa…

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"

[0] https://spaceweatherarchive.com/2022/02/25/the-termination-e...

Re: Unexpected solar weather is accelerating satellites' orbital decay

#80

Post by kmbfjr »

FunnyBadger wrote: post #70

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).

>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.

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