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The BBC News article Aurora photographers find new night sky lights and call them Steve says:

A group of aurora enthusiasts have found a new type of light in the night sky and named it Steve.

Eric Donovan from the University of Calgary in Canada spotted the feature in photos shared on a Facebook group.

He did not recognise it as a catalogued phenomenon and although the group were calling it a proton arc, he knew proton auroras were not visible. Testing showed it appeared to be a hot stream of fast-flowing gas in the higher reaches of the atmosphere.

The European Space Agency (ESA) sent electric field instruments to measure it 300km (190 miles) above the surface of the Earth and found the temperature of the air was 3,000C (5,432F) hotter inside the gas stream than outside it.

Inside, the 25km-wide ribbon of gas was flowing at 6 km/s (13,000mph), 600 times faster than the air on either side.

Relatively little else is known about the big purple light as yet but it appears it is not an aurora as it does not stem from the interaction of solar particles with the Earth's magnetic field. (emphasis added)

I'm wondering, what is Steve and why wasn't Steve characterize earlier?

But more importantly: Could this 6 km/s flow of glowing gas and plasma have affected the ISS when it was orbiting closer to 300 km, or other low-orbiting spacecraft? According to the article, this is not an aurora, or a 'proton arc'. This seems to be something very different, and the complete phenomenon may not be necessarily limited to an altitude of 300 km.

I'm not thinking that the ISS would be "blown off course", but a sudden transient charging event may be difficult to effectively neutralize, just as an example.

uhoh
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    Found more information here: https://phys.org/news/2017-04-swarm-explores-feature-northern.html – uhoh Apr 24 '17 at 02:07
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    So much for "ESA sent ... instruments to measure it" – Organic Marble Apr 24 '17 at 02:09
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    I think this question is very relevant. It is a newly discovered phenomenon, and as such might have an impact on satellites. It is also discovered by the european Swarm mission, which are satellites flying at 450 km. – mike Apr 24 '17 at 11:43
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    I could envision it creating issues with charging and corona discharge if the potential gets high enough, particularly on the solar arrays, which develop their own relatively high voltage potential relative to the rest of the vehicle. As to the exact effects, well, it depends on the gas constituents and the density, which I don't see mentioned either. If it is known that ISS flew through it (along with when it did so), data from instruments such as the FPMU could be pulled to see if anything showed up. – Tristan Apr 24 '17 at 13:11
  • If Steve was watched from Calgary, how far away is it from the ISS? Calgary is 51 ° north and the ISS orbital inclination is 51 ° too. But the exact location of the watchers of Steve is not given, it may be farther north than 51 °. – Uwe Apr 25 '17 at 10:11
  • I've asked a followup question and show more detailed information there. – uhoh Apr 25 '17 at 15:21
  • I am going to say no. The flows involved here are most likely not super dense and their speeds are really not that large compared to lots of other things happening at those altitudes. The ISS does charge up, as do all things in space, but these issues are usually well managed with material design. Further, electric fields do work to get rid of themselves, which usually mitigates charging by itself. When poor materials and improper grounding are used, then excess charging can lead to arcing and other damaging effects. – honeste_vivere Feb 01 '18 at 14:23
  • @honeste_vivere Do you have any actual basis for believing that an unexplained, only-recently-discovered phenomenon is "most likely not super dense"? – uhoh Feb 01 '18 at 14:30
  • Because we know the densities of the particles at those altitudes. Yes the density is higher in the auroral regions than, say, the outer magnetosphere but it is still ~20 orders of magnitude less dense than Earth's atmosphere at sea level. That is, the density/pressure is low enough that drag is quite small. This is why we only need to thrust the ISS periodically to keep it in orbit and it's been going for nearly 20 years now. – honeste_vivere Feb 01 '18 at 14:35
  • @honeste_vivere I think terms like "quite small" and "not that large" are meaningless. If you have something quantitative, consider posting an answer! I'm interested to know what velocities and densities of charged particles are considered "safe" and "dangerous" to the ISS. Of course it's not related to neutral density, it's the charged species that are worrying me the most. – uhoh Feb 01 '18 at 14:37
  • Fair enough, but I do know that no spacecraft have fallen from the sky because of Steve and since Steve is a common atmospheric phenomena, I am not too worried. – honeste_vivere Feb 01 '18 at 14:39
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    Wellp-- pack it in folks, that's one of the better titles I've read on this SE if not the best. Imagining some bloke named steve with a claw hammer pounding on a solar panel made my week. – Magic Octopus Urn Aug 05 '18 at 23:09

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Science Magazine carried a March 2018 research article about this: Elizabeth MacDonald et al "New science in plain sight: Citizen scientists lead to the discovery of optical structure in the upper atmosphere" (hopefully not paywalled) Much of the observation are Earth based (including some by the Berkeley group), but the Swarm LEO satellites also contributed observations:

enter image description here

Swarm made intensity (really, detector counts) measurements with passes at 170, 200 and 230 km altitude, and count a 20% increase in activity. (Note suppressed zero in top plot)

To establish whether there was any possibility that Steve could hurt the ISS, there are a few elements to assess:

1) Where they in the same place? The original observation was WNW (i.e. a little above at the latitude of) Regina, Saskatchewan (50 degrees North). The figure shows a peak at 60 magnetic latitude, which is about 48 regular north. Other observations are at 53 degrees North and even further north.

With an orbital inclination of 51.6 degrees, ISS does get that far north. It would be an unlikely coincidence to be that far north just at the same latitude and time as a STEVE (it's an acronym now: Strong Thermal Emission Velocity Enhancement ), but not actually all that much rarer than being over any other spot within it's orbital coverage.

2) If it hit, how big would the drag increase be? Note the density in the bottom plot: about $40 \times 10^{9}$ electrons per cubic meter. That's an increase, but not at all a significant one if it's just electrons.

I don't understand the physics enough to know whether there's also be increased numbers of nuclei (i.e. photons to go with the electrons), but let's assume arguendo that they are. The effect is still small, as the atmospheric number density is [already a factor of a thousand higher, above $10^{12}][3]$.

3) How about radiation? That electron flux is at 6000k or so (4th plot). Typical kinetic temperatures are 1000k or so, so this is quite a bit more energetic. But it's still only 150eV; any X-rays generated will be quite soft, not very penetrating and not carrying very much radiation flux.

4) How about charging? That's a complicated subject, beyond what I really know. Probably the highest risk time is during an EVA due to the possibility of charging the astronauts separately from the vehicle. (See "Electrostatic Discharge Issues in International Space Station Program EVAs", J.B. Bacon, NASA 2009) STEVE is providing an increase in the number of electrons. Sweeping 10km (flight arc through STEVE) by 1mx1m (a notional person cross-section) is $10^4 m^3$, $40 \times 10^13$ electrons, about $70 \times 10^{-6}$ Coloumb. That's not a lot to create a static shock.

I may have missed a risk mechanism, but it sounds like STEVE is like many of my Canadian colleagues: Interesting, and not likely to be a threat.

Bob Jacobsen
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  • Thank you very much! I hadn't realized Steve has now been officially "promoted" (acronymized) to STEVE. If you haven't seen it yet, Canadian scientis Eric Donovan has chimed in with an answer to If Steve is at 300 km, and SWARM is >440km, how did SWARM measure Steve's temperature? – uhoh Aug 05 '18 at 05:20