STEREO A Approaches Earth

[Drax Spacex]

As STEREO A moves closer to Earth in the coming months, the farside view behind the east limb will become less and less.  On about 2023-08-12, STEREO A will be at inferior conjunction (along a straight line between the Earth and the Sun).  The viewpoint of the Sun from STEREO A will be essentially the same as from the Earth and satellites at L1.

https://stereo-ssc.nascom.nasa.gov/where.shtml

To what degree will this lack of a partial farside view of the Sun impact space weather prediction?

 

[Sam Warfel]

In my opinion the glimpses of hotspots we'd see incoming on Stereo A really did more to stir up false hopes than aid forecasting.  I don't really remember being tipped off to any approaching big ARs due to Stereo, seeing CMEs off from behind the limb is a much better indicator.  Compared to what feels like hundreds of times we got excited about a big bright spot on Stereo and it turns out to be just plages or an alpha spot.

[Newbie]

20 minutes ago, Orneno said:

In my opinion the glimpses of hotspots we'd see incoming on Stereo A really did more to stir up false hopes than aid forecasting.  I don't really remember being tipped off to any approaching big ARs due to Stereo, seeing CMEs off from behind the limb is a much better indicator.  Compared to what feels like hundreds of times we got excited about a big bright spot on Stereo and it turns out to be just plages or an alpha spot.

I tend to agree with Orneno best indication of 'behind the E limb activity' is flaring with an increase in solar flux not attributable to active regions on the Earth side of the Sun. Certainly when STEREO A and B were first commissioned in 2006 they did provide unique 3D images of the structure of CMEs enabling scientists to determine their fundamental nature and origin.

STEREO was also a key addition to the fleet of space weather detection satellites, providing more accurate alerts for the arrival time of Earth-directed solar ejections with its unique side-viewing perspective. Unfortunately that perspective has greatly diminshed as Drax Spacex points out. STEREO B has been out of operation since 2014.

N.

[Drax Spacex]

I agree.  Early indications of strong ARs behind the east limb can be seen with SDO and SUVI as bright areas of flux extending outward.

We will also be losing the STEREO A Coronograph view.  This is useful for confirming generally whether a CME seen in LASCO is a farside or Earth-facing eruption (but this can be confirmed from SDO and SUVI imagery by checking for coronal dimming without STEREO A Coronograph).   I think what we might lose though is some confidence in CME launch directions, as we will not have the benefit of the stereoscopic view from the combination of partial farside STEREO A and LASCO coronograph viewpoints.

 

[MinYoongi]

Im sad theres no replacement for Stereo planned. Why is Spaceweather so underfunded?

[Drax Spacex]

18 minutes ago, MinYoongi said:

Im sad theres no replacement for Stereo planned. Why is Spaceweather so underfunded?

Because we're a!ready spending so much money trying to fill old space shuttle tanks with liquid hydrogen.

[Jesterface23]

Hopefully they can get STEREO B back up and running. I think there was going to be a planned attempt once it is nearest to Earth unless that was scrapped.

[Newbie]

49 minutes ago, Jesterface23 said:

Hopefully they can get STEREO B back up and running. I think there was going to be a planned attempt once it is nearest to Earth unless that was scrapped.

That was the plan to re establish communication. It was meant to be making it's closest approach this year, I thought it was around August. Already September now and no word. The satellites sit at L4 and L5 in heliocentric orbits where dust and asteroids also gather due to stable orbit and which might explain why STEREO B took a hit.

STEREO A and B first reached a point 180° apart in their respective orbits, affording the first full 360° view of the Sun, on February 6, 2011. If only...

N.

[Drax Spacex]

1 hour ago, Newbie said:

It was meant to be making it's closest approach this year, I thought it was around August. Already September now and no word.

N.

I think the next closest approach of STEREO B will be in July, 2023.

You can use this online tool to see the location of Stereo A and Stereo B on a particular date:

https://stereo-ssc.nascom.nasa.gov/cgi-bin/make_where_gif

Edited September 6, 2022 by Drax Spacex
correction

[Newbie]

13 minutes ago, Drax Spacex said:

I think the next closest approach of STEREO B will be in July, 2023.

You can use this online tool to see the location of Stereo A and Stereo B on a particular date:

https://stereo-ssc.nascom.nasa.gov/cgi-bin/make_where_gif

That's a good graphic Drax Spacex Thanks. My information came from someone in NASA last year. The re-establishment of comms. was planned for this year. There may have been reasons pertaining to the orientation of the satellite that they were making the attempt this year. 

N.