Why our solar-storm sats corrode – and probably not what you expected Spacecraft monitoring the Sun for potentially deadly solar storms have been degrading – and now scientists think they've worked out why. Boffins at America's National Institute of Standards and Technology (NIST) and the University of Colorado Boulder's Laboratory for Atmospheric and Space Physics (LASP) have spent years trying …
They reject visible solar light, which is many orders of magnitude brighter than the extreme ultraviolet (EUV) light the instruments observe, while transmitting, as noted, most of the EUV light.
Why, you may ask, do we want instruments that observe EUV emission from the Sun? Most of it comes from the solar corona, the tenuous, outermost part of the Sun's atmosphere where a good deal of solar activity originates — and where variability in the solar output is much larger than in the visible.
Why, you may ask, do we want instruments that observe EUV emission from the Sun? Most of it comes from the solar corona, the tenuous, outermost part of the Sun's atmosphere where a good deal of solar activity originates — and where variability in the solar output is much larger than in the visible.
Yup. UV plays a huge role in atmospheric photochemistry, so variations in UV would lead to variability in our atmosphere. Most commonly known one is probably the effect on ozone, and the ozone 'hole'. Understanding that variability helps us understand our atmosphere better, which then feeds into understanding our climate. Ripping from wiki-
https://en.wikipedia.org/wiki/Solar_irradiance
This means that the approximately circular disc of the Earth, as viewed from the Sun, receives a roughly stable 1361 W/m2 at all times.
Which is a typically bold assumption. We know from observations that gross output does vary by a few W/m2. For climate change, that leads into an 'effect exceeds cause' problem because the effect isn't energetic enough to really explain past (or present) climate change. Experiments like these do show variability in spectral output though, and we know different wavelengths have different effects on photochemisty from atmosphere down to plant life. What we don't have is a lot of data to show variability over time to draw meaningful conclusions from though.
Would it not be better to change the thermal blanket material to something less hygroscopic?
Is this a case of optical scientists only seeing the solution that is within their skill set?
Maybe both solutions together would give the filters a much longer life.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2025
