Did anybody capture good views of the 'ring of fire' effect (with
apologies to Eric Flint) just prior to MECO? Since the ring collapsed
at MECO I'm presuming it was the shock wave of the engine plume and
the upper atmosphere. Even though shot backwards at 3000 meters/sec,

Yep, think so too

the combustion productions were impacting ambient upper atmosphere at
about that same speed because the stack was nearly at orbital velocity
(8000 meters/sec).

The light was not the plume -- LH2/LO2 flame is essentially invisible.

Why it should be green is a bigger question -- I wonder about color
imbalance
in the low light level situation. Ground observers were seeing orange and
yellow-orange colors, not green -- and that's the proper wavelength for the

but it may be a color shift due to atmos extinction (affecting more the
shorter wavelenghts

source of the light, atomic oxygen recombination immediately following O2
dissociation from molecular impacts.

Some dim colorfule light was visible on daylight shoots before. It was
a high atmosphere impact plasma effect. As the ET camera this time was
tuned to dim light - the "green" glow maybe was the same, just less
visible on the daytime shoots.


Illumination at ET sep, on the other hand, was white -- the color of flares
from RCS jets.

I got the impression they used a serie of flashlights from the umbilical
doors to image the ET just after sep. Hm. I never read they build it in.
But should not be a secret. Good work anyway. Wonderfule images. Thats
the stuff I like. Was a good idea to stay up till 3 in the morning!



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