SPECTACULAR -- observations of Soyuz launch [dec 15] from ISS, ground, air

Soyuz TMA-19M launch of Dec 15, 2015, created possibly most diverse collection of visual imaging observations of large-booster exoatmospheric plume effects ever recorded.

Here's my draft report for comment and suggestions.

The cultural impact of misinterpretations of such images around the world is pretty profound, too.

satobs.org...

a reply to: JimOberg

Wow, that's an impressive plume!

originally posted by: greencmp
a reply to: JimOberg

Wow, that's an impressive plume!

That looks like a giant space spermatozoa (can I say that here? )

a reply to: JimOberg

Your best ever contribution to ATS!
Take a bow!

originally posted by: greencmp
a reply to: JimOberg

Wow, that's an impressive plume!

The 'necklace' effect is directly traceable to second stage shutdown and the 'hot start' of stage 3, with the stage-2 plume falling behind at 3,000 meters/sec even as both stages are speeding at about 43% of orbital velocity, or about 3,500 meters/sec. That means the ejected combustion products have only a 500 meter/sec ground speed, but still forward.

Stage 3 takes a few seconds to emerge from its base atop stage 2, its plume splashes randomly off the stage 2. This interruption in the tailwards ejection creates that 'gap' in the pictures from the ground AND from the space station.

At an altitude of 170 km, with g = 10 meters/sec/sec, to fall back below the Karman line [100km] into 'sensible' atmosphere would take about 85 seconds, even as it expands and thins.

During that period of falling 70 km, the 2nd stage plume's front end forward velocity carries it 85 x 500 or ~40,000 meters [40 kilometers] down track.

This 'plume' is more like a comet's tail than ANYTHING we're familiar with down on Earth.

No wonder for thousands of people all over Earth who see such apparitions, the sight blows their minds.