The NPR News item I Spy, Via Spy Satellite: Melting Himalayan Glaciers discusses use of declassified historical satellite images that include glaciers, and link to the newly published and Open Access article in Science Acceleration of ice loss across the Himalayas over the past 40 years.

It also links to a short pdf fact sheet on the NRO's website Hexagon; America's Eye in Space which contains the image/infographic below.

I don't understand what's being illustrated for the first stage core and the two side boosters. The two boosters look to be very different from each other and have different names, and I can't figure out where the separation of the first stage of the core separates from the second stage. What is actually happening here?

from NRO's Hexagon; America's Eye in Space

  • 1
    $\begingroup$ It's a poor image. More shortly. $\endgroup$ Jun 20 '19 at 0:46

Here's a much better diagram (it's for Titan IIIe, but it's the same except for the upper stage, which doesn't feature in the question).

enter image description here

  1. Solid Rocket Motor (SRM) ignition followed by liftoff
  2. First stage ignition (trigger event: g-switches)
  3. SRM separation (trigger event: timer started by the g-switches)
  4. Second stage ignition / stage separation ("fire in the hole" staging) (trigger event: first stage propellant depletion)
  5. Payload shroud jettison (trigger event: timer started at first stage shutdown)
  6. Second stage shutdown / stage separation (trigger event: guidance system)

(Then the third stage does whatever it does)



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