In article ,
Pat Flannery wrote:
At one point they show footage of what appears to be a Atlas-Agena (it's
from quite a distance, so it's a bit hard to be certain) in which the
unfueled rocket is sitting on the pad when the Agena falls off the top
as the Atlas suffers a Lox tank failure and comes apart like shredding
aluminum foil- does anyone know about this particular incident?

As it happens, the September issue of Spaceflight had an article by Joel
Powell on "unreported Atlas depressurization accidents".

You probably saw the Atlas-Agena collapse sequence from the Vandenberg PAO
videotape "30 Years of Glory", which was unidentified for a number of
years. It's now thought to have been Atlas 190D, destroyed 11 May 1963,
probably during facilities checkout or crew training in preparation for
the first KH-7 GAMBIT launch (which occurred two months later). The Agena
and payload do not seem to have been flight hardware.

Did the Lox tank lose it's nitrogen stabilizing pressure, or was it
over-pressurized and rupture?

A gas bubble in the plumbing created a hydraulic ram effect that damaged
the LOX plumbing connections to the Atlas. The launch crew managed to
drain the LOX tank but ended up depressurizing it in the process, and so
it collapsed, dropping the Agena. The still-full Atlas RP-1 tank then
split and spilled, but fortuitously there was no fire or explosion, and
after cleanup the pad needed only minor repairs.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |