Jim Davis wrote:

The number probably reads 67D, which would make it the unmanned
Mercury-Atlas 2 (MA-2) launch of February 21, 1961.


Speaking of Atlas rockets- last night I was watching the Discovery Wings
channel, and their program "Secret Satellite" about the Corona program.
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? Did the
Lox tank lose it's nitrogen stabilizing pressure, or was it
over-pressurized and rupture?
It might have been a Thor-Agena, but it looked more Atlas-Agena to me.

Pat