Falcon 1 Staging Recontact - Engine Burp

Jeff Findley wrote:
"richard schumacher" wrote in message
...
A potential problem with single-impulse separation methods such as
springs arises if the first stage continues to generate thrust, because
it can then catch up with the second stage. This is exactly what
happened with the 3rd Falcon 1 flight.

On another discussion forum, Henry Spencer said this is almost exactly what
nearly happened during Apollo 15's S-IC separation, so naturally I went
digging for details.

http://history.nasa.gov/alsj/a15/a15mrp6.pdf

Quote from above:

Four of the eight S-IC retromotors and all of the S-II stage
ullage motors were removed for this flight; therefore, the
S-IC/S-II separation sequence was revised. This sequence change
extended the coast period between S-IC outboard engine cutoff
and S-II engine start command by one second. The S-IC/S-II
separation sequence and S-II engine thrust buildup performance
was satisfactory.

From what I understand, the above deleted motors were added back for
subsequent flights, but I can't find a PDF online to confirm this.

Apollo 16 press kit:

http://history.nasa.gov/alsj/a16/A16_PressKit.pdf

p. 140 (144 of the PDF):

Significant Vehicle Changes
Saturn vehicle SA-511 is similar in configuration to the
Apollo 15 launch vehicle. The first stage (S-1C) has eight retrorocket
motors, double the number on the SA-510 vehicle, because
flight evaluation of the Apollo 15 mission revealed that the
separation distance between the first and second stages was
less than predicted. Eight retrorockets will give a greater
safety margin should one motor fail during separation.

Apollo 17 press kit:

http://history.nasa.gov/alsj/a17/A17_PressKit.pdf

p. 94 (146 of the PDF):

The first stage has eight solid-fuel retro-rockets that
fire to separate the first and second stages. Each rocket
produces a thrust of 337,000 newtons (75,800 pounds) for
0.54 seconds.