On Wed, 31 Mar 2004, Henry Spencer wrote:

In article ,
Uddo Graaf wrote:
I read that the Russian N-1 moon rocket kept blowing up because the Russians
couldn't control the thrust of 30 rocket engines firing in tandem.

The N-1 had various problems -- it was different each time -- but it
wasn't anything as simple as being unable to control the engines. If
memory serves, the first two failures were actual mechanical failures in
the propulsion system, the third was a deliberate maneuver that wasn't
well thought out, and the fourth was an engine fire (at the very end of an
otherwise-successful first-stage flight).


The first flight of the N-1 on February 21, 1969 failed in part due to
mechanical problems; small metallic particles got lodged in the #2
engine's gas generator turbine. This in turn caused high frequency
oscillation, which resulted in engine components to wear out and tear off
their mounts. A propellant leak soon followed, a fire broke out not long
after. The KORD system detected the fire, but gave an incorrect signal
shutting down all of the engines at 68.7 seconds into flight. Range safety
destroyed the N-1 vehicle just 1.3 seconds later. Ironically the launch
escape system worked, and the 7K-L1S capsule was recovered.


The second flight on July 3, 1969 also involved a failure partially due to
the KORD system as well.


Metal slag fragments were ingested by the #8 engine's oxidzer turbopump at
just 0.25 seconds after liftoff. A fire soon broke out. and the KORD
reacted by shutting down the engines unecessarily in pairs until the
vehicle acceleration fell below 1G, and quickly fell back onto the launch
pad.


It is rather a shame that the Soviets could not get the N-1 to work, and
progress was being made, abeit slowly, in solving the massive rocket's
problems. The final flight lasted 106 seconds, and was a mere 7 seconds
from first stage seperation; a root cause was never identified for the
failure of the #4 engine oxidizer turbopump explosion. Had the seperation
between the first and second stages occured before the range safety
destruct, it is likely that the 7L flight would have been a success, and
the program could have continued.
-Mike