Forwarded message below at Bill's request.
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
<http://www.cesaronitech.com/> http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
---------- Forwarded message ----------
From: William Claybaugh <wclaybaugh2@xxxxxxxxx
<javascript:_e(%7B%7D,'cvml','wclaybaugh2@xxxxxxxxx');> >
Date: Friday, November 6, 2015
Subject: Nels Anderson data request
To: Arocket@xxxxxxxxxxxx
<javascript:_e(%7B%7D,'cvml','Arocket@xxxxxxxxxxxx');>
My regular email server is under DDOS attack and so I have neither been
receiving or replying to arocket posts.
A review of the archive showed that Nels had asked for the data backing up
the assertion that the 1980 - 2010 space launch data set shows a liquid
failure rate double the solid motor failure rate; I'd like to try and reply
to that request:
The organizations for which I--twice--developed this data set paid a very
great deal of money to get it done; naturally, I did not take a copy when I
left each of those organizations.
Building a accurate data set required access to the private data of three
space insurance companies; after reconciling those, it was necessary to
further reconcile that "master" data set against a classified data set.
This is because, 1) despite treaty obligations, not all launches to earth
orbit are registered with the UN, and, 2) failed attempts are sometimes not
announced--particularly during the first decade of this timeframe. Further,
the binning of failure modes into GN&C, liquid, or solid caused often
requires access to classified analysis for certain foreign systems.
Obviously, it is not possible to reconstruct this data set for public
release; further, any data set based only on publicly available information
is certain to underrepresent the overall failure rate and, particularly, the
cause of failures.
That said, there are certain conclusions that have been publicly drawn from
the comprehensive data: that overall, the failure rate is just under 10%,
that after GN&C failures liquid rocket bits account for about 2/3 of the
remainder and solid motors for 1/3; it is also public knowledge that half of
all failures occur in the first 14 launches of new vehicles--the long run
failure rate is less than 5%. This last observation is the technical basis
for NASA requiring 14 consecutive successful launches before it will
contract to fly it's most valuable payloads on a new vehicle.
We might also note the Aerospace Corporation observation that launch
failures are initially design or manufacturing failures but after about a
dozen launches failures tend to be process failures.
Bill
