Re: Towed Booster Stability

From: Henry Spencer (henry_at_spsystems.net)
Date: 07/03/04 

Date: Sat, 3 Jul 2004 18:28:02 GMT

In article <0lrFc.11198$uK.4385@twister.tampabay.rr.com>,
Kim Keller <kimekeller@yahoo.com> wrote:
>...When's the last time a mature rocket design had problems staging? I
>can think of one Delta II that had an odd separation problem with an SRM
>that led to loss of mission, but that's about it. The Japanese separation
>problem not long ago was due to an immature design.

Since today's rockets seldom see huge production batches between design
changes, any failed rocket can be accused of being immature. This is
circular: if it works it's mature, if it doesn't it's immature! It's
fairer to just count all the failures, at least in orthodox modern
programs where the customers and stockholders are assured ahead of time
that everything has been analyzed to death, failures are most unlikely,
and so there is no need for a flight-test program.

Don't forget the second Pegasus XL (interstage ring initially failed to
separate, crippling nozzle gimbaling, and by the time it did finally fall
off, the guidance system had gotten hopelessly confused), the first PSLV
(attitude transients during separation of second stage confused guidance),
and the 1999 IUS failure (electrical connector didn't separate due to
thermal tape, preventing proper second-stage operation). IUS was mature
beyond doubt; the other two were upgraded vehicles, but the failures were
in areas with extensive design heritage from earlier ones. 

-- 
"Think outside the box -- the box isn't our friend."    |   Henry Spencer
                                -- George Herbert       | henry@spsystems.net

Relevant Pages