Ken,
Please don’t say you’re not trying to turn this discussion into a heated
debate because that’s exactly what you were doing - read back your posts – it’s
not subtle!
Fortunately this list is wise enough to appreciate that with propulsion systems
(as with many other things), there are horses for courses. Some things are
suited to solids, some are suited to liquids and others are suited to hybrids
and other. For a long time now we’ve all moved on from the narrow-minded “my
favourite system is the only choice worth considering” due to these (cherry
picked) stats.
I think there’s general agreement here for quite some time now that liquids are
the only sensible option for manned launch vehicles. There’s little to be
gained by jumping up on a soap box here (repeatedly) and preaching that. Maybe
save your efforts for your local congressional representative?
Troy
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On ;
Behalf Of roxanna Mason
Sent: Wednesday, 29 April 2020 10:49 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Restart-able solid rocket motors for cubesats
No Bill, just talking about propulsion failures. Also the liquid core had a
leak to failure in another flight, but I'm not really trying to turn this
discussion into a heated debate just showing both systems are not perfect..
On another topic completely for early am tomorrow:
Asteroid
<https://www.ucf.edu/news/asteroid-visiting-earths-neighborhood-brings-its-own-face-mask/>
1998 OR2, a 1.2 mile (2 kilometer)-wide space rock. And though the asteroid is
on the list of potentially hazardous objects (PHOs), the April 29th pass at
0.042 Astronomical Units (AU) from Earth at 9:56 Universal Time (UT)/5:56 AM
Eastern Daylight Saving Time (EDT),
dawn your hardhats.
On Tue, Apr 28, 2020 at 5:42 PM William Claybaugh <wclaybaugh2@xxxxxxxxx
<mailto:wclaybaugh2@xxxxxxxxx> > wrote:
Ken:
Are you intentionally overlooking the three Titan 4’s lost due to other
failures?
Facts matter: One SRB failure in 78 flights vs. three other failures in 39
flights; one in 78 vs. one in 13. It is not SRB failures that drove
reliability in that vehicle.
Bill
On Tue, Apr 28, 2020 at 5:51 PM roxanna Mason <rocketmaster.ken@xxxxxxxxx
<mailto:rocketmaster.ken@xxxxxxxxx> > wrote:
FYI, Another major solid failure on a Titan 4,:an SRM exploded at T+101s.
Non tit for tat but it seem liquids are inordinately successful despite their
complexity. I think as time passes this discussion will fade as
Space X all liquids dominates the west and Russia the other side with China the
wild card pending the outcome of the new deal with US and the virus.
On Tue, Apr 28, 2020 at 3:20 PM William Claybaugh <wclaybaugh2@xxxxxxxxx
<mailto:wclaybaugh2@xxxxxxxxx> > wrote:
Sigh.
As I have posted many times before, a careful analysis of all space launches
worldwide between 1980 and 2010 shows that liquid stages (of space launch
vehicles) fail twice as often as solid stages.
Even if we ignore all non-western launches, liquid stages still fail more
often, although not quite twice as much.
The reason for this difference appears to be complexity. An open question—for
which there is some statistical evidence—is whether reuse improves reliability,
a potential advantage that would tend to favor liquid stages.
Bill
On Tue, Apr 28, 2020 at 4:03 PM roxanna Mason <rocketmaster.ken@xxxxxxxxx
<mailto:rocketmaster.ken@xxxxxxxxx> > wrote:
On the liquid side of the equation let's throw in the liquid Centaur, almost
100% except for that pesky purge failure where the turbopump iced up preventing
its start up. So a know failure mode led to a reliable fix a hindsight issue of
fixing something that worked just fine.
On Tue, Apr 28, 2020 at 2:51 PM Henry Spencer <hspencer@xxxxxxxxxxxxx
<mailto:hspencer@xxxxxxxxxxxxx> > wrote:
On Tue, 28 Apr 2020, George Herbert wrote:
I would add the Titan III and IV solids to those numbers. Segmentation
is a good breakpoint.
