Jon S. Berndt wrote:
... Considering that (according to the original
article in TSR about SRBs used for a CEV launcher) the concept has
the
support of some in the astronaut office, and that strap-on SRBs would
be used anyway to supplement an Atlas or Delta Medium launcher for
CEV
(according to AvWeek, above), I feel that Dinerman shouldn't have
blown
off the concept so casually.

The overall reliability record is good for solid
boosters, but when they've gone, they've gone
nasty in a hurry. I'm thinking of the Titan 34D
in 1986, of a Titan 4 in the early 90s, and of
the Delta II during the late 90s and a Delta
during the late 70s. These all ended in big
detonations. That is why incorporating them into
manned launchers is so difficult.

Again: which one is safer, a single STS
SRB as a first stage, or a Delta IV or Atlas Medium with several
strap-on SRBs?


Single SRB is statistically more reliable. But is
it safer? Probably. On the other hand, an argument
can be made that neither SRB or EELV with solids
would be safer than an all-liquid system.

The problem with this editorial is that it starts out
arguing for a new heavy-lifter, but ends up talking
about whether solid boosters should be used for
manned launches. It would have been better to keep
the two topics separate.

Few will argue that solids shouldn't be used for
unmanned, heavy-lift launchers. That discussion is
about how big heavy-lifters should be - or whether
they're needed at all.

The solids-for-humans question is an entirely different
problem. The astronaut office is going to have a say
in this one. Right now, if sounds like the majority is
saying "no". It could be that we already have the heavy
launcher (EELV Heavy - just augmenting a little can get
it up to 30 tons to LEO) but that a new or derived
all-liquid Medium is needed to boost the 20 ton-ish CEV.
It could be a matter of adding a second RS-68 or RD-180
to the EELV boosters.

- Ed Kyle