Well, as it turned out, Johnson was right. I think that the LAS for
Orion is horrific.
On 2020-01-03 10:22, Henry Spencer wrote:
On Fri, 3 Jan 2020, Rand Simberg wrote:
Yes, but they did have to "man rate" Redstone, Atlas, and Titan II (of
the same vintage) to put people on top. They didn't just pull one off
the assembly line...
In fairness, though, much of that was the result of the dismally bad
reliability of Atlas at the time. (Deke Slayton once said that, early
in Project Mercury, everyone expected that at least one astronaut
riding an Atlas would have to use the escape system.) Assembly-line
Atlases really were unsuited for manned flight, then. And that set
the pattern -- all subsequent launchers had to be "man-rated".
(Similarly, because Mercury obviously needed a highly-capable escape
system to fly on Atlas, subsequent manned spacecraft had to have one.
Caldwell Johnson, one of the main designers of the Apollo spacecraft,
argued that Apollo didn't need an escape tower, since it was going to
fly on a properly-designed rocket.)
And they had problems with Titan due to POGO.
Essentially all large rockets of the time had Pogo problems, of
varying severity. The Saturn V was never entirely cured of its
upper-stage Pogo, which once (Apollo 13) came within a hair's breadth
of catastrophic launch failure. Modern preference is to just
automatically put a Pogo suppressor on any large liquid-fuel engine,
without waiting to see whether Pogo shows up in flight.
Henry
