Re: Future of Orion??

"ed kyle" <edkyle99@xxxxxxxxxxx> wrote in
news:1173283973.145899.139360@xxxxxxxxxxxxxxxxxxxxxxxxxxx:

On Mar 7, 8:42 am, "Jorge R. Frank" <jrfr...@xxxxxxxxxxx> wrote:
"ed kyle" <edkyl...@xxxxxxxxxxx> wrote
innews:1173244154.705840.40180@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:

On Mar 6, 10:24 pm, "Jorge R. Frank" <jrfr...@xxxxxxxxxxx> wrote:
"ed kyle" <edkyl...@xxxxxxxxxxx> wrote
innews:1173240759.534853.186140@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:

But it will fly. When it does, I think that it has a very good
chance
of proving to be the safest human launch system ever fielded.

I think Orion's chances of flying over fifty flights in its entire
operational lifetime are low, but assuming it does, its chances of
getting through its first 58 flights without a fatal accident
(which is what it will need just to match the shuttle's safety
record, currently the best of any manned spacecraft) are even
lower.

What makes you think that?

Several reasons. I've been thinking about it overnight to try to rank
them and right now this is the best I have:

1) Human error is the cause of 80% of aviation accidents and this
pattern is continuing in spaceflight. Out of five fatal accidents
(Apollo 1, Soyuz 1 and 11, STS-51L and 107), human error was a
primary cause of all but Soyuz 11. .... There is no reason to believe
that Orion will be immune to this.

2) All spacecraft have design flaws; ... And Orion already has one
obvious flaw, common to all current and historical capsules: the
necessity of jettisoning critical parts of the spacecraft during the
window between deorbit and entry interface. ....

3) Orion's projected flight rate is so low that I believe reusability
will prove to be non-viable. That means a big hit to component
reliability since Orion's systems will never get out of the "infant
mortality" part of the "bathtub curve."

I attribute at least some of the failures you mentioned
(the U.S. failures especially) to design flaws.

I don't. The design flaws were there, sure, and I consider them a primary
cause *if* they weren't known before flight. But in all three US
accidents, the flaws *were* known before flight (or ground test) and
conscious decisions were made to proceed nonetheless. In my opinion, that
makes the human error the primary cause and the design flaw a
contributing cause.

It is true that Orion won't be immune to any type of
failure, but I believe that it has a good chance of
being measurably safer than Shuttle and Soyuz and
Shenzhou, for the following reasons.

<snipped reasons for brevity>

This is all on paper, of course.

Good thing you included that disclaimer. The reasons you cite are all
reasons why Orion *should* *theoretically* be safer. The only way Orion
can *prove* itself safer is via flight record. I don't believe Orion will
ever fly enough to prove that; at NASA's projected flight rates, it won't
hit 58 flights until around 2040 or so.

Orion should, and
could, prove safer, but the development has a long
way to go. The CEV design was born with safety
as the primary design driver in the immediate wake
of the Columbia disaster. It remains to be seen if
safety will remain paramount during the execution
of the spacecraft's development phase.

Good thing you included that disclaimer too. Now you have something to
point back to after Orion has its first fatality.

--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.
.

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