And don't forget that a capsule has a good chance of bringing a crew home
alive its entry flight control system fails. This was THE requirement
that took NASA from winged vehicles back to capsules during the Orbital
Space Plane program. The entry without flight control requirement has
been watered down now, but a capsule will give the crew a good shot of
surviving a passive entry.

Right up until the parachute fails to open.

Or the de-orbit burn fails.

ultimately there are no truly passive systems. Just different re-entry
failures.

"Jorge R. Frank" <jrfrank@ibm-pc.borg> wrote:

2) All spacecraft have design flaws; unlike aviation, we have not gone
through enough design generations to weed them out. The staleness of the
current US experience base due to the long gap between design generations
increases the likelihood of a flaw in Orion.

It's not like we had a significant experience base to go stale in the
first place Jorge. Not only did the Mercury-Gemini-Apollo series
overlap each other to a large degree, they were all essentially first
generation systems.[1] Each program experienced significant flight
anomalies, and in Apollo's case, had at least two inflight failures
(15 docking, 17 SPS) that could easily have lead to LOM or LOCV.
2 inflight failures: What about Apollo 13 (exploded O2 tank)??

The brutal fact is that we only avoided losing more crews by sheer
good luck and the extremely limited number of flights. The
'experience base' and 'design generations' are non issues - because
niether existed then or now.

[1] In the sense that experience with one had only an extremely
limited 'feed forward' to the next.

D.

Before re-entry but not before the entry burn. Soyuz is committed
after the burn and *must* seperate cleanly. Shuttle can make sure
everything is good before committing to the burn.

Soyuz 5 had a failure to separate and the crew lived.

The mount between the
entry and orbit module failed due to heat and the entry capsule brought the
crew back alive. I tried to get a failure to separate requirement into the
system, but I was shot down. If you make the attachments out of aluminum
and expose them to the airstream, they should fail in time for the entry
capsule to flip around in time.

To a certain degree, yes. It will get mission designers back into the
practice of deep space operations sooner than a straight-to-Mars
project would, so we should (re-)learn many lessons before we start
the much higher risk Mars expeditions.

Going to the moon is like a weekend camping trip. Going to Mars is a real
expedition lasting more than a year.

Forget the word "re-entry" and I'd agree with you. There are MANY failure
modes in any complex system. Why worry about just the one phase?

Derek Lyons was zeer hard aan het denken :
"Jorge R. Frank" <jrfrank@ibm-pc.borg> wrote:

2) All spacecraft have design flaws; unlike aviation, we have not gone
through enough design generations to weed them out. The staleness of the
current US experience base due to the long gap between design generations
increases the likelihood of a flaw in Orion.

It's not like we had a significant experience base to go stale in the
first place Jorge. Not only did the Mercury-Gemini-Apollo series
overlap each other to a large degree, they were all essentially first
generation systems.[1] Each program experienced significant flight
anomalies, and in Apollo's case, had at least two inflight failures
(15 docking, 17 SPS) that could easily have lead to LOM or LOCV.

inflight failures: What about Apollo 13 (exploded O2 tank)??

On Wed, 7 Mar 2007 08:42:50 -0600, Jorge R. Frank wrote
(in article <Xns98EC58A4DD032jrfrank@216.196.97.131>):


2) All spacecraft have design flaws; unlike aviation, we have not gone
through enough design generations to weed them out

I would argue strongly that design flaws still exist in just about every
aircraft ever built and flown. They just haven't all bitten anyone on the
ass yet.

On Wed, 07 Mar 2007 14:04:17 -0500, John Doe <jdoe@doe.org> wrote:

To a certain degree, yes. It will get mission designers back into the
practice of deep space operations sooner than a straight-to-Mars
project would, so we should (re-)learn many lessons before we start
the much higher risk Mars expeditions.

Going to the moon is like a weekend camping trip. Going to Mars is a real
expedition lasting more than a year.

You forget, NASA isn't re-doing Apollo sorties. Their plan is to build
a moonbase beginning with Landing No.1. That, most decidedly, will be
useful for follow-on Mars operations. So will any sorties from the
Moonbase that later astronauts make for exploration missions. That
will really help pave the way for how to explore Mars.

"Jorge R. Frank" <jrfrank@ibm-pc.borg> wrote:

2) All spacecraft have design flaws; unlike aviation, we have not gone
through enough design generations to weed them out. The staleness of
the current US experience base due to the long gap between design
generations increases the likelihood of a flaw in Orion.

It's not like we had a significant experience base to go stale in the
first place Jorge.

André, PE1PQX <pe1pqx_geenviagra@planet.nl> wrote:

Derek Lyons was zeer hard aan het denken :
"Jorge R. Frank" <jrfrank@ibm-pc.borg> wrote:

It's not like we had a significant experience base to go stale in the
first place Jorge. Not only did the Mercury-Gemini-Apollo series
overlap each other to a large degree, they were all essentially first
generation systems.[1] Each program experienced significant flight
anomalies, and in Apollo's case, had at least two inflight failures
(15 docking, 17 SPS) that could easily have lead to LOM or LOCV.

inflight failures: What about Apollo 13 (exploded O2 tank)??

I discounted Apollo 13 because the accident was caused by component
damage during handling - unlike 15 and 17 where the causes are unknown
and could easily be failure modes which are rare but inherent to the
design. Apollo 13 type accidents from human error can happen even in
a mature program, 15 and 17 type incidents we cannot classify as the
causes are unknown.

D.

On Mar 7, 8:42 am, "Jorge R. Frank" <jrfr...@ibm-pc.borg> wrote:
"ed kyle" <edkyl...@hotmail.com> wrote
innews:1173244154.705840.40180@j27g2000cwj.googlegroups.com:

On Mar 6, 10:24 pm, "Jorge R. Frank" <jrfr...@ibm-pc.borg> wrote:
"ed kyle" <edkyl...@hotmail.com> wrote
innews:1173240759.534853.186140@c51g2000cwc.googlegroups.com:

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.

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.

This is all on paper, of course.

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.

On Wed, 7 Mar 2007 14:41:52 -0600, "Danny Deger"
dannydeger@hotmail.com> wrote:

Before re-entry but not before the entry burn. Soyuz is committed
after the burn and *must* seperate cleanly. Shuttle can make sure
everything is good before committing to the burn.

Soyuz 5 had a failure to separate and the crew lived.

STS-51C Discovery had o-ring blow-by and the crew lived...

You forget, NASA isn't re-doing Apollo sorties. Their plan is to build
a moonbase beginning with Landing No.1.

On Wed, 7 Mar 2007 15:12:11 -0600, Greg D. Moore \(Strider\) wrote
(in article <LUFHh.7498$PL.4233@newsread4.news.pas.earthlink.net>):

Forget the word "re-entry" and I'd agree with you. There are MANY failure
modes in any complex system. Why worry about just the one phase?

--
You can run on for a long time,
Sooner or later, God'll cut you down.
~Johnny Cash

"ed kyle" <edkyle99@hotmail.com> wrote in
news:1173283973.145899.139360@64g2000cwx.googlegroups.com:


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

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