Faulty hardware found on shuttle

"Bruce Palmer" wrote in message
. net...
Exeter wrote:

"WASHINGTON NASA said Monday that two pieces of hardware were
installed incorrectly on the space shuttle Discovery and that such a
mistake could have resulted in the loss of the spacecraft and its crew
during a landing."

http://www.usatoday.com/news/nation/...le-probs_x.htm


"Welcome home Discovery! First Shuttle landing in over two years! Oh
****!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!"

Exeter wrote:
mistake could have resulted in the loss of the spacecraft and its crew
during a landing."

http://www.usatoday.com/news/nation/...le-probs_x.htm


Fro what I read, it was some sort of a cogged wheel that could be inserted
either way in the mechanism, which allowed the actuators to switch from being
port or starboard mounted, and they found one unit with that cogged wheel
inserted the wrong way.

While this is definitely a "mistake", I have to wonder: Wouldn't the actuator
have broken/failed the first time the speed btake was tested/used ? If it
lasted 30 flights (and I woudl assume lots of testing during orbiter
maintenance) without anyone noticing any performance problem, wouldn't this
mean that an inverted gear didn't really make such a big difference ?

Secondly, lets say that one side of the speed brake failed and didn't deploy,
but the other did. (isn't that worse case scenario ?)

At the time the speed brakes are deployed, is the nosewheel already on the
ground ? Would an asymetric speed brake veer the shuttle into an aligator
swamp, or could it maintain its course on the runway ?

Would the decreased braking result in the shuttle overshooting the runway, or
would it just have to rely on the parachute and wheel brakes more ?

Bruce Palmer wrote:

Exeter wrote:

Disturbing on many levels.


I have an idea how to expand the "Civilians In Space" program. Screw
the teachers, when the CEV is built I propose that the first manned
flights include one crewmember from the design and engineering teams.
Hell, if they decide to include auto-land functionality in the CEV then
the initial manned test flights should be crewed entirely by contractor
personnel.

--
bp
Proud Member of the Human O-Ring Society Since 2003



Igor Sikorski was quoted something like,

"There are good designers with good designs,
good designers with bad designs,
bad designers with good designers
and bad designers with bad designs.

If designers flew their own designs,
there would soon be only good designers
with good designs."

Pretty cocky, huh?

As an experienced amateur aircraft designer,
given to occasional fits of introspection,
and one who flies his own design,
I often wonder where I fit in that list.



Richard Lamb

http://www.flash.net/~lamb01

For the gory details of the
Trials and Tribulations
of designing and building
a super simple little airplane.

Richard Lamb writes:

Igor Sikorski was quoted something like,

"There are good designers with good designs,
good designers with bad designs,
bad designers with good designers
and bad designers with bad designs.

If designers flew their own designs,
there would soon be only good designers
with good designs."

Pretty cocky, huh?

As an experienced amateur aircraft designer,
given to occasional fits of introspection,
and one who flies his own design,
I often wonder where I fit in that list.

Since you're still alive, Igor would say your design is good. It says
little about whether or not you're a good designer, because bad
designers can have good designs. Build and fly a few more
experimental aircraft and Igor might say that you're a good designer,
if you live through all the test flights. ;-)

Jeff
--
Remove "no" and "spam" from email address to reply.
If it says "This is not spam!", it's surely a lie.

I have an idea how to expand the "Civilians In Space" program. Screw
the teachers, when the CEV is built I propose that the first manned
flights include one crewmember from the design and engineering teams.
Hell, if they decide to include auto-land functionality in the CEV then
the initial manned test flights should be crewed entirely by contractor
personnel.

--
bp
Proud Member of the Human O-Ring Society Since 2003

You're pretty callus to think that the contractors don't care about the
lives of the astronauts. I don't think making a contractor fly first would
have any impact into the design and build of the new craft.

"John Doe" wrote in message:

At the time the speed brakes are deployed, is the nosewheel already on the
ground ? Would an asymetric speed brake veer the shuttle into an aligator
swamp, or could it maintain its course on the runway ?

The speed brakes are used long before landing, with control being
provided between Mach 10 to 5. The rudder is still functional when the
speedbrake is deployed.

--
Sent to you by Ken at
Replace "who?" with "b2" to reply by e-mail.

jeff findley wrote:

Richard Lamb writes:

Igor Sikorski was quoted something like,

"There are good designers with good designs,
good designers with bad designs,
bad designers with good designers
and bad designers with bad designs.

If designers flew their own designs,
there would soon be only good designers
with good designs."

Pretty cocky, huh?

As an experienced amateur aircraft designer,
given to occasional fits of introspection,
and one who flies his own design,
I often wonder where I fit in that list.

Since you're still alive, Igor would say your design is good. It says
little about whether or not you're a good designer, because bad
designers can have good designs. Build and fly a few more
experimental aircraft and Igor might say that you're a good designer,
if you live through all the test flights. ;-)

Jeff
--
Remove "no" and "spam" from email address to reply.
If it says "This is not spam!", it's surely a lie.

I've done eight of 'em in 15 years.

Faulty hardware is something we deal with all the time.
Most often from service wear.
Especially in hard use.
Sometimes for maintenance errors.
Occassionally from design faults, metal fatugue, overstress, etc.

It just comes along for free when you mave to make complez
machinery that is light enough to fly.

But even a Boeing 7^7 is only a pale glimmer of the complexity
involved in designing and building something on the level of
the Orbiter.

As much as I know about airplanes, I _know_ I'm not qualified to
question whether some system may or may not have been needed.

Especially on the first design - ever.

Forgive me if you can, but this whole thread reads like a Monday
morning criticism by someone with too much detailed knowledge
about one tiny piece of a huge 3D puzzle.


But that's just me.
I could be wrong.

Richard

"Bruce Palmer"

How many other situations exist that nobody knows about?

A few hundred.

Why can't anyone pinpoint the reason no
inspection was previously done? Was it a requirement that was
overlooked?

The thing was assembled wrong. It was not obvious to casual observation.
One day a guy was looking at the tech manual and the assembly and said "Hey,
wait a minute....."

I propose that the first manned
flights include one crewmember from the design and engineering teams.

If this scheme were implemented, you'd still have a few parts put in
backwards.

Bruce Palmer wrote in
. net:

If this was the case with Columbia would it have made a difference?
"... in unusual situations such as an emergency landing, an actuator in
a crucial position could fail if it had upside-down gears."

In Columbia's case it probably wouldn't have made a difference given the
severity of damange to the left wing, but nobody really knows.

Nope, it can be said for sure it would not have made a difference. Columbia
broke up at Mach 18, long before the RSBs become active.

Last but not least... since "... the No. 4 actuator doesn't bear a
particularly heavy load", and Discovery has flown many times without
incident, it makes you wonder if the #4 actuator was necessary at all
from a design standpoint.

It is, if you want a design that has *margin* in it.

--
JRF

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

Richard Lamb wrote in
:

But even a Boeing 7^7 is only a pale glimmer of the complexity
involved in designing and building something on the level of
the Orbiter.

Actually, Boeing's modern 7*7 designs are comparable in complexity to the
orbiter. The biggest difference is that modern airliners have several
design generations behind them, so their designers have a pretty good idea
what works and what doesn't.

The orbiter is still essentially a first-generation design. If it's balky
and temperamental, it's mainly because its designers did *not* have a prior
experience base for reusable spacecraft.

--
JRF

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