When does the Pilot and Commander get to do their Walk Around?

Well, float around.

The Pilot and Commander are going to do their walk around? You know kick
the tires, look for dents in the aerosurfaces, pull off any debris, ...

Most good pilots do a walk around don't they?

--
Craig Fink
Courtesy E-Mail Welcome @

Craig Fink wrote in
news
Well, float around.

The Pilot and Commander are going to do their walk around? You know kick
the tires, look for dents in the aerosurfaces, pull off any debris, ...

They already did one on flight day 2, and are planning to do another on
flight day 11 (port wing) and 12 (starboard wing and nose cap).

Except they're doing it from inside the cabin, using the RMS/OBSS, and
they're delegating the arm work to Lisa and Stephanie.

And they're not planning to kick the tires until they're on the ground.
Would be pretty stupid to try that in orbit, since the gear can't be
retracted in flight once deployed.

--
JRF

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

Craig Fink wrote:


Well, float around.

The Pilot and Commander are going to do their walk around? You know
kick
the tires, look for dents in the aerosurfaces, pull off any debris, ...

Most good pilots do a walk around don't they?

Kicking the tires? That’s a good one! Considering that it's Zero-G and the
tire kicks back at you with the same force I doubt they'd want to do that
...


--
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On Thu, 13 Jul 2006 04:13:10 +0000, DA wrote:

Craig Fink wrote:


Well, float around.

The Pilot and Commander are going to do their walk around? You know
kick
the tires, look for dents in the aerosurfaces, pull off any debris, ...

Most good pilots do a walk around don't they?

Kicking the tires? That’s a good one! Considering that it's Zero-G and the
tire kicks back at you with the same force I doubt they'd want to do that
..


Well, yeah. A figure of speech, but there is debris hanging out on the
heat shield which may significantly reduce their heat load margin on
entry. The study by the MMT did indicated that it could bring them right
to their limit, a good reason to remove it. Even thought the Orbiter has
probably flown every mission except one (the last one) with gap fillers
hanging out, doesn't mean they have to continue doing it. Flying at
possibly 98% heat load instead of 80%, because some analytical study says
you can.

It's more of a philosophical issue. Has the NASA culture really changed?

Also, a philosophical issue about who is "in charge" of the vehicle,
especially when safety is concerned? The Commander or Flight Director (or
MMT)? NASA seems to be going against a Millennium or two of tradition
where the Commander is in charge of "his" vessel and crew. I'd guess
because communications has improved making the distance much closer. Well,
that's about to change again, if we go to Mars where communication times
are, and will always be, much longer.

Is the Commander of Discover free to go for a walk around, kick the tires,
pull off the debris and wiggle the tiles around it. To make sure the glue
that's holding them on doesn't have the same problem that the gap filler
glue has? Or, is this particular safety issue the responsibility of the
Flight Director, who's making it from the relative safety of his chair in
a windowless building. Exactly who decided a study was the proper thing to
do instead of removing the debris and wiggling the tiles?

--
Craig Fink
Courtesy E-Mail Welcome @

On Wed, 12 Jul 2006 21:38:29 -0500, Jorge R. Frank wrote:

Craig Fink wrote in
news
Well, float around.

The Pilot and Commander are going to do their walk around? You know
kick the tires, look for dents in the aerosurfaces, pull off any
debris, ...

They already did one on flight day 2, and are planning to do another on
flight day 11 (port wing) and 12 (starboard wing and nose cap).

Except they're doing it from inside the cabin, using the RMS/OBSS, and
they're delegating the arm work to Lisa and Stephanie.

Yes, and they found problems with gap fillers, before some other
astronauts went outside on three separate space walks. The last ending
with plenty of air in the tank to go pull the gap fillers out. Instead of
just fixing a very simple problem, NASA gathers together a team to do a
study. The findings of the study being, in the worst case they are only 5
degrees below their heat load limit. In my other posting I was being
generous with the 80% heat load to 98% heat load. From the numbers they
quoted to the press, its more like going from 50% heat load to 98% heat
load, worst case.

This is the heat load that soaks into the structure over time, on the
bottom of the Orbiter. This is the structure that is in tension, the part
of the structure that keeps the wings from falling off when lift is
applied to the wings. So late in the flight, when the structural
temperatures are getting their highest, the Orbiter is flying around the
hack, pulling the most gees. Using that structure at it's weakest point
due to temperature.

To me, it looks like NASA is choosing to fly a high structural loads entry
(higher temperatures weaken the structure), because no one can point to a
requirements violation. PreColumbian thinking. One of the touchy-feely
things that you know just can't be right.

An analogy would be, if during my preflight checkout of my Cessna 152, I
notice a bird's nest between two of the cylinders. Instead of pulling it
out and being on my way, I send Cessna some pictures and ask them about
it. They go off and do a bunch of studies and come the conclusion that
engine won't overheat, worst case it's going to be at 98% of it's maximum
allowable temperature. So, what should I do? Hop in the plane and head
out, secure in the knowledge that the engine won't overheat. Or, pull the
nest out and be happy, secure in the knowledge that the plane is in the
best possible shape to complete my flight?

It's much better and safer to save the structural/heat load margin for
some unknown failure that might occur on entry, than to use it all up on a
known defect that is extremely easy to fix.

Personally, I think the gap fillers burn off rather quickly. You can see
the Shockwave V pattern on the tiles from previous flights. With the
thickness of the lines of the V being related to Mach range and the time
it takes to burn off. But, it's more of a philosophical safety issue. A
known defect, that when fixed would increase margins, reduces long term
structural fatigue and improve the safety of this and future flights.

--
Craig Fink
Courtesy E-Mail Welcome @

Today's MMT press briefing was interesting, saying they wanted to collect
good data on the gap fillers. This would be the first time knowing exactly
what is hanging out before entry, and have sensors downstream to see how
they effect the boundary layer. They've lost a total of about a thousand
gap fillers on previous missions and want to know how they really effect
the boundary layer.

Much better than saying, no problem with flying at 98% structural heat
load.

I wonder if the sensors are on the surface of the tile, or attached to the
structure under the tiles. On the surface of the files, would be much
better for determining what is really going on. They wouldn't have the
huge time lag that would average or reduce the resolution of the data.

That way they could tell if it's the Shockwave (V pattern that shows up on
the heat shield) created by the debris that can trip the boundary layer.
And if the boundary layer returns to normal after the debris burns off.
With debris, maybe the boundary layer is already turbulent at Mach 25, but
the heating is really low because the density is extremely low. Then the
debris burns off and flow returns to laminar.

--
Craig Fink
Courtesy E-Mail Welcome @

in article , Craig Fink at
wrote on 7/14/06 5:25 AM:

On Wed, 12 Jul 2006 21:38:29 -0500, Jorge R. Frank wrote:

Craig Fink wrote in
news
Well, float around.

The Pilot and Commander are going to do their walk around? You know
kick the tires, look for dents in the aerosurfaces, pull off any
debris, ...

They already did one on flight day 2, and are planning to do another on
flight day 11 (port wing) and 12 (starboard wing and nose cap).

Except they're doing it from inside the cabin, using the RMS/OBSS, and
they're delegating the arm work to Lisa and Stephanie.

Yes, and they found problems with gap fillers, before some other
astronauts went outside on three separate space walks. The last ending
with plenty of air in the tank to go pull the gap fillers out. Instead of
just fixing a very simple problem, NASA gathers together a team to do a
study. The findings of the study being, in the worst case they are only 5
degrees below their heat load limit. In my other posting I was being
generous with the 80% heat load to 98% heat load. From the numbers they
quoted to the press, its more like going from 50% heat load to 98% heat
load, worst case.

This is the heat load that soaks into the structure over time, on the
bottom of the Orbiter. This is the structure that is in tension, the part
of the structure that keeps the wings from falling off when lift is
applied to the wings. So late in the flight, when the structural
temperatures are getting their highest, the Orbiter is flying around the
hack, pulling the most gees. Using that structure at it's weakest point
due to temperature.

To me, it looks like NASA is choosing to fly a high structural loads entry
(higher temperatures weaken the structure), because no one can point to a
requirements violation. PreColumbian thinking. One of the touchy-feely
things that you know just can't be right.

An analogy would be, if during my preflight checkout of my Cessna 152, I
notice a bird's nest between two of the cylinders. Instead of pulling it
out and being on my way, I send Cessna some pictures and ask them about
it. They go off and do a bunch of studies and come the conclusion that
engine won't overheat, worst case it's going to be at 98% of it's maximum
allowable temperature. So, what should I do? Hop in the plane and head
out, secure in the knowledge that the engine won't overheat. Or, pull the
nest out and be happy, secure in the knowledge that the plane is in the
best possible shape to complete my flight?

It's much better and safer to save the structural/heat load margin for
some unknown failure that might occur on entry, than to use it all up on a
known defect that is extremely easy to fix.

Personally, I think the gap fillers burn off rather quickly. You can see
the Shockwave V pattern on the tiles from previous flights. With the
thickness of the lines of the V being related to Mach range and the time
it takes to burn off. But, it's more of a philosophical safety issue. A
known defect, that when fixed would increase margins, reduces long term
structural fatigue and improve the safety of this and future flights.

Or you could look at this as an experimental flight and purposely leave the
well studied gap fillers protruding so you can compare before and after
pictures of the tiles in the area. In this way there is a better chance of
reaching your goal of "improve the safety of this and future flights."

George Evans