Shuttle - looking dirty

Gidday!

I know that there are a lot more important problems to worry about with the
return to flight but after trolling through various images on the Nasa site,
one thing that stands out, in particular with the night shots of Discovery
on the launch pad, is how dirty or marked Discovery appears.

During the time that its taken to prepare for the return to flight, wouldn't
Nasa have wanted to paint the shuttle, if not for protection, just for
public relations? If you think of Discovery as the Space equivalent of Air
Force 1, then comparatively every shot you ever see of Air Force 1 shows it
in pristine condition. Are all the Orbiters like Discovery?

As I say, I know there are more important issues but this is just something
I've noticed and thought that people who know much more in this area than I
do (I'm just an enthusiast from Oz) could shed some light on.

Regards,

David.

"David" wrote in message
...
Gidday!

I know that there are a lot more important problems to worry about with
the
return to flight but after trolling through various images on the Nasa
site,
one thing that stands out, in particular with the night shots of Discovery
on the launch pad, is how dirty or marked Discovery appears.

During the time that its taken to prepare for the return to flight,
wouldn't
Nasa have wanted to paint the shuttle, if not for protection, just for
public relations? If you think of Discovery as the Space equivalent of Air
Force 1, then comparatively every shot you ever see of Air Force 1 shows
it
in pristine condition. Are all the Orbiters like Discovery?

As I say, I know there are more important issues but this is just
something
I've noticed and thought that people who know much more in this area than
I
do (I'm just an enthusiast from Oz) could shed some light on.

You're kidding, right? Besides the added weight of the paint (e.g. the
first ET's were painted white, but the paint was dropped when it was decided
it wasn't needed to protect the spray on foam insulation), you really don't
want bits of paint, seared by launch heating, to fleck off while in orbit.
Finally, the paint wouldn't likely survive reentry anyway, at least on the
areas that get the highest heating, so you'd have to paint it after every
flight.

Jeff
--
Remove icky phrase from email address to get a valid address.

one thing that stands out, in particular with the night shots of
Discovery
on the launch pad, is how dirty or marked Discovery appears.

I thought dirt on airplanes caused aerodynamic issues, such as a loss of
performance. Is this not true?

Walter

"David" wrote in message
...
Gidday!


During the time that its taken to prepare for the return to flight,
wouldn't
Nasa have wanted to paint the shuttle, if not for protection, just for
public relations? If you think of Discovery as the Space equivalent of Air
Force 1, then comparatively every shot you ever see of Air Force 1 shows
it
in pristine condition. Are all the Orbiters like Discovery?

Its not a simple as running the shuttle through a paint barn like they do
with airliners. The tiles are colored so it would mean replacing the tiles
with new tiles.

I remember a few years ago when NASA changed their logo back to the blue
"meatball", this meant changing it on all of the orbiters and I seem to
recall that it was quite an ordeal. I think it needed to be done during a
major modification period at Palmdale rather than at KSC.

To answer your question: Yes, all of the other orbiters look like Discovery
after a few flights in space. This is just the wear and tear of re-entry.

JD

On Tue, 19 Jul 2005 08:25:38 -0500, Walter L. Preuninger II wrote
(in article ):

one thing that stands out, in particular with the night shots of
Discovery
on the launch pad, is how dirty or marked Discovery appears.

I thought dirt on airplanes caused aerodynamic issues, such as a loss of
performance. Is this not true?

Walter


Aircraft spend their entire lifetimes operating inside the atmosphere
and everything about them is a compromise weighted toward reducing
operating costs over their lifetimes. A few dollars' worth of fuel
saved per day adds up to substantial savings over 20 years of
operations. That makes it worth washing them every so often.

The Orbiter spends so little time accelerating through dense atmosphere
that any drag due to surface dirt is entirely inconsequential. Surface
drag from the tiles themselves as well as the lower-temperature thermal
blankets is much higher than any drag attributable to dirt.

--
"Fame may be fleeting but obscurity is forever."
~Anonymous
www.angryherb.net

Walter L. Preuninger II wrote:
one thing that stands out, in particular with the night shots of
Discovery
on the launch pad, is how dirty or marked Discovery appears.

I thought dirt on airplanes caused aerodynamic issues, such as a loss of
performance. Is this not true?


It's not dirt on the orbiter. It is thin sheen
of surface contamination deposited by the effects
of reentry heating. The deposits include calcium
and zinc oxide from gap filler materials and
RTV, bits of melted metal from surface-mounted
sensors, aluminum oxide deposited by the SRBs,
etc. Some of this stuff becomes embedded in
the outer layers of the TPS so that it can't
easily be cleaned.

- Ed Kyle

On Tue, 19 Jul 2005 20:42:05 +1000, "David"
wrote:


During the time that its taken to prepare for the return to flight, wouldn't
Nasa have wanted to paint the shuttle, if not for protection, just for
public relations?

You don't paint tiles that are going to be scorched by re-entry. It
would just make a much bigger mess.

Like they say about masonry walls - if you don't paint it you'll never
have to paint it again.

"Burnham Treezdown" wrote in message
...
On Tue, 19 Jul 2005 20:42:05 +1000, "David"
wrote:


During the time that its taken to prepare for the return to flight,
wouldn't
Nasa have wanted to paint the shuttle, if not for protection, just for
public relations?

You don't paint tiles that are going to be scorched by re-entry. It
would just make a much bigger mess.

Like they say about masonry walls - if you don't paint it you'll never
have to paint it again.

Thanks to everyone for their reply and clearing that up - What material are
the actual white parts of the shuttle made of?

Regards,

David.

"David" wrote in message
...

"Burnham Treezdown" wrote in message
...
On Tue, 19 Jul 2005 20:42:05 +1000, "David"
wrote:


During the time that its taken to prepare for the return to flight,
wouldn't
Nasa have wanted to paint the shuttle, if not for protection, just for
public relations?

You don't paint tiles that are going to be scorched by re-entry. It
would just make a much bigger mess.

Like they say about masonry walls - if you don't paint it you'll never
have to paint it again.

Thanks to everyone for their reply and clearing that up - What material
are
the actual white parts of the shuttle made of?


"it depends"

In many cases, the heat resistant tiles.

On tops of the wings tends to be a felt-like blanket.

Not sure about areas like the payload bay doors.

Check out Jenkin's "Space Shuttle" for a good read on it all.


Incidently, the underside especially ends up looking "used" after a few
flights... lots of gray streaks,etc.


Regards,

David.

I'd also imagine that any tiles that do get too damaged are replaced, and
those would no doubt look entirely different to older ones as well.

I heard that an awful lot of the damage is in fact on landing from muh and
rubbish kicked up. also, the rear parts get damaged at launch.

So what exactly causes the streaking?

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Greg D. Moore (Strider)" wrote in message
k.net...

"David" wrote in message
...

"Burnham Treezdown" wrote in message
...
On Tue, 19 Jul 2005 20:42:05 +1000, "David"
wrote:


During the time that its taken to prepare for the return to flight,
wouldn't
Nasa have wanted to paint the shuttle, if not for protection, just for
public relations?

You don't paint tiles that are going to be scorched by re-entry. It
would just make a much bigger mess.

Like they say about masonry walls - if you don't paint it you'll never
have to paint it again.

Thanks to everyone for their reply and clearing that up - What material
are
the actual white parts of the shuttle made of?


"it depends"

In many cases, the heat resistant tiles.

On tops of the wings tends to be a felt-like blanket.

Not sure about areas like the payload bay doors.

Check out Jenkin's "Space Shuttle" for a good read on it all.


Incidently, the underside especially ends up looking "used" after a few
flights... lots of gray streaks,etc.


Regards,

David.