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Re: Columbia's safety margins misread, expert tells panel



Hello all.

>From what I have seen, it appears clear that the foam most likely with some
heavy ice attached to it had an impact that might have been enough to create
damage. It would have been nice if an EVA could have been done, seeing this
was a concern of NASA. Maybe in the future there will be EVA's or maybe a
remote camera that can be sent around the vessel.

It is a shame, but an awakening too.
These Shuttles are considered old, but there is a lot of old military and
civilian aircraft still in service. With new technologies available,
maybe we can have a space plane that launches off a 747 and get rid of one
of the potential dangers of space flight. That is the violent masses of
energy produced to get the Shuttle from ground to space.

Then again, we have a military exercise going on now in Iraq, and I am
sure that will be a hefty price tag!

My best to all our Military Service Personal!!


Just my 2 bits..

73, Scott



----- Original Message -----
From: "Bruce Bostwick" <lihan161051@earthlink.net>
To: <sarex@AMSAT.Org>
Sent: Wednesday, March 26, 2003 4:25 PM
Subject: Re: [sarex] Columbia's safety margins misread, expert tells panel


>
> On Wednesday, Mar 26, 2003, at 13:23 US/Central, John A. Magliacane
> wrote:
>
> > --- g6tmk <g6tmk@thersgb.net> wrote:
> >
> >> I don't believe I have heard anyone explain why it is that foam falls
> >> off
> >> the fuel tank during launch.
> >
> > This is just a GUESS based on some speculation I've heard, but perhaps
> > air leaks underneath the foam, becomes liquified as it comes in contact
> > with the supercooled external tank, then freezes (which causes the
> > frozen
> > air to expand) which in turn causes the foam to break away from the
> > tank
> > under the vibration of launch.
> >
> >
> > 73, de John, KD2BD
>
> I don't think liquefied air expands, although if any water vapor
> condenses on the tank it might swell up a bit on freezing, unless it
> condenses directly to frost which it usually does at those
> temperatures.  Water is about the only substance I know of whose volume
> increases when it turns solid .. almost everything else shrinks.
>
> As far as I know, the foam doesn't debond per se, it tends to scour due
> to the aerodynamic forces and sometimes gets weighed down with ice and
> breaks off when the humidity is high.  The early STS flights used ET's
> whose insulation was coated to control the scouring but this was
> omitted on later flights to save weight and allow slightly larger
> payloads, and unless I'm mistaken there are at least three insulation
> configurations for various ranges of payload weights.  STS-107 was
> flying a Spacelab mission and its payload was on the high side, so it
> got one of the lightest ET configurations.
>
> The piece that hit the left wing looked like about the largest piece
> I've ever seen fall off an ET, but I haven't seen much launch film
> showing foam separation/impacts.  I wish someone had been able to film
> the impact from another angle because I would very much have liked to
> see the bottom HRSI surface of the wing before and after -- it's too
> hard to tell what the white stuff is falling below the wing after
> impact from the only angle I've seen ..
>            --... ...-- -.. . -. ..... ...- -...
>                    Bruce Bostwick N5VB
>
> ----
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>
----
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