[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Sending in Columbia pics and info - alternate



At the end of each of NASA'a twice daily Columbia briefings, the Shuttle
Program Manager has been supplying a frame with location(s) to which to send
in any information, pictures, recordins, files, etc.:

Nasa Operations Center telephone: 281.483.3388

Email of any files, info, etc.:
        columbiaimages@nasa.gov

Snail mail:
    NASA Operations Center
    Columbia  m/s JA17
    Johnson Space Center
    Houston, TX 77058

'
This must be in addition to the psiweb.com ftp site noted (by azrowe on this
list) on the NASA web site at:
http://www.jsc.nasa.gov/instructions.html

-------------

In a previous posting, I was looking for some technical info on the cameras.
Some of it was supplied in the Wednesday afternoon (4"30PM CST) briefing.

At T+82, Shuttle speed was approx 2550fps (feet per second).

Air speed between the Shuttle and the External Tank (ET) was only applox
755fps.

Note: 1 statute mile per hour = approx 1.467 fps.

This slower speed between the craft and ET is due to the 'damming' effect of
the air.  It is similar, but more extreme, to what happens to underwing
airflow whenever an aircraft is flying very close to the ground (in 'ground
effect').  The higher difference in underwing and overwing airspeed than in
normal flight creates a higher pressure differenctial and some additional
lift.  In an aircraft's case, this 'extra lift' from the damming effect goes
away as the aircraft climbs to more than 1 wing legth in altititude.  This
can be a problem if a pilot 'lifts off' too slow and then climbs out of
ground effect before gaining enough speed to generate adequate lift.  This
often shows up when pilots try to take off when well over max gross weight.
The aircraft climbs in 'ground effect', but cannot generate enough lift to
climb any further than 1/2 to 1 wing width in height...

In Columbia's case, this 'lift' is not needed to lift the Shttle/ET/SRBs.
At this point in the flight (mostly vertical travel flight path), overall
thrust is doing the lifiting.

Engineers apparantly thought the rather slow relative airspeed (755fps) and
the light weight of the foam insulation could not have caused enough damage
to account for loss of the vehicle.  However, this low-speed damming abates
as you progress away from the Shuttle/ET space... It's my guess is that
airspeed at the point of contact with the wing eas much higher than the
755fps - and maybe even as high as the 2550fps shuttle speed.  At a point
just above the leading edge of the wing, out from the ET, airspeed could
possible have been higer than the 2550+fps vehicle speed offered.

The program manager, Mr Ditmoore, has assued everyone that nothing has been
ruled out and nothing has yet pointed to an exact cause.  It was interesting
to see NASA's honmesty in explaining how suspicion of the foam tile impact
went from none to some to very little.  NASA does appear to be very frank.

--------------
As to cameras... I had seen some footage from previous Delta rocket launches
at Vandenberg a few years ago.  I was doing some work for a sat maker who
had 5 of their comm birds lifted on each of a few launches.  The film
resolution was still good enough to 'count rivits' at T+45 secs.  Those
images a few years ago were a telescope looking movie (film) camera that
tracks the launch vehicle to a point well out of range for the naked eye.

--------------

The Shuttle Program Manager noted that at least some of their photographic
equipment used to film the launch from multiple views was down at the time
of the Columbia launch.  I was surprised that none of the newsies asked him
to elaborate.  The 'best view' of the foam tile impact, according to NASA,
was from a video camera that was, as luck would have it, out of focus. The
few out-of-focus frames with the foam tile do not have enough detail to tell
if any damage was done from the impact with the wing.  However, and again
IMHO, 2550pfs --approx. 1740mph-- against a 1.5 pound item (even ithough it
is s not a very dense item) should in fact be suspect.

Time will tell.

God bless the crew. They have 'landed'. Let's hope it is in a better place.

=====================





---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.449 / Virus Database: 251 - Release Date: 1/27/2003
----
Via the sarex mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe sarex" to Majordomo@amsat.org



AMSAT Top AMSAT Home