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Columbia -Technical

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#1 JezMan


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Posted 02 February 2003 - 06:19 AM

The following posts would gave us clear view on two factors:

1. Heat wasn't the main cause

2. "Lose tile" or broken tail wings, is out of the question (the theory about 'foam dropping on the tail wings'...)

BTW, I am not sure if Atossa have seen the RV in dark or light. At night one can see the orbiter by naked eye even on orbit (I think it was CaptainA, who didn't believ Atossa could see it at 200,000ft)

Always concerning the shuttle , which is the height range of its re-entry
into the atmosphere ? How long does the friction last (in minutes) ?

ANSWER from Glen Davis on September 8, 1999:

The orbiter begins entry at a distance of 5063 statute miles from
the runway and about 557,000 feet (105 miles) above the earth, traveling at
25,400 feet per second.

The entry to the atmosphere starts at 400,000 feet
(75 miles) at a velocity of 25,000 feet per second. This is called the
entry interface.

At approximately 265,000 feet, the spacecraft enters an
area of atmosphere that blacks out communications to and from the
spacecraft. The black out lasts until the orbiter reaches an altitude of
approximately 162,000 feet.

Between these altitudes, heat is generated as
the spacecraft enters the atmosphere, ionizing atoms of air form a layer of
ionized gas particles around the spacecraft. Radio signals cannot penetrate
this sheath of ionized particles, and communications are blocked for
approximately 16 minutes.

The next phase is called the thermal control
phase. The thermal control phase is designed to keep the thermal protection
system within temperature limits.

A constant heating rate is maintained by
keeping the angle of attack at or near 40 degrees, or until the velocity is
below 19,000 feet per second.

The orbiter then enters the entry phase at
about 83,000 feet and at a velocity of 2,500 feet per second (mach 2.5) and
59 statute miles from the runway.

At this point the build up of heat on the
outer tile is not a problem although a great deal of heat is still being
generated because of the high speed at which the orbiter is traveling.

time from the start of entry to the moment it stops rolling on the runway is
about 45 minutes.

Heat build up from friction with the air is present and
is a problem until the spacecraft is below mach 1.

Mach 1 occurs around
49,000 feet or 25 statute miles from landing which is about 5 minutes from

To summarize the atmosphere height is 400,000 feet and the time is
about 40 minutes.
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#2 JezMan


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Posted 02 February 2003 - 06:20 AM


Is the adhesive used to 'glue' the heat tiles to the shuttle
surface strong enough that the tiles would never come unglued
(or have any tiles ever come off)? And if a tile were to come off
during re-entry in a critical place such as underbelly or nose,
would the heat penetrate and destroy the shuttle?

ANSWER from Bob Speece on August 10, 1999:

The adhesive used to bond Space Shuttle tiles is RTV-560. This RTV is
specially processed in that surface preparations, material mix and handling
are controlled to yield the optimum product. The RTV strength is 250 psi
(1723.7 N/m2) in shear and 400 psi (2757.9 N/m2) tensile at room

On STS-2, we had a hypergolic spill that resulted in multiple tiles coming
loose at the launch Pad, these were repaired and the Shuttle subsequently
launched. On STS-4, we applied too much waterproofing material to upper
surface tiles and tiles came off during the mission.

Our greatest concern with tiles is damage, this is due to their fragility
(they are silica glass).

On mission STS-27R, we suffered much tile damage
and in the area of the L-band antenna a tile was so severely damaged that
the L-band antenna cover was heat-damaged and had to be replaced.

The tile system protects critical areas on the Shuttle such that if a
"burn-through" occurs the results could be catastrophic. We control the
design of the Shuttle and ground systems to eliminate or reduce the effects
of damaging debris.

The Debris team, of which I am a member, performs
routine tasks and inspections that work to protect the Shuttle from damaging

This team performs an intense post-launch film review that looks
for damage to the vehicle from debris. If damage is known, the Shuttle
flight crew can take measures to reduce the effects of this damage, for
example, a more benign attitude for reentry that will reduce atmospheric
heat effects.

Our most heat critical areas are those protected by black tiles, these offer
the greatest protection against high heat and are normally of increased

The Shuttle system uses both high and low heat protection tiles,
flexible reusable surface insulation, and re-enforced carbon-carbon heat
shields to protect flight surfaces.
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#3 Uncle Sam

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Posted 02 February 2003 - 06:26 AM

what is RV?
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#4 JezMan


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Posted 02 February 2003 - 07:28 AM

Rerturn Vehicle.

(It could also read "returning orbiter")
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#5 Guest_piehunt_*

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Posted 02 February 2003 - 05:20 PM

Originally posted by JezMan
Rerturn Vehicle.

(It could also read "returning orbiter")

RV=Re-entry Vehicle

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#6 MirrorMan


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Posted 17 July 2004 - 12:37 AM

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#7 MirrorMan


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Posted 13 December 2004 - 12:48 AM

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