Observation on TPS damage on Orbiter

I don't care what shuttle critics say... that bird is one amazing vehicle!

If you can love a machine, I'd say that I love that bird.

It's the culmination of decades of aeronautical research and the fact that it flies is amazing.

I can't help but feel like each of these flights is a step towards the darkening of a historic stage in manned spaceflight.

I feel like I'm watching a patient slowly dying in an ICU...totally helpless as the life ebbs from a miraculous thing.

4301-bump - "the fact that it flies is amazing"

search on [NASA Michoud external tank manufacturer]

http://www.sptimes.com/2003/02/04/Worldandnation/Foam_insulation_has_h.shtml

Shuttle Disaster

Foam insulation has history of damaging shuttle
By WES ALLISON, ANITA KUMAR and CRAIG PITTMAN
© St. Petersburg Times
published February 4, 2003

NEW ORLEANS -- The foam insulation that peeled off as the Columbia lifted off Jan. 16, striking the shuttle's left wing, has been a headache for NASA officials for years.

The foam, sprayed onto the external fuel tank that carries the shuttle into space, has a history of coming unglued and damaging the sensitive tiles that protect the craft from burning up as it re-enters Earth's atmosphere.

NASA tried to fix the problem, but never believed it posed a risk to astronauts. Instead, it was seen as a money problem: Fixing damaged tiles is expensive.

But on Monday NASA officials called the flying foam the leading suspect in Columbia's demise.

"We're making the assumption that the external tank was the root cause of the accident," said Ron Dittemore, the shuttle's program manager. "It is a drastic assumption and it's sobering, but I think that's what we need to do."

It's not unusual for shuttle tiles to be lost or damaged in flight. Every time a shuttle goes into orbit, at least 40 of the thousands of tiles that cover the wings and belly of the craft are damaged or lost.

A 1995 paper by NASA scientists estimated that 90 percent of all tile damage on the shuttle belly resulted from the foam "debonding" during liftoff and smacking into the craft.

The solution: a laser to inspect the insulation for weak spots.

But in nine or 10 shuttle missions in 1997 and 1998, the foam popped off "like snow flurries," damaging about 100 of the tiles on one shuttle, said NASA engineer Greg Katnik, who inspects shuttles after they land.

"It never caused damage that we considered a flight safety issue, but it was something we were anxious to cure," Katnik said Monday.

Fixing the problem took time because the fuel tanks, constructed by Lockheed Martin Space Systems at NASA's Michoud Assembly Facility in New Orleans, are built years in advance of each mission and shipped by barge to Cape Canaveral.

"All these tanks were already fabricated and sitting on the line ready to go," Katnik said.

So technicians tried stopgap measures -- shaving the insulation down to lessen what could peel off and poking tiny holes in the foam to let air pockets escape. But the foam kept peeling off.

Then, Katnik said, scientists tried tweaking the formula. But as recently as October, a piece of insulation peeled off Atlantis and hit the solid rocket boosters. The foam apparently did no damage.

NASA has tried sticking pieces of the insulation in a Tennessee wind tunnel and onto the fuselage of an F-15 fighter jet, trying to mimic the conditions of shuttle liftoff. In 1999 they even hired researchers in Texas to fire chunks of the foam at shuttle tiles using a compressed-gas gun.

But their pursuit of the answer was always focused on cutting the expense and time lost in repairing the damage after each flight, not on whether the foam could cause a crash of the shuttle's orbiter craft.

"We've seen it hit the tiles before and pulverize, but we've always seen the orbiter come back," Katnik said.

The foam is as light as Styrofoam, but Dr. Hans Mark, a former deputy administrator of NASA, said speed of the shuttle is more important than mass.

"If it's moving fast enough, it can cause trouble, no question about it," said Mark, who left NASA in 1984 and is now a professor of aerospace engineering at the University of Texas in Austin. "Any material that's moving fast enough can cause damage."

The insulation's purpose: protect the tiles, not damage them.

The foam is sprayed on the outside of the 154-foot external fuel tank. The liquid hydrogen fuel inside the tank is kept at 423 degrees below zero. Without insulation, ice would form on its aluminum skin, break off during launch and severely damage tiles.

The foam insulation also protects the volatile fuel inside the tank from the enormous heat generated by the shuttle's rockets and the friction of the air during a launch that reaches four times the speed of sound.

The foam insulation is one of the last of a half-million parts and compounds that goes into each external fuel tank. The work is done in a World War II-era defense plant owned by NASA but operated by Lockheed Martin, which has built the external fuel tanks here since the shuttle program's infancy in 1973.

The sprawling Michoud plant covers a milelong stretch of two-lane road in a flat industrial strip in east New Orleans, near a thriving Vietnamese community and a Folger's coffee plant.

The tank is covered by 10 types of insulation made by six different companies.

The majority of the tank is covered with a polyurethane foam made by North Carolina Foam Industries in Mount Airy, N.C., that also makes insulation for homes and taxidermy molds for mounting deer and other game.

However, Lockheed officials said the foam that peeled away from Columbia was made by another manufacturer, whom they would not name.

The foam usually arrives in semiliquid form in two separate parts. The two compounds are mixed in the spray gun as they are applied. A metal primer is applied first to help it adhere. As it hardens, the foam cures to a mustard brown after about 24 hours.

NASA has touted the foam as a great example of the space program's spinoff technology. Besides roofing insulation, the foam has replaced the plaster used to produce molds for artificial limbs.

But the foam has been a problem from the start. During a 1981 test-loading of fuel in Columbia's external tank, the super-cold fuel caused shrinkage in the adhesive. During subsequent ground tests, technicians wrapped a cargo net around the tank to keep foam from shaking off.

In 1991, technicians scrambled to replace a four-inch-square of foam that came unglued before launch.

A series of missions in the mid 1990s saw small pieces pop off because heat from the launch created air pockets under the insulation, Katnik said.

"It was like watching popcorn," he said. "It would pop off a little piece here and a moment later there'd be another piece over there."

The problem appeared to peak with a 1997 launch of Columbia. Katnik's crew discovered about 100 damaged tiles.

The angle and location of the damage suggested the foam was at fault, but there were no pictures from liftoff of any foam chunks coming loose.

Finally, though, they found pictures that confirmed the foam had come unglued. They were photos taken by Columbia's crew.

-Times staff writer Chuck Murphy and researchers Kitty Bennett and Cathy Wos contributed to this story.

Foam insulation problems
The shuttle has had numerous problems with foam insulation coming off the external tank and various fixes have been tried. Here are some examples:

FEBRUARY 1981: First test loading fuel in Columbia's external tank causes shrinkage in adhesive of insulation on tank. Cargo net wrapped around tank to prevent insulation from flying off.

JUNE 1991: Columbia launches after technicians replace 4-inch-square of insulation.

JUNE 1995: NASA estimates 90 percent of tile damage on the shuttle's underside caused by insulation debris.

DECEMBER 1997: Technicians find about 100 damaged tiles on Columbia, conclude cause was loss of insulation unseen by launch cameras.

MAY 1998: Despite new insulation precautions, abnormal amount of tile damage discovered.

JANUARY 1999: Six panels of shuttle insulation mounted to fighter plane to test stress of shuttle takeoff. No erosion of insulation noted.

MARCH 1999: Wind tunnel tests of insulation determines it flies loose because of speed and heat on ascending aircraft. Marshall Space Center "tweaks" formula.

MAY 1999: Discovery launch delayed after hailstorm gouges 150 holes in insulation.

OCTOBER 2002: Atlantis loses piece of insulation that strikes rear section of one solid rocket booster. Analysis indicates no harm, flight proceeds.

JANUARY 2003: As Columbia lifts off, chunk of insulation breaks loose from external rocket and strikes left wing.

search on [NASA external tank manufacturer]

http://www.space.com/missionlaunches/sts107_fl01_030322.html

Cape Weather Ripe for Icy Debris to Fall from Columbia's Tank
By John Kelly
FLORIDA TODAY
posted: 12:00 pm ET
22 March 2003

CAPE CANAVERAL, Fla. -- NASA fueled and launched shuttle Columbia in weather in which ice almost certainly formed on its 15-story fuel tank. The presence of ice made it more likely that debris smacking the shuttle's wing in flight was heavy enough to cause catastrophic damage.

A six-week Florida Today investigation has found:

Wet, humid conditions throughout Columbia's 39 days at the seaside launch pad provided a near-perfect environment for moisture and ice.

The chunks of burnt-orange insulation that hit Columbia come from an area where the foam is hand-crafted in a way that makes it likely to soak up moisture, which could freeze into an icy crust that would be hard for inspectors to see.

Foam sopped with water or coated in ice would be far heavier than dry foam and capable of far more damage.

Launch-day video shows debris striking the lower front edge of the wing, an area where super-hot gas breached the shuttle's protective armor as it entered Earth's upper atmosphere Feb. 1.

Investigators already have concluded that breach is one link in the chain of events that led to the disintegration of the $2 billion spacecraft high above Texas, killing seven astronauts.

Early on in the 16-day mission, NASA and its contractors assumed what they saw hitting Columbia was dry foam, something akin to a Styrofoam cooler or a boater's life jacket. The assumption colored the engineering analysis that deemed dry foam was too light to do enough damage to endanger Columbia or its crew.

If the debris included ice, it could be heavier, a possibility raised by engineers inside and outside the agency.

"Think bowling ball," said former NASA engineer Gregory Sakala of Titusville.

The makeup of the debris has become a major line of inquiry for the Columbia Accident Investigation Board, which has assigned at least a dozen teams to one job: "Follow the foam."

The analysis to determine what the debris is made of may be finished as early as this week.

"I think that that's still an open question as to whether or not there might be ice in there or not," said inquiry board chairman, retired Adm. Harold Gehman.

Conditions show recipe for ice

In an effort to resolve the ice question, Florida Today obtained weather readings from launch pad 39A and compared the conditions with past weather data, NASA ice research and inspection reports from past shuttle missions. A computer-assisted analysis of the data, and interviews with shuttle and weather specialists, indicates a recipe for moisture, frost and ice on the big tank.

Columbia made the three-mile journey from the Vehicle Assembly Building to the launch pad Dec. 9. The tank sat outside for 39 days, exposed to nearly 10 inches of rain and almost daily humidity above 90 percent.

In the overnight hours of its last day on Earth, the shuttle was aglow on Pad 39A, towering out of a soupy fog blanketing the Cape.

It was jacket weather in Florida, moist and temperatures in the mid-40s Fahrenheit on the ground. Sixty feet up, on the launch platform, the temperature hovered below 50 degrees Fahrenheit. The humidity was almost 100 percent when the launch team gave the go-ahead to start pumping super-cold liquid fuel into the massive tank.

Anywhere else, that's just nippy weather. Up on the pad, it's a different world. The presence of a half million gallons of liquid hydrogen, at minus 423 degrees Fahrenheit, and liquid oxygen, at minus 298 degrees Fahrenheit, changes everything.

That's one reason why manufacturer Lockheed Martin sprays an inch-thick layer of polyurethane foam onto the tank. The insulation stems the growth of frost and ice that could come off the tank and pelt the shuttle during launch. But the deep freeze inside means temperatures on the insulation surface can be 10 to 30 degrees cooler than the air outside.

So with temperatures as high as 60 degrees, and high humidity, condensation can turn to frost and ice. That's especially true where the foam is thinner, cracked or somehow altered, according NASA-sponsored research.

Thick ice can form in warm weather

In 1983, the U.S. Army Corps of Engineers recreated the wide range of atmospheric conditions the foam must endure, including varying temperatures, humidity and wind. Then they watched what happened when moisture formed on the insulation.

Droplets trickled down the test foam. Even at air temperatures far above freezing, the drips pooled and froze on thinner foam as well as inside cracks or tiny defects in the surface. The researchers found ice grew dangerously thick in conditions warmer than NASA's models had predicted. Experiments also showed ice patches could linger for hours even as temperatures rose.

"A potential hazard to the orbiter tiles which has not been previously identified could occur during relatively cool and humid ambient conditions as a result of extensive frost formations," the report said.

". . . The avalanche of frost at liftoff could be large enough to be of concern."

The Florida Today analysis compared the Army experiments, weather and ice reports from past missions and the conditions at Pad 39A to determine ice likely formed on Columbia's tank Jan. 16.

The weather that day was similar to a past Columbia launch.

That day in 1990, temperatures stayed under 54 degrees, with 100 percent humidity. Inspectors touring the pad three hours before launch saw condensation running down the tank and forming patches of ice and frost. They reported ice at the pad did not violate safety rules and, once things warmed up, Columbia blasted off.

Once in orbit, the tank tumbled away. Pictures showed divots, including one as wide as 28 inches, in the tank near the same spot where foam came off on Columbia's last flight. When Columbia landed, inspectors counted more than 100 tiles hit by debris and measured one gouge 2-by-3 inches. The damage was deemed less than average.

The ice formation that day was not unique. Some frost or ice forms on almost every tank, even during hot, sunny Florida summers.

Treatments allow moisture to penetrate

NASA discounts any suggestion of water or ice-laden debris.

The fuel tank foam is closed-celled. That means individual cells are tightly packed together so other molecules, even water or gas, can't get inside. The bulk of it is sprayed on the tank at a plant near New Orleans, mostly by robots. The outer layer hardens into a sort of rind, an orangish skin that further protects it from the moist air outside. This is the kind of foam shuttle program manager Ron Dittemore showed the news media in the days after the accident to bolster his point that the material is lightweight and impervious to moisture.

But the foam suspected of popping off Columbia's tank is different. It doesn't have that protective outer layer. It's called "close-out" foam because it's applied near the end of manufacturing, by workers using their hands, molds and tools. Some of the work is done in Louisiana; some at KSC where crews attach the tank to its orbiter and solid rocket boosters.

A perfect example of that kind of foam are the bipod ramps, the triangular blocks that fell off during Columbia's launch and at least four previous launches. Workers pour the foam for the twin ramps into place near metal struts that attach the tank to the orbiter's nose. They use tools to cut the foam to an aerodynamic shape.

In that general area, workers shave or sand other close-out foam. They also use what looks like a wire brush to poke tiny holes in large tracts of nearby foam. The process called venting was meant to let gas trapped inside escape instead of expanding and blasting the foam off the tank.

These treatments can provide a path for gas and moisture to get inside the foam. The workers are slicing open the walls of those closed cells and removing the polyurethane's hard skin.

"The presence or the absence of that skin has a dramatic effect," said Gordon Nelson, professor of chemistry at Florida Tech in Melbourne, Fla.. Nelson studies how polymers and similar materials behave under different conditions.

Experiments by companies that make similar closed-cell foams, which are used for everything from airplanes to roofing, show the skinless foam absorbs moisture during prolonged exposure to humidity. A study in the late 1990s by Huntsman Polyurethanes showed the skinless foam could triple in weight after 30 days in a very moist environment.

In the case of Columbia's final mission, the formula could mean the left wing was hit by a chunk of foam/ice weighing up to 71/2 pounds instead of a 21/2-pounds.

But NASA says such tests were conducted on a slightly different kind of foam.

Neil Otte, deputy manager of the NASA program that oversees design and manufacture of the tanks, said the agency tested the foam's resistance to moisture by exposing it to 125-degree temperatures and 95 percent humidity for seven days. The foam absorbed a little water, but never gained more than 1 percent in weight, Otte said. NASA tested both intact and shaved foam.

Otte conceded shaving the foam on the bipod ramps, for example, slices open a layer of cells several millimeters deep. He acknowledged that area could absorb moisture that could freeze into an icy crust under certain atmospheric conditions. But he said that's too thin to be dangerous.

NASA has been redesigning the bipod ramps since last fall, when foam from that area fell off during launch. The foam redesign and efforts to preclude foam loss altogether are on Dittemore's official checklist for preparing the shuttles for return to flight.

Cracks, dents increase ice risks

Other common defects in the foam, such as cracks, dents or shoddy repairs, also can cause problems made worse by moisture.

Moisture can accumulate in the tiniest crevice, freeze into ice and form dangerous projectiles during launch. The temperature can plummet hundreds of degrees as the moisture gets fractions of an inch closer to the tank's metal surface.

Freezing material can expand and aggravate a phenomenon called cryopumping. Gas or moisture gets into air pockets or voids between the insulation and the tank, expanding as the temperature rises during launch. If the resulting gas can't escape as quickly as it needs to, the pressure can blow foam off the tank.

Otte said that's why NASA treats cracks or other defects very seriously.

Florida Today's review of ice team inspections for dozens of past missions indicates some cracks are deemed acceptable, but only in certain locations away from the shuttle's belly or when there is no dangerous ice buildup.

The assessment depends on judgment by inspectors and launch managers.

NASA has delayed launches because of fears about ice. The delays have ranged from several hours of waiting for the air around the pad to warm up, to weeks for repairing cracks or holes in foam.

In two examples in the 1990s, NASA rolled Discovery back from the launch pad to the Vehicle Assembly Building to touch up holes drilled in the foam by woodpeckers and hail.

The reason? NASA engineers determined any holes an eighth of an inch in diameter posed a danger. Ice one-sixteenth of an inch thick can be deemed dangerous enough to scrub a launch, depending on where it forms.

Launch conditions deemed safe

The conditions on Jan. 16 did not violate NASA's weather standards meant to minimize ice. TV monitors, computer temperature models and the human inspection before launch are the last line of defense against ice and debris. A squad of hawk-eyed veterans climbs up and down the launch tower three hours before launch. They look for possible debris, including cracked insulation, condensation, frost and ice. The inspectors use temperature scanners and binoculars to spot problems.

A 130-page checklist the team used during its Jan. 16 inspection of Columbia, obtained by Florida Today under the Freedom of Information Act, shows inspectors saw no ice buildup that violated safety rules.

Handwritten notes indicate frost was spotted on at least three regions of the tank. The team also noticed frost and ice coming off the shuttle stack during liftoff. A more detailed report like those from past missions may not be prepared about STS-107, NASA said Friday.

The checklist indicates the team was allotted 10 minutes at the 195-foot-high level of the launch tower to inspect the bipod ramp and at least seven other areas. There's no indication they looked again at those places.

Otte said NASA data challenges the Florida Today conclusions about ice, but would not elaborate. He suggested interviewing ice team members, but KSC has denied requests to interview the inspectors.

Shuttle and ice experts, including workers who've performed the final ice inspection, say there is no way to see everything as they scan the 15-story tank from platforms 75 feet from the tank.

Cracks in the foam, even if spotted by the team, could harbor moisture and ice that would not be spotted. Ice can worsen in the three hours between the inspection and liftoff, even if conditions at the pad warm up.

NASA engineer Gregory Katnik, an 18-year veteran of the inspections, said despite not being able to see everything, the team knows what it's looking for.

"It gets to the point where you can tell when something is wrong," Katnik said of the inspection team. "You have looked at so many vehicles over the years, you can tell something is out of the ordinary. There are pages and pages of checklists. . . . You know there should not be liquid dripping here and there should not be a protrusion there."

B.K. Davis, a retired NASA external tank manager who now lives in Cocoa Beach, Fla., trusts the inspection and other processes that make sure there is no dangerous ice before launch.

"Everyone talks about ice, but that is a red herring," Davis said.

Still, as part of the investigation, NASA weather experts are analyzing rain, humidity and other data from Columbia's stay on the pad and previous launches. They're analyzing tile damage reports to see whether there's a relation between atmospheric conditions and debris, weather officer John Madura said.

If investigators conclude there was ice, it would raise new questions about how NASA managers and their contractors analyzed possible damage while Columbia still orbited Earth.

The analysis assumed the debris was light foam only. The mission managers concluded that foam could damage the wing but not badly enough to destroy the ship during re-entry. The analysis said small changes in the weight of the debris could cause more serious damage.

In the end, the space agency's managers apparently rejected the possibility of icy debris. Not all engineers liked that assumption.

In a pre-Feb. 1 e-mail to colleagues debating the damage, engineer Dan Mazanek of Langley Research Center noted if the debris were solid ice, it could be 30 times as heavy as foam.

"That would be the equivalent of a 500-pound safe hitting the wing at 365 miles per hour."

Published under license from FLORIDA TODAY. Copyright © 2003 FLORIDA TODAY. No portion of this material may be reproduced in any way without the written consent of FLORIDA TODAY.

http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/centers.html

GETAWAY SPECIAL PROGRAM...

NASA CENTERS AND RESPONSIBILITIES

The space transportation system operates under the direction of the National Aeronautics and Space Administration.

NASA's John F. Kennedy Space Center.in Florida is responsible for all launch, landing and turnaround operations for STS missions requiring equatorial orbits.

The Lyndon B. Johnson Space Center in Houston, Texas, is responsible for the integration of the complete space shuttle vehicle and is the central control point for space shuttle missions.

NASA's George C. Marshall Space Flight Center in Huntsville, Ala., is responsible for the space shuttle main engines, external tanks and solid rocket boosters.

NASA's National Space Technology Laboratories at Bay St. Louis, Miss., is responsible for testing the space shuttle main engines.

NASA's Goddard Space Flight Center in Greenbelt, Md., operates a worldwide tracking station network.

The United States Air Force operates the space shuttle launch and landing facility at Vandenberg Air Force Base in California for STS missions requiring polar orbit.

JOHN F. Kennedy Space Center.p> The Kennedy Space Center.has primary responsibility for prelaunch checkout, launch, ground turnaround operations and support operations for the space shuttle and its payloads. Space shuttle payloads are processed in a number of facilities at KSC and the nearby Cape Canaveral Air Force Station. Payloads are installed in the space shuttle orbiter horizontally in the Orbiter Processing Facility or vertically at the launch pad. Payloads to be installed horizontally in the orbiter at the Orbiter Processing Facility are verified in the Operations and Checkout Building at KSC. Payloads installed vertically in the orbiter at the launch pad consist primarily of automated spacecraft involving upper stages and their payloads (e.g., satellites).

KSC's responsibility extends to ground operations management systems and plans, processing schedules, facility design and logistics in support of the space shuttle system and payloads.

The center established the requirements for facilities and ground operations support at Vandenberg Air Force Base and designated contingency landing sites. KSC also supports the Department of Defense for ground operations at Vandenberg Air Force Base and maintains NASA facilities and ground support equipment there.

The launch facilities-Launch Complexes 39-A and 39-B-and the technical support base of the center's industrial area were carved out of virgin savanna and marsh in the early 1960s for the Apollo program.

In reshaping KSC for the space shuttle, planners took maximum advantage of existing buildings and structures from the Apollo program that could be modified, scheduling new ones only when a unique requirement existed. New facilities that have been built to support space shuttle operations are the shuttle landing facility (runway); the Orbiter Processing Facility; and recently the Orbiter Modification and Refurbishment Facility, Tile Processing Facility, Solid Rocket Booster Storage and Processing Facility, Shuttle Logistics Building and Solid Rocket Booster Assembly and Refurbishment Facility.

KSC is located at 28.5 degrees north latitude and 80.5 degrees west longitude. It encompasses approximately 140,000 acres of land and water. This area, with the adjoining bodies of water, is sufficient to afford adequate safety to the surrounding communities during space shuttle launch and landing activities.

The shuttle processing contractor performs all launch processing and turnaround activities at the Kennedy Space Center.and Vandenberg Air Force Base. Lockheed Space Operations Company, Titusville, Fla., was awarded the contract in 1983 to perform space shuttle launch processing operations previously carried out by more than a dozen separate contractors, which included the major hardware manufacturers.

The SPC is responsible for processing individual vehicle elements, integrating those elements in preparation for launch, performing cargo integration and validation activities with the orbiter, operating and maintaining assigned facilities and required support equipment and performing those tasks necessary to accomplish launch and postlaunch activities successfully.

ORBITER PROCESSING FACILITY

Kennedy Space Center

Orbiter

OPF

Vehicle Assembly Building

orbiter

The OPF has two identical bays that are each 197 feet long, 150 feet wide and 95 feet high; have an area of 29,000 square feet; and are equipped with two 30-ton bridge cranes with a hook height of approximately 66 feet. A low bay separating the two bays is 233 feet long, 97 feet wide and 24.6 feet high. A 10,000-square- foot annex is located on the north side of the facility. Another new 34,000-square- foot, three-story annex will provide additional office space.

In the high bays, a trench system under the floor contains electrical, electronic, communication, instrumentation and control cabling; hydraulic supply and return plumbing; gaseous nitrogen, oxygen and helium plumbing; and compressed air distribution plumbing. Gaseous nitrogen, helium and compressed air are supplied by the systems in the Vehicle Assembly Building. All of these systems are used to support processing and maintenance of the orbiters during ground turnaround operations.

The two high bays have an emergency exhaust system in case of hypergolic spills. The low bay houses areas for electronic equipment, a launch processing system interface, mechanical and electrical equipment shops and thermal protection system repair. The low bay also includes provisions for a communications room, offices and supervisory control rooms.

Some orbiter processing activities performed in the OPF are hazardous, and personnel who are directly involved are required to wear protective suits, called self-contained atmosphere protective ensembles. The use of SCAPE suits is required during operations involving the reaction control system, orbital maneuvering system, and auxiliary power units and their hypergolic propellants.

Fire protection systems are provided in all three bays.

Two large rolling bridges span the main access bridge to provide complete access to installed payloads, radiators, internal areas of the payload bay and external areas of the payload bay doors. Each of the rolling bridges supports two independently movable trucks with a personnel bucket at the bottom of each vertically telescoping arm. The buckets are manually rotatable around a full circle. The bridges, trucks and telescoping arms are electrically powered and controlled from the buckets or the catwalk.

Flip-up work platforms parallel the payload bay area to provide access to radiators, the inside payload bay doors, payload bay door hinges and trunnion points.

Other platforms provide access to other orbiter elements.

The hinges of the payload bay doors are not designed to support the weight of the doors while they are open horizontally in the Earth's 1-g environment. A counterweight zero-gravity device supports the weight of the doors while they are open for processing in the OPF.

The orbiter processing flow begins when an orbiter lands at the shuttle landing facility after a mission in space or a ferry flight aboard the shuttle carrier aircraft. In either case, the orbiter is towed to the OPF within hours of its arrival.

Access to the crew module is established soon after the orbiter lands. Flight crew equipment is removed at that time, along with any middeck experiments flown on the mission.

Processing starts when the orbiter is jacked up off its landing gear and leveled, workstands are moved into position and preparations begin to gain access to various orbiter areas. The orbiter is connected to ground power, facility ground coolant, purge air and the LPS.

Initial safing operations include hooking up purge, vent and drain lines. Any unexpended pyrotechnics (ordnance devices), such as those used for backup landing gear deployment, are disabled and safed. Purging and deservicing of the orbiter's orbital maneuvering system/reaction control system, forward reaction control system and auxiliary power unit hypergolic systems are initiated.

Some of these are hazardous operations, which require that the OPF be cleared of all non-essential personnel. Hypergolic deservicing operations require that personnel wear SCAPE suits.

The hypergolic lines of the OMS/RCS and forward RCS are drained of trapped propellants and their interface connections are purged. Residual hypergolic fuels in onboard tanks are not usually drained.

When required, the OMS/RCS pods and the forward RCS are removed and taken to the Hypergolic Maintenance and Checkout Facility in the industrial area for maintenance.

After the orbiter has been rolled into the OPF, a purge of the space shuttle main engines is initiated to remove moisture produced as a by-product of the combustion of liquid oxygen and liquid hydrogen.

Fuel cell cryogenic tanks are drained of residual reactants and rendered inert using gaseous nitrogen in the oxygen system and gaseous helium in the hydrogen system. High-pressure gases are vented from the environmental control and life support system.

Before postflight deservicing can continue beyond initial safing operations, certain vehicle systems must be mechanically secured and personnel access installed.

Space shuttle main engine gimbal locks and engine covers are installed, and engine heat shields are removed. Aft access doors are removed, and workstands are installed in the orbiter's rear compartment.

The payload bay doors are opened, and access provisions are installed to support payload operations. Any hazardous payloads are also rendered safe during these early OPF operations.

Payloads and the associated airborne support equipment from the previous flight are removed from the orbiter payload bay, and the bay is prepared for the installation of new payloads. The remote manipulator system arm is removed or installed, as required for the next mission.

During routine deservicing operations, non-storable consumables are off-loaded from the orbiter and waste products are removed. Potable water, water from the water spray boilers and lube oil from the auxiliary power units are drained, and APU lube oil filters are removed.

After initial safing is completed, postflight troubleshooting of anomalies that occurred during launch, flight or re-entry begins.

Orbiter components are removed and repaired or replaced as required based on anomaly reviews and then retested in parallel with other processing activities.

Visual inspections are made of the orbiter's thermal protection system, selected structural elements, landing gear, tires and other systems to determine if they sustained any damage during flight and landing.

Any damage to the thermal protection system must be repaired before the next mission. TPS operations are conducted in parallel with most of the activities in the Orbiter Processing Facility. There are some 27,446 tiles and thermal blankets on the outside of each orbiter and some 6,000 thermal control blankets on the inside.

TPS maintenance is provided in the new Thermal Protection System Facility across the street from the OPF. The 33,000-square- foot facility was located near the OPF to minimize the time it takes to transport the tiles and thermal control system blankets between the two facilities. Several trips are required before the tiles and some blankets are installed on the orbiter. The closeness of the facilities is also expected to minimize damage to the delicate tiles.

During OPF processing, any vehicle modifications required in addition to routine postflight deservicing/servicing and checkout are performed. Planned modifications are typically put into work as soon as practical after the orbiter returns and are completed in parallel with prelaunch servicing whenever possible.

Modifications may be performed to meet future mission requirements, resolve an identified deficiency or enhance vehicle performance by replacing existing hardware with new, improved designs.

Orbiter modifications, if they are extensive, may be performed with the vehicle powered down. Many modifications, however, can be completed in parallel with routine servicing while the orbiter is powered up.

Where possible, modification work is completed in the OPF and Orbiter Modification and Refurbishment Facility while the orbiter is in a horizontal position. While some modification work can be carried out in the Vehicle Assembly Building or on the pad if necessary, the OPF and OMRF offer the best access and support equipment for conducting such work.

Except during hazardous operations, routine preflight servicing can begin while deservicing activities are still under way or modifications are in work. Routine servicing includes reconfig uring orbiter systems for flight, performing routine maintenance, replacing parts and installing new mission flight kits and payloads. Consumable fluids and gases are loaded aboard, and the APU lube oil system is serviced.

As systems servicing is completed, functional checks are performed to verify flight readiness prior to closeout. Any system that fails the functional check undergoes troubleshooting to identify the problem. If required, subsequent repairs or replacements are performed.

The orbiter's hydraulically activated flight control surfaces are thoroughly checked out.

A new payload may be installed in the OPF before shuttle vehicle integration or at the launch pad after shuttle integration. Depending on the particular mission, new payloads could be installed at both locations. If payloads are installed in the OPF, the orbiter-to-payload interfaces are verified before the orbiter is moved to the VAB.

A crew equipment interface test is performed during the OPF flow to identify any problems associated with flight crew equipment.

Following all space shuttle main engine work, the orbiter's main propulsion system, including the three main engines, undergoes a helium signature leak check. Successful completion of this test generally clears the way for the closeout of the aft engine compartment.

Electrically initiated pyrotechnic devices (ordnance) required for orbiter systems are installed and checked out. These include small explosive charges like those used for the backup deployment of the orbiter landing gear or emergency jettison of the remote manipulator system, Ku-band antenna, side hatch jettison and secondary emergency egress jettison.

Upon completion of all payload installation activities or any other work being performed in the payload bay, the clamshell-shaped payload bay doors are closed and latched. If no payloads are to be installed at the pad, this represents final closeout of the orbiter midbody for flight.

The final tasks to be completed in the OPF before the orbiter is moved to the Vehicle Assembly Building are to weigh the orbiter and determine its center of gravity. Vehicle performance is affected by both weight and center of gravity, and flight programming requires an accurate determination of both parameters.

All ground support and access equipment is then removed, and the orbiter is towed into the Vehicle Assembly Building transfer aisle through the large door at the north end of the high bay.

ORBITER MODIFICATION AND REFURBISHMENT FACILITY

Orbiter

The OMRF high bay is 197 feet long, 150 feet wide and 95 feet high, the same as the two OPF bays. The facility's electrical, mechanical and communications control rooms are located in an adjacent support bay. There is office space for personnel and a conference room with a window that overlooks the processing bay.

Only non-hazardous work will be performed in the OMRF until it is properly outfitted like the OPF to handle hazardous operations. In the meantime, work on the orbiter includes most thermal protection system operations, thermal protection system rewaterproofing, modifications that the facility can support and general maintenance.

Future upgrades to the facility will allow safing and deservicing; limited orbiter power-up using mobile electrical ground power; servicing of the orbiter's power reactant storage and distribution system; dumping of the orbiter's flight recorders, which requires support of the Launch Control Center computers; servicing of the orbiter's Freon coolant loop systems; and other tests requiring support of the Launch Control Center.

LOGISTICS FACILITY

Logistics Facility

Vehicle Assembly Building

Logistics Facility

VEHICLE ASSEMBLY BUILDING

Vehicle Assembly Building

One of the largest buildings in the world, the VAB covers 8 acres and has a volume of 129,428,000 cubic feet. It is 525 feet tall, 715 feet long and 518 feet wide. The building is divided into a 525-foot-tall high bay and a 210-foot-tall low bay. A transfer aisle running north and south connects and transects the two bays, permitting easy movement of vehicle elements.

The high bay is divided into four separate bays. The two on the west side of the structure-Bays 2 and 4-are used for storing space shuttle orbiter external tanks. The two bays facing east-Bays 1 and 3-are used for the vertical assembly of space shuttle vehicles on the mobile launcher platform.

Extendable platforms, modified to fit the space shuttle configuration, move in around the vehicle to provide access for integration and final testing. When checkout is complete, the platforms move back, and the VAB doors are opened to permit the crawler-transporter to move the mobile launcher platform and assembled space shuttle vehicle to the launch pad. The high bay door is 456 feet high. It is divided into lower and upper sections. The lower door is 152 feet wide and 114 feet high with four door leaves that move horizontally. The upper door is 342 feet high and 76 feet wide with seven door leaves that move vertically.

The low bay was the initial site for refurbishment and subassembly of solid rocket booster segments. These activities now occur at a new facility north of the VAB.

Existing pneumatic, environmental control, light and water systems have been modified in both bays. The north doors to the VAB transfer aisle have also been widened 40 feet to permit the orbiter to enter when it is towed over from the Orbiter Processing Facility. The doors are slotted at the center to accommodate the orbiter's vertical stabilizer.

The Vehicle Assembly Building has more than 70 lifting devices, including two 250-ton bridge cranes.

The VAB is designed to withstand winds of up to 125 miles per hour. Its foundation rests on more than 4,200 open- end steel pilings 16 inches in diameter driven down 160 feet to bedrock.

EXTERNAL TANK PROCESSING

external tank

Kennedy Space Center

external tank

Vehicle Assembly Building

transporter

external tank

The storage cells provide only the minimum access and equipment required to secure the external tank in position. After the tank is transferred to the checkout cell, permanent and mobile platforms are positioned to provide access to inspect the tank for possible damage during transit and to remove hoisting equipment. The liquid oxygen and liquid hydrogen tanks are then sampled and receive a blanket pressure of gaseous nitrogen and gaseous helium, respectively, in preparation for a normal checkout.

The external tank subsystem checkout includes an inspection of the external insulation and connection of ground support equipment (including the launch processing system) to the appropriate interfaces. Electrical, instrumentation and mechanical function checks and tank and line leak checks are performed in parallel.

After satisfactory checkout of the external tank subsystems, ground support equipment and launch processing system equipment are removed and stored, and external tank closeout is initiated. Forward hoisting equipment is attached and work platforms are stored-or opened-in preparation for transferring the tank to the mobile launcher platform.

The external tank is hoisted vertically from the checkout cell by the 250-ton high bay crane and transferred to the mobile launcher platform in High Bay 1 or 3 for mating with the already-assembled solid rocket boosters. After the external tank and solid rocket booster are mated, the integration cell ground support equipment is connected, and intertank work platforms are installed.

A considerable amount of final closeout work is performed on the boosters and the tank after they are mated.

SPACE SHUTTLE MAIN ENGINE WORKSHOP

space shuttle main engine workshop

Vehicle Assembly Building

SSME

Three engine workstands are available to support major stand-alone engine work, if required. The facility can support main engine disassembly and reassembly, checkout and leak testing.

Engines, mounted on engine handling devices and protected by a cylindrical shipping cover, arrive by truck from NASA's National Space Technology Laboratories and are off-loaded in the VAB transfer aisle next to the engine workshop. The engines are then pulled into the workshop and undergo receiving inspections. Normally, newly delivered engines are transferred to an engine installer and transported to the Orbiter Processing Facility for installation.

Routine postflight deservicing of the engines is performed in the OPF with the engines in place aboard the orbiter. More extensive between-flight servicing can be performed in the main engine workshop. The shop also supports engine removal operations and the preparation of engines for shipment back to NSTL or Rocketdyne in Canoga Park, Calif., the manufacturer of the SSMEs.

The shop provides storage for test equipment and serves as a staging area for SSME operations performed in the OPF and VAB and at the launch pad.

SOLID ROCKET BOOSTER PROCESSING

Kennedy Space Center

propellant

When they arrive at KSC, the segments are delivered to the solid rocket motor Rotation, Processing and Surge Facility, a group of steel-framed structures designed to withstand hurricane-force winds.

The RPSF, located north of the Vehicle Assembly Building, comprises a processing facility, a support building and two segment surge (storage) buildings. The facilities isolate hazardous operations associated with solid rocket motor rotation and processing (formerly performed in High Bay 4 of the VAB) and avert impacts to VAB launch-support capabilities.

The rotation building is 98.6 feet high and has an area of 18,800 square feet.

The main facility in the complex is used for solid rocket motor receiving, rotation and inspection and supports aft booster buildup. Rail tracks within the building permit railroad cars containing the segments to be positioned directly under one of the two 200-ton overhead bridge cranes. A tug vehicle capable of pulling and stopping a fully loaded segment car moves and positions railcars in the building.

Recovered booster segments are loaded onto railcars for shipment back to the manufacturer at a site on Contractor Road.

Two surge buildings located nearby contain 6,000 square feet each of floor area for storage of eight segments (one flight set). The buildings are 61 feet in height in the aft segment storage area and 43 feet in the forward and center segment storage area.

Paved roads between the processing facility, the two storage buildings and the VAB permit transporters to transfer the segments and other hardware from one facility to another.

Live solid rocket motor segments arrive at the processing facility and are positioned under one of the cranes. Handling slings are then attached to the railcar cover, and it is removed. The segment is inspected while it remains in the horizontal position.

The two overhead cranes hoist the segment, rotate it to the vertical position and place it on a fixed stand. The aft handling ring is then removed. The segment is hoisted again and lowered onto a transportation and storage pallet, and the forward handling ring is removed to allow inspections. It is then transported to one of the surge buildings and temporarily stored until it is needed for booster stacking in the VAB.

In 1986, a new Solid Rocket Booster Assembly and Refurbishment Facility was constructed at KSC after recompetition of the Marshall Space Flight Center's booster assembly contract.

Solid rocket booster operations are performed by both the shuttle processing contractor and the booster assembly contractor, who is responsible for booster disassembly and refurbishment and the assembly and checkout of forward and aft skirt subassemblies in the VAB. Booster retrieval operations, parachute refurbishment and booster stacking activities, in addition to integrated checkout, are performed by the shuttle processing contractor.

Refurbishment and subassembly operations previously performed in the VAB low bay and other outlying facilities are now conducted in the new facility located south of the VAB.

Aft skirts, fully configured and checked out in the Solid Rocket Booster Assembly and Refurbishment Facility, are delivered to the RPSF on dollies and hoisted into position on workstands. An inspected aft segment is then hoisted into position for mating with the aft skirt. When the aft segment assembly is completed and transferred to a pallet, it is transported directly to the VAB or to one of the two storage buildings.

Solid rocket booster elements, such as forward skirts, aft skirts, frustums, nose caps, recovery systems, electronics and instrumentation components, and elements of the thrust vector control system are received in this facility.

Assembly and checkout of the forward assembly (nose cap, frustum and forward skirt) and aft skirt assembly are also performed here in addition to refurbishment of recovered booster flight hardware.

The structural assemblies and components required to build up the forward assembly, aft skirt and external tank attach hardware are either shipped to KSC new or refurbished on site.

When completed, the aft skirt assemblies are transferred to the RPSF for assembly with the aft solid rocket motor segments.

An SRB hydraulic power unit ''hot fire'' facility is located in the southeast corner of the 44-acre site. The facility features a test stand that supports the hot-firing of the solid rocket booster's hydrazine-fueled thrust vector control system. Before each flight, the solid rocket booster aft skirt assemblies containing the TVC are transported to the facility and test-fired before the aft booster buildup.

The stacking of the solid rocket booster major assemblies begins after the buildup of aft booster assemblies at the Solid Rocket Motor Processing Facility (north of the VAB) and checkout of the forward nose skirt assemblies in the Solid Rocket Booster Assembly and Refurbishment Facility.

The booster stacking operation is accomplished in the following sequence:

1. The aft booster assemblies are transferred from the buildup area in the Rotation, Processing and Surge Facility to the High Bay 1 or 3 integration cells in the VAB and attached to the mobile launcher platform support posts.

2. Continuing serially, the aft, aft center, forward center and forward rocket motor segments are stacked to form complete solid rocket motor assemblies. As each segment is mated, the joint seal is inspected visually.

3. Segment seal integrity is then demonstrated by a leak check and decay test between the redundant seals. The forward skirt/nose assemblies are transferred from the SRB ARF to the High Bay 1 or 3 integration cell and stacked atop the completed solid rocket motor assemblies to form a complete set of boosters.

An alignment check of the complete flight set of solid rocket booster assemblies is performed after the stacking operations are completed. Integrated and automated systems testing of the assembled solid rocket boosters is accomplished on the mobile launcher platform, using the launch processing system to simulate the external tank and orbiter.

Before the space shuttle vehicle is transferred to the launch pad, solid rocket booster flight batteries are installed. Final connection of the solid rocket booster pyrotechnic systems is performed at the launch pad.

The solid rocket booster's hydraulic power units are serviced with hydrazine during the prelaunch propellant-servicing operations at the launch pad.

Almost complete external access to the shuttle vehicle is provided in the Vehicle Assembly Building. Access to the payload bay is through the crew compartment since the payload bay doors cannot be opened in the Vehicle Assembly Building.

MOBILE LAUNCHER PLATFORM

mobile launcher platforms

The mobile launcher platform is a two-story steel structure 25 feet high, 160 feet long and 135 feet wide. It is constructed of welded steel up to 6 inches thick. At their park site north of the Vehicle Assembly Building, in the Vehicle Assembly Building high bays and at the launch pad, the mobile launcher platforms rest on six 22-foot- tall pedestals.

Three openings are provided in the mobile launcher platform-two for solid rocket booster exhaust and one for space shuttle main engine exhaust. The solid rocket booster exhaust holes are 42 feet long and 20 feet wide. The space shuttle main engine exhaust opening is 34 feet long and 31 feet wide.

Inside the platform are two levels with rooms and compartments housing launch processing system hardware interface modules, system test sets, propellant-loading equipment and electrical equipment racks.

Unloaded, the mobile launcher platform weighs 8.23 million pounds. The total weight with an unfueled space shuttle aboard is 11 million pounds.

The space shuttle vehicle is supported and restrained on the mobile launcher platform during assembly, transit and pad checkout by the solid rocket booster support/hold-down system. Four conical hollow supports for each booster are located in each solid rocket booster exhaust well. The supports are 5 feet high and have a base diameter of 4 feet.

Posts on the aft skirts of the SRBs rest on spherical bearings atop the mobile launcher platform hold-down posts. A 28-inch-long, 3.5-inch-diameter stud passes vertically through the SRB post, spherical bearing and hold-down post casting to secure the booster to the platform. A frangible, or explosive, nut at the top of the stud and a nut at the bottom are tightened to preload the stud to a tension of up to 850,000 pounds.

When full main engine thrust is developed during the final moments of the launch countdown, ignition signals are sent to the two SRBs. Simultaneously, the explosive nuts at the tops of the studs are triggered. The preloaded studs are expelled downward into deceleration stands (''sandbuckets'') and the fractured halves of the explosive nuts are contained within spherical, 10-inch-diameter debris catchers on top of the solid rocket booster aft skirt posts. This sequence releases the solid rocket boosters and the entire space shuttle vehicle for flight.

Two tail service masts, one located on each side of the space shuttle main engine exhaust hole, support the fluid, gas and electrical requirements of the orbiter's liquid oxygen and liquid hydrogen aft T-0 umbilicals. The TSM assembly also protects the ground half of those umbilicals from the harsh launch environment. At launch, the solid rocket booster ignition command fires an explosive link, allowing a 20,000-pound counterweight to fall, pulling the ground half of the umbilicals away from the space shuttle vehicle and causing the mast to rotate into a blastproof structure. As it rotates backward, the mast triggers a compressed-gas thruster, causing a protective hood to move into place and completely seal the structure from the main engine exhaust.

Each TSM assembly rises 31 feet above the mobile launcher's deck, is 15 feet long with umbilical retracted, and is 9 feet wide. The umbilical carrier plates retracted at launch are 6 feet high, 4 feet wide and 8 inches thick, or about the size of a thick door.

The liquid oxygen umbilical runs through the TSM on the east side of the mobile launcher, and the liquid hydrogen umbilical runs through the TSM on the west.

Gaseous hydrogen, oxygen, helium and nitrogen; ground and flight system coolants; ground electrical power; and ground-to-vehicle data and communications also flow through the TSM umbilical links.

Work platforms used in conjunction with the mobile launcher platform provide access to the space shuttle main engine nozzles and the solid rocket boosters after they are erected in the Vehicle Assembly Building or while the space shuttle is undergoing checkout at the pad.

The main engine service platform is positioned beneath the mobile launcher platform and raised by a winch mechanism through the exhaust hole to a position directly beneath the three engines. An elevator platform with a cutout may then be extended upward around the engine bells. The orbiter engine service platform is 34 feet long and 31 feet wide. Its retracted height is 12 feet, and the extended height is 18 feet. It weighs 60,000 pounds.

Two solid rocket booster service platforms provide access to the nozzles after the vehicle has been erected on the mobile launcher platform. The platforms are raised from storage beneath the mobile launcher into the solid rocket booster exhaust holes and hung from brackets by a turnbuckle arrangement. The solid rocket booster platforms are 4 feet high, 20 feet long and 20 feet wide. Each weighs 10,000 pounds.

The orbiter and solid rocket booster service platforms are moved down the pad ramp to a position outside the exhaust area before launch.

CRAWLER-TRANSPORTER

crawler-transporter

Vehicle Assembly Building

Launch Complex 39-A

crawler

The transporters have a leveling system designed to keep the top of the space shuttle vehicle vertical within plus or minus 10 minutes of arc-about the dimensions of a basketball. This system also provides the leveling operations required to negotiate the 5-percent ramp leading to the launch pads and to keep the load level when it is raised and lowered on pedestals at the pad and in the Vehicle Assembly Building.

The overall height of the transporter is 20 feet, from ground level to the top deck, on which the mobile launcher platform is mated for transportation. The deck is flat and about the size of a baseball diamond (90 feet square).

Each transporter is powered by two 2,750-horsepower diesel engines. The engines drive four 1,000-kilowatt generators that provide electrical power to 16 traction motors. Through gears, the traction motors turn the four double-tracked crawlers spaced 90 feet apart at each corner of the transporter.

North of the Orbiter Processing Facility is a weather-protected crawler-transporter maintenance facility in which components of the crawler-transporters can be repaired or modified. It includes a high bay with an overhead crane for lifting heavy components and a low bay for shops, parts storage and offices. A pit has been built outside on the crawlerway to accommodate track segment removal and installation.

The crawler-transporters move on a roadway 130 feet wide, almost as broad as an eight-lane turnpike. The crawlerway from the VAB to the launch pads consists of two 40-foot-wide lanes separated by a 50-foot-wide median strip. The distance from the Vehicle Assembly Building to Launch Complex 39-A is 3.4 miles and 4.2 miles to Launch Complex 39-B. The roadway is built in three layers with an average depth of 7 feet. The top surface is river gravel. The gravel is 8 inches thick on curves and 4 inches on straightaway sections.

When the space shuttle vehicle is fully assembled and checked out in the VAB, the crawler-transporter is driven into position beneath the mobile launcher platform. The transporter jacks the mobile launcher off its pedestals, and the rollout to the launch pad begins. It takes approximately five hours for the unusual transport vehicle to make the trip from the VAB to the launch pad. During the transfer, engineers and technicians aboard th crawler, assisted by ground crews, operate and monitor systems while drivers steer the vehicle towards its destination.

After the mobile launcher platform is ''hard down'' on the launch pad pedestals, th crawler is backed down the ramp and returned to its parking area.

Click Here for LAUNCH COMPLEXES 39-A AND 39-B

Click Here for Shuttle Mission Info

Return to KSC Home Page

Table of Contents

Information content from the NSTS Shuttle Reference Manual (1988)
Last Hypertexed Thursday August 31 10:07:40 EDT 2000
Jim Dumoulin (dumoulin@titan.ksc.nasa.gov)

What about going back to the STS-1 white-painted tanks which would seal out the moisture? Oh, I forgot, too much weight to reach the Russian orbit.

Then there is the Vandenberg AFB solution: A jet engine underneath the tank to blow hot exhaust up and around the tank.

But of course they have never admitted that the change in solvents and blowing agents caused the foam to fall off, so fugagitaboutit...

Thanks for posting that picture of the shuttle being crane-lifted. I think there is a possibility that *much* of the wing's leading-edge structure was damaged before the launch by some undetermined, perhaps many, ways (one possibility being an improperly applied shuttle harness) providing multiple vulnerable targets on the wing for a lethal foam strike, the largest ever recorded (ie bipod):

This article talks about the great number of damaged T-seals on shuttles:
http://www.contracostatimes.com/mld/cctimes/news/5918674.htm

"Atlantis' eight cracked T-seals were replaced with spares. Discovery's seven damaged T-seals were returned to the manufacturer -- now known as Lockheed Martin Missiles and Fire Control in Dallas -- for repairs. The May 8 report provides no details on what happened to Columbia's cracked T-seals."

---

.. and repeating for your reference, my earlier post: the article by Matthew L. Wald and John Schwartz:

HOUSTON April 8: "Investigators said today that most of the recovered U-shaped panels from the leading edge of the Columbia's left wing had been split along the middle. They said the finding was significant, but they did not know what it meant."

and again from CAIB:
"We don't right now have a good answer for why we seem to see this fracture pattern, where not all, but most of R.C.C. panels seem to have broken right at that narrow neck there," Adm. Harold W. Gehman Jr., chairman of the independent commission in charge of the investigation, said of the reinforced carbon-carbon wing panels. "It could be they were all put under some torsion or some tension and they all cracked that way." (35)

---

This would line up with typical double-fault scenarios - where *only* having pre-existing leading edge fractures or *only* having a large foam hit wouldn't be enough to damage the RCC...

and could also help explain how foam can break an RCC panel, contrary to the early prevaling thought that even large foam just shouldn't be able to.

I think it might be interesting to see a drawing of the left wing showing known or possible wing-component fractures/weaknesses. The Admiral said most of the RCC's split, which ones did and which didn't, could there be a pattern?

4306- Keep on thinking, but tests 12 years and 17 missions prior, do not indicate a problem there.

However, take a piece styrafoam and stick it into the wind out your window driving at 70 mph and watch it crack.

Look at the construction of the leading edges, made from RCC. They aren't designed to fly sideways at 12000 mph or what ever it was. IMO The breaks/fractures were a result of the lack of aerodynamic control, not the cause of it.

think it might be interesting to see a drawing of the left wing showing known or possible wing-component fractures/weaknesses. The Admiral said most of the RCC's split, which ones did and which didn't, could there be a pattern?

All that was pretty well hashed out.

I understand your questioning of the results of the investigation, but if they had found any inkling of prior launch damage they would have jumped on it.

The foam idea was very hard for them to accept. The dynamic pressures the parts were subjected to during the breakup are of unimaginable scale. I would not read much into cracked carbon panels. (You should see what I can do to a carbon part accidentally)

I've said all along that there was probably another factor that made the RCC leading edge succeptable to damage by the foam/ice.

I still believe that the clowns in Palmdale may have damaged the RCC or the attachments when Columbia was out there for OMDP prior to STS-109. Earlier in this thread I posted an example of their screwups regarding the leading edge T-seals. All of those technicians out there were temporary hires, not long-term dedicated permanent workers like at KSC.

I think it is highly unlikely that somebody at KSC dropped anything on the RCC - I know (knew) these people and had they done that, they would have confessed.

It is not physically possible for the lifting sling to contact the wing leading edge - see the picture I posted.

another factor that made the RCC leading edge susceptible to damage by the foam/ice.

I think we can agree on this:

They went through a major weight/mass reduction on that particular shuttle.

It is quite possible that they screwed up the structural strength of the RCC by changing/removing hardware.

We may never know..................

With great regret, I must announce that due to the activity of the sysadmin and lack of an apology for it... I am totally disappointed with the ridiculous decision of the sysadmins here.

I have contributed innumerable hours to this board. I have been responsible for the content's accelerated legitimacy... so choosing to bar me from debating with unAmerican individuals with SPLIT loyalities (who apparently favor Israel's war mongers over American children and our families) is DISGUSTING!

http://www.freerepublic.com/focus/f-news/1073924/posts?page=81#81

I am stopping activity on this website due to the totally biased activity by the sysadmin on Sunday.

Instead of permitting free discussion and defense of our national interests, this website's sys admin elected to delete messages and to bar me from responding to the illegitimate postings of rancorous neocons who favor Israel's interests over United States national interests.

The altercations occured in that manipulated thread... you will see many postings by me deleted... they were referenced stories about the abusive conduct of Irving Moscowitz... a casino operator who is harassing the community of Hawaiian Gardens and surrounding areas...diverting money from the casino to fund arms dealers in Israel and more Jewish settlements creating more war and more arms purchases.

Instead of cogent discussion, these idiots decided to delete my messages.

OUTRAGEOUS!

This is Bones McCoy signing off... if you need to reach me... I will monitor Freepmail for one week.

Due to the conduct of this board, I am now of the conclusion that we will mobilize the citizens of our area to defeat liberal republicans at every turn.

If you want a war, we will defeat you with the Love of OUR sovereign Lord with A PASSION!

http://www.freerepublic.com/focus/f-news/1075193/posts

NASA Says 'No' To Hubble Reprieve

I think the shuttle's flight control software is partly responsible for loss of control of the Columbia.

In the CAIB's "Appendix D.9, Data Review and Timeline Reconstruction Report" page 7:

13:59:31 EI+922 Observed elevon deflections at LOS Left: -8.11 deg (up) Right: -1.15 deg (up)

13:59:32 EI+923 Observed aileron trim at LOS -2.3 degrees

This is exactly when CMDR Husband is speaking and is cut-off:

13:59:32 a.m. - STS-CDR: "Roger, uh be(cutoff; may have be 'before')"

13:59:32 a.m. - Loss of signal; last valid data frame.

and a little further down in Appendix D.9 ...

13:59:37.n EI+928.n Last aileron data The aileron position is now approx -5.2 deg with approx -2.5 deg of aileron trim. The rate of change of aileron trim had reached the maximum allowed by the flight control system.

.. we learn that the flight control system (software) didn't allow additional critically-needed aileron trim beyond it's pre-programmed (and possibly arbitrary) maximum rate.

I don't think it a coincidence that the shuttle went unstable at the same instant that the airleron trim rate reached it's software maximum.
And apparently, the CAIB missed this potential software error in their Fault tree:

"Volume II Appendix D.3, Fault Tree Closure Summary"

ACCF-CALC-6-08 FLIGHT CONTROL ERROR DUE TO FC SOFTWARE ERROR

The shuttle still may or may not have survived, but there should not have been unused control surfaces contributing to this disaster - at least CMDR Husband could have finished his sentence...

thanks for the ping and good catch, but I think no. (note - in this are I am not qualified). However, look at:

"13:59:31 EI+922 Observed elevon deflections at LOS Left: -8.11 deg (up) Right: -1.15 deg (up)"

Those are massive deflections, particularly at the super-hypersonic speed.

IMHO they are indications of just how screwed up the aerodynaics were at that point, and how hard they were automatically working to keep the ship stable, when it finally lost it.

And while, this is not a necessarily comparative example, think about what turning your steering wheel 8 degrees at 60 mph means - it means you are off the road in a second. (and how many turns does it take to go from center to hard turn?

I don't know what the full travel of the elevon, but 8 degrees is an awful lot, and only seen on landing, at about 500 feet or less above the ground.

In addition, it seems to me that there were some compensating thrusters firing also at this very same time.

So, what we have is stuff going very wrong, very fast and no warning bells going off, just as the bird 'trips' into instability.

Do you have a link for the report you are citing?

I know we have some pilots on FR, though I don't know if we have any on this thread, but I think we need a pilot to evaluate this.

But on thinking about it one more time, if nothing much was wrong, at this critical time, a programming error could have caused the excessive deflections, causing the fatal 'trip'.

But I think in the end, it was the last valient effort of the craft to maintain its stability in an untenable, disintigrating condition.

It's quite possible that the Flight Control software has built-in limits for each flight regime to protect the elevons from ripping off.

I doubt that software was designed to work with a gaping hole in the leading edge of one wing.

Aside: I talked to some USA people last week. USA had laid-off or fired about 100 people recently - mostly the older, higher paid ones. The management never learns.

This thread is still the most educational thread ever.

While I still pop in in an attempt to keep up, y'all are so far above me in knowledge that I don't think I could contribute much, but that won't stop me from putting my 2 cents in every now and then!

Keep up the great work guys and gals!

Yes, I agree that the flight control software did a fair job of keeping the shuttle stable under bad conditions, but the people flying it were 2 very good test pilots that are trained to fly hardware that doesn't quite work right. If the extra aileron trim were truly available to the flight control software, and wasn't used just for the sake of some software (arbitrary???) trim-rate number, then the flight control software made for a very poor test pilot.

I would doubly fault the flight control software for lulling the real test pilots into a false sense of security by not making it apparent much earlier that things were falling apart. Why is it that in post-mortum *anyone* could see in the flight data that things were terribly amiss but in-flight, *everyone* (ground control, Columbia crew) was completely clueless? Why put experienced test pilots in the shuttle when all they'll ever do is sit and watch while the flight control software burns-up everything around them?

By the time the flight control software had indicated anything to the pilots... "Hey, I'm having some trouble with stability here, could you guys downmode to inertial and help me out? Oh and by the way, the left wing is gone."

Parts of the left wing had been continually coming off and stability maintained, but the shuttle spinning out-of-control was Columbia's death.

D09.PDF

This appendix contains the basic timeline data that was used to reconstruct the final minutes of Columbiaʼs re-entry on February 1, 2003.

4315 - "It's quite possible that the Flight Control software has built-in limits for each flight regime to protect the elevons from ripping off. "

Sounds right to me. And not only that, the motors and gears and screws controlling them are limited in their speed range, and the computer program must take this into account.

Thanks for the info on more layoff at USA.

Thanks Budge. Glad you are member of our team. You support was invaluable in the creation of this thread. Too bad we have apparently lost Bones.

4317 - "I would doubly fault the flight control software for lulling the real test pilots into a false sense of security by not making it apparent much earlier that things were falling apart. Why is it that in post-mortum *anyone* could see in the flight data that things were terribly amiss but in-flight, *everyone* (ground control, Columbia crew) was completely clueless? Why put experienced test pilots in the shuttle when all they'll ever do is sit and watch while the flight control software burns-up everything around them? "

Yes, in fact that is one of the major things which most (at least me) of us noted, right at the beginning of this thread. Here they were, happily tooling along in a 'routine' return, and then all of a sudden, with no apparent warning, sploosh, right in mid sentence.

I thought we basically concluded that your summary:

"By the time the flight control software had indicated anything to the pilots... "Hey, I'm having some trouble with stability here, could you guys downmode to inertial and help me out? Oh and by the way, the left wing is gone."

is really, quite accurate, except they never figured out that the wing was gone.

I think the 'flight control' software worked well, but the 'craft configuration reporting system', failed miserably.

Just a note for you, pilots are not necessary on the shuttle. The systems are totally automated, from take off to landing. In fact, they have to purposely turn off the autopilot on landing, just to give the pilots something to do. The russian shuttle made two 'successful' flights with no crew (good thing as they couldn't survive the heat that entered the cockpit).