El sistema de protección térmica del Transbordador Espacial (TPS) es la barrera que protegió al Transbordador Espacial Orbiter durante el abrasador calor de 1.650 ° C (3.000 ° F ) de la reentrada atmosférica . Un objetivo secundario era protegerse del calor y el frío del espacio mientras estaba en órbita. [1]
Materiales [ editar ]
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El TPS cubría esencialmente toda la superficie del orbitador y constaba de siete materiales diferentes en diferentes ubicaciones según la cantidad de protección térmica requerida:
- Carbono-carbono reforzado (RCC), utilizado en la tapa del morro, el área del mentón entre la tapa del morro y las puertas del tren de aterrizaje de morro, la punta de flecha detrás de la puerta del tren de aterrizaje de morro y los bordes de ataque del ala. Se utiliza cuando la temperatura de reentrada supera los 1260 ° C (2300 ° F).
- Baldosas de aislamiento de superficie reutilizable de alta temperatura (HRSI), utilizadas en la parte inferior del orbitador. Fabricado en cerámica de sílice revestida LI-900 . Se utiliza cuando la temperatura de reentrada es inferior a 1260 ° C.
- Baldosas de aislamiento de compuesto refractario fibroso (FRCI), que se utiliza para proporcionar mayor resistencia, durabilidad, resistencia al agrietamiento del revestimiento y reducción de peso. Algunas baldosas HRSI fueron reemplazadas por este tipo.
- Mantas de aislamiento flexible (FIB), un aislamiento de superficie acolchado y flexible similar a una manta. Se utiliza cuando la temperatura de reentrada es inferior a 649 ° C (1200 ° F).
- Baldosas de aislamiento de superficie reutilizable de baja temperatura (LRSI), anteriormente utilizadas en la parte superior del fuselaje, pero en su mayoría fueron reemplazadas por FIB. Se utiliza en rangos de temperatura más o menos similares a FIB.
- Baldosas de aislamiento fibroso unipiece endurecido (TUFI), una loseta más fuerte y resistente que se empezó a utilizar en 1996. Se utiliza en áreas de alta y baja temperatura.
- Aislamiento de superficie reutilizable de fieltro (FRSI). Mantas de fieltro blanco Nomex en las puertas de la bahía de carga superior, partes del fuselaje medio y de popa del fuselaje, partes de la superficie superior del ala y una parte de las cápsulas OMS / RCS . Se utiliza cuando las temperaturas se mantienen por debajo de 371 ° C (700 ° F).
Cada tipo de TPS tenía características específicas de protección contra el calor, resistencia al impacto y peso, que determinaban los lugares donde se usaba y la cantidad utilizada.
El transbordador TPS tiene tres características clave que lo distinguen del TPS utilizado en naves espaciales anteriores:
- Reutilizable
- Las naves espaciales anteriores generalmente usaban escudos térmicos ablativos que se quemaban durante la reentrada y, por lo tanto, no se podían reutilizar. Este aislamiento era robusto y confiable, y la naturaleza de un solo uso era apropiado para un vehículo de un solo uso. Por el contrario, la lanzadera reutilizable requería un sistema de protección térmica reutilizable.
- Ligero
- Los escudos térmicos ablativos anteriores eran muy pesados. Por ejemplo, el escudo térmico ablativo en el módulo de comando Apollo comprendía aproximadamente el 15% del peso del vehículo. El transbordador alado tenía mucha más superficie que las naves espaciales anteriores, por lo que un TPS liviano era crucial.
- Frágil
- La única tecnología conocida a principios de la década de 1970 con las características térmicas y de peso requeridas también era tan frágil, debido a la muy baja densidad, que se podía triturar fácilmente una loseta de TPS a mano.
Propósito [ editar ]
La estructura de aluminio del orbitador no podía soportar temperaturas superiores a 175 ° C (347 ° F) sin fallas estructurales. [2] El calentamiento aerodinámico durante la reentrada empujaría la temperatura muy por encima de este nivel en áreas, por lo que se necesitaba un aislante eficaz.
Calefacción de reentrada [ editar ]
El calentamiento de reentrada difiere del calentamiento atmosférico normal asociado con los aviones a reacción, y esto regía el diseño y las características del TPS. La piel de los aviones a reacción de alta velocidad también puede calentarse, pero esto se debe al calentamiento por fricción debido a la fricción atmosférica , similar a calentarse las manos frotándolas. El orbitador volvió a entrar en la atmósfera como un cuerpo contundente al tener un ángulo de ataque muy alto (40 °) , con su amplia superficie inferior orientada hacia la dirección de vuelo. Más del 80% del calentamiento que experimenta el orbitador durante la reentrada es causado por la compresión del aire delante del vehículo hipersónico, de acuerdo con la relación termodinámica básica entre presión y temperatura . Una onda de choque calientefue creado frente al vehículo, lo que desvió la mayor parte del calor e impidió que la superficie del orbitador contactara directamente con el pico de calor. Por lo tanto, el calentamiento de reentrada fue en gran parte una transferencia de calor por convección entre la onda de choque y la piel del orbitador a través de plasma sobrecalentado . [1] La clave para un escudo reutilizable contra este tipo de calentamiento es un material de muy baja densidad, similar a cómo una botella termo inhibe la transferencia de calor por convección. [ cita requerida ]
Algunas aleaciones metálicas de alta temperatura pueden soportar el calor de reentrada; simplemente se calientan y vuelven a irradiar el calor absorbido. Esta técnica, llamada protección térmica del disipador de calor , fue planificada para el vehículo espacial alado X-20 Dyna-Soar . [1]Sin embargo, la cantidad de metal de alta temperatura necesaria para proteger un vehículo grande como el Space Shuttle Orbiter habría sido muy pesada y habría supuesto una grave penalización para el rendimiento del vehículo. De manera similar, el TPS ablativo sería pesado, posiblemente perturbaría la aerodinámica del vehículo ya que se quemó durante el reentrada y requeriría un mantenimiento significativo para volver a aplicarlo después de cada misión. (Desafortunadamente, la loseta TPS, que originalmente se especificó para que nunca recibiera golpes de escombros durante el lanzamiento, en la práctica también debía ser inspeccionada y reparada de cerca después de cada aterrizaje, debido a los daños incurridos invariablemente durante el ascenso, incluso antes de que se establecieran nuevas políticas de inspección en órbita tras la pérdida del transbordador espacial Columbia ).
Descripción detallada [ editar ]
El TPS era un sistema de diferentes tipos de protección, no solo baldosas de sílice. Están en dos categorías básicas: TPS de mosaico y TPS sin mosaico. [1] Los principales criterios de selección utilizaron la protección de peso más ligero capaz de soportar el calor en un área determinada. Sin embargo, en algunos casos se utilizó un tipo más pesado si se necesitaba una resistencia adicional al impacto. Las mantas FIB se adoptaron principalmente para un mantenimiento reducido, no por razones térmicas o de peso.
Gran parte de la lanzadera estaba cubierta con baldosas de sílice LI-900 , hechas de arena de cuarzo esencialmente muy pura. [1] El aislamiento impidió la transferencia de calor a la piel y estructura de aluminio del orbitador subyacente . Estos azulejos eran tan malos conductores de calor que uno podía sostener uno por los bordes mientras aún estaba al rojo vivo. [3] Había alrededor de 24,300 [4] baldosas únicas instaladas individualmente en el vehículo, [ cita requerida ] por lo que el orbitador ha sido llamado "la fábrica de ladrillos voladores". [5] [6] Investigadores de la Universidad de Minnesota y la Universidad Estatal de Pensilvania están realizando las simulaciones atomísticas para obtener una descripción precisa de las interacciones entre el oxígeno atómico y molecular con superficies de sílice para desarrollar mejores sistemas de protección contra la oxidación a alta temperatura para los bordes de ataque en vehículos hipersónicos. [7]
Las baldosas no se sujetaron mecánicamente al vehículo, sino que se pegaron. Dado que las baldosas quebradizas no podían flexionarse con la piel del vehículo subyacente, se pegaron a almohadillas de aislamiento de deformación (SIP) de fieltro Nomex con adhesivo de silicona vulcanizante a temperatura ambiente (RTV), que a su vez se pegaron a la piel del orbitador. Estos aislaron las baldosas de las desviaciones y expansiones estructurales del orbitador. [1]
Tipos de mosaicos [ editar ]
Aislamiento de superficie reutilizable de alta temperatura (HRSI) [ editar ]
Las baldosas negras HRSI brindan protección contra temperaturas de hasta 1.260 ° C (2.300 ° F). Había 20.548 tejas HRSI que cubrían las puertas del tren de aterrizaje, las puertas de conexión umbilical del tanque externo y el resto de las superficies inferiores del orbitador. También se utilizaron en áreas en el fuselaje delantero superior, partes de las cápsulas del sistema de maniobra orbital , borde de ataque del estabilizador vertical, elevonbordes posteriores y superficie de la solapa de la parte superior del cuerpo. Varían en grosor de 1 a 5 pulgadas (2,5 a 12,7 cm), dependiendo de la carga de calor encontrada durante la reentrada. A excepción de las áreas de cierre, estas baldosas eran normalmente de 15 por 15 cm (6 por 6 pulgadas) cuadradas. La loseta HRSI estaba compuesta de fibras de sílice de alta pureza. El noventa por ciento del volumen de la baldosa era espacio vacío, lo que le da una densidad muy baja (9 lb / pie cúbico o 140 kg / m 3 ) lo que lo hace lo suficientemente ligero para vuelos espaciales. [1] Las baldosas sin revestimiento tenían un aspecto de color blanco brillante y se parecían más a una cerámica sólida que al material espumoso que eran.
El revestimiento negro de las baldosas era vidrio curado por reacción (RCG), del cual el vidrio de borosilicato y tetrasilicida eran algunos de varios ingredientes. Se aplicó RCG a todos menos un lado de la loseta para proteger la sílice porosa y aumentar las propiedades del disipador de calor. El revestimiento estaba ausente en un pequeño margen de los lados adyacentes al lado no revestido (inferior). Para impermeabilizar la baldosa, se inyectó dimetiletoxisilano en las baldosas con una jeringa. La densificación de la loseta con ortosilicato de tetraetilo (TEOS) también ayudó a proteger la sílice y agregó impermeabilización adicional.
An uncoated HRSI tile held in the hand feels like a very light foam, less dense than styrofoam, and the delicate, friable material must be handled with extreme care to prevent damage. The coating feels like a thin, hard shell and encapsulates the white insulating ceramic to resolve its friability, except on the uncoated side. Even a coated tile feels very light, lighter than a same-sized block of styrofoam. As expected for silica, they are odorless and inert.[citation needed]
HRSI was primarily designed to withstand transition from areas of extremely low temperature (the void of space, about −270 °C or −454 °F) to the high temperatures of re-entry (caused by interaction, mostly compression at the hypersonic shock, between the gases of the upper atmosphere & the hull of the Space Shuttle, typically around 1,600 °C or 2,910 °F).[1]
Fibrous Refractory Composite Insulation Tiles (FRCI)[edit]
The black FRCI tiles provided improved durability, resistance to coating cracking and weight reduction. Some HRSI tiles were replaced by this type.[1]
Toughened unipiece fibrous insulation (TUFI)[edit]
A stronger, tougher tile which came into use in 1996. TUFI tiles came in high temperature black versions for use in the orbiter's underside, and lower temperature white versions for use on the upper body. While more impact resistant than other tiles, white versions conducted more heat which limited their use to the orbiter's upper body flap and main engine area. Black versions had sufficient heat insulation for the orbiter underside but had greater weight. These factors restricted their use to specific areas.[1]
Low-temperature reusable surface insulation (LRSI)[edit]
White in color, these covered the upper wing near the leading edge. They were also used in selected areas of the forward, mid, and aft fuselage, vertical tail, and the OMS/RCS pods. These tiles protected areas where reentry temperatures are below 1,200 °F (649 °C). The LRSI tiles were manufactured in the same manner as the HRSI tiles, except that the tiles were 8 by 8 inches (20 by 20 cm) square and had a white RCG coating made of silica compounds with shiny aluminium oxide.[1] The white color was by design and helped to manage heat on orbit when the orbiter was exposed to direct sunlight.
These tiles were reusable for up to 100 missions with refurbishment (100 missions was also the design lifetime of each orbiter). They were carefully inspected in the Orbiter Processing Facility after each mission, and damaged or worn tiles were immediately replaced before the next mission. Fabric sheets known as gap fillers were also inserted between tiles where necessary. These allowed for a snug fit between tiles, preventing excess plasma from penetrating between them, yet allowing for thermal expansion and flexing of the underlying vehicle skin.
Prior to the introduction of FIB blankets, LRSI tiles occupied all of the areas now covered by the blankets, including the upper fuselage and the whole surface of the OMS pods. This TPS configuration was only used on Columbia and Challenger.
Non-tile TPS[edit]
Flexible Insulation Blankets/Advanced Flexible Reusable Insulation (FIB/AFRSI)[edit]
Developed after the initial delivery of Columbia and first used on the OMS pods of Challenger.[8] This white low-density fibrous silica batting material had a quilt-like appearance, and replaced the vast majority of the LRSI tiles. They required much less maintenance than LRSI tiles yet had about the same thermal properties. After their limited use on Challenger, they were used much more extensively beginning with Discovery and replaced many of the LRSI tiles on Columbia after the loss of Challenger.
Reinforced Carbon-Carbon (RCC)[edit]
The light gray material which withstood reentry temperatures up to 1,510 °C (2,750 °F) protected the wing leading edges and nose cap. Each of the orbiters' wings had 22 RCC panels about 1⁄4 to 1⁄2 inch (6.4 to 12.7 mm) thick. T-seals between each panel allowed for thermal expansion and lateral movement between these panels and the wing.
RCC was a laminated composite material made from carbon fibres impregnated with a phenolic resin. After curing at high temperature in an autoclave, the laminate was pyrolized to convert the resin to pure carbon. This was then impregnated with furfural alcohol in a vacuum chamber, then cured and pyrolized again to convert the furfural alcohol to carbon. This process was repeated three times until the desired carbon-carbon properties were achieved.
To provide oxidation resistance for reuse capability, the outer layers of the RCC were coated with silicon carbide. The silicon-carbide coating protected the carbon-carbon from oxidation. The RCC was highly resistant to fatigue loading that was experienced during ascent and entry. It was stronger than the tiles and was also used around the socket of the forward attach point of the orbiter to the External Tank to accommodate the shock loads of the explosive bolt detonation. RCC was the only TPS material that also served as structural support for part of the orbiter's aerodynamic shape: the wing leading edges and the nose cap. All other TPS components (tiles and blankets) were mounted onto structural materials that supported them, mainly the aluminium frame and skin of the orbiter.
Nomex Felt Reusable Surface Insulation (FRSI)[edit]
This white, flexible fabric offered protection at up to 371 °C (700 °F). FRSI covered the orbiter's upper wing surfaces, upper payload bay doors, portions of the OMS/RCS pods, and aft fuselage.
Gap fillers[edit]
Gap fillers were placed at doors and moving surfaces to minimize heating by preventing the formation of vortices. Doors and moving surfaces created open gaps in the heat protection system that had to be protected from heat. Some of these gaps were safe, but there were some areas on the heat shield where surface pressure gradients caused a crossflow of boundary layer air in those gaps.
The filler materials were made of either white AB312 fibers or black AB312 cloth covers (which contain alumina fibers). These materials were used around the leading edge of the nose cap, windshields, side hatch, wing, trailing edge of elevons, vertical stabilizer, the rudder/speed brake, body flap, and heat shield of the shuttle's main engines.
On STS-114, some of this material was dislodged and determined to pose a potential safety risk. It was possible that the gap filler could cause turbulent airflow further down the fuselage, which would result in much higher heating, potentially damaging the orbiter. The cloth was removed during a spacewalk during the mission.
Weight considerations[edit]
While reinforced carbon–carbon had the best heat protection characteristics, it was also much heavier than the silica tiles and FIBs, so it was limited to relatively small areas. In general the goal was to use the lightest weight insulation consistent with the required thermal protection. Density of each TPS type:
| Material | Density | |
|---|---|---|
| (kg/m³) | (lb/cu ft) | |
| Reinforced carbon–carbon | 1986 | 124 |
| LI-2200 tiles | 352 | 22 |
| Fibrous refractory composite insulation tiles | 192 | 12 |
| LI-900 tiles (black or white) | 144 | 9 |
| Flexible insulation blankets | 144 | 9 |
Total area and weight of each TPS type (used on Orbiter 102, pre-1996):
| TPS type | Color | Area (m2) | Areal density (kg/m2) | Weight (kg) |
|---|---|---|---|---|
| Felt reusable surface insulation | White | 332.7 | 1.6 | 532.1 |
| Low-temperature reusable surface insulation | Off-white | 254.6 | 3.98 | 1014.2 |
| High-temperature reusable surface insulation | Black | 479.7 | 9.2 | 4412.6 |
| Reinforced carbon–carbon | Light gray | 38.0 | 44.7 | 1697.3 |
| Miscellaneous | 918.5 | |||
| Total | N/A | 1105.0 | N/A | 8574.4 |
Early TPS problems[edit]
Slow tile application[edit]
Tiles often fell off and caused much of the delay in the launch of STS-1, the first shuttle mission, which was originally scheduled for 1979 but did not occur until April 1981. NASA was unused to lengthy delays in its programs, and was under great pressure from the government and military to launch soon. In March 1979 it moved the incomplete Columbia, with 7,800 of the 31,000 tiles missing, from the Rockwell International plant in Palmdale, California to Kennedy Space Center in Florida. Beyond creating the appearance of progress in the program, NASA hoped that the tiling could be finished while the rest of the orbiter was prepared. This was a mistake; some of the Rockwell tilers disliked Florida and soon returned to California, and the Orbiter Processing Facility was not designed for manufacturing and was too small for its 400 workers.[10]
Each tile used cement that required 16 hours to cure. After the tile was affixed to the cement, a jack held it in place for another 16 hours. In March 1979 it took each worker 40 hours to install one tile; by using young, efficient college students during the summer the pace sped up to 1.8 tiles per worker per week. Thousands of tiles failed stress tests and had to be replaced. By fall NASA realized that the speed of tiling would determine the launch date. The tiles were so problematic that officials would have switched to any other thermal protection method, but none other existed.[10]
Because it had to be ferried without all tiles the gaps were filled with material to maintain the Shuttle's aerodynamics while in transit.[11]
Concern over "zipper effect"[edit]
The tile TPS was an area of concern during shuttle development, mainly concerning adhesion reliability. Some engineers thought a failure mode could exist whereby one tile could detach, and resulting aerodynamic pressure would create a "zipper effect" stripping off other tiles. Whether during ascent or reentry, the result would be disastrous.
Concern over debris strikes[edit]
Another problem was ice or other debris impacting the tiles during ascent. This had never been fully and thoroughly solved, as the debris had never been eliminated, and the tiles remained susceptible to damage from it. NASA's final strategy for mitigating this problem was to aggressively inspect for, assess, and address any damage that may occur, while on orbit and before reentry, in addition to on the ground between flights.
Early tile repair plans[edit]
These concerns were sufficiently great that NASA did significant work developing an emergency-use tile repair kit which the STS-1 crew could use before deorbiting. By December 1979, prototypes and early procedures were completed, most of which involved equipping the astronauts with a special in-space repair kit and a jet pack called the Manned Maneuvering Unit, or MMU, developed by Martin Marietta.
Another element was a maneuverable work platform which would secure an MMU-propelled spacewalking astronaut to the fragile tiles beneath the orbiter. The concept used electrically controlled adhesive cups which would lock the work platform into position on the featureless tile surface. About one year before the 1981 STS-1 launch, NASA decided the repair capability was not worth the additional risk and training, so discontinued development.[12] There were unresolved problems with the repair tools and techniques; also further tests indicated the tiles were unlikely to come off. The first shuttle mission did suffer several tile losses, but they were in non-critical areas, and no "zipper effect" occurred.
Columbia accident and aftermath[edit]
On February 1, 2003, the Space Shuttle Columbia was destroyed on reentry due to a failure of the TPS. The investigation team found and reported that the probable cause of the accident was that during launch, a piece of foam debris punctured an RCC panel on the left wing's leading edge and allowed hot gases from the reentry to enter the wing and disintegrate the wing from within, leading to eventual loss of control and breakup of the shuttle.
The Space Shuttle's thermal protection system received a number of controls and modifications after the disaster. They were applied to the three remaining shuttles, Discovery, Atlantis and Endeavour in preparation for subsequent mission launches into space.
On 2005's STS-114 mission, in which Discovery made the first flight to follow the Columbia accident, NASA took a number of steps to verify that the TPS was undamaged. The 50-foot-long (15 m) Orbiter Boom Sensor System, a new extension to the Remote Manipulator System, was used to perform laser imaging of the TPS to inspect for damage. Prior to docking with the International Space Station, Discovery performed a Rendezvous Pitch Maneuver, simply a 360° backflip rotation, allowing all areas of the vehicle to be photographed from ISS. Two gap fillers were protruding from the orbiter's underside more than the nominally allowed distance, and the agency cautiously decided it would be best to attempt to remove the fillers or cut them flush rather than risk the increased heating they would cause. Even though each one protruded less than 3 cm (1.2 in), it was believed that leaving them could cause heating increases of 25% upon reentry.
Because the orbiter did not have any handholds on its underside (as they would cause much more trouble with reentry heating than the protruding gap fillers of concern), astronaut Stephen K. Robinson worked from the ISS's robotic arm, Canadarm2. Because the TPS tiles were quite fragile, there had been concern that anyone working under the vehicle could cause more damage to the vehicle than was already there, but NASA officials felt that leaving the gap fillers alone was a greater risk. In the event, Robinson was able to pull the gap fillers free by hand, and caused no damage to the TPS on Discovery.
Tile donations[edit]
As of 2010[update], with the impending Space Shuttle retirement, NASA is donating TPS tiles to schools, universities, and museums for the cost of shipping -- US$23.40 each.[13] About 7000 tiles were available on a first-come, first-served basis, but limited to one each per institution.[13]
See also[edit]
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- Space Shuttle program
- Space Shuttle Columbia disaster
- Columbia Accident Investigation Board
References[edit]
- "When the Space Shuttle finally flies", article written by Rick Gore. National Geographic (pp. 316–347. Vol. 159, No. 3. March 1981).
- Space Shuttle Operator's Manual, by Kerry Mark Joels and Greg Kennedy (Ballantine Books, 1982).
- The Voyages of Columbia: The First True Spaceship, by Richard S. Lewis (Columbia University Press, 1984).
- A Space Shuttle Chronology, by John F. Guilmartin and John Mauer (NASA Johnson Space Center, 1988).
- Space Shuttle: The Quest Continues, by George Forres (Ian Allan, 1989).
- Information Summaries: Countdown! NASA Launch Vehicles and Facilities, (NASA PMS 018-B (KSC), October 1991).
- Space Shuttle: The History of Developing the National Space Transportation System, by Dennis Jenkins (Walsworth Publishing Company, 1996).
- U.S. Human Spaceflight: A Record of Achievement, 1961–1998. NASA – Monographs in Aerospace History No. 9, July 1998.
- Space Shuttle Thermal Protection System by Gary Milgrom. February, 2013. Free iTunes ebook download. https://itunes.apple.com/us/book/space-shuttle-thermal-protection/id591095660?mt=11
Notes[edit]
- ^ a b c d e f g h i j k Jenkins, Dennis R. (2007). Space Shuttle: The History of the National Space Transportation System. Voyageur Press. p. 524 pages. ISBN 978-0-9633974-5-4.
- ^ Day, Dwayne A. "Shuttle Thermal Protection System (TPS)". U.S. Centennial of Flight Commission. Archived from the original on 2006-08-26.
- ^ Gore, Rick (March 1981). "When the Space Shuttle Finally Flies". National Geographic. 159 (3): 316–347. Retrieved 2012-12-20.
- ^ https://www.nasa.gov/sites/default/files/atoms/files/shuttle_tiles_2_4v2.pdf
- ^ https://www.nytimes.com/2011/07/05/science/space/05shuttle.html
- ^ https://www.nytimes.com/1982/11/17/us/ugly-duckling-of-space-taught-skeptics-to-beleive.html
- ^ Anant D. Kulkarni, Donald G. Truhlar, Sriram Goverapet Srinivasan, Adri C. T. van Duin, Paul Norman, and Thomas E. Schwartzentruber (2013). "Oxygen Interactions with Silica Surfaces: Coupled Cluster and Density Functional Investigation and the Development of a New ReaxFF Potential". J. Phys. Chem. C. 117: 258–269. doi:10.1021/jp3086649.CS1 maint: multiple names: authors list (link)
- ^ "STS-6 Press Information" (PDF). Rockwell International – Space Transportation & Systems Group. March 1983. p. 7. Retrieved 12 July 2013.
Orbital maneuvering system/reaction control system low temperature reusable surface insulation tiles (LRSI) replaced with advanced flexible reusable surface insulation (AFRSI) consisting of a sewn composite quilted fabric blanket with same silica tile material sandwiched between outer and inner blanket.
- ^ [1]
- ^ a b Lewis, Richard S. (1984). The voyages of Columbia: the first true spaceship. Columbia University Press. pp. 83–91. ISBN 0-231-05924-8.
- ^ [2]
- ^ Houston Chronicle, March 9, 2003
- ^ a b "NASA offers space shuttle tiles to school and universities". December 1, 2010. Archived from the original on 2011-07-08.
External links[edit]
- https://web.archive.org/web/20060909094330/http://www-pao.ksc.nasa.gov/kscpao/nasafact/tps.htm
- https://web.archive.org/web/20110707103505/http://ww3.albint.com/about/research/Pages/protectionSystems.aspx
- http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_sys.html
- https://web.archive.org/web/20160307090308/http://science.ksc.nasa.gov/shuttle/nexgen/Nexgen_Downloads/Shuttle_Gordon_TPS-PUBLIC_Appendix.pdf
