AVCOAT 5026-39 is a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...

code for a specific

ablative In grammar, the ablative case (pronounced ; sometimes abbreviated ) is a grammatical case for nouns, pronouns, and adjectives in the grammars of various languages; it is sometimes used to express motion away from something, among other uses. ...

heat shield material created by

Avco Avco Corporation is a subsidiary of Textron which operates Textron Systems Corporation and Lycoming. History The Aviation Corporation was formed on March 2, 1929, to prevent a takeover of CAM-24 airmail service operator Embry-Riddle Compa ...

(acquired by

Textron Textron Inc. is an American industrial conglomerate based in Providence, Rhode Island. Textron's subsidiaries include Arctic Cat, Bell Textron, Textron Aviation (which itself includes the Beechcraft, and Cessna brands), and Lycoming Engin ...

in 1984). It is an epoxy

novolac Novolaks (sometimes: novolacs) are low molecular weight polymers derived from phenols and formaldehyde. They are related to Bakelite, which is more highly crosslinked. The term comes from Swedish "lack" for lacquer and Latin "novo" for new, sinc ...

resin with special additives in a

fiberglass Fiberglass (American English) or fibreglass ( Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clo ...

honeycomb matrix. In fabrication, the empty honeycomb is bonded to the primary structure and the resin is gunned into each cell individually.

History

AVCOAT was used for the heat shield on NASA's

Apollo command module The Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother shi ...

. In its final form, this material was called AVCOAT 5026-39. Although AVCOAT was not used for the

Space Shuttle orbiter The Space Shuttle orbiter is the spaceplane component of the Space Shuttle, a partially reusable orbital spacecraft system that was part of the discontinued Space Shuttle program. Operated from 1977 to 2011 by NASA, the U.S. space agency, thi ...

s, NASA is using the material for its next generation

Orion spacecraft Orion (officially Orion Multi-Purpose Crew Vehicle or Orion MPCV) is a partially reusable crewed spacecraft used in NASA's Artemis program. The spacecraft consists of a Crew Module (CM) space capsule designed by Lockheed Martin and the Euro ...

. The Avcoat to be used on Orion is reformulated to meet environmental legislation that has been passed since the end of Apollo.

Specifications

*Material: epoxy

phenol formaldehyde resin Phenol formaldehyde resins (PF) or phenolic resins (also infrequently called phenoplasts) are synthetic polymers obtained by the reaction of phenol or substituted phenol with formaldehyde. Used as the basis for Bakelite, PFs were the first commerc ...

with special additives in a fiberglass

honeycomb A honeycomb is a mass of hexagonal prismatic wax cells built by honey bees in their nests to contain their larvae and stores of honey and pollen. Beekeepers may remove the entire honeycomb to harvest honey. Honey bees consume about of honey ...

matrix. *Density: *Post-ablation char-layer composition: of

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

and of

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...

Notable AVCOAT Installations

AVCOAT for Orion Crew Module

The

Orion Crew Module Orion () may refer to: Common meanings * Orion (constellation), named after the mythical hunter * Orion (mythology), a hunter in Greek mythology * Orion (spacecraft), NASA crew vehicle first launched in 2022 Arts and media Fictional en ...

was first designed for the NASA's

Constellation program The Constellation program (abbreviated CxP) was a crewed spaceflight program developed by NASA, the space agency of the United States, from 2005 to 2009. The major goals of the program were "completion of the International Space Station" and a " ...

, but later adapted the

Space Launch System The Space Launch System (SLS) is an American super heavy-lift expendable launch vehicle developed by NASA. As of 2022, SLS has the highest payload capacity of any rocket in operational service, as well as the greatest liftoff thrust of any r ...

to replace the

Space Shuttle program The Space Shuttle program was the fourth human spaceflight program carried out by the U.S. National Aeronautics and Space Administration (NASA), which accomplished routine transportation for Earth-to-orbit crew and cargo from 1981 to 2011. I ...

. This spacecraft was planned to take astronauts to the

International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ( ...

in 2015 and to the moon in 2024. ASRC AVCOAT

In the past, the honeycomb paste-lik
fiberglass material is gunned into each cells individually
On the other hand, the Orion heat shield is bonded onto the base of the heat shield. To protect the Crew Module during Earth re-entry, the dish shaped AVCOAT heat shield ablator system was selected.

announced that this module will encounter temperature as high as 5,000 degrees Fahrenheit (2760°C). Licensed by

, AVCOAT material is produced at New Orleans's

Michoud Assembly Facility The Michoud Assembly Facility (MAF) is an manufacturing complex owned by NASA in New Orleans East, a district within New Orleans, Louisiana, in the United States. Organizationally it is part of NASA's Marshall Space Flight Center, and is current ...

by Lockheed Martin. This heat shield will be installed at the base of the crew module to provide a controlled erosion moving heat away from the crew module into the atmosphere. This process of erosion is called “ablation” - where materials are removed by vaporization or erosion by continuous contact with the supersonic velocity of gas flow and high temperature; thus the construction of honeycomb structure was made. AVCOAT Specimen Testing

John Kowal, Orion's thermal protections systems manager at Johnson Space Center, discussed the biggest challenge with AVCOAT has been reviving the technology for manufacturing with similar performance as demonstrated in the Apollo Missions. The EFT-1 mission performed two orbits of Earth providing the opportunity for Orion's systems to be tested. It took about four hours with the splash down in the ocean.

AVCOAT for Apollo Missions

AVCOAT was first used on the parts of the Apollo spacecraft orbiter and as a unit attached to the crew module in the past. It is a honeycomb structure. NASA confirmed that this is made of silica fibers with an epoxy novolac resin filled in a fiberglass-phenolic manufactured directly onto the heat shield. NASA's Apollo Flight Test Analysis, AVCOAT 5026-39/HC-G material was tested on the nose cap of a peacemaker vehicle. The temperature and ablation measurements were made at four locations on the nose cap. The report noted that the wear of the shield is due to the aerodynamic shear and heating rate. The report also noted that scientists believed that the ablation was done in a controlled manner. After the Apollo missions, the production was then put in place for the purpose of studying. Orion Chief Engineer requested the heat shield to be redesigned, however the final design was not selected.

AVCOAT Heat Shield Research and Installation for Orion Crew Module

The AVCOAT material heat shield went through several rounds of testing before being chosen for the installation. The Investigating the Thermochemical Response of Avcoat TPS from First Principles for Comparison with EFT-1 Data, things being tested on the heat-shield include: model gas transport, heat transfer, and TPS material regression. Orion's 16.5 feet AVCOAT heat shield was secured onto the Orion Crew Module using 68 bolts by Technicians at NASA's Kennedy Space Center (KSC) in Florida. This heat shield is covered in titanium truss and a composite substitute with an addition skin made of carbon fiber layers. Orion's heat-shield was designed and manufactured by Lockheed Martin. The heat shield is like pieces of a honeycomb puzzle that all must fit together perfectly and the bolt fittings must be lined up. After the heat-shield's installation, access to components of the crew module became difficult or no longer accessible.

Flight use

Uncrewed

*Several subscale test flightsFlight-Test Analysis Of Apollo Heat-Shield Material Using The Pacemaker Vehicle System

Technical Note D-4713, pp. 8, 1968-08, accessed 2010-12-26. ''"Avcoat 5026-39/HC-G is an epoxy novolac resin with special additives in a fiberglass honeycomb matrix. In fabrication, the empty honeycomb is bonded to the primary structure and the resin is gunned into each cell individually. ... The overall density of the material is 32 lb/ft³ (512 kg/m³). The char of the material is composed mainly of silica and carbon. It is necessary to know the amounts of each in the char because in the ablation analysis the silica is considered to be inert, but the carbon is considered to enter into exothermic reactions with oxygen. ... At 2160 ° R (1200° K), 54 percent by weight of the virgin material has volatilized and 46 percent has remained as char. ... In the virgin material, 25 percent by weight is silica, and since the silica is considered to be inert the char-layer composition becomes 6.7 lb/ft³ (107.4 kg/m³) of carbon and 8 lb/ft³ (128.1 kg/m³) of silica."'' *

AS-201 AS-201 (or SA-201), flown February 26, 1966, was the first uncrewed test flight of an entire production Block I Apollo command and service module and the Saturn IB launch vehicle. The spacecraft consisted of the second Block I command module ...

Apollo Experience Report - Thermal Protection Subsystem (Jan. 1974)
/ref> *

AS-202 AS-202 (also referred to as SA-202) was the second uncrewed, suborbital test flight of a production Block I Apollo command and service module launched with the Saturn IB launch vehicle. It was launched on August 25, 1966, and was the first fl ...

Apollo 4 Apollo 4 (November 9, 1967), also known as SA-501, was the uncrewed first test flight of the Saturn V launch vehicle, the rocket that eventually took astronauts to the Moon. The space vehicle was assembled in the Vehicle Assembly Build ...

Apollo 6 Apollo 6 (April 4, 1968), also known as AS-502, was the third and final uncrewed flight in the United States' Apollo Program and the second test of the Saturn V launch vehicle. It qualified the Saturn V to be used on crewed missions, as happen ...

* EFT-1 * Artemis 1

Crewed

* Apollo 7, Apollo 8,

Apollo 9 Apollo 9 (March 313, 1969) was the third human spaceflight in NASA's Apollo program. Flown in low Earth orbit, it was the second crewed Apollo mission that the United States launched via a Saturn V rocket, and was the first flight of the ful ...

Apollo 10 Apollo 10 (May 18–26, 1969) was a human spaceflight, the fourth crewed mission in the United States Apollo program, and the second (after Apollo8) to orbit the Moon. NASA described it as a "dress rehearsal" for the first Moon landing, and ...

Apollo 11 Apollo 11 (July 16–24, 1969) was the American spaceflight that first landed humans on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin landed the Apollo Lunar Module ''Eagle'' on July 20, 1969, at 20:17 UTC, ...

, Apollo 12, Apollo 13, Apollo 14 * Apollo 15, Apollo 16, Apollo 17 *

Skylab 2 Skylab 2 (also SL-2 and SLM-1) was the first crewed mission to Skylab, the first American orbital space station. The mission was launched on an Apollo command and service module by a Saturn IB rocket on May 25, 1973, and carried NASA astronau ...

Skylab 3 Skylab 3 (also SL-3 and SLM-2) was the second crewed mission to the first American space station, Skylab. The mission began on July 28, 1973, with the launch of NASA astronauts Alan Bean, Owen Garriott, and Jack Lousma in the Apollo command ...

Skylab 4 Skylab 4 (also SL-4 and SLM-3) was the third crewed Skylab mission and placed the third and final crew aboard the first American space station. The mission began on November 16, 1973, with the launch of Gerald P. Carr, Edward Gibson, and Wil ...

Apollo–Soyuz Test Project Apollo–Soyuz was the first crewed international space mission, carried out jointly by the United States and the Soviet Union in July 1975. Millions of people around the world watched on television as a United States Apollo spacecraft docked ...

References

External links

Apollo Experience Report - Thermal Protection Subsystem (Jan. 1974)

Apollo Seals: A Basis for the Crew Exploration Vehicle Seals (Nov. 2006)

Notes on Earth Atmospheric Entry for Mars Sample Return Missions (Sept. 2006)
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