When the Apollo 11 flight crew returned from the historic Moon expedition on July 24, 1969, their command module pierced the Earth’s atmosphere traveling at 36,237 feet per second and became engulfed in a fireball burning at 5,000 degrees Fahrenheit.
The capsule’s heat shield – developed with input from Southern Research – protected the astronauts, with a special epoxy resin in the shield’s honeycomb backing structure dissipating the intense heat while vaporizing in the hellish environment.
Long before the Apollo 11 crew splashed down in the Pacific, Southern Research’s expertise in high-temperature testing provided NASA with important information about the materials being considered for the spacecraft’s thermal protection system.
Under contracts with NASA’s Langley Research Center in Virginia during the 1960s, Southern Research engineers working in test facilities exposed specimens of various classes of materials to the harsh conditions of re-entry, including temperatures nearly three times the melting point of steel.
In rigorous evaluations under extreme conditions, Southern Research engineers recorded more than a dozen different thermal and mechanical properties of the heat shield materials. Afterwards, mathematical models were developed to predict actual performance during re-entry.
AN UNUSUAL ‘BALL OF STRING’
Before the Apollo program even got off the ground, Birmingham-based Southern Research had performed high-temperature work for government sponsors and aerospace companies, beginning in the 1950s. Under the guidance of Coultas “Colt” Pears, its high-temp testing lab gained an international reputation for work on advanced materials like carbon-carbon composites.
Pears recalled that he first saw the exotic composite material early on, when “a fellow walked in with a ball of string and asked me to dip it in sugar water and heat it to 5000°F.”
“It was 15 years before the material became a heat shield or nose tip,” he said.
In addition to work on the space program, Southern Research engineers conducted important materials evaluation work on key U.S. missile systems. In 1967, the U.S. Navy recognized the organization’s role in the development of the Polaris missile system with a special award.
Pears’ ambition at Southern Research was to create a world-class high-temperature materials characterization laboratory. His lab developed a facility that could make accurate measurements of loads on brittle high-temperature metals. Another innovation involved new optical strain measurement techniques.
The first known measurements of tensile properties at 6,000 degrees Fahrenheit took place at Southern Research, and extreme-temperature testing and analysis became a core competency of the organization.
ASSISTING APOLLO SPACECRAFT
Southern Research’s contributions to the Apollo program weren’t limited to materials evaluation.
Engineers were involved in several instrument development programs. One of those focused on the design of a radiometer that was paired with a telescope to take temperature readings on the Moon’s surface. The instrument was part of a critical NASA program to select landing sites for Apollo missions to the lunar surface.
In another Apollo project, Southern Research engineers used graphite sensing elements to build several calorimeters to measure heating rates on various portions of the Saturn booster exit.
Other groups at Southern Research also got involved in work on the Apollo spacecraft program.
Around the time of the Apollo 1 fire in 1967, the organization established onsite laboratory operations at Kennedy Space Center to support contractors involved in launches of the giant Saturn rockets. The 25 staffers evaluated spacecraft materials and attempted to pinpoint the causes of malfunctions in connections.
At that time, chemist Ruby James was Southern Research’s specialist in gas chromatography, a means to separate the different components of a mixture by forcing gas through a column.
The program at Kennedy Space Center ran for two years.
After the last Apollo mission, Southern Research remained active in the nation’s space program, making important contributions to the Space Shuttle and working on projects including the Voyager probe and the James Webb Space Telescope.
Today, Southern Research engineers are involved in the Space Launch System, a NASA project that aims to put man on Mars.
This is Part Five of a series looking at the history of Southern Research.