Thursday, February 20, 2020

Upclose: Two Engineers Discuss Servicing Space Shuttle Atlantis


CAPE CANAVERAL, Fla. -- NASA's space shuttle fleet served as an orbiting workshop for thirty years -- a space truck which delivered a variety of spacecraft and segments of the International Space Station into orbit.

Five space-worthy orbiters were built to allow astronauts to live and work in space. Behind the pressurized living quarters, a massive 60-foot cargo bay housed commercial and scientific satellites, or a pressurized module, which extended the volume of the crew's work space.

Each orbiter named to honor a sailing vessel -- Columbia, Challenger, Discovery, Atlantis, and Endeavour. Each was structurally built the same, however there were differences to those who knew them on an intimate basis.

Between 1981 through 2011, NASA launched 135 space shuttle missions from the Kennedy Space Center. Of those, two orbiters -- Columbia and Challenger -- did not return home after launch due to failures.

At the Kennedy Space Center's Visitor Complex, one shuttle is on display following her retirement. Atlantis, a veteran of 33 space flights, rests inside a multi-level building built especially for the spacecraft.


The orbiter is on public view with her payload bay doors open and a Canadian-built 50-foot robotic arm extended out. The docking port used to dock with the International Space Station is also located inside an otherwise empty bay.

Two former space shuttle processing employees work as docents near Atlantis to educate the public about the winged spacecraft. Jean Wright sewed the thermal blankets which protected the shuttle's exterior.

Columbia and Challenger were constructed using thermal tiles to protect the shuttles from extreme heating during re-entry. Later, the introduction of thermal blankets were used on later shuttles where reentry temperatures reached up to 1,200° F.
Space shuttle Atlantis made 33 voyages into space. (Atkeison)

"We made 11 classes of blankets as we didn't use the term thickness in our world," Wright noted as we moved around Atlantis. "They ranged from 1/4"- 2" thick. The class was decided by what surface on the orbiter it was being bonded to."

Wright highlighted the difference between the traditional heat absorbing tiles and the white blankets. Using a massive 30 needle sewing machine, each thermal blanket was quilted for a select area of the orbiter. It would take the machine nearly four minutes to quilt the blanket one way.

"Here at the OMS, since the frame was made of composites, we had to use our two-inch thick blankets," Wright pointed as we gazed up at one of Atlantis' two orbital maneuvering system pods. "NASA required that in areas made of composites, the skin of the orbiter couldn't be exposed to temps over 250-degrees, thus thicker blankets were needed there."

Challenger was flown with a small section of thermal blankets to test their effectiveness in 1983. They were located on her OMS pods and later added to her sides.

"After each blanket was quilted, they under went a process known as heat cleaning," Wright continued. "They were baked in a blue pizza oven at 650-degrees for four hours. Then baked for two more hours at 850-degrees."

Atlantis is poised just as she was while in space with her port side tilted downward 43.21-degrees. The great tilt allowed for us to have a birdseye view of the entire open payload bay.

Brad Byron worked to configure the payload bay with its cargo and keep it free of contamination. Each orbiter was prepared for her next flight in the Orbiter Processing Facility. It was here that the hardware or payloads were installed inside the massive bay.

"It was always a challenge working in the orbiter cargo bays," Byron began as he reflected on a job he enjoyed so much. "But when the launch was successful and the mission went as planned it was worth it."
Atlantis' payload bay with docking adapter. (Atkeison)

One of Brad's favorite payloads was the Hubble Space Telescope. The shuttle completed five servicing visits to upgrade the great observatory located about 420 miles above the planet.

"Hubble servicing flights always required extraordinary cleanliness beyond the already high standards we always worked to," he added. Atlantis flew the final servicing mission in 2009.

The Spacelab was a pressurized module fitted inside the cargo bay. The reuseable module gave astronauts more room to conduct science experiments in microgravity.

"Installing a Spacelab module in the cargo bay would take maybe 6 to 8 hours if everything went according to plan," Byron said standing only two meters from Atlantis' bay. "Every one was always different depending on what OPF bay the orbiter was in."

Brad noted that anything which went into the payload bay was recorded. He and his crew ensured that foreign objetcs not designed for that space flight would be seen floating out of the bay once on orbit.

"Everything that was going into the cargo bay had to be logged in - tools, chemicals, cleaning materials, flight hardware for accountability," he added. "When we left the cargo bay everything was logged back out."

The years of dedication in preparing the space shuttle's for flight has transitioned over to NASA's new Artemis Program. From the protective outer skin to spacecraft processing, today's Artemis engineers stand proudly on the shoulder's of the space shuttle's engineers.

(Charles A. Atkeison reports on aerospace and technology. Follow his updates via social media @Military_Flight.)

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