shuttle TPS characteristics – Michael Stephen Wills Photography

Behind the Scenes of the Final Frontier: Our Tour with NASA’s “Launch Director” – 3

Step beyond Earth’s bounds and glimpse the astounding intricacies of the Space Shuttle’s journey. Discover the engineering marvels that propelled humanity into orbit and back, navigating the cosmos with precision. Unveil the secrets of the stars now.

March 14, 2024March 15, 2024 MichaelStephenWills3 Comments

The Space Shuttle, officially known as the Space Transportation System (STS), was an iconic spacecraft operated by NASA from 1981 to 2011. It consisted of an orbiter with wings for landing like an airplane, external fuel tanks, and solid rocket boosters. With its multiple missions ranging from satellite deployment to the construction of the International Space Station, the Space Shuttle was a symbol of human ingenuity in space exploration. Central to the Shuttle’s success was its navigational system, which combined state-of-the-art technology of its time with human expertise.

The navigation of the Space Shuttle was a complex orchestration involving both internal and external elements designed to work in the harsh environment of space. The photographs attached illustrate some of the external navigational elements.

External Navigational Elements

The external surface of the Space Shuttle, as seen in the following images, was covered with thousands of thermal protection system tiles. These tiles were crucial not only for protecting the Shuttle from the extreme temperatures experienced during re-entry into Earth’s atmosphere but also housed the critical sensors for navigation.

One of the key external navigational features was the Reaction Control System (RCS), seen as clusters of small circular ports below the cockpit windows. The RCS was composed of small thrusters that could fire in short bursts to adjust the Shuttle’s orientation or speed in space. This system was vital during the maneuvers in orbit, such as satellite deployment, docking with the International Space Station, and repositioning for re-entry into Earth’s atmosphere.

Internal Navigational Elements

Internally, the Space Shuttle featured a complex avionics system. The following image depicts part of the orbiter’s internal structure with an array of docking mechanisms and sensor housings. The round port, surrounded by a ring of bolts, is likely an interface for the Orbiter Docking System, used for rendezvous and docking with the International Space Station.

The following image shows a close-up of one of the orbiter’s windows, surrounded by reinforced panels. Each window was crucial for manual navigation, allowing astronauts to visually confirm their orientation and position relative to celestial objects and the Earth. The windows were also essential during landing, which was conducted manually by the Shuttle’s commander.

Navigational Avionics

The Shuttle’s navigation was supported by an avionics system that included inertial measurement units (IMUs), star trackers, and various other sensors. IMUs tracked the Shuttle’s position by measuring its velocity and direction, while star trackers used sightings of known star patterns to calibrate the Shuttle’s orientation in the vastness of space.

The navigational computers onboard processed data from these systems to maintain the trajectory and manage the Shuttle’s multiple systems. The computers were capable of autonomous operation, although astronauts were trained to take over manually if necessary.

Ground Support and Telemetry

In addition to onboard systems, navigation relied heavily on ground-based tracking and data relay satellites. The Shuttle communicated with NASA’s Mission Control Center, which monitored its position and trajectory, providing updates and corrections as needed. Telemetry data sent back to Earth included velocity, altitude, and engine performance metrics, which were crucial for ensuring the Shuttle’s safe passage in and out of orbit.

In Summary

The Space Shuttle’s navigational capabilities were a testament to the integration of technology and human skill. From the RCS ports on its tiled exterior to the sophisticated avionics inside, every component played a critical role in the Shuttle’s missions. This harmonious blend of internal mechanisms and external sensors, complemented by vigilant ground support, enabled the Space Shuttle to navigate the cosmos and return safely home, mission after mission.

Copyright 2024 Michael Stephen Wills All Rights Reserved

Behind the Scenes of the Final Frontier: Our Tour with NASA’s “Launch Director” – 2

Peer through the Space Shuttle’s windows, marvels of human ingenuity that withstood the cosmos’s extremes. Experience the awe of Earth’s view from orbit and the intense blaze of re-entry, all behind the clarity of fused silica glass. Dive into the fusion of science and exploration—read the full voyage of these extraordinary panes.

March 13, 2024March 3, 2024 MichaelStephenWills2 Comments

The windows of the Space Shuttle represent a pinnacle of engineering and material science, intricately designed to withstand the harsh realities of space travel while providing astronauts with a vital connection to the outside universe. The journey of these windows, from concept to creation and through their performance in the harsh environment of space, is a testament to human ingenuity and the relentless pursuit of exploration.

At the heart of the Space Shuttle’s windows is fused silica glass, a material selected for its exceptional properties, including high thermal resistance, strength, and optical clarity. This choice was crucial, as the windows had to endure rapid temperature shifts from the cold vacuum of space to the searing heat of re-entry, which could exceed 1,650 degrees Celsius (3,000 degrees Fahrenheit). Corning Incorporated, known for its innovative glass solutions, was responsible for manufacturing this fused silica, utilizing a high-purity synthesis process that ensured the material could withstand the extreme conditions of space without degrading.

The design and assembly process of the Shuttle’s windows was a feat of engineering. Each window was carefully framed and installed to maintain the spacecraft’s integrity and internal pressure in the vacuum of space. This involved a complex sealing mechanism that had to be both robust and fail-safe, ensuring the safety of the crew and the success of the mission. The installation process was rigorous, involving a series of tests that simulated the harsh conditions of space to validate the windows’ performance. These tests were crucial to identifying and rectifying any potential issues that could compromise the mission or the astronauts’ safety.

In space, the Shuttle’s windows faced numerous challenges, from the threat of micrometeoroid impacts to the intense radiation of the sun. Despite these hazards, the windows performed admirably, a testament to their design and the materials used. One notable instance of their resilience was observed during the STS-61 mission, where despite micrometeoroid impacts, the windows’ integrity remained intact, ensuring the crew’s safety and mission success.

The windows also played a critical role during the Shuttle’s re-entry into Earth’s atmosphere, a phase of the mission that subjected the spacecraft to extreme heat. The windows’ ability to withstand this heat while providing the crew with a clear view for navigation was vital for a safe landing. This was achieved through the use of multiple glass layers and protective coatings, which insulated the interior from the re-entry heat.

Beyond their technical specifications and performance, the Space Shuttle’s windows served a more profound purpose. They provided astronauts with a visual connection to the Earth and space, offering perspectives that few humans have experienced. These views not only aided scientific observation and mission operations but also offered moments of unparalleled beauty, inspiring both astronauts and people on Earth.

The legacy of the Space Shuttle’s windows extends beyond their technical achievements, embodying the spirit of exploration and the human quest for knowledge. They were not merely components of a spacecraft but windows to the universe, enabling us to look beyond our planet and dream of the possibilities that lie in the vast expanse of space. Through their resilience, clarity, and performance, the Space Shuttle’s windows stand as a symbol of human ingenuity, a small but significant part of our journey to the stars.

Copyright 2024 Michael Stephen Wills All Rights Reserved

Behind the Scenes of the Final Frontier: Our Tour with NASA’s “Launch Director” – 1

Discover an insider’s voyage to the heart of NASA’s launch operations with us as we relive the awe-inspiring Kennedy Space Center Tour, where every corner whispers tales of cosmic ventures and human courage.

March 12, 2024March 3, 2024 MichaelStephenWills11 Comments

Introduction

Late winter 2017 my wife Pam and I embarked on an extraordinary adventure that would etch an indelible mark on our memories. On March 2nd, we had the unique privilege of experiencing the Kennedy Space Center through the eyes of a NASA Launch Director. This wasn’t just any tour; it was a journey through the heart of space exploration, a narrative brought to life by someone who had been at the helm of launching dreams into the cosmos.

The Kennedy Space Center, a beacon of human achievement on Florida’s coastline, stood before us, brimming with stories of courage, innovation, and the relentless pursuit of the unknown. As we stepped onto the grounds, we were not just visitors but participants in a legacy stretching back to the earliest days of space travel. The “NASA Launch Director Tour” promised an inside look at the complexities and triumphs of space missions, a perspective few ever witness.

This series of blog posts is an attempt to capture the essence of that day, to share the insights, emotions, and awe-inspiring moments we experienced. From the thunderous silence of the launch pads to the intimate stories of missions past, each post will explore a different facet of our journey. Join us as we relive an unforgettable exploration of human ingenuity and the boundless reaches of space, all through the lens of a day that brought the stars within reach.

Gathering and Introductions

On the negative side, we enjoyed the expertise of “Jeff” who stood in for the retired Launch Director who was “out sick.” On the positive side, our very expensive fee for the tour was refunded. Jeff was everything we could expect from the tour — he had extensive and detailed insider knowledge of NASA and the launch facilities.

Shuttle Booster and Fuel Tank, standing below

We gathered in a media room, an antechamber to the Space Shuttle Atlantis.

Entry to the Atlantis and the

Space Shuttle Atlantis lifted off on its maiden voyage STS-51-J on October 3, 1985. This was the second shuttle mission that was a dedicated Department of Defense mission. It flew one other mission, STS-61-B (the second shuttle night launch) before the Challenger disaster temporarily grounded the shuttle fleet in 1986. Among the five Space Shuttles flown into space, Atlantis conducted a subsequent mission in the shortest time after the previous mission (turnaround time) when it launched in November 1985 on STS-61-B, only 50 days after its previous mission, STS-51-J in October 1985. Atlantis was then used for ten flights from 1988 to 1992. Two of these, both flown in 1989, deployed the planetary probes Magellan to Venus (on STS-30) and Galileo to Jupiter (on STS-34). With STS-30 Atlantis became the first Space Shuttle to launch an interplanetary probe.

The orbiter’s aluminum structure could not withstand temperatures over 175 °C (347 °F) without structural failure. Aerodynamic heating during reentry would push the temperature well above this level in areas, so an effective insulator was needed.

The Thermal protection system (TPS) covered essentially the entire orbiter surface, and consisted of seven different materials in varying locations based on amount of required heat protection:

–Reinforced carbon–carbon (RCC), used in the nose cap, the chin area between the nose cap and nose landing gear doors, the arrowhead aft of the nose landing gear door, and the wing leading edges. Used where reentry temperature exceeded 1,260 °C (2,300 °F).

Reinforced carbon–carbon (RCC) of the nose cap and “chin area”

–High-temperature reusable surface insulation (HRSI) tiles, used on the orbiter underside. Made of coated LI-900 silica ceramics. Used where reentry temperature was below 1,260 °C.
–Fibrous refractory composite insulation (FRCI) tiles, used to provide improved strength, durability, resistance to coating cracking and weight reduction. Some HRSI tiles were replaced by this type.
–Flexible Insulation Blankets (FIB), a quilted, flexible blanket-like surface insulation. Used where reentry temperature was below 649 °C (1,200 °F).

–Low-temperature Reusable Surface Insulation (LRSI) tiles, formerly used on the upper fuselage, but were mostly replaced by FIB. Used in temperature ranges roughly similar to FIB.
–Toughened unipiece fibrous insulation (TUFI) tiles, a stronger, tougher tile which came into use in 1996. Used in high and low temperature areas.
–Felt reusable surface insulation (FRSI). White Nomex felt blankets on the upper payload bay doors, portions of the mid fuselage and aft fuselage sides, portions of the upper wing surface and a portion of the OMS/RCS pods. Used where temperatures stayed below 371 °C (700 °F).
Each type of TPS had specific heat protection, impact resistance, and weight characteristics, which determined the locations where it was used and the amount used.

The shuttle TPS had three key characteristics that distinguished it from the TPS used on previous spacecraft:

Reusable
Previous spacecraft generally used ablative heat shields which burned off during reentry and so could not be reused. This insulation was robust and reliable, and the single-use nature was appropriate for a single-use vehicle. By contrast, the reusable shuttle required a reusable thermal protection system.
Lightweight
Previous ablative heat shields were very heavy. For example, the ablative heat shield on the Apollo Command Module comprised about 15% of the vehicle weight. The winged shuttle had much more surface area than previous spacecraft, so a lightweight TPS was crucial.
Fragile
The only known technology in the early 1970s with the required thermal and weight characteristics was also so fragile, due to the very low density, that one could easily crush a TPS tile by hand.

Reinforced carbon–carbon (RCC) of the nose cap, close-up

The Space Shuttle thermal protection system (TPS) is the barrier that protected the Space Shuttle Orbiter during the searing 1,650 °C (3,000 °F) heat of atmospheric reentry. A secondary goal was to protect from the heat and cold of space while in orbit.

During the launch of STS-27 in 1988, a piece of insulation shed from the right solid rocket booster struck the underside of the vehicle, severely damaging over 700 tiles and removing one tile altogether. The crew were instructed to use the remote manipulator system to survey the condition of the underside of the right wing, ultimately finding substantial tile damage. Due to the classified nature of the mission, the only images transferred to the mission control center were encrypted and of extremely poor quality. Mission control personnel deemed the damage to be “lights and shadows” and instructed the crew to proceed with the mission as usual, infuriating many of the crew. Upon landing, Atlantis became the single-most-damaged shuttle to successfully land. The survival of the crew is attributed to a steel L band antenna plate which was positioned directly under the missing tile. A similar situation would eventually lead to the loss of the shuttle Columbia in 2003, albeit on the more critical reinforced carbon-carbon.

**References: extensive sections of the following Wikipedia articles were quoted, "Space Shuttle thermal protection system," "Space Shuttle Atlantis."**