Tag: NASA

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.

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.

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."

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