Thermal Protection System (Part 1)

The Thermal Protection System(TPS) is of utmost importance in a rocket as it protects the inner layers of the rocket from extreme heat.

Thermal Protection System (TPS)

The TPS consists of various material applied the outer surface of the orbiter to protect the orbiter from the extreme temperatures especially while re-entry into the atmosphere.

During re-entry , the TPS materials perform in temperature ranges from minus 250 F in the cold soak of space to entry temperatures that reach nearly 3,000 F. Because the thermal protection system is installed on the outside of the orbiter skin, it establishes the aerodynamics over the vehicle in addition to acting as the heat shield.

There are many types of different tiles used in the TPS system.Some of them are:

1. Reinforced carbon-carbon  (RCC) is used on the wing leading edges; the nose cap, including an area near the nose cap on the lower surface, and an area around the forward orbiter/external tank structural attachment. RCC protects areas where temperatures exceed 2,300 F during entry.

2. Black High-Temperature Reusable Surface Insulation (HRSI) tiles are used all over the orbiter; there are nearly 20,000 of these tiles on the orbiter.  They do not encounter the most extreme temperatures but must withstand some heat.  The HRSI tiles protect areas where temperatures are below 2,300 F.

3. Black tiles called Fibrous Refractory Composite Insulation (FRCI) were developed later in the thermal protection system program. FRCI tiles replace some of the HRSI tiles in selected areas of the orbiter.  There are nearly 3,000 FRCI tiles on the shuttle, primarily in areas of high heat.  FRCI tiles are mostly used on the base of the shuttle; this is where the highest heat is encountered.

4. Low-Temperature Reusable Surface Insulation (LRSI) white tiles are used in selected areas of the orbiter; such as the vertical tail and upper wing. These tiles protect areas where temperatures are below 1,200 F. The tiles are white since while in orbit the shuttle encounters extremely low temperatures and the white surface provides better thermal characteristics when the temperature is below 0 F.

5. Advanced Flexible Reusable Surface Insulation (AFRSI) blankets were developed after the orbiter Columbia was built. AFRSI blankets consist of sewn compositequilted fabric insulation that is sandwiched between two layers of white fabric that are sewn together to essentially form a quilted blanket. AFRSI blankets were used on Discovery and Atlantis and replaced the vast majority of the LRSI tiles. Columbia had the AFRSI blankets added after its seventh flight.  Each orbiter has about 1,900 square feet of AFRSI blankets.  The advantages to the AFRSI blankets to LRSI tiles are that they are more durable, less fabrication, less installation time and costs, and a weight reduction.  These blankets are used in areas where the temperature does not exceed 1,200 F.

6. White blankets made of coated Nomex Felt Reusable Surface Insulation(FRSI) are used on the upper payload bay doors, and portions of the upper wing surface. These blankets are used in areas where the temperature does not exceed 700 F.

Stay tuned for the next part............

Book Review of the 'The Lost Symbol' by Dan Brown

I recently read the book 'The Lost Symbol' by Dan Brown. It was really interesting and had me riveted till the last page. It was another gripping Robert Langdon story. In this story Robert is forced to help a mysterious man solve an ancient riddle or watch his friend and prominent Mason Peter Solomon die. The story starts with Robert being tricked into going to the Capitol Building,Washington D.C. The story unearths many of America's most guarded secrets. 
Though the story is dragged a little in the end it is overall a really good book. The author is well versed in American history and Masonic customs. The grammar used is really good and the plot is outstanding . I'll give the book four-and-a-half stars out of five. Dan Brown once again showed us why he is the No.1 bestselling author in the U.S. I surely recommend this book to all readers. Read the book to find out what happens to Peter and Robert.