Wednesday, April 18, 2012

The Airplane Geeks "Spacecraft" of the week: OV-103 the STS DISCOVERY

The Rockwell Space Transportation System OV-103 aka the Space Shuttle Discovery.
First flown on August 20th, 1984 Discovery was the fourth Shuttle built and the third to fly into space. Discovery was the first of the second generation shuttles.   She was 6000+ pounds lighter than Columbia. It was this Optimization that made it able to dock with the International Space Station.  Columbia was never able to do that due to its weight.   Discovery is 6 pounds heavier than her sister Atlantis. 
All of the Orbiters were (seems strange to say past tense) equipped with three Pratt & Whitney Rocketdyne RS-25 Liquid Fuelled Cryogenic Rockets. The SSME or Space Shuttle Main Engines develop 418 thousand pounds of force each.  The three engines are fueled by the mix of  Liquid Oxygen and Liquid Hydrogen. The Nozzles are 10 inches at the top and 90 inches at the main opening.  The engines themselves reach a temperature of 5,999 degrees Fahrenheit that is higher than the boiling point of Iron.  The nozzles are gimbled to that they can be vectored to help control flight.  The Fuel source for the engines is the Central tank. The Orbiter the SRBs and the main tank are called the Stack.   The SRBs or Solid Rocket Boosters are attached to the tank,  they do not draw fuel from it.  They are self-contained.
There are also two sets of Orbital Maneuvering System.  They are the large pods next to the Vertical Tail. The OMS is used to orbit or correct orbits, and most importantly de-orbit the shuttle so she can return to earth. The OMS pods also include the Reaction Control System for the rear of the shuttle. The RCS which uses Helium controls Pitch Yaw and Roll of the Shuttle in orbit.  The forward RCS are the holes at the nose of the Shuttle.
This week the Smithsonian National Air and Space Museum’s Steven Udvar-Hazy Center will be receiving the Discovery in its collection.  But anyone who’s been to Udvar-Hazy knows that in the James A McDonnell Space Hangar has a shuttle already.  Why the swop?  The Shuttle in there currently is OV-101 the Enterprise.  Enterprise while significant never flew in Space.  She was part of the Approach and Landing Tests. Enterprise was the largest placeholder in the world.  She lived at NASM until another would replace her. It was finally decided it would be Discovery.  I believe that originally the Smithsonian was to get Columbia.  Enterprise will be transferred to NYC to sit next to the Concorde at the USS Intrepid Museum.
Why is Discovery going to NASM over the other remaining Shuttles; Atlantis and Endeavour?  Discovery is the most significant of the remaining shuttles.  Here are some of the stats that make her special:
·       She was the third shuttle to fly into space however the has been in space the longest. 
·       She has spent 365 days in space.
·       She has flown 149 Million Miles, and completed 5,830 orbits. 
·       She, three times brought the program back to life.  She completed the three “Return to Flight” missions after the losses of Columbia and Challenger.  
·       She was the one who deployed the Hubble Space Telescope.  
·       She has carried two Senators, Jake Garn and John Glenn, who at 77 still is the oldest person to have been in space. 
·       Discovery was the first shuttle with a woman pilot Eileen Collins.
·       Discovery was the First shuttle to dock with the International Space Station. 
·       She also has the record for longest duration mission STS-131 with 15 days in orbit. 
·       She also flew the 100th Space Shuttle Mission.
Discovery now grounded begins this week a new mission.  She will represent 27 years of Human Space Flight!

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