The First Space Plane
Even before the Apollo moon program was complete, construction plans were being developed for a reusable spacecraft, a spaceplane designed to be launched, flown in space with heavy payloads, re-enter Earth’s atmosphere, and land on a runway instead of splashing down in the ocean. In 1969, President Nixon made the decision to proceed with the Shuttle program, thus launching a new era in space travel.
There were five space-certified shuttle orbiters constructed. Two of those were destroyed in tragic accidents.
These space planes were about half the length of a 747 jet. They took off from Kennedy Space Center using 3 massive onboard engines and 2 external rockets for additional lift. So much fuel was required to give the shuttle into Earth orbit, than a massive fuel tank was necessary. Once released, the fuel tank would be destroyed upon re-entry. The booster rockets would be recovered downrange and reused.
Once the shuttle reaches low-Earth orbit, it makes a maneuver so that the spaceplane is flying backwards to protect the sensitive thermal protection system (the tiles) from damage from any space debris that might be unexpectedly encountered.
During its 30 year span, the shuttles launched and repaired a great number of satellites including the Hubble. They made construction of the International Space Station possible.
However, the idea of a reusable spacecraft was to reduce costs. It would be the costs involved to fly the shuttle safely, that ultimately doomed it. At the end of the shuttle program, it was cheaper to lift heavy payloads into space with a single rocket, than to launch the shuttle.
End of the Shuttles
In 2011, the shuttle program officially came to an end. The 3 remaining space-certified shuttles are being modified for museum display and are heading for various areas across the country. Atlantis is the only shuttle that will remain at the Kennedy Space Center as part of a new pavilion dedicated to the shuttle program. This pavilion is part of a renovation of the Kennedy Space Center and is expected to open sometime in 2012.
The first shuttle to take to the skies was Enterprise. Originally planned to be named Constitution, fans of the science fiction TV series Star Trek conducted an unofficial write-in campaign to then President Ford to plead their case for naming the new spaceship “Enterprise” after their much beloved USS Enterprise (NCC-1701). Maybe President Ford was a Trekkie too, or maybe it was because he served on an aircraft carrier in the battle group that included the aircraft carrier USS Enterprise. For whatever the reason President Ford overrode NASA officials and strongly suggested they name the new shuttle Enterprise.
Re-entry of vehicles from space back into Earth’s atmosphere has always been a dangerous proposition from the very beginning. As the speeding spacecraft begins its final descent, the friction between the spacecraft and the atmosphere can cause temperatures on the surface of the craft to exceed 3,000 degrees, more than enough to melt most metals. For the early manned capsule flights, a heat shield was incorporated on the bottom portion of the capsule that would take the brunt of these extremes.
ABOVE NASA PHOTO: Shuttle Discovery’s tiles being photographed from the International Space Station in an effort to determine any damage.
The space shuttle was designed to be reused and so a system using small silica ceramic tiles was developed. They were lightweight and could be replaced if damaged.
It took 24,300 special ceramic tiles to cover the exterior of the shuttle. However, it soon became apparent that the lightweight tiles often suffered damage during the flight and required much more extensive repairs after returning to earth. Much of the damage was caused by a change in the foam insulation design on the external tank that caused some chunks of the insulating material to break loose during liftoff. Even small pieces of foam could damage the lightweight tiles.
NASA PHOTO: Launch of STS-107 – 1/16/2003
NASA’s Freedom and Liberty
Freedom Star and Liberty Star are 2 seagoing ships and that were on standby on standby whenever there was going to be a shuttle launch. Their mission was to retrieve the 2 solid rocket boosters that helped lift the shuttle into orbit.
In position usually the day before a scheduled launch, the 2 ships make sure the area is kept clear of other ships. After the shuttle launches, the crew on board the two ships can see the spent rocket boosters returning to Earth. As they wait for splash down, they can hear the sonic boom the boosters make as they speed back to Earth. As the boosters approach the water, parachutes are deployed for a safe splashdown.
Once the ship arrives at the splashdown point, the chutes are retrieved and attached to the ship. Divers are then sent down to plug the hole in the bottom of the booster. A tube is then attached that fills the spent rocket with pumped in air causing it to rise to the surface and float horizontally. The rockets are then towed back shore where they went through a complete inspection and refitting before the next use.
The Shuttle’s External Fuel Tank
The Space Shuttle’s External Tank (ET) actually contains several tanks underneath one shell. It provides the liquid hydrogen and liquid oxygen during lift-off to the 3 space shuttle main engines.
Once the main engines shut down, the massive tank is released from the shuttle and it returns to Earth and breaks up in the atmosphere and lands in the Indian Ocean.
ABOVE: Diagram of the External Tank showing the combined Liquid Oxygen Tank and the Liquid Hydrogen Tanks.
Over the years the ET has been redesigned to reduce the weight. Originally the tank was painted white to help reduce damage caused by ultra-violet light, which turned out to not be a problem. Instead only the primer paint was sufficient to protect the foam.
Not painting the ET saved over 600 lbs. In subsequent versions the ET was further refined until the Super Lightweight Tank was developed and first used in 1998. That tank was about 18,000 pounds lighter than the original.
The tanks were manufactured by Lockhead Martin at their assembly facility in New Orleans and then shipped by barge to the Cape Canaveral docks not far from the Vehicle Assembly Building.