Background: The orbiters (OV99-OV105) are a highly specialized group of individual aircraft bred for the sole purpose of high altitude operations. The concept came about in 1971 when NASA in partnership with the US Air Force, wanted a craft capable of going up into low earth orbit and returning like an airplane. The reusable capability was like a dream to the science based organization which had spent billions of dollars on the one time only Saturn Vs of the Apollo program. The Air Force, liking the idea of an aircraft with the capacity to carry a satellite to orbit or snatch up a Soviet one was too appealing to ignore. Their breeding program went into full affect for the concept beginning in 1972. Early on it was determined which aircraft would make up the genome of the Space Shuttle. A C-5 Galaxy for large payload capacity. A SR-71 Blackbird for speed and endurance. A U2 for altitude capabilities and endurance. And NASA's 737 prototype/testbed for the proper size. Pathfinder was the first born in 1974. She was of the proper size but lacked the speed needed to reach orbital velocity. Inspiration had the speed but lacked the endurance. Both went on the have successful careers as training aircraft in the Air Force. But these failures coupled with the cost of the program nearly grounded the shuttle before it even began. Hope appeared in the third craft born. The first sign that anyone had that they were on the right track came in 1975 with Enterprise. Enterprise had a near perfect combination of size, endurance, and cargo carrying capacity. She was strong, intelligent and most importantly easy to handle. Pathfinder and Inspiration were more high strung and could even be aggressive at times. Enterprise was far more tolerant. Unfortunately, while proving to be faster than a Blackbird, she was not fast enough. But it was a sign to the Air Force that they were starting to get their combinations right.
Gene Combination: The shuttle was carefully selectively bred. It takes a very specific combination of genes from these four different aircraft to produce a proper orbiter with very little room for variation. Challenger was the first true space shuttle. Born in 1977, she was 2 years older than Columbia. She was 10% Galaxy, 50% Blackbird, 25% U2, and 15% 737. Compared to her sisters, she was a bit heavier on the Blackbird side which resulted in a much lighter frame. With softer bones, it was unclear if she was up to the rigors of space flight but Challenger was tough where it counted and found a place in NASA's fleet. Columbia, born in 1979, by contrast was a brute of a shuttle. Where Challenger was thin bone, Columbia was thick muscle. She was 15% Galaxy, 45% Blackbird, 25% U2, and 15% 737. The extra 5% of Galaxy made an 8000 lbs and 5 foot difference in height between her and her later siblings. Discovery, Atlantis, and Endeavour born in 1981, 1982, and 1988 respectively all were 10% Galaxy, 45% Blackbird, 25% U2, and 20% 737. With them, the Air Force and NASA finally found the perfect combination.
Personalities: This part was crucial. NASA could have the most beautifully bred craft in the world but if she was too aggressive then the point was moot. But neither could she be too docile. These craft were expected to go on highly dangerous and classified military missions and if they were too spooked to do it then once again the problem remained.
Challenger- Challenger was in a league of her own. Raised by Challis Lovergood and her husband, her nickname Challie was in honor of her foster mother. Challenger was a ham and would go out of her way to seek attention from people. She would often come up to someone, rub on them a bit and when they returned her affections with pets she would roll on her back for a belly rub. She did this even as an adult. It was unusual because most aircraft and especially shuttles are extremely ticklish on their bellies and wings. But Challenger never showed signs she was and its assumed she wasn't ticklish anywhere. While not high strung, it was a good idea to keep her away from caffeine and sugar unless you wanted her pulling an all-nighter. She had a high metabolism and would frequently eat twice as much as Columbia but have little to no weight gain to show for it, much to Columbia's annoyance. Challenger could also be quite mischievous and was always pulling pranks. The most famous (or infamous depending on how one looks at it) was the Molasses Disaster of 1985. Pulled on April Fools Day of that year, Challenger along with her 747 caretaker Irene filled Kennedy's plumbing with molasses so whenever someone turned a faucet on that was all that came out. It took 3 weeks to properly clean all the pipes. Discovery claims to still find chunks of molasses coming out of faucets to this day! Pranks are a common theme at KSC and are done now mostly in the spirit of Challenger. Each year on the anniversary of her death, a pranking contest is held between the shuttles to celebrate her life. Challenger was one of two shuttles to enter the Navy and was a Commander when she died. She was posthumously given the rank of Captain.
Columbia- Columbia was born to lead. Raised by Caroline Gray, a descendant of Captain Robert Gray, she was a no nonsense type. She drew very clear lines even as a planeling and inspired others to follow them and her. While she had her own mischievous side she would maintain a certain level of professionalism unlike Challenger who just didn't care either way. Columbia's professionalism hid a deeper more sensitive side that was in complete contrast to how she usually presented herself. Underneath her sharp military bearings was a loving, kind, and compassionate shuttle who's sweetness could rival Challenger's adorable attitude. Challenger was the only shuttle who really knew this side of Columbia and it always made her sad to see her big sister hide it the way she did. Columbia started to change that after Challenger died. Her remaining sisters always made comments on how sometimes she'd slip up and do things that went against what she'd normally be up to. Columbia must've felt that it was necessary to have a wall between her true self and what she presented perhaps because as the first shuttle to fly she believed she had to keep her true side secret. This wall was both a blessing and a curse. Columbia would always secretly doubt herself, sometimes wishing she could show what she was really like. Despite this she became a mentor and close friend to Discovery who only learned of her sister's demons after she died, having read through Columbia's diaries. "I wish she showed it more." She said later. "The world will never know how big her heart really was." Columbia was posthumously given the rank of Major General in the Air Force.
Discovery- Out of all the shuttles Discovery is by far the most aggressive. She is borderline what NASA will accept. Like Columbia, she has a no-nonsense attitude and a stubborn streak miles wide! Unlike her big sister however she's more high strung and easily jolted into action. When her anger was aroused it could sometimes take hours and the efforts of both Atlantis and Columbia to calm her. She got a bit better as she got older, her temper calming. Discovery is an extreme extrovert and will wear her heart on her sleeve so to speak. She's a terrible liar and equally bad at hiding what she's feeling. Her sisters and even a stranger can see right through her. Like Challenger, she's a ham and will seek people out for pets. Unlike Challenger she isn't rough about it and is a bit more docile to handle than her late sister. A Colonel in the Air Force, she was raised by James Collins and his wife Rose.
Atlantis- A calm, cool professional would be the best way to describe this shuttle. Nothing seems to faze her. At least on the outside. Atlantis is the complete opposite of Discovery, a dedicated introvert who will accept interaction only if its offered to her. She's notorious for her off duty habits which include a high level of indulgence with legal and illegal substances. Though not an addict, Atlantis does infrequently use drugs such as marijuana which is illegal in Florida most often as a coping mechanism. As an introvert, she's not one to talk about her feelings and will avoid any painful subjects. On a different note, Atlantis does come out of her shell to impart her wisdom on others. She's much like Columbia in that regard. Her tolerance, docile attitude and desires to teach others make her the perfect training shuttle. She's one of two shuttles in the Navy, the other being her late big sister Challenger. She currently holds the rank of Captain. She was raised by astronaut Jim Lovell.
Endeavour- High strung like Challenger but not aggressive like Discovery, Endeavour is the middle shuttle in terms of temperament. She can put up with just about anything but will attack if provoked. She's closest to Discovery who is not afraid to show her temper at anyone who threatens her baby sister. Endeavour will pester people for attention much like how Challenger did but she prefers a treat over a petting session. She feels a strong connection to Challenger and is said to have communed with her spirit on several occasions. This makes her the most religious of the shuttles and she's the KSC's official chaplain. She doesn't tolerate hearing any disrespect for her deceased sibling nor does she like hearing people call her "Challenger's replacement". A Major in the Air Force, she was raised by Virginia Kent.