Eles transportam aeronaves transportadoras são modificadas conforme os requisitos da NASA. Por exemplo, a fuselagem é reforçada, os estabilizadores verticais são adicionados e os suportes montados. No entanto, sua pergunta se refere ao impacto no desempenho da transportadora, que inclui (da Wikipedia):
Flying with the additional drag and weight of the Orbiter imposed
significant fuel and altitude penalties. The range was reduced to
1,000 nautical miles (1,200 mi; 1,900 km), compared to an unladen
range of 5,500 nautical miles (6,300 mi; 10,200 km), requiring an SCA
(shuttle carrier aircraft) to stop several times to refuel on a
transcontinental flight.[4] Without the Orbiter, the SCA needed to
carry ballast to balance out its center of gravity.[3] The SCA had an
altitude ceiling of 15,000 feet (4,600 m) and a maximum cruise speed
of Mach 0.6 with the orbiter attached.