heptane. n. 1. (Elements & Compounds) an alkane existing in nine isomeric forms, esp the isomer with a straight chain of carbon atoms (n-heptane), which is found in petroleum and used as an anaesthetic. Formula: C7H16. [C19: from hepta- + -ane, so called because it has seven carbon atoms].
technically it's not any of those three... After the Apollo program in the late 1960's ended, the president of the United States, Richard Nixon declared in 1973 that the USA would build the Space Shuttle to continue space exploration in low earth orbit.
However, development of the Shuttle was delayed, and Skylab reentered Earth's atmosphere and disintegrated in 1979, with debris striking portions of Western Australia. Post-Skylab NASA space laboratory projects included Spacelab, Shuttle-Mir, and Space Station Freedom (later merged into the International Space Station).lthough NASA worked on plans to reboost Skylab with the Space Shuttle through 1978 and the TRS was almost complete, the agency gave up in December when it became clear that the shuttle would not be ready in time; its first flight, STS-1, did not occur until April 1981.