X33

X33 or x33 is a designation that has been applied in different domains. In aerospace, the X-33 refers to an experimental technology demonstrator developed in the 1990s by NASA and Lockheed Martin as part of the VentureStar program. The project was intended to test single-stage-to-orbit concepts and advanced materials, including a composite cryogenic fuel tank. The effort encountered technical and cost challenges, and NASA canceled the program in 2001, with the X-33 technology later absorbed into other research.

In computing and digital contexts, x33 commonly appears as a hexadecimal value. The hexadecimal 0x33 equals 51 in decimal, and corresponds to the ASCII character '3'. In programming, escape sequences such as \x33 denote the same value, used in strings to represent characters.

Other uses of the designation occur as model numbers or product identifiers in various industries. Without further context, x33 is ambiguous and can refer to multiple unrelated items, including fictional works that use X-33 as a craft or artifact name.