747 The Boeing 747 is a widebody commercial airliner, often referred to by the nickname "Jumbo Jet".[5][6] It is among the world's most recognizable aircraft,[7] and was the first widebody ever produced. Manufactured by Boeing's Commercial Airplane unit in the US, the original version of the 747 was two and a half times the size of the Boeing 707,[8] one of the common large commercial aircraft of the 1960s. First flown commercially in 1970, the 747 held the passenger capacity record for 37 years.[9]
The four-engine 747 uses a double deck configuration for part of its length. It is available in passenger, freighter and other versions. Boeing designed the 747's hump-like upper deck to serve as a first class lounge or (as is the general rule today) extra seating, and to allow the aircraft to be easily converted to a cargo carrier by removing seats and installing a front cargo door. Boeing did so because the company expected supersonic airliners, whose development was announced in the early 1960s, to render the 747 and other subsonic airliners obsolete, but that the demand for subsonic cargo aircraft would be robust into the future.[10] The 747 in particular was expected to become obsolete after 400 were sold[11] but it exceeded its critics' expectations with production passing the 1,000 mark in 1993.[12] As of June 2009, 1,416 aircraft have been built, with 107 more in various configurations remaining on order.[2]
The 747-400, the latest version in service, is among the fastest airliners in service with a high-subsonic cruise speed of Mach 0.85 (567 mph or 913 km/h). It has an intercontinental range of 7,260 nautical miles (8,350 mi or 13,450 km).[13] The 747-400 passenger version can accommodate 416 passengers in a typical three-class layout or 524 passengers in a typical two-class layout. The next version of the aircraft, the 747-8, is in production and scheduled to enter service in 2010.[14] The 747 is to be replaced by the Boeing Y3 (part of the Boeing Yellowstone Project) in the future.[15]
Navette A reusable launch system (or reusable launch vehicle, RLV) is a launch system which is capable of launching a launch vehicle into space more than once. This contrasts with expendable launch systems, where each launch vehicle is launched once and then discarded.
No true orbital reusable launch system is currently in use. The closest example is the partially reusable Space Shuttle. The orbiter, which includes the main engines, and the two solid rocket boosters, are reused after several months of refitting work for each launch. The external fuel drop tank is typically discarded, but it is possible for it be re-used in space for various applications.[1][2]
Orbital RLVs are thought to provide the possibility of low cost and highly reliable access to space. However, reusability implies weight penalties such as non-ablative reentry shielding and possibly a stronger structure to survive multiple uses, and given the lack of experience with these vehicles, the actual costs and reliability are yet to be seen.
