Expendable launch system

An expendable launch system (or expendable launch vehicle/ELV) is a launch vehicle that uses disposable components to carry a payload into space. ELVs typically consist of several rocket stages that are discarded sequentially as their fuel is exhausted and the vehicle gains altitude and speed. Most satellites and human spacecraft are currently launched on ELVs, with advantages including the possibility of cost savings through mass production, a greater payload fraction, and extensive development history. An expendable launch system (or expendable launch vehicle/ELV) is a launch vehicle that uses disposable components to carry a payload into space. ELVs typically consist of several rocket stages that are discarded sequentially as their fuel is exhausted and the vehicle gains altitude and speed. Most satellites and human spacecraft are currently launched on ELVs, with advantages including the possibility of cost savings through mass production, a greater payload fraction, and extensive development history. In contrast, a few companies are developing reusable launch systems intended to cut costs. The now-retired Space Shuttle launch vehicle was intended to reduce costs through reuse, but was not successful. Arianespace produces, operates and markets the Ariane launcher family. Arianespace's 23 shareholders represent scientific, technical, financial and political entities from 10 different European countries. Mitsubishi Heavy Industries manufactures ELVs. Russia currently operates several state-owned families of expendable launch vehicles, including Proton and Soyuz. All of the Russian space sector has been renationalized, starting in 2013 with the formation of the United Rocket and Space Corporation to consolidate a large number of disparate companies and bureaus. On 19 May 2015 State Duma passed a bill creating the Roscosmos State Corporation, further consolidating the industry. Several governmental agencies of the United States purchase ELV launches. NASA is a major customer with the Commercial Resupply Services and Commercial Crew Development programs, also launching scientific spacecraft. A state-owned ELV, the Space Launch System, is intended to being flying in 2020. The United States Air Force is also an ELV customer. Both the Delta IV and Atlas V from the 1994 Evolved ELV (EELV) program remain in active service, operated by the United Launch Alliance. The National Security Space Launch (NSSL) competition is currently ongoing to select EELV successors to provide assured access to space.