The European Space Agency (ESA) is Europe's civilian space agency. It is sometimes disparagingly referred to as the _other NASA.

The European Space Agency (ESA) is Europe's gateway to space. Its mission is to shape the development of Europe's space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world. -- From esa.int

The European Space Agency is not an arm of the European Union, it is a transnational agency that includes states that are not part of the European Union (e.g. the United Kingdom, and Canada).

Unlike NASA, the European Space Agency does very little research and development work directly. It acts mainly as a funding body, managing the execution of contracts by partners.