Updates with details and background from paragraph 2 onwards

March 4 (Reuters) - NASA plans to select United Launch Alliance to supply a critical component for future missions of its moon rocket, Bloomberg News reported on Wednesday, citing people familiar with the matter.

The move could replace planned Boeing-built hardware, which NASA's inspector general has said will cost nearly $2.8 billion through 2028, the report said.

NASA is looking to use the upper portion of ULA's Vulcan rocket, known as the Centaur V, by the Space Launch System $(SLS)$ rocket's fourth flight, when the agency aims to send humans to the moon for the first time in more than 50 years, Bloomberg added.

ULA is a joint venture between Boeing BA.N and Lockheed Martin LMT.N.

NASA, Boeing and Lockheed Martin did not immediately respond to Reuters' requests for comment, while ULA referred to NASA for comments.

Last month, NASA added a spacecraft docking test to its Artemis moon programme before attempting its first crewed moon landing, overhauling the U.S. moon effort amid mounting delays and competitive pressure from China.

The agency also scrapped efforts to upgrade the SLS rocket, opting to focus on boosting the rocket's production and flight rate, which has lagged behind newer launch systems.

The decision affects Boeing's roughly $2 billion contract to build a more powerful SLS upper stage, current plans for which have been canceled.

(Reporting by Rhea Rose Abraham in Bengaluru; Editing by Sumana Nandy and Sherry Jacob-Phillips)

((RheaRose.Abraham@thomsonreuters.com;))