NVO meaning in Space Science ?

The US National Virtual Observatory'-NVO- (nowadays VAO - Virtual Astronomical Observatory) was conceived to allow scientists to access data from multiple astronomical observatories, including ground and space-based facilities, through a single portal. Originally, the National Science Foundation (NSF) funded the information technology research that created the basic NVO infrastructure through a multi-organization collaborative effort. The NVO was more than a “digital library”; it was a vibrant, growing online research facility akin to a bricks-and-mortar observatory for professional astronomers.

As of October 1, 2014, funding ceased for the National Virtual Observatory (NVO) and all code and digital assets of the project were made publicly available at the VAO Closeout Repository.