NASA asks Northrop Grumman to stop working on lunar HALO module

Three months ago, during a flashy event at its Washington, DC, headquarters, NASA announced that it was shifting the focus of its lunar plans from an orbital space station to a Moon base on the surface. As part of this, officials said work would be paused on the Lunar Gateway planned to orbit the Moon. Of the two elements that were furthest along, NASA also revealed that one of them—the  Power and Propulsion Element— would be repurposed to serve as a core module for a nuclear-electric propulsion