Photos: Atlas 5 rocket aims for International Space Station

Engineers ran into problems repressurizing the Artemis 2 moon rocket’s upper stage helium tanks overnight Friday, a problem that will require rolling the huge rocket off the launch pad and back to its processing hangar for troubleshooting. The work will push the already delayed mission from March to at least early April, officials said Saturday.

The 377th Delta rocket begins its journey to space carrying a military communications satellite funded by Canada, Denmark, the Netherlands, Luxembourg and New Zealand in a deal that gives the allies access to the U.S. military’s worldwide Wideband Global SATCOM system.

Spaceflight Now’s Stephen Clark reports from Starbase in South Texas as SpaceX prepares the largest rocket in history for a second launch attempt after calling off a launch attempt Monday due to a valve problem.