An unpiloted test flight of Boeing’s Starliner crew capsule to the International Space Station will be delayed from its previous target launch date of April 2 until at least May, after the arrivals of Russian Soyuz and SpaceX Crew Dragon ships bringing fresh crew members to the orbiting complex, NASA officials said Monday.

A covert communications relay station to route spy satellite data directly to users was successfully launched by a million-pound Atlas 5 rocket overnight.

SpaceX’s final planned Crew Dragon test flight before astronauts ride the commercial spaceship into orbit is scheduled for Saturday, when an unpiloted crew capsule will fire off the top of a Falcon 9 rocket shortly after launch from the Kennedy Space Center in Florida to test the craft’s in-flight emergency escape capability.