Video: Marc Buie, New Horizons Occultation Team Lead (members only)

SpaceX’s proposal to land astronauts on the moon using the company’s reusable Starship vehicle could be “game-changing” for space exploration, but comes with risks and complexity that “threaten the schedule viability” to achieve NASA’s goal of returning crews moon by the end of 2024, agency officials said.

The capsule flying the Ax-4 mission was originally set to launch in support of the Crew-10 mission to the ISS, which launched in mid-March.

Preparations for the planned liftoff Thursday of a SpaceX Dragon capsule with a four-person crew to the International Space Station cleared another readiness review Tuesday at NASA’s Kennedy Space Center in Florida, but officials are tracking marginal wind and sea conditions in downrange abort zones in the Atlantic Ocean that could force a launch delay.