SpaceX delayed the Starship rocket test flight due to an unspecified issue. The launch, aimed at furthering Mars colonization, was to occur from Texas. A reschedule is expected within 24 hours. The rocket requires improvements for reliability and safety before future crewed missions.

Starship had been expected to launch again Monday. A previous launch ended in an explosion over the Caribbean, and sent commercial airlines scattering to avoid falling rocket debris.

Last-minute problems forced a launch delay Monday for SpaceX’s mega rocket Starship, attempting a comeback following an explosion on the last test flight. The countdown got down to the 40-second mark,