The countdown clock was halted about 40 minutes before the targeted launch time of 6:03pm (IST), as the 32-story-tall, two-stage Space Launch System (SLS) rocket and its Orion crew capsule awaited liftoff from the Kennedy Space Center in Cape Canaveral, Florida.
The US space agency cited a problem detected on one of the rocket’s main engines, after launch teams had begun filling the rocket’s core fuel tanks with super-cooled liquid oxygen and hydrogen propellants.
Nasa did not give a new launch date but said its first available backup launch opportunity was set for Friday, September 2.