The uncrewed rocket took off from South Texas a little after 8 a.m. ET (6.30 pm IST)
“Liftoff of Starship!” SpaceX wrote on X.
However, the Super Heavy booster just blew up in a "rapid unscheduled disassembly", the company said.
In its first attempt at liftoff in April, the integrated Starship and Super Heavy rocket blew apart the launchpad shortly after the launch. It spewed debris up to 20 acres outside the area that federal regulators initially expected.
The company had said that the “lessons learned” from the first Starship launch are contributing to “several upgrades” to the vehicle and ground infrastructure.
The second flight test debuted a hot-stage separation system and a new electronic Thrust Vector Control (TVC) system for Super Heavy Raptor engines, in addition to reinforcements to the pad foundation and a water-cooled steel flame deflector, among many other enhancements.
After the liftoff, the rocket's two stages appeared to separate successfully -- a key milestone -- with the Super Heavy booster falling back to Earth as the Starship spacecraft continued into space.
Starship won't get into orbit, but it will take a suborbital trip to test its heat shield and ability to withstand re-entry from orbit.
The second orbital flight test was earlier scheduled to launch on Thursday but was delayed due to the need for a hardware swap on the powerful rocket, CEO Musk confirmed on X.
"We need to replace a grid fin actuator, so launch is postponed to Saturday," Musk wrote in a post on X.
Grid fins are crucial aerodynamic components that help control and stabilise the rocket during its descent phase, ensuring it can land upright.
The company, early this week, received approval from the US Federal Aviation Administration (FAA) for the second test flight.
The FAA said it “has given licence authorisation for the second launch of the SpaceX Starship Super Heavy vehicle".
"The FAA determined SpaceX met all safety, environmental, policy and financial responsibility requirements," the agency wrote in a statement on X.
Starship is the tallest rocket ever assembled. The fully integrated Starship and Super Heavy rocket stands 394 feet tall, and is about 30 feet in diameter.
SpaceX aims to use Starship as a fully reusable transportation system to carry both crew and cargo to Earth orbit, help humanity return to the Moon, and travel to Mars and beyond. IAS/KB