Though expectations were high for Monday’s scheduled first launch of Nasa’s new Space Launch System rocket, or the SLS, the space agency was careful to temper expectations ahead of the planned liftoff. It emphasised that this was a test flight and that engineers were still learning how to work with the still-untested rocket.

“The complexity is daunting when you bring it all into the focus of a countdown,” said Bill Nelson, administrator of Nasa.

Ahead of Monday’s event, experts within the space community also downplayed the odds of the SLS actually flying on schedule. Still, Nasa gave it the agency’s best shot –  and Vice-President Kamala Harris flew in to be on hand – before an issue with one of the four main engines triggered a scrub.

But the truth is such problems are not uncommon for new launch vehicles, especially ones as big and as complex as the SLS – and Nasa has been here before. The first Space Shuttle launch way back in 1981 was scrubbed and delayed before it finally lifted off. And risk-averse Nasa would rather hold a launch than fly with an anomaly its engineers would have been unable to fix once the mission was under way.

The earliest available opportunity to try again is on September 2, which Mike Sarafin, Nasa’s Artemis mission manager, said in a press conference was “definitely in play”. No decision has been made on rescheduling.

Official confirmation of the delay came after the space agency spent the morning hours investigating issues including a potential crack in material in the main body of the rocket as well as the temperature issue, officials said earlier Monday. Those came after engineers examined and resolved a suspected leak affecting the hydrogen tanking process.

During the countdown, the SLS’s engines need to chill down in preparation for launch. But one of the four – Engine 3 – was not cooling properly. Engineers weren’t able to test the process during the rocket’s final dress rehearsal due to a hydrogen leak. Engineers also discovered a leak in a valve in one of the rocket’s tanks. The engine and the valve issue ultimately prompted the abort.

The Artemis mission will be the first major flight in Nasa’s ambitious plan to send the first woman and the first person of colour to the lunar surface as early as 2025. Artemis I is aimed at testing out the SLS, made by Boeing, and a new deep-space crew capsule called Orion that was developed by Lockheed Martin.

If Artemis I is able to launch on September 2, the SLS will be sending Orion on a mission of more than five weeks, along with a host of payloads and sensors to track the journey. The length of the mission will vary depending on the launch date.

The capsule is tasked with inserting itself into lunar orbit and entering deep space before return to Earth in the Pacific Ocean off San Diego. Nasa plans to stress-test the systems ahead of later crewed missions.

The SLS already is more than five years behind schedule. It has been in development for roughly a decade, slowed by a myriad delays and cost overruns. Development costs of the programme have soared from an original $7-billion to about $23-billion, according to an estimate by the Planetary Society.

If successful, the Artemis programme – named for the twin sister of the god Apollo in Greek mythology – will see the return of people to the moon for the first time in 50 years. No one has visited since Apollo 17 in December 1972.

Boeing and Lockheed Martin shares each rose less than 1% at 2.23pm in New York.

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