Canadian astronaut David Saint-Jacques says today's decision to scrub the launch of NASA's new moon rocket is disappointing but necessary due to another leak found ahead of the planned test flight.

The Artemis 1 rocket sprang another fuel leak, forcing controllers to call off the second attempt this week to send a crew capsule with test dummies aboard into lunar orbit.

The first attempt on Monday was also aborted due to escaping hydrogen elsewhere on the 98-metre NASA-built rocket.

Saint-Jacques, who was set to watch the launch from the Canadian Space Agency headquarters in suburban Montreal, says the space buff in him is disappointed but the sober engineer knows it was the right call.

It wasn't immediately clear when NASA may try again. 

Saint-Jacques says a window remains open until about Tuesday, but after that the moon won't be in the right spot in the sky for a few weeks.

He says the test flight is an important one as a Canadian astronaut is expected to be on the first crewed flight of the Artemis 2 rocket, which is slated to fly around the moon and return in 2024.

NASA is expected to brief reporters later Saturday.

This report by The Canadian Press was first published Sept. 3, 2022.

- with files from The Associated Press