It's make or break time for NASA's new moon rocket. 

With 8.8 million pounds of thrust, the rocket — called the Space Launch System (SLS) — is designed to be mightier than NASA's mighty Saturn V. Its Orion space capsule outsizes its Apollo ancestor by one-third. Yet neither spacecraft has passed the ultimate test: a trip to the moon and back.

That will change Monday (Aug. 29), when NASA aims to launch the SLS megarocket and Orion on Artemis 1, a test flight that serves as the vanguard of the agency's Artemis program to return astronauts to the moon by 2025. Liftoff is set for 8:33 a.m. EDT (1233 GMT) from Pad 39B here at NASA's Kennedy Space Center. You can watch the launch live online Monday starting at at 6:30 a.m. EDT (1030 GMT). 

"Our zero hour approaches for the Artemis generation," Mike Sarafin, NASA's Artemis 1 mission manager, told reporters here Saturday. "We do have a heightened sense of anticipation."

That anticipation is not something NASA owns alone. Up 200,000 spectators are expected(opens in new tab) to flood Florida's Space Coast here to catch a glimpse of NASA's first moon rocket to fly in over 50 years. Their hopes mirror NASA's for a successful mission where success is far from certain.

"This is a very risky mission," said Jim Free, NASA's associate director for exploration systems development. "We do have a lot of things that could go wrong during the mission in places where we may come home early, or we may have to have to abort to come home."