NASA is set to launch the first moon rocket in its Artemis program Monday morning, the primary step in a complex series of missions aimed at enabling further human exploration of the moon and eventually, Mars.

The mission, dubbed Artemis I, will send an unmanned capsule on a 42-day trip around the moon before splashing down back into the Pacific Ocean.

Artemis I's main priority: testing Orion's new heat shield as it  reenters Earth's atmosphere at 25,000 mph. The capsule will have to survive the fiery descent during the process that will likely become one of the fastest reentries to date.

If all goes according to plan with the 322-foot rocket, an Artemis II mission will do roughly the same, but with astronauts.

Then, Artemis III aims to put two astronauts on the lunar surface sometime after 2025 – all part of NASA's program to return humans to the moon for the first time since 1972.

It will cost taxpayers $4.1 billion every time it launches, according to NASA's internal watchdog, the Office of Inspector General.

Atop the rocket will be an Orion space capsule carrying special mannequins – Moonkin Campos, Helga and Zohar – to collect data on the stresses the mission will place on future astronauts.

About eight hours after liftoff, the spacecraft will leave Earth's orbit and begin the 250,000 mile trip to the moon.

The two-hour launch window at the Kennedy Space Center begins at 8:33 a.m. Weather conditions look favorable, forecasters say.