NASA had barely finished a repeat fueling test Thursday when another problem cropped up. This time, the rocket’s helium system malfunctioned.

The four astronauts heading to the moon for the lunar fly-by are the first humans to venture there since 1972. The ten-day mission will travel more than 600,000 miles.

NASA's Jared Isaacman slammed Boeing for failures with its Starliner spacecraft, which was deemed unsafe to return its crew of two astronauts from the International Space Station

During a similar test earlier this month, sensors detected a leak of super-cooled liquid hydrogen – rocket fuel for NASA's SLS rocket.

The four are set to dock with the space station on Saturday, returning the orbital lab to its full complement of seven. NASA's last mission, Crew-11, left a month early due to an ill crew member.

Engineers are investigating a hydrogen leak that cut short a fueling test last week, delaying the moon mission by at least a month.

A number of issues uncovered during a practice run of the launch prompted the move of the mission to no earlier than March 6.

NASA is moving the fueling test of its SLS rocket to Monday as frigid temps move into Florida's Space Coast this weekend

The Wet Dress Rehearsal is a critical test of the fueling and countdown of NASA's SLS rocket, which could launch a crew of four as early as Feb. 6.

The Museum of Science and Industry is now the Museum of Science and Innovation. Along with the name change, officials unveiled a new Center for STEAM Learning.

Forty years after the Challenger disaster, NPR explores the engineers' last-minute efforts to stop the launch, their decades of guilt and the vital lessons that remain critical for NASA today.

The SLS rocket arrived at its launch pad Saturday. Teams are working toward a launch as early as Feb. 6.