Today's planned launch of the Artemis 1 mission, which incorporates NASA's most powerful rocket ever, has been cancelled. According to NASA, there was a problem with the engines which couldn't be fixed within the two-hour launch window.
Plans had called for the launch to take place this Monday from the Kennedy Space Center in Florida, sometime within a two-hour window starting at 8:33am EDT. The uncrewed mission was designed to test the deep space travel capabilities of the Orion space capsule and the SLS (Space Launch System), the latter of which is the most powerful launch rocket ever made by NASA.
At 8:19am EDT this morning, the space agency issue the following statement:
Teams are in a hold in the countdown at T-40 minutes while engineers evaluate why the bleed test to condition the engines was not successful. Engineers are looking at options to gather as much data as possible. The Artemis I rocket and spacecraft are in a stable, safe condition.
This was followed at 8:50am, when the space agency stated:
The launch director halted today’s Artemis I launch attempt at approximately 8:34 a.m. EDT. The Space Launch System rocket and Orion spacecraft remain in a safe and stable configuration. Launch controllers were continuing to evaluate why a bleed test to get the RS-25 engines on the bottom of the core stage to the proper temperature range for liftoff was not successful, and ran out of time in the two-hour launch window. Engineers are continuing to gather additional data.
There's currently no word on when the next launch attempt will be made.
Source: NASA