SLS CORE STAGE HOT FIRE TEST, Jan 16, 2021, Stennis Space Center, MS, 4:00 pm ET (NASA TV begins 3:20 pm ET)

Update, January 16, 2:45 pm ET:  NASA has issued an update saying the test is running an hour ahead of schedule and NASA TV now will start at 3:20 pm ET instead of 4:20 pm ET.  So it’s back to what Stennis originally tweeted yesterday.  ¯\_(ツ)_/¯

Currently running up to an hour ahead of schedule for @NASA_SLS hot fire test. NASA TV broadcast will now begin at 3:20pm ET.

— Jim Bridenstine (@JimBridenstine) January 16, 2021

Update, January 15, 5:45 pm ET:  Stennis issued a corrected tweet with the original times.  Window is open 4:00-6:00 pm Central (5:00-7:00 pm Eastern).  NASA TV begins 4:20 pm ET.

Tune in tomorrow, Jan. 16, for a major milestone in the #Artemis program!
NASA is targeting the final test in the Green Run series, the hot fire, between 4:00 p.m. and 6:00 p.m. CST tomorrow! pic.twitter.com/bauhxsyGr1

— Stennis Space Center (@NASAStennis) January 15, 2021

Updated, January 15, 1:15 pm ET:  Stennis Space Center just tweeted that the test will take place between 3:00 and 6:00 pm Central Time, which is 4:00-7:00 pm Eastern, meaning it is a 3 hour window, not 2, and opens an hour earlier than NASA had said.  The NASA TV schedule still says (as of 1:15 pm ET Friday) that its coverage begins at 4:20 pm ET, however.

Tune in tomorrow, Jan. 16, for a major milestone in the #Artemis program!
NASA is targeting the final test in the Green Run series, the hot fire, between 3:00 and 6:00 p.m. CST tomorrow! pic.twitter.com/l4BlT2tJa0

— Stennis Space Center (@NASAStennis) January 15, 2021

Update, January 13: NASA says NASA TV coverage of the test will begin at 4:20 pm ET and clarifies that 5:00 pm ET is the opening of a two-hour window for the test.  A press conference will take place about 2 hours after the test concludes.

Update, January 12:  NASA officials said on a media telecon today that the test will begin at 4:00 pm local time (5:00 pm Eastern) on January 16.

Update, January 11:  in a rarity in the space business, NASA has accelerated the date for the hot fire test by one day.  It is now planned for January 16 instead of January 17.

Original Entry: NASA will conduct a “hot fire” test of the core stage of the Space Launch System (SLS) on January 17, 2021 at Stennis Space Center, MS.  It is the eighth of eight tests in the Green Run series to validate the core stage is ready for launch.

The core stage with its four RS-25 engines, left over from the space shuttle program, attached to an enormous test stand at Stennis, will be fueled and fired for eight minutes, the duration they must fire to reach orbit.

The test will take place even though the seventh in the series, the Wet Dress Rehearsal (WDR), did not go as planned on December 20.  As NASA explained, that test ended “a few minutes early due to timing on a valve closure.”

SLS has been delayed for many years.  NASA is anxious to conduct its first test flight, an uncrewed mission with an Orion spacecraft, in November 2021.