Artemis I managers convened Monday afternoon to review the status of countdown operations as well as two open technical items, and gave a “go” to proceed toward launch Wednesday, Nov 16. The two-hour window for launch opens at 1:04 a.m. EST.

Engineers examined detailed analysis of caulk on a seam between an ogive on Orion’s launch abort system and the crew module adapter and potential risks if it were to detach during launch. The mission management team determined there is a low likelihood that if additional material tears off it would pose a critical risk to the flight.

The area where caulk was detached during Hurricane Nicole.
The area where caulk on a seam between the Orion launch abort system’s ogive and crew module adapter detached during Hurricane Nicole.
Close view of the caulk frayed during Hurricane Nicole.
A close-up view of the area.

Technicians also completed replacing a component of an electrical connector on the hydrogen tail service mast umbilical. While swapping the component did not fully fix the issue, engineers have redundant sources of information supplied through the connector.

Listen to a replay of the media teleconference Nov. 14.

The countdown, which began Monday at 1:54 a.m., is progressing smoothly. All elements of the rocket and spacecraft are powered up. Overnight, teams will charge flight batteries, conduct final walkdowns at the launch pad, and check out communications with Orion.

The following milestones remaining in the countdown are below. Live coverage of tanking operations with commentary on NASA TV will begin on Tuesday, Nov. 15 at 3:30 p.m. Full launch coverage in English will begin at 10:30 p.m. Click here for the latest information on launch briefings and events.

L-32 hours and counting 

  • Core stage composite overwrapped pressure vessel (COPV) Pressurization to Flight Pressure (L-32M – L-23H)
  • The ICPS is powered down (L-31H – L-30H30M)
  • Charge Orion flight batteries to 100% (L-31H – L-27H)
  • Charge core stage flight batteries (L-28H – L-22H)
  • The ICPS is powered-up for launch (L-19H30M – L-16H30M)

L-15 hours and counting 

  • All non-essential personnel leave Launch Complex 39B (L-13H – L-11H)
  • Ground Launch Sequencer (GLS) activation (L-11H15M – 10H15M)
  • Air-to-gaseous nitrogen (GN2) changeover and vehicle cavity inerting (L-11H45M – launch)

L-10 hours, 40 minutes and counting

  • 3.5-hour built in countdown hold begins (L-10H40M – L-7H10M)
  • Launch team conducts a weather and tanking briefing (L-10H40M – L-9H50M)
  • Launch team decides if they are “go” or “no-go” to begin tanking the rocket (L-9H40M)
  • Core stage LOX transfer line chilldown (L-9H15M – L-9H)
  • Core stage LH2 transfer line chilldown (L-9H15M – L-8H45M)

L-8 hours and counting

  • Core stage LOX main propulsion system chilldown (L-9H – L-8H20M)
  • Core stage LH2 slow fill start (L-8H45M – L-7H50M)
  • Core stage LOX slow fill (L-8H20M – L-8H5M)
  • Core stage LOX fast fill (L-8H5M – L-5H15M)
  • Core stage LH2 fast fill (L-7H50M – L-6H10M)
  • Engine bleed kick start (L-7H40M – L-7H20M)
  • Core stage LH2 topping (L-6H10M – L6H5M)
  • Core stage LH2 replenish (L-6H5M – launch)
  • Core stage LOX topping (L-5H15M– L-5H5M)
  • ICPS LH2 ground support equipment and tank chilldown (L-5H20M – L-5H)

L-5 hours and counting 

  • Core stage LOX replenish (L-5H5M – launch)
  • ICPS LOX main propulsion system chilldown (L-5H5M– L-4H45M)
  • ICPS LH2 fast fill start (L-5H5M – L4H5M)
  • Orion communications system activated (RF to mission control) (L-4H20M – L-3H45M)
  • ICPS LOX fast fill (L-4H55M– L-4H10M)
  • ICPS LOX validation and leak test (L-4H10M – L-3H40M)
  • ICPS LH2 validation and leak test (L-4H – L-3H40M)
  • ICPS LH2 tank topping start (L-3H40M – L-3H25M)
  • ICPS LH2 replenish (L-3H25M – launch)
  • ICPS LOX topping (L-3H40M – L-3H20M)
  • ICPS LOX replenish (L-3H20M – launch)
  • ICPS/Space Launch System telemetry data verified with Mission Control Center and SLS Engineering Support Center (L-2H55M – L-2H45M)
  • ICPS LOX validation and leak test (L-2H55M – L-2H30M)
  • ICPS LH2 replenish (L-2H50M – launch)
  • ICPS LOX topping (L-2H30M – L-2H10M)
  • ICPS LOX replenish (L-2H10M – launch)
  • ICPS/Space Launch System (SLS) telemetry data verified with Mission Control Center and SLS Engineering Support Center (L-3H – L-2H50M)

L-50 minutes and counting

  • Final NASA Test Director briefing is held (L-50M)

L-40 minutes and holding 

  • Built in 30-minute countdown hold begins (L-40M)

L-15 minutes and holding  

  • The launch director polls the team to ensure they are “go” for launch

T-10 minutes and counting 

  • Ground Launch Sequencer (GLS) initiates terminal count (T-10M)
  • GLS go for core stage tank pressurization (T-6M)
  • Orion ascent pyros are armed (T-6M)
  • Orion set to internal power (T-6M)
  • Core stage LH2 terminate replenish (T-5M57S)
  • GLS is go for flight termination system (FTS) arm (T-5M)
  • GLS is go for LH2 high flow bleed check (T-4M40S)
  • GLS is go for core stage auxiliary power unit (APU) start (T-4M)
  • Core Stage APU starts (T-4M)
  • Core stage LOX terminate replenish (T-4M)
  • ICPS LOX terminate replenish (T-3M30S)
  • GLS is go for purge sequence 4 (T-3M10S)
  • ICPS switches to internal battery power (T-1M56S)
  • Core stage switches to internal power (T-1M30S)
  • ICPS enters terminal countdown mode (T-1M20S)
  • ICPS LH2 terminate replenish (T-50S)
  • GLS sends “go for automated launch sequencer” command (T-33S)
  • Core stage flight computer to automated launching sequencer (T-30S)
  • Hydrogen burn off igniters initiated (T-12S)
  • GLS sends the command for core stage engine start (T-10S)
  • RS-25 engines startup (T-6.36S)


  • Booster ignition, umbilical separation, and liftoff






Managers Give “Go” to Proceed Toward Launch, Countdown Progressing