The Artemis I mission management team met today to review the status of operations and has given the “go” to proceed toward tanking operations. Weather conditions are 80% favorable for the two-hour launch window which opens at 1:04 a.m. EST Nov. 16, with the primary concern being the potential for thick clouds.

Launch director Charlie Blackwell-Thompson is expected to give the “go” shortly to officially begin propellant loading operations. During tanking operations, teams will load the Space Launch System (SLS) rocket with liquid oxygen (LOX) and liquid hydrogen (LH2), beginning with the rocket’s core stage and then the interim cryogenic propulsion stage.

Tanking begins with chilling down the LOX and LH2 lines for the core stage.  In sequential fashion, LOX and LH2 will flow into the rocket’s core stage tank and be topped off and replenished as some of the cryogenic propellant boils off. The process involves slowly filling the core stage with propellant to thermally condition the tank until temperature and pressure are stable before beginning fast fill operations, which is when the tank is filled at a quicker pump speed. As the super cold liquid oxygen fills the core stage tank, some venting may be visible.

At 3:30 p.m., NASA TV coverage begins with commentary of tanking operations to load propellant into the SLS rocket. Full coverage begins at 10:30 p.m. in English and at midnight Wednesday, Spanish coverage begins on NASA en español YouTube page.

Below are the countdown milestones as planned for tanking:

  • Core stage LOX transfer line chilldown (L-9H15M – L-9H)
  • Core stage LH2 transfer line chilldown (L-9H15M – L-8H45M)
  • 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)
  • 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)
  • Final NASA Test Director briefing is held (L-50M)
  • Built in 30-minute countdown hold begins (L-40M)
  • The launch director polls the team to ensure they are “go” for launch
  • 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)
  • T-0: Booster ignition, umbilical separation, and liftoff
Mission Managers Give “Go” to Proceed Toward Tanking Operations for Artemis I