Today Still Looking Good for Artemis II — No Fooling!

It may be April Fool’s Day to some, but to NASA it’s launch day to send humans around the Moon for the first time in more than 50 years. As of noon ET, everything is going according to plan and the weather outlook remains 80 percent favorable.  The 2-hour launch window today opens at 6:24 pm ET.

NASA’s livestream of “tanking,” when propellant is loaded into the Space Launch System (SLS) rocket and its Interim Cryogenic Propulsion Stage (ICPS), began at 7:45 am ET.  NASA is livestreaming the countdown and posting text updates as well.

The SLS core stage and ICPS upper stage use Liquid Oxygen (LOX) as the oxidizer and Liquid Hydrogen (LH2) as fuel. Oxygen must be chilled to -297º F to be in liquid form, and hydrogen to -423ºF. The propellants are so cold, they boil off and evaporate while sitting on the launch pad and must be constantly replenished until just before liftoff.

By 11:45 am ET, the SLS core stage and ICPS upper stage LH2 tanks were full and in replenish mode. The SLS core stage was loaded with LOX and in the topping phase, just before replenish, and the ICPS upper stage was beginning to be filled.

By 12:51 pm ET, all the tanks were full and in replenish mode. At 2:14 pm ET, the crew arrived at Launch Complex 39B and soon were settling into their seats in the Orion capsule, which they’ve named Integrity.

 

The hatches to the Orion capsule and the Launch Abort System (LAS) are closed and the countdown is proceeding at 5:24 pm ET, an hour before the opening of the 2-hour launch window. An earlier issue with the Flight Termination System (FTS) has been resolved. The problem was with a communications system with the FTS. The FTS is needed if ground operators must send a signal to destroy the rocket if it goes off course — in which case the LAS would separate the crew module from the rocket and they’d land in the ocean.

At 5:45 pm ET, the weather has improved to 90 percent “go.”  Ground control teams are working an issue with the LAS batteries. The temperature on one of the two batteries is out of range. They are trying to determine if it is a sensor issue or the battery itself.  The countdown is proceeding while they investigate.

At 6:05 pm ET, they’ve resolved the battery issue and the countdown continues to launch at 6:24 pm ET.  They concluded it was instrumentation (sensor) issue.

At 6:15 pm ET, they said they still have some work to do, so will go into an extended hold at T-10 minutes. They have a 2- hour launch window.

The final poll by Launch Director Charlie Blackwell-Thompson is “go” for launch. Terminal count — the last 10 minutes — will start soon.

At 6:27 pm ET, the clock is now counting down to launch at 6:35:12 pm ET.

Liftoff was indeed at 6:35:12 pm ET on April 1, 2026.  The crew will spend about a day in earth orbit checking out Orion’s systems before heading toward the Moon. They will fly around the Moon, not go into orbit or land, on this first crewed test flight of the SLS/Orion system.