Turn to CNN for live coverage from Kennedy Space Center in Florida on Saturday afternoon. Space correspondent Kristin Fisher will bring us moment-by-moment reporting from the launch, along with a team of experts.
The launch window opens at 2:17 p.m. ET and closes at 4:17 p.m. ET on Saturday. Currently, weather conditions are 60% favorable during the launch window, according to weather officer Melody Lovin. She doesn’t expect weather to be a “showstopper” for the launch.
The Artemis I stack, which includes the Space Launch System rocket and Orion spacecraft, continues to sit on Launchpad 39B at Kennedy Space Center in Florida.
While there is no guarantee of a launch on Saturday, “we’re going to try,” said Mike Sarafin, Artemis mission manager, during a news conference Thursday evening. And while the launch team will assume a little more risk heading into the launch attempt, they are acceptable risks that the team is comfortable with, Sarafin said. The Artemis I mission is uncrewed.
One of the areas where the team is assuming more risk is with the conditioning of engine #3, which contributed to the scrub of Monday’s launch attempt. Another is a crack in the foam of the core stage intertank which could break apart and hit part of the solid rocket booster, but the team feels that the chances of that are very low, Sarafin said.
It’s “a marginal increase in risk,” Sarafin said, but “we are clearly ready to fly.”
“We had a plan going into the August 29th launch attempt. It used the sensors to help confirm the proper thermal conditioning of the engines. We had trained that plan, and then we ran into other issues,” Sarafin said.
“We were off the script in terms of the normal tanking operation, and the team did a fantastic job working through the managing of a hazardous condition. One of the worst things that you can do when you find yourself in a hazardous condition is just go even further off script.”
After reviewing the data, the team has a plan for moving forward.
Work has been completed at the launchpad to address two different hydrogen leaks that occurred Monday. The team has also completed a risk assessment of the engine conditioning issue and a foam crack that also cropped up, according to NASA officials.
On Monday, a sensor on one of the rocket’s four RS-25 engines, identified as engine #3, reflected that the engine could not reach the proper temperature range that is required for the engine to start at liftoff.
The engines need to be thermally conditioned before super-cold propellant flows through them before liftoff. To prevent the engines from experiencing any temperature shocks, the launch controllers increase the pressure of the core stage liquid hydrogen tank to send a little bit of the liquid hydrogen to the engines. This is known as a “bleed.”
Now, the team has determined it was a bad sensor providing the reading.
“We’ve had time to go back and look at look at the data and compare many sources of data and do some independent analysis that confirmed it’s a bad sensor,” said John Honeycutt, SLS program manager at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “We’re getting good quality propellant through the engine.”
On launch day, the team will ignore the bad sensor, said John Blevins, SLS chief engineer.
The automated launching sequencer on the rocket checks the temperature, pressure and other parameters. The bad sensor, which is not part of the sequencer, is not considered to be a flight instrument, Blevins said.
The team plans to begin the bleed earlier in the countdown than it occurred on Monday. The countdown for launch will pick up on Saturday at 4:37 a.m. ET during a planned hold. That’s when mission managers receive a weather briefing and decide if the team should proceed with loading propellant into the rocket. The bleed is expected to occur around 8 a.m. ET, said Charlie Blackwell-Thompson, Artemis launch director for NASA’s Exploration Ground Systems Program.
There is no longer a need for a two-day countdown, like during the first launch attempt, “because many of the configurations needed for launch are already in place,” according to NASA.
NASA’s live coverage will begin at 5:45 a.m. ET on their website and TV channel.
“We’ve got to show up, we’ve got to be ready, and we’ve got to see what the day brings,” Sarafin said.
If the mission launches on Saturday, it wil go on a journey around the moon and splashdown in the Pacific Ocean on October 11.
There is still a backup opportunity for the Artemis I mission to launch on September 5 as well.
The Artemis I mission is just the beginning of a program that will aim to return humans to the moon and eventually land crewed missions on Mars.