Head to CNN for live coverage from the Kennedy Space Center in Florida on Saturday afternoon. Space correspondent Kristin Fisher will provide us with moment-by-moment coverage of the launch, along with a team of experts.
The launch window opens at 2:17 PM ET and closes at 4:17 PM ET on Saturday. Currently, weather conditions are 60% favorable during the launch window, according to weather officer Melody Lovin. She doesn’t expect it to be another “showstopper” before launch.
The Artemis I stack, which includes the Space Launch System rocket and the Orion spacecraft, will remain on Launchpad 39B at the Kennedy Space Center in Florida.
While there’s no guarantee of a Saturday launch, “we’re going to give it a try,” Artemis mission manager Mike Sarafin said at a news conference Thursday night. And while the launch team will take a little more risk in the launch attempt, there are acceptable risks that the team is comfortable with, Sarafin said. The Artemis I mission is unmanned.
One of the areas where the team is taking more risk is the conditioning of engine #3, which contributed to the deterioration of Monday’s launch attempt. Another is a crack in the foam of the core stage’s intertank that could break and hit part of the solid rocket booster, but the team thinks the chances are very slim, Sarafin said.
It’s “a marginal increase in risk,” Sarafin said, but “clearly we’re ready to fly.”
“We had a plan for the August 29 launch attempt. It used the sensors to confirm the correct thermal conditioning of the engines. We had trained that plan and then we ran into other problems,” Sarafin said.
“We were off script in terms of normal tank operation, and the team did a fantastic job of managing a dangerous situation. One of the worst things you can do when you’re in a dangerous situation is just go. even further from the script.”
After reviewing the data, the team has a plan to move forward.
Work on the launch pad has been completed to address two separate hydrogen leaks that occurred Monday. The team also completed a risk assessment of the engine conditioning problem and a foam crack that also surfaced, according to NASA officials.
On Monday, a sensor on one of the rocket’s four RS-25 engines, identified as engine #3, indicated that the engine was unable to reach the proper temperature range necessary for the engine to start on takeoff.
The engines must be thermally conditioned before super-cold propellant flows through them before taking off. To prevent the engines from experiencing temperature shocks, the launch controllers increase the pressure of the liquid hydrogen tank in the core stage to send a small amount of the liquid hydrogen to the engines. This is known as a ‘bleeding’.
Now the team has determined that it was a bad sensor that provided the reading.
“We’ve had time to go back and look at the data and compare many data sources and do an independent analysis that confirmed it’s a bad sensor,” said John Honeycutt, SLS program manager at NASA’s Marshall Space Flight Center. Huntsville, Alabama. “We get good quality propellant through the engine.”
On launch day, the team will ignore the bad sensor, said John Blevins, SLS chief engineer.
The automated launch sequencer on the rocket monitors temperature, pressure, and other parameters. The bad sensor, which isn’t part of the sequencer, isn’t considered a flight instrument, Blevins said.
The team plans to start the bleed earlier in the countdown than Monday. The launch countdown begins Saturday at 4:37 a.m. ET during a scheduled stop. that is when mission managers receive a weather briefing and decide whether the team should continue loading propellant into the rocket. The hemorrhage is expected to occur around 8 a.m. ET, said Charlie Blackwell-Thompson, Artemis launch director for NASA’s Exploration Ground Systems Program.
It is no longer necessary to count down two days, as during the first launch attempt, “because many of the configurations necessary for the launch are already in place,” according to NASA.
“We have to show up, we have to be ready, and we have to see what the day brings,” Sarafin said.
If the mission launches on Saturday, it will circumnavigate the moon on October 11 and crash into the Pacific Ocean.
There is still a backup option for the Artemis I mission which also launches on September 5.
The Artemis I mission is just the beginning of a program that aims to return humans to the moon and eventually land manned missions on Mars.