After a series of difficulties blocked liftoff on Monday, the Artemis I launch crew is preparing for another countdown that will begin early Saturday morning.
The launch window starts at 2:17 p.m. ET on Saturday and concludes at 4:17 p.m. ET. According to meteorological officer Melody Lovin, weather conditions are now 60% favourable for the launch window. She does not anticipate weather being a “showstopper” for the launch.
The Artemis I stack, which contains the Space Launch System rocket and the Orion spacecraft, remains on Launchpad 39B at Florida’s Kennedy Space Centre.
While a Saturday launch is not guaranteed, “we’re going to attempt,” said Mike Sarafin, Artemis mission manager, during a news conference Thursday evening. And, while the launch crew will incur a bit of extra risk before the launch attempt, Sarafin explained that these are reasonable risks that the team is comfortable with. The Artemis I mission is currently unmanned.
One area where the crew is taking greater chances is with the conditioning of engine #3, which led to the cancellation of Monday’s launch attempt. Another possibility is a split in the foam of the core stage intertank, which may break apart and damage part of the solid rocket booster, although Sarafin believes the odds are very low.
“We are certainly ready to fly,” Sarafin added, despite the “little increase in danger.”
“We had a strategy in place for the August 29th launch attempt. It employed the sensors to certify that the engines were properly thermally conditioned. We had practised that approach, but then we ran into additional problems “Sarafin said.
“In terms of the typical tanking operation, we were off the script, and the crew did an outstanding job working through the management of a dangerous scenario. When you’re in a dangerous situation, one of the worst things you can do is go even farther off script.”
Following an assessment of the data, the team has devised a strategy for going forward.
Work on the launchpad has been completed to remedy two separate hydrogen leaks that happened on Monday. According to NASA officials, the crew has also conducted a risk assessment of the engine conditioning issue and a foam crack that has also emerged.
On Monday, a sensor on one of the rocket’s four RS-25 engines, labelled as engine #3, indicated that the engine was unable to achieve the acceptable temperature range for the engine to start during liftoff.
Before super-cold propellant goes into the engines, they must be thermally conditioned. To prevent temperature shocks in the engines, the launch controllers boost the pressure in the core stage liquid hydrogen tank, sending a little amount of liquid hydrogen to the engines. This is referred to as a “bleed.”
The team has since discovered that the reading was provided by a faulty sensor.
“We’ve had time to look at the data, compare various sources of data, and perform some independent research that showed it’s a broken sensor,” said John Honeycutt, SLS programme manager at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “The engine is producing high-quality propellant.”
According to John Blevins, SLS chief engineer, the crew will disregard the malfunctioning sensor on launch day.
The rocket’s automatic launching sequencer monitors temperature, pressure, and other factors. According to Blevins, the faulty sensor, which is not part of the sequencer, is not considered a flight instrument.
The team intends to start the bleeding sooner in the countdown than it did on Monday. During a scheduled pause, the countdown to launch will begin on Saturday at 4:37 a.m. ET. When mission managers receive a weather briefing, they determine whether or not to proceed with fuel loading into the rocket. According to Charlie Blackwell-Thompson, Artemis launch director for NASA’s Exploration Ground Systems Program, the bleed is predicted to occur approximately 8 a.m. ET.
According to NASA, there is no longer a need for a two-day countdown, as there was during the first launch attempt, “since many of the configurations required for launch are already in place.”
NASA’s live coverage on their website and TV channel will begin at 5:45 a.m. ET.
“We have to show up, we have to be ready, and we have to see what the day delivers,” Sarafin added.
If the mission is conducted on Saturday, it will go around the moon before splashing down in the Pacific Ocean on October 11.
There is still a chance for the Artemis I mission to launch on September 5th.
The Artemis I mission is merely the beginning of a programme that will eventually land crewed spacecraft on Mars and return people to the moon.