NASA will attempt for a second time to launch the Artemis 1 on Saturday, September 3, reported Reuters. The Moon mission had been postponed due to a malfunctioning RS-25 engine on the Space Launch System (SLS) rocket.
Artemis 1 ran into trouble as team engineers noticed that one of the engines had an issue with the liquid hydrogen. The launch director had signed off on a plan to troubleshoot one of the RS-25 engines which was malfunctioning. But the troubleshooting plan did not work. The countdown clock was put on hold at T-40 minutes as the hydrogen team discussed options with the launch director. Here is a full recap of what went wrong during the mission.
Artemis I is an uncrewed mission that will be the first in a series of increasingly complex missions to the Moon, eventually taking humans back to Earth’s lone satellite. During the mission, NASA will demonstrate the performance and capabilities of its most powerful launch vehicle ever, the Space Launch System (SLS), and the Orion crew capsule. During the approximately six-week-long mission, SLS and Orion will travel a distance of around 65,000 kilometres to the Moon and back.
Do you know why NASA's Moon mission is named after an ancient Greek goddess? After Apollo, the space shuttled program shunned mythological monikers in favour of names that represented a spirit of innovation, like Columbia, Challenger, Discovery, Atlantis and Endeavour. But after 50 years, Artemis will pick up where her twin left off.
NASA will attempt for a second time to launch the Artemis 1 on Saturday, September 3, reported Reuters. The Moon mission had been postponed due to a malfunctioning RS-25 engine on the Space Launch System (SLS) rocket.
Read this Explained article to get a full recap of the Artemis 1 mission, what happened during the first launch attempt and NASA’s long-term objectives with the program.
While the scrubbing of the Artemis 1 mission launch is a setback, it might look like nothing but a small speed bump in the rearview mirror if NASA goes on to achieve the ambitious objectives of the Artemis mission, which includes the assembly of the Gateway Space Station orbiting the Moon.
The next launch window for the Artemis 1 mission is between 10.18 PM IST on September 2 and 12.18 AM IST on September 3. There is another launch window between 2.42 AM and 3.54 AM IST on September 5. Even though NASA is yet to confirm whether it will attempt another launch during these windows, Artemis mission manager Mike Sarafin hinted that the launch could still happen this week during the post-scrub press conference. “Friday is definitely in play. We just need a little bit of time to look at the data. But the team is setting up for a 96-hour recycle,” said Sarafin during the conference.
The RS-25 engine that malfunctioned is not new. NASA began developing the engine model in 1970 and the it had its first launch in 1981.
NASA has not yet announced when it will next attempt launch with the SLS rocket. Here is what we can expect the space agency to do.
NASA will hold a media teleconference at 6 pm EDT later today. For India, this translates to 3.30 am at night by August 31. The conference will discuss the flight test of the agency’s mega Moon rocket and uncrewed Orion spacecraft.
According to NASA’s Artemis blog, the four RS-25 engines need to be “thermally conditioned before super cold propellant begins flowing through them for liftoff.” This take place by increasing pressure on the “core stage liquid hydrogen tank to route,” which is called a ‘bleed’. But engine number 3 did not bleed as expected. According to NASA, managers suspect the reason for this is likely a problem with the engine itself.
While NASA has not set “a precise time frame for retrying a launch of the mission,” according to Reuters, senior NASA officials said a second attempt could be made on Friday depending on what data analysis results reveal. Engineers will still need to fix the issue of the engine bleed. “Friday is definitely in play,” Michael Sarafin, NASA’s Artemis mission manager told reporters, according to Reuters.
NASA Administrator Bill Nelson has explained why the mission was scrubbed. “They’ve got a problem with the gases going on the engine bleed on one engine. You can’t go, you there are certain guidelines. And I think it’s just illustrative, that this is a very complicated machine, a very complicated system, and all those things have to work,” he said in a short statement. Watch full video below:
NASA has officially scrubbed its first attempt at launching the Artemis 1 mission to the moon due to a malfunctioning core stage RS-25 engine. From what appeared to be a “crack” in the inner tank to a hydrogen leak when the core stage was being fuelled to the RS-25 bleeding issue, here is our recap of everything that went wrong during this attempt.
The launch director has announced that the mission will be postponed since the issue with the RS-25 engine has not yet been resolved. The next available launch window is on September 2.
Engineers are working with data models to come up with a troubleshooting plan for the malfunctioning RS-25 engine, and the launch director is waiting to hear from them. The countdown clock is still on hold at T minus 40 minutes and that will not change till the launch team has come up with a solution to troubleshoot the malfunctioning engine.
#Artemis I update: Launch is currently in an unplanned hold as the team works on an issue with engine number 3 on the @NASA_SLS core stage. Operations commentary continues at https://t.co/z1RgZwQkWS https://t.co/mFyoeRMC6q
Engineers have looked at the line of ice that built up on the inner tank on the exterior of the core stage near the flange and have concluded that the ice was formed by frozen air that was chilled by the tank and trapped inside a crack in the foam. This should mean that there is no crack in the actual tank. NASA spokesperson added that there has been a history of this phenomenon going back to the space shuttle days. In the meanwhile, the hydrogen team is still working on plans to troubleshoot the malfunctioning RS-25 engine.
The countdown clock was put on hold at T-40 minutes. The hydrogen team will now discuss plans with the launch director before deciding on how to proceed
The countdown clock is on a hold at T-40 minutes. The hydrogen team of the @NASA_SLS rocket is discussing plans with the #Artemis I launch director. Operational commentary continues at https://t.co/z1RgZwQkWS. pic.twitter.com/5J6rHVCe44
The launch director had signed off on another troubleshooting plan. One of the four RS-25 engines is not getting the right amount of engine bleed to condition it for launch. The latest plan was to close the pre-valves on engines 1,2 and 4 and let the tank vent through the third engine. Even after going through with the plan, the teams didn’t see the engine bleed that they were looking for on engine number 3. 
There appears to be a crack in the inner tank flange of the upper stage. There is frost build-up and there is a trail of vapour from it as can be seen from the image below. Artemis launch control is currently monitoring the situation. Another issue is what appears to be a line of frost on the inner tank seal on the exterior part of the core stage. We don’t yet have an image of that. All of this could mean that the launch will be delayed. 
Liquid hydrogen replenish is closed and now in revert to troubleshoot the bleed on engine number 3. Teams are working to increase pressure in the bleed on engine 3 to continue conditioning the four RS-25 engines on @NASA_SLS for launch. https://t.co/wEUPRpb8q2
The RS-25 engines are bleeding but the liquid hydrogen team reports that they are not getting enough bleed from one of the four (engine number 3). The liquid hydrogen tank of the core stage is now closed. The upper stage is currently being loaded. The RS-25 engines are pictured in the screenshot below. The launch team is working on the engine bleed, trying to get engine number 3 to work in the right configuration. 
Both the liquid oxygen and liquid hydrogen cryogenic tanks are filled up. NASA is currently filling up the ICPS liquid hydrogen tank and will start filling its liquid oxygen tank as well. The mission was delayed by close to an hour due to the potential of lightning storms and the teams had to wait till all storm clouds were outside a 5-kilometre radius from Launch Complex 39B.
“As that leak showed itself, the team went into a configuration called “revert,” which means we took the pressure off the tank so that the leak is no longer fed with pressure. Once they did that, we did some discussion and troubleshooting to understand where that leak was coming from and during this, we got back into slow fill. The leak then flattened out below our limits and we have not had an increase in that leak throughout that fill. Now we are in great shape,” said Jeremy Graeber, assistant launch director.
Now, the NASA team will evaluate all the work that happened and establish a new “T-0” or launch time. Graeber said the team is still working on finding an optimum launch time and can’t yet say when the launch will happen during the window.
NASA’s critical Artemis 1 mission has been delayed. The rocket was supposed to take off yesterday — the first step in part of NASA’s mission to put humans back to the Moon– but the launch did not take place due to an issue with one of the engines. According to the space agency, there was inadequate flow of liquid hydrogen to one of the rocket’s four engines and the hydrogen team was not able to fix the problem. The next possible launch date is September 2, though NASA has not confirmed if they will carry out the mission on this particular date.
