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Author
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Topic: [Discuss] NASA's Artemis II mission (Orion)
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Jim Behling
Member Posts: 2027
From: Cape Canaveral, FL
Registered: Mar 2010
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posted 02-03-2026 04:44 PM
   
quote:
Originally posted by Axman:
I believe "historic" is being severely abused here.
I agree. Artemis II isn't a first, it comes in second to Apollo 8 or 13. It is the Cygnus to Cargo Dragon, Starliner to Crew Dragon, Rusty Schweickart or Story Musgrave to Ed White.Sports fans do the same thing with current events versus the past. I forgot the term that is used to describe it. |
Robert Pearlman
Editor Posts: 55914
From: Houston, TX
Registered: Nov 1999
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posted 02-03-2026 04:57 PM
quote:
Originally posted by Jim Behling:
Artemis II isn't a first...
When was the last time a Canadian left low Earth orbit? How about someone other than an American? A woman? A person of color?Mercury-Redstone 3, Mercury-Atlas 6, Gemini-Titan 3, Apollo 7, Apollo 8, STS-1, Demo-2 and Starliner CFT are all firsts: the first crewed flight of a rocket. How is Artemis II any different? The four Artemis II astronauts are going to travel farther into deep space than anyone before them. It was historic when the Apollo 13 crew did it, so why is it not historic now? I think some people may be conflating "historic" with "famous." The whole world may not know their names, but they are going to make history and some of what Artemis II achieves is going to be historic. |
mf451
Member Posts: 89
From: NY, NY
Registered: Nov 2014
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posted 02-03-2026 07:36 PM
With the delay until March, will they roll it back into the VAB or keep it out on the pad? |
Robert Pearlman
Editor Posts: 55914
From: Houston, TX
Registered: Nov 1999
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posted 02-03-2026 08:24 PM
As of now, the vehicle is staying on the pad. The mission's managers said today that they anticipate being able to address the issues that arose during the tanking test and then conduct another wet dress. |
Kite
Member Posts: 1218
From: Northampton UK
Registered: Nov 2009
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posted 02-04-2026 09:25 AM
quote:
Originally posted by Robert Pearlman:
...is going to be historic.
I could not agree with you more Robert. The Artemis II mission is historic for all of the reasons you name. As someone who followed the Mercury, Gemini, Apollo, Skylab, ASTP and Space Shuttle flights avidly at the time I am still excited by this forthcoming venture. Really pleased for all of those who were not around at the time and this is their time and no one should begrudge them that. Just hope everything works to plan and we witness humans on the moon again soon. Exhilarating times ahead for all. |
Blackarrow
Member Posts: 3917
From: Belfast, United Kingdom
Registered: Feb 2002
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posted 02-04-2026 05:25 PM
It seems that the problem relates to liquid hydrogen leaks, possibly because the hydrogen atom is the smallest and lightest atom and molecular hydrogen can (I assume) slip through the narrowest of gaps in the plumbing. But it isn't a new problem. Liquid hydrogen is currently used on many other rockets, and was of course used in the second and third stages of the Saturn V. I seem to recall hydrogen leaks during Saturn V countdowns (including Apollo 11) but no Saturn V launch was ever delayed or scrubbed because of a hydrogen leak. Has the retirement and death of all the old Saturn engineers robbed NASA of the necessary expertise to achieve the leakless flow of liquid hydrogen into SLS? |
Headshot
Member Posts: 1447
From: Vancouver, WA, USA
Registered: Feb 2012
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posted 02-04-2026 06:25 PM
I believe there were liquid hydrogen issues with the Space Shuttle as well. I am relieved that the issue is with the interface and not with the SLS design itself. |
Robert Pearlman
Editor Posts: 55914
From: Houston, TX
Registered: Nov 1999
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posted 02-04-2026 08:05 PM
NASA did not solve the problem of hydrogen leaks during the Apollo or space shuttle program. They did, as they do now, work to halt the leak and then decided whether to press forward or scrub. In the final hours of the Apollo 11 launch countdown on July 16, 1969, as the crew was getting to board, a major hydrogen leak was detected. This is Apollo Saturn Launch Control; T minus 2 hours, 45 minutes, 55 seconds and counting... We have discovered a problem at the launch pad itself as the crew is about to arrive. We have a leak in a valve located in a system associated with replenishing liquid hydrogen for the third stage of the Saturn V launch vehicle. We have sent a team of three technicians and a safety man to the pad and these technicians are now tightening bolts around the valve. Once the technicians depart, we will send hydrogen again through the system to assure that the leak has been corrected. Sometimes NASA didn't catch the leak until the situation worsened. On STS-41D... ... a hydrogen fire, invisible to the naked eye, had broken out at the aft end of the orbiter. Had the crew evacuated at that time, they would have run through the invisible flames. The pad's fire suppression system came on to deal with the fire, and when the crew did finally egress the shuttle, they received a good dousing of water. The crew returned safely, if a little drenched, to crew quarters. After ground teams assessed the cause of the abort, they made the decision to roll the stack back to the VAB, demate Discovery from the ET and SRBs and tow it back to the OPF. Workers replaced the faulty engine, and Discovery rolled back out to the launch pad on Aug. 9 for another launch attempt... These situations are, at their essence, the same that occurred during the Artemis II wet dress but occurred during a live launch countdown instead of a test. |
Blackarrow
Member Posts: 3917
From: Belfast, United Kingdom
Registered: Feb 2002
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posted 02-05-2026 10:13 AM
If we assume that knowledge and experience about hydrogen leaks during Apollo was bequeathed to the early shuttle programme; and that the "old hands" on the shuttle passed their knowledge and experience to younger shuttle engineers, has that knowledge and experience been lost or is it simply impossible to work with liquid hydrogen without having to expect regular leaks? (Of course, SpaceX and Blue Origin are using liquid methane in their launchers, and I'm pretty sure one of the reasons was to avoid those hydrogen leaks...) |
Robert Pearlman
Editor Posts: 55914
From: Houston, TX
Registered: Nov 1999
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posted 02-05-2026 01:53 PM
NASA has never stopped hydrogen leaks. It has been and continues to be the concentrations of the leaking hydrogen that drives the concern. During the shuttle era, the threshold was about four percent. After what was learned on Artemis I, NASA raised the allowable concentration level to 10 percent. During the Artemis II tanking test, the first leak reached 12 to 14 percent concentration, approaching but not exceeding the 16 percent limit set by NASA. It was only the replenish valve leak late in the terminal count that exceeded the limits and called off the count. This isn't really a matter of institutional knowledge being lost, but having to adjust to a still new configuration and fine tuning what works best for it. |
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