Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 02:16 AM
Just as the loading of liquid hydrogen switched over to fast fill, a leak was detected in the tail service masts. Loading was halted and the leak decreased.
The issue is being worked.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 02:25 AM
The plan moving forward it to resume the slow fill of liquid hydrogen.
If the concentration being recorded by sensors in the core stage drops below 4 percent, it will indicate a leak and the slow fill will again be halted and reverted.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 02:54 AM
Liquid hydrogen loading has been halted again, this time due to a spike in pressure that was detected in the line feeding the hydrogen tank.
It is possible that between the transition from slow to fast fill and the subsequent troubleshooting for a leak, the line warmed up, causing the flash. The line will now be chilled again in an attempt to address the issue.
Liquid oxygen tanking continues at 47 percent filled, but that also raises a concern. There is a constraint, called the aft-strut constraint, in which the liquid hydrogen tank has to be over 5 percent filled before the liquid oxygen tank can go past 50 percent.
A plan is now in place to switch the liquid oxygen tank into slow fill.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 03:09 AM
Fast fill of liquid hydrogen has resumed.
The liquid hydrogen tank is now 17 percent full. The liquid oxygen tank is at 63 percent full.
The concern if there is a liquid hydrogen leak remains.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 04:04 AM
Now at 92 percent full for both the liquid oxygen and liquid hydrogen tanks in the core stage.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 04:20 AM
Now in "topping off" mode for both the liquid hydrogen and liquid oxygen tanks in the core stage, as both are full.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 05:02 AM
Now working an issue with the bleed of liquid hydrogen through RS-25 no. 3, which is needed to get the engine to the proper temperature for launch.
A possible crack in the intertank flange has been spotted and is being investigated.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 06:32 AM
The countdown has entered a unplanned hold at T-40 minutes to give the team working the RS-25 engine problem time to troubleshoot. Attempts to pressurize the liquid hydrogen tank to force the bleed have not been successful.
The possible crack spotted earlier has been determined to only be a crevice in the foam where ambient air is getting trapped, super chilled and then escaping as vapor. There is no crack in the flange itself.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 07:36 AM
Scrub! The engine issue could not be resolved in time for a launch to proceed.
Data is now being collected about the status of the vehicle to assist with further troubleshooting.
The next available launch opportunity is at 12:48 p.m. EDT on Friday, Sept. 2, but if the issue can be corrected by then is still to be seen.
SpaceAngel Member
Posts: 453 From: Maryland Registered: May 2010
posted 08-29-2022 12:25 PM
What are the chances of resolving the engines issue before Friday's next launch attempt?
Buel Member
Posts: 887 From: UK Registered: Mar 2012
posted 08-29-2022 12:37 PM
An extract from Gerry Griffin's oral history with Doug Ward seems particularly pertinent today;
Ward: I've got one other thought along those lines: Gilruth and Kraft really in a way had a kind of a paradoxical concept of returning to the Moon, as I remember it. Gilruth said that "People will never realize how difficult it was to do it the first time until they try to do it again."
Griffin: Right.
Buel Member
Posts: 887 From: UK Registered: Mar 2012
posted 08-29-2022 12:41 PM
quote:Originally posted by Robert Pearlman: The seven refers to the major component welds
Do we have any more detail on the seven welds, such as who/what performed them, how they were checked (X Ray, perhaps), etc?
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-29-2022 12:52 PM
The work is done at the Michoud Assembly Facility in Louisiana, as described in this 2016 NASA article:
Welding Orion's seven large aluminum pieces, which began in September 2015, involved a meticulous process. Engineers prepared and outfitted each element with strain gauges and wiring to monitor the metal during the process. The pieces were joined using a state-of-the-art process called friction-stir welding, which produces incredibly strong bonds by transforming metals from a solid into a plastic-like state, and then using a rotating pin tool to soften, stir and forge a bond between two metal components to form a uniform welded joint, a vital requirement of next-generation space hardware.
quote:Originally posted by SpaceAngel: What are the chances of resolving the engines issue before Friday's next launch attempt?
To quote Mike Sarafin, Artemis mission manager at NASA Headquarters, from today's post-scrub press conference:
There is a number greater than zero chance that we go on Friday.
SpaceAngel Member
Posts: 453 From: Maryland Registered: May 2010
posted 08-29-2022 07:45 PM
A possible launch on Fiday might be tricky; there's a 60% chance of mother nature being a show stopper.
Though the weather can change by that time...
OV-105 Member
Posts: 909 From: Ridgecrest, CA Registered: Sep 2000
posted 08-30-2022 04:28 AM
I don’t think they willl make a Friday launch window. I figure they will not be able to get into the engine area until early Tuesday. Find the problem, if it is a quick fix maybe have it done by early Wednesday. Get everything buttoned back up and cleared late Thursday it is too late to start the countdown for a Friday launch. I hope I am wrong.
oly Member
Posts: 1462 From: Perth, Western Australia Registered: Apr 2015
posted 08-30-2022 05:55 AM
Besides the commitment to return to the moon by 2024, there is no time pressure to risk getting things right. Given how long it has taken so far, a few more days or weeks is insignificant.
onesmallstep Member
Posts: 1428 From: Staten Island, New York USA Registered: Nov 2007
posted 08-30-2022 08:33 AM
There is really no 'commitment' (goal, perhaps) to get to the moon by 2024, if by that you mean a crewed flight. The earliest Artemis 2 (manned flight around the moon, but no landing) can get off is May 2024, per current NASA planning. Of course it's contingent on a successful Artemis 1 mission. And the metal is just being cut on the Artemis 3 lunar lander, so that's a big item on the checklist too.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 08-30-2022 05:12 PM
NASA will make its second attempt at the Artemis I launch on Saturday, Sept. 3. during a two hour window opening at 2:17 p.m. EDT (1817 GMT), pending a mission management team review on Thursday.
It is believed that the temperature issues with engine no. 3 were due to a faulty sensor and not a hardware issue with the engine. During Saturday's attempt, the bleed test will done earlier in the count.
There is a 40 percent chance of favorable weather conditions at the time of liftoff. If there is a weather scrub, the next attempt would be on Monday, Sept. 5.
J Blackburn Member
Posts: 297 From: Riner Registered: Sep 2011
posted 08-30-2022 06:55 PM
September 5th, which is Labor Day, and we all know how NASA loves launches on holidays. 😁
I am betting on a Monday launch but if she launches Saturday afternoon I will not shed a tear. Fingers crossed she lights and climbs into the darkness of space. Most of all, I want NASA to get it right so the program will not only continue but succeed.
GACspaceguy Member
Posts: 2999 From: Guyton, GA Registered: Jan 2006
posted 09-01-2022 10:37 AM
How does the launch window move as the opportunities move right such as the 4-6th? Also do any of the days available after the 6th have a night launch (I would think not just from a data gathering point of view)?
damnyankee36 Member
Posts: 61 From: Alamogordo, NM USA Registered: Aug 2017
posted 09-01-2022 12:45 PM
Speaking of launch windows, I am curious as how the Saturday window suddenly opened up. Initially, only Friday and Monday were the next opportunities. I haven't seen a reason given.
onesmallstep Member
Posts: 1428 From: Staten Island, New York USA Registered: Nov 2007
posted 09-01-2022 02:09 PM
Per the query about launch windows, and one on Saturday the third 'suddenly opening up;' It was announced by NASA on May 16 (and posted by Robert on this thread), that twelve launch opportunities would occur between Aug.23-Sept. 6 (except on Aug. 30, 31 and Sept. 1). So not so sudden, which of course is subject to technical or weather reasons.
SpaceAngel Member
Posts: 453 From: Maryland Registered: May 2010
posted 09-01-2022 03:06 PM
Saturday's weather for the second launch attempt now calls for a 60% of mother nature being cooperative; it was reversed from the other day...
Headshot Member
Posts: 1253 From: Vancouver, WA, USA Registered: Feb 2012
posted 09-01-2022 03:11 PM
How does the mass of this Orion compare to one that will carry a crew? I read that some systems are not onboard this unmanned version. I am curious what systems will added to the Orion used for Artemis II.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-01-2022 03:22 PM
The Artemis I Orion's mass at liftoff is 20,600 pounds. For Artemis II, it will be 22,900 pounds.
The Artemis I Orion is flying without avionics displays, three seats, the waste management system, the galley (food warmer) and the environmental control system.
quote:Originally posted by GACspaceguy: Also do any of the days available after the 6th...
The launch day must account for the Moon's position in its lunar cycle so that the SLS rocket’s upper stage can time the trans-lunar injection burn with enough performance to successfully intercept the "on ramp" for the lunar distant retrograde orbit.
The resulting trajectory for a given day must ensure Orion is not in darkness for more than 90 minutes at a time so that the solar array wings can receive and convert sunlight to electricity and the spacecraft can maintain an optimal temperature range.
The launch date must support a trajectory that allows for the skip entry technique planned during Orion’s return to Earth.
The launch date must support daylight conditions for Orion’s splashdown to initially assist recovery personnel when they locate, secure, and retrieve the spacecraft from the Pacific Ocean.
The current span of acceptable launch dates ends on Sept. 6. The next period opens on Sept. 19 and runs through Oct. 4 (excluding Sept. 29 and Sept. 30).
That said, the next set of launch opportunities results in a much shorter mission duration, so NASA may opt to target Oct. 17 to Oct. 31 (excluding Oct. 24, 25, 26, and 28) instead, to preserve the "long" mission profile.
SpaceAholic Member
Posts: 5296 From: Sierra Vista, Arizona Registered: Nov 1999
posted 09-01-2022 07:46 PM
"Artemis by the Numbers" soon to be on internet store bookshelves (in another decade or two).
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-03-2022 03:35 AM
NASA live video
Watch live as our mega Moon rocket launches an uncrewed Orion spacecraft on a six-week mission around the Moon and back to Earth.
Liftoff is from Launch Pad 39B at NASA's Kennedy Space Center in Florida. The two-hour launch window opens at 2:17 p.m. EDT (18:33 UTC) Saturday, Sept. 3.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-03-2022 06:20 AM
During tanking operations for today's launch attempt, as liquid oxygen loading entered fast fill and liquid hydrogen began slow fill, a hydrogen leak was detected in the engine cavity. Concentrations reached 80 percent, resulting in an automatic revert and halt to hydrogen tanking.
The launch team is going to let the source of the leak, a plate associated with a quick disconnect, to warm up and then will try resuming hydrogen loading in the hope the change in temperature will reseat the plate.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-03-2022 07:19 AM
Liquid hydrogen loading is now in manual fill with 4 percent of the tank full.
Liquid oxygen is in fast fill at 40 percent of the tank full.
SpaceAngel Member
Posts: 453 From: Maryland Registered: May 2010
posted 09-03-2022 07:45 AM
Does engineers have a game plan if the same issue reoccur like what happened on Monday's first attempt?
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-03-2022 07:51 AM
If you are referring the temperature issue with the RS-25 engines, it will not repeat (at least, not in the same way) because the sensor that was the culprit on Monday's attempt is being ignored.
quote:Originally posted by Robert Pearlman: ...a hydrogen leak was detected in the engine cavity.
Liquid hydrogen loading is being halted again to troubleshoot the leak. The vehicle's fill and drain valve is going to be closed and then helium is going to be fed into the ground transfer line in an attempt to reseat a quick disconnect.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-03-2022 08:13 AM
Helium pressurization complete, liquid hydrogen loading is slowly resuming with the hope the quick disconnect has reseated.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-03-2022 08:32 AM
The quick disconnect is still leaking. Hydrogen loading is currently halted again.
Engineers continue troubleshooting the issue.
OV-105 Member
Posts: 909 From: Ridgecrest, CA Registered: Sep 2000
posted 09-03-2022 08:36 AM
This is starting to remind me of the spring and summer of 1990 and the hydrogen leaks back then.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-03-2022 09:00 AM
quote:Originally posted by Robert Pearlman: Engineers continue troubleshooting the issue.
Engineers are letting the quick disconnect warm up for 30 minutes and then will attempt hydrogen loading again in hopes it reseats the connection and makes a tight seal.
Update: No joy. Troubleshooting continues.
Ken Havekotte Member
Posts: 3718 From: Merritt Island, Florida, Brevard Registered: Mar 2001
posted 09-03-2022 09:11 AM
quote:Originally posted by OV-105: This is starting to remind me of the spring and summer of 1990 and the hydrogen leaks back then.
Boy do I recall covering that incident with STS-35 that had been set to launch in May 1990 with Shuttle Columbia. It was a 17-inch umbilical problem requiring a rollback to the VAB on June 12.
The shuttle stack went back to Pad A on Aug. 9 for another launch attempt on Sept. 1. While at the pad during tanking, an unrelated leak was detected with high concentrations of hydrogen in the orbiter's aft compartment, forcing another postponement.
Liftoff was rescheduled for Sept. 18 and the fuel leak resurfaced, once again in the same area, during tanking of the vehicle. Launch scrubbed again in which NASA put the mission on hold until the problem had been resolved by a special Tiger assessment Team.
STS-35 was moved to Pad B to make room for STS-38/Atlantis, and finally, on Dec. 2 liftoff occurred after only a 21-minute delay to allow Air Force range time to observe low-level clouds that might impede tracking of shuttle's ascent, NASA reported. But--when tanking for this attempt on 39B, there was no excessive hydrogen leakage, finally, huh, after half-a-year trying to get 35 to fly!
OV-105 Member
Posts: 909 From: Ridgecrest, CA Registered: Sep 2000
posted 09-03-2022 09:42 AM
And Atlantis had the leak too for STS-38. The first time I went to Houston in 1991 everywhere we went there was an STS-35 autographed crew photo. I think they ate at every restaurant in the Clear Lake Houston area.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-03-2022 10:18 AM
Scrub! Having exhausted the available options to troublehsoot a liquid hydrogen leak, launch director Charlie Blackwell-Thompson called off today's (Sept. 3) launch attempt.
SpaceAngel Member
Posts: 453 From: Maryland Registered: May 2010
posted 09-03-2022 01:55 PM
I can imagine how disappointing that another technical snafu has thwarted today's second launch attempt; on the other hand, I know it was the right thing to call off the attempt and not letting the launch vehicle blow up as well as causing a huge domino effect of the entire Artemis program.
Robert Pearlman Editor
Posts: 51365 From: Houston, TX Registered: Nov 1999
posted 09-03-2022 03:35 PM
NASA will make no more tries this launch period (ending on Tuesday, Sept. 6).
When Artemis I will next attempt to launch is to be determined. Mission managers are still weighing options about conducting work at the launchpad, performing a cryo test and then rolling back to the Vehicle Assembly Building or doing the work in the VAB and forgoing the test. A decision should come next week.
posted 08-29-2022 02:16 AM
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