NASA's mission management team is meeting again this morning to discuss whether to proceed with cryogenic tanking of the Space Launch System rocket today at the Kennedy Space Center. The tanking test was delayed from yesterday due to a ground system issue. https://spaceflightnow.com/2022/04/03/sl...-status-center/
1:33 PM · Apr 4, 2022·TweetDeck
Zitat Spaceflight Now @SpaceflightNow
The countdown clock for the Artemis 1 wet dress rehearsal did not resume from its built-in hold at 7:30am EDT (1130 GMT), indicating a delay in today’s planned cryogenic tanking of the Space Launch System.
Zitat 04/04/2022 14:26 Stephen Clark Stephen Clark
NASA confirms the mission management team has given approval to proceed with cryogenic tanking of the Space Launch System today at the Kennedy Space Center. However, the launch team is waiting for a vendor to resolve an outage of the gaseous nitrogen supply at the pad.
Once this issue is resolved, the countdown clock will resume at T-minus 6 hours, 40 minutes, NASA says.
"The issue has been resolved at the gaseous nitrogen (GN2) plant and we are currently in switchover to GN2. When completed, we will pick up the clock at T-6.40."
Zitat 04/04/2022 15:42 Stephen Clark Stephen Clark
NASA says the issue with the Air Liquide gaseous nitrogen plant at the Kennedy Space Center has been resolved, and teams are switching over the environmental control system at the pad to gaseous nitrogen. This nitrogen is used to ensure there's not a flammable environment inside the rocket during cryogenic tanking operations.
Zitat 04/04/2022 16:38 Stephen Clark Stephen Clark
The SLS countdown clock remains in an extended hold. The timeline is now running more than three hours behind schedule today for the Artemis 1 wet dress rehearsal, and the last official update from NASA came more than hour ago.
17:08 MESZ. Countdown läuft seit 16:55 wieder. (Hatte ich mein Motto also doch richtig gewählt...)
Zitat 04/04/2022 17:25 Stephen Clark Stephen Clark
Liquid oxygen chilldown for the core stage is underway. This process thermally conditions the liquid oxygen plumbing before loading of the oxidizer begins at T-minus 5 hours, 55 minutes.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat Saturn 5’s total propellant capacity was 960,000 gallons of RP-1, LH2, and LOX. Space shuttle’s external tank contained 528,000 gallons of LOX and LH2.
The SLS moon rocket will be filled with 755,000 gallons of liquid hydrogen & liquid oxygen for the practice countdown. •Core Stage LOX: 196,000 gallons •Core Stage LH2: 537,000 gallons •Upper stage LOX: 5,000 gallons •Upper stage LH2: 17,000 gallons
Zitat T-05:35:00: Core stage liquid hydrogen chilldown begins • T-05:30:00: Core stage liquid hydrogen slow fill begins • T-05:10:00: Core stage liquid hydrogen fast fill begins • T-04:00:00: Core stage liquid hydrogen topping begins • T-03:55:00: ICPS liquid hydrogen chilldown begins; Core stage liquid hydrogen in replenish mode • T-03:50:00: Orion communications system activation begins • T-03:30:00: ICPS liquid hydrogen fast fill begins • T-02:55:00: Core stage liquid oxygen topping begins • T-02:50:00: Core stage liquid oxygen in replenish mode; ICPS liquid oxygen chilldown begins • T-02:45:00: ICPS liquid hydrogen validation and leak test begins • T-02:30:00: ICPS liquid hydrogen topping begins; ICPS/SLS telemetry data verified with MCC and SLS support center • T-02:10:00: ICPS liquid hydrogen in replensh mode; ICPS liquid oxygen validation and leak test begins • T-01:50:00: ICPS liquid oxygen topping begins • T-01:40:00: ICPS liquid oxygen in replenish mode • T-01:30:00: Core stage liquid hydrogen/liquid oxygen stop flow and recover test begins
• T-00:10:00: Final 30-minute built-in hold begins; Final NASA Test Director briefing; Final Launch Director poll • T-00:10:00: Countdown resumes • T-00:06:00: Orion ascent pyros armed; Orion transitions to internal battery power • T-00:05:57: Core stage liquid hydrogen replenish terminates • T-00:04:00: Core stage auxiliary power unit starts; Core stage liquid oxygen replenish terminates; Solid rocket boosters armed for ignition • T-00:03:30: ICPS liquid oxygen replenish terminates • T-00:03:07: RS-25 main engine purge sequence 4 • T-00:01:56: ICPS transitions to internal battery power • T-00:01:30: Core stage transitions to internal battery power; Countdown pauses for approximately 3 minutes to demonstrate “launch ready” hold • T-00:01:20: ICPS enters terminal countdown mode • T-00:00:50: ICPS liquid hydrogen replenish terminates • T-00:00:33: Ground Launch Sequencer sends cutoff command; Countdown recycles back to T-minus 10 minutes EDITOR’S NOTE: The countdown will recycle back to T-minus 10 minutes to allow the launch team to rehearse their ability to hold the countdown and set up for a second launch attempt on the same day.
• T-00:10:00: Final NASA Test Director briefing; Final Launch Director poll • T-00:10:00: Countdown resumes • T-00:06:00: Orion ascent pyros armed; Orion transitions to internal battery power • T-00:05:57: Core stage liquid hydrogen replenish terminates • T-00:04:00: Core stage auxiliary power unit starts; Core stage liquid oxygen replenish terminates; Solid rocket boosters armed for ignition • T-00:03:30: ICPS liquid oxygen replenish terminates • T-00:01:56: ICPS transitions to internal battery power • T-00:01:30: Core stage transitions to internal battery power; Countdown pauses for approximately 3 minutes to demonstrate “launch ready” hold • T-00:01:20: ICPS enters terminal countdown mode • T-00:00:50: ICPS liquid hydrogen replenish terminates • T-00:00:33: Ground launch sequencer sends “go for automated launch sequencer” command • T-00:00:30: Core stage flight computer transitions to automated launch sequencer • T-00:00:28: Solid rocket booster hydraulic power unit starts • T-00:00:19: Solid rocket booster thrust vector control gimbal profile • T-00:00:10: Ground launch sequencer sends “go for core stage engine start” command • T-00:00:09.34: Ground launch sequencer sends cutoff command The countdown will stop at T-minus 9.34 seconds, just before ignition of the SLS core stage’s RS-25 main engines
Zitat 04/04/2022 18:22 Stephen Clark Stephen Clark
NASA says the launch team "ran up against a temperature limit" for the liquid oxygen before the start of cryogenic loading into the SLS core stage. "Team is working through updating procedures and adjusting pressures based on data on console."
Presumably, this means liquid oxygen loading has not yet begun at pad 39B.
Zitat 04/04/2022 18:26 Stephen Clark Stephen Clark
The countdown clocking is continuing, for now, and the test team will assess where to resync the countdown steps after reconfiguring propellant loading procedures, according to NASA.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat 04/04/2022 20:41 Stephen Clark Stephen Clark
NASA's exploration ground systems team at the Kennedy Space Center reports engineers have "reworked procedures" and has resumed the liquid oxygen chilldown operation that was halted earlier in the day.
"Team is pressing and using every operation as test objective risk buy down," NASA says. The countdown clock, which is now at T-minus 2 hours, 51 minutes, will be resynced with the status of the countdown later.
Continuing to let the countdown clock move allows the launch team to accomplish other tasks while engineers have discussed the liquid oxygen temperature issue.
Zitat 04/04/2022 20:58 Stephen Clark Stephen Clark
The launch team "has not taken any options off the table yet" as engineers continue to work through the Space Launch System countdown rehearsal. There was discussion earlier about proceeding into liquid hydrogen loading while teams work the liquid oxygen temperature issue. However, NASA says that hasn't happened yet.
Zitat Irene Klotz @Free_Space @SenBillNelson This isn't the transparency NASA pledges to practice.
Zitat William Harwood @cbs_spacenews · 1h SLS/Artemis 1: The countdown clock is still ticking and is now inside T-minus 3h:45m; but we have no idea where they actually stand in terms of propellant flow or whether they can still complete fueling today
21:50 MESZ. Countdown läuft seit 3 Minuten wieder; Stand 01:40:50.
Zitat Spaceflight Now @SpaceflightNow
NASA confirms chilldown of the core stage liquid hydrogen loading system has begun, conditioning the transfer lines leading into the Space Launch System.
The countdown rehearsal is running about 7 hours behind the original timeline.
Zitat 04/04/2022 22:18 Stephen Clark Stephen Clark
The Artemis launch team is evaluating a balky vent valve on the Space Launch System’s mobile launch tower. The valve on the mobile launcher's 160-foot-level failed to open, preventing the start of liquid hydrogen tanking into the core stage for today’s countdown dress rehearsal.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
NASA has called off the Artemis 1 countdown dress rehearsal due to an issue with a vent valve. The launch team will offload liquid oxygen from the core stage and discuss when they will make another attempt to load cryogenic propellants into the rocket.
Zitat Edinburgh, 6 April 2022. – After an earlier issue with delays of gaseous nitrogen supply required for tanking preparations and resolving an issue with malfunctioning fans that caused the first wet dress rehearsal to come to a halt, the second attempt had to be cancelled halfway through as well.
The Artemis I team ended Monday’s attempt after partially loading liquid oxygen into the Space Launch System’s core stage tank. A temperature limit issue for the liquid oxygen delayed the second countdown by several hours. Because of this, the team could only fill the tank to 50% before the launch director stopped the test.
Liquid oxygen is an extremely cold (cryogenic) propellant which has to be maintained at minus 297 degrees Fahrenheit. During cooldown of the system, there was an issue with the core stage vent valve’s control panel. The vent valve is crucial in relieving pressure from the core stage during tanking. After investigations, the team found that the valve was configured physically in a closed position. This prevented it from being controlled remotely to an open position, which has since been corrected.
Despite both wet dress rehearsals having been called off, they provided the teams valuable opportunities for training and testing. The wet dress rehearsal is the last major test before launch, allowing for a thorough check up. The next such rehearsal is yet to be scheduled.
Weder NASA noch SpaceX, hat aber auch mit dem Griff nach den Sternen zu tun. Rocket Lab haben gestern angekündigt, daß sie beim nächsten Start der Electron versuchen wollen, die Startstufe nicht sanft auf dem Erdboden zu landen, sondern in der Luft abzufangen.
Zitat LONG BEACH, Calif.--(BUSINESS WIRE)--Rocket Lab USA, Inc (Nasdaq: RKLB) (“Rocket Lab”), a leading launch and space systems company, has announced today that during its next Electron launch, a commercial rideshare mission currently scheduled in April 2022, the company will attempt a mid-air helicopter capture of the Electron launch vehicle for the first time.
The “There and Back Again” mission, Rocket Lab’s 26th Electron launch, will lift off from Pad A at Launch Complex 1 on New Zealand’s Māhia Peninsula within a 14-day launch window scheduled to commence on April 19, 2022 UTC. Electron will deploy 34 payloads from commercial operators Alba Orbital, Astrix Astronautics, Aurora Propulsion Technologies, E-Space, Unseenlabs, and Swarm Technologies via global launch services provider Spaceflight Inc. The launch is expected to bring the total number of satellites launched by Electron to 146.
For the first time, Rocket Lab will also attempt a mid-air capture of Electron’s first stage as it returns from space after launch, the next major step in the Company’s development program to make Electron a reusable rocket. Rocket Lab will be attempting the catch with a customized Sikorsky S-92, a large twin engine helicopter typically used in offshore oil & gas transport and search and rescue operations.
Catching a returning rocket stage mid-air as it returns from space is a highly complex operation that demands extreme precision. Several critical milestones must align perfectly to ensure a successful capture.
After deploying a drogue parachute at 13 km (8.3 miles) altitude, the main parachute will be extracted at around 6 km (3.7 miles) altitude to dramatically slow the stage to 10 metres per second, or 36 km (22.3 miles) per hour. As the stage enters the capture zone, Rocket Lab’s helicopter will attempt to rendezvous with the returning stage and capture the parachute line via a hook.
Daß SpaceX dazu übergegangen ist, die beiden Schanzverkleidungen (Fairings) der Falcon 9, die die Satelliten während des Starts schützen, mit Netzen aufzufangen, dürfte bekannt sein. Die beiden Schiffe Go Ms. Tree & GO Ms. Chief muten ein wenig wie Fischkutter an, die zuviel Anabolika gefuttert haben; die letzten 10 Versuche seit Oktober 2020 waren allesamt ein Schlag ins Wasser. Die beiden Hälften wiegen jeweils 950 kg, haben eine Länge von fast 14 m & einen Durchmesser von 5,5 m. Aber das ist noch zu Wasser.
Das einzige luftgestützte Satelliten-Auffangprogramm gab es in den 1960er Jahren im Rahmen des ersten US-amerikanischen Projekts für Spionagesatelliten, den "Corona"-Satelliten, die nach Beendigung ihrer Mission die belichteten Filme mit einer Landekapsel erdwärts schossen, die in der Luft von einem Flugzeug mit einer langen geschleppten Drahtschleife aufgefangen wurde, in der sich der Fallschirm verhedderte. Beim 13. Versuch hat das im August 1960 zum 1. Mal wie vorgesehen geklappt.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat von 04/07/2022 18:28NASA is tentatively targeting Monday for another try at completing a practice countdown for the SLS Moon rocket at launch pad 39B. However, an issue with the rocket's upper stage, the Interim Cryogenic Propulsion System (ICPS), is being investigated. We are awaiting further details from NASA.
If the upper stage issue is resolved, the countdown for the Wet Dress Rehearsal (WDR) could resume as early as Saturday. The simulated T-0 would occur at 2:40pm EDT (1840 GMT) on Monday. A SpaceX Crew Dragon is scheduled to launch Friday on the privately-funded Axiom 1 mission from neighboring launch pad 39A and any delays to that could push back the SLS practice countdown.
Zitat 04/08/2022 03:09 Spaceflight Now Spaceflight Now
NASA said Thursday evening it was continuing to troubleshoot a problem with the Artemis 1 upper stage and hoped to firm up plans on Friday for a third Wet Dress Rehearsal attempt, which could occur as early as Monday.
In a blog post, the agency said "teams encountered an issue maintaining helium purge pressure on the upper stage engine after change-out of a regulator on the mobile launcher." It did not explain when or why the regulator had been replaced or when the pressure problem had been detected.
Zitat The countdown for the two-day test is currently slated to begin with call to stations beginning at 5 pm EDT on Saturday, April 9 with T-0 planned for 2:40 pm on Monday, April 11.
Allmählich fange ich an, hinter meine zuversichtliche Voraussage "daß wir in den nächsten Wochen, höchstens Monaten tatsächlich einen Start zum Mond sehen werden," ein kleines Fragezeichen zu setzen.
Zitat Citing valve problem, NASA will load only the SLS core stage in next countdown test
A problem with a helium valve on the Space Launch System moon rocket’s upper stage will require ground teams to only partially load the giant launcher with cryogenic propellants during an upcoming countdown dress rehearsal, NASA officials said Saturday.
Instead of fully loading both stages of the rocket cryogenic liquid hydrogen and liquid oxygen, NASA will now focus only on pumping propellants into the core stage, the largest element of the giant launch vehicle.
NASA also confirmed teams now targeting Thursday for the next opportunity to load cryogenic propellants in the Space Launch System moon rocket at the Kennedy Space Center. This is three days later than previously planned.
The “modified” wet dress rehearsal will have “minimal propellant operations” on the SLS interim cryogenic propulsion stage, NASA said in a blog post early Saturday. NASA officials decided Friday to delay the cryogenic tanking operation from Monday to Thursday, but did not announce the decision until early Saturday.
A “call to stations” in the firing room at the Kennedy Space Center is scheduled for Tuesday, leading up to tanking Thursday morning.
Update. Sh. Punkt 8. Bei Apollo 13 war das übrigens auch solch ein winziges Ventil, das beim letzten Check auf der Startrampe ein klein wenig klemmte. Im 2. Sauerstofftank des Versorgungsmoduls der Kapsel. Weil das vorher stets problemlos geklappt hatte, ist das unter einmal-ist-keinmal verbucht worden. Der Funktionstest fand am 28. März 1970 statt & die Entlüftung des Tanks gelang nur teilweise; das Ventil war beschädigt worden, als der Tank, der für die Mission Apollo 10 gefertigt worden war, beim Austausch abrutschte & 5 cm tief hart aufsetzte. Die Explosion erfolgte um 03:08 Greenwich-Zeit am 14. April. Vielleicht sollte man solche Unternehmen nicht nach ollen griechischen Göttern benennen. Die hatten bekanntlich einen speziellen Humor.
Zitat Wet Dress Rehersal update from #NASA. A thread: 1/x 10:02 PM · Apr 11, 2022·Twitter Web App
2/x: NASA confirms "minimal propellant operations" on the ICPS (interim cryogenic propulsion stage) with a heavily modified Wet Dress on Thursday, April 14 focusing on the Core Stage with T0 slated for 14:40 EDT / 18:40 UTC.
3/x: "We think this is a great path forward" said NASA official.
4/x: Charlie Balckwell-Thomson says "chill down ops" for the upper stage -- indicating no propellant flow to the ICPS will occur. "Believe we can meet majority of test objective prior to roll back."
5/x: They do still plan to count beyond 10 minutes into terminal count, cutoff, recycle and then count back down to T-9.34 seconds and then cut-off and scrub... ending the Wet Dress Rehearsal.
6/x: The issue with the helium check valve on the ICPS. Helium supply inlet leakage on ML was found and replaced. They had to reduce COPV (pressure vessel) on ICPS, & when they repressed it, didn't see proper pressurize valves. Issue identified as being with flight hardware.
7/x: This appears to be the first flight hardware issue identified in the wet dress. All others had been ground-side of the system.
8/x: Reverse flow check on the helium check valve should have stopped all helium flow. It did not, so the check valve is bad. It's only 3 inches (76 mm) long. And it's a "high-reliability part" according to NASA. So failure was unexpected. Just can't access on pad; only VAB.
9/x: Sounds like this helium check valve had been operating fine, but it was after equipment swap out at the pad after last Monday when it didn't work.
10/x: How do you have confidence ICPS will work if you don't wet dress it? Charlie confirms ICPS fueling was a big part of wet dress and says data from wet dress will drive their decision. (From me: But if they don't fuel in wet dress, how can they get that data?)
11/x: COPVs in the ICPS are pressurized at this time; NASA just aren't adding more pressure at this time due to the failed helium check valve.
12/x: NASA confirms that the ICPS helium check valve is the first flight-side issue seen during wet dress. That is encouraging across the board given first-time ops for this vehicle.
13/x: Charlie running through that the only critical thing they won't get from the modified wet dress is the ICPS cryo data. They'll still get everything else. Just not the ICPS data.
14/x: There are 25 critical terminal count (T-10mins and under) items. 2 are related to the ICPS, so they'll get 23 of the 25. Overall, there are about 3 of 75 critical things in wet dress they won't get by not fueling the ICPS.
15/x: Point of the helium check valve is so that on launch they don't evacuate pressure during ascent.
16/x: NASA now saying they'll flow "cold gas" right up to the point where they'd load propellant. This will allow leak checks at cryogenic temperatures. But does not sound like propellant will flow into the ICPS... they'll just cool it does to cryo leak check it.
17/x: A couple Ground Launch Sequencer commands will not be able to be sent as they will have to on launch day in the modified wet dress count for Thursday.
Falls es noch jemanden interessiert: Der Countdown für den Wet Dress Rehearsal Nr.3 hat offiziell begonnen. Die Uhr steht aktuell (Di., 12.4., 23:37 MESZ) bei - 1 T, 19 St, 3 Min.
Zitat NASA restarted a two-day dress-rehearsal countdown Tuesday for the agency’s new Space Launch System moon rocket after a series of unrelated glitches, mostly involving ground systems, blocked two earlier attempts to fully fuel the huge launcher to verify its readiness for flight.
The lone rocket-related problem — trouble with a one-way helium pressurization valve in the booster’s second stage — cannot be fixed at the launch pad and engineers will be unable to pump supercold cryogenic propellants into the stage during fueling operations Thursday as originally planned.
Instead, the team will concentrate on loading the SLS core stage with 537,000 gallons of liquid hydrogen fuel and 196,000 gallons of liquid oxygen Thursday morning, testing their ability to monitor and control the flow of propellants, verifying control room commanding and validating software through two terminal countdown test runs.
In one, the countdown will tick down to the T-minus 33-second mark before a recycle back to T-minus 10 minutes to test procedures that could be needed should a problem interrupt an actual launch countdown.
A second run will then will tick all the way down to T-minus 9.3 seconds, the moment before main engine ignition commands would be sent for an actual launch. At that point, the ground launch sequencer computer will stop the countdown and the test will end.
Wie gesagt - allmählich neige ich dazu, ein hinter meine Zuversicht zu setzen.
Zitat While the upper stage will not be loaded with propellants, liquid oxygen and hydrogen will flow through launch pad transfer lines and into the ICPS plumbing to make sure the system is leak free.
After the test is complete, engineers will spend about 10 days readying the rocket and its mobile launch platform for the 4.2-mile trip back to the Vehicle Assembly Building where the helium valve will be replaced.
What happens after that is not yet known. NASA wants to launch the SLS on its maiden flight, boosting an unpiloted Orion crew capsule beyond the moon and back, some time this summer, but that will depend on what additional testing is required.
Nachtrag. MESZ 19:07. Zählerstand -23 : 31.
Zitat NASA's Exploration Ground Systems @NASAGroundSys The mission management team just received an update at the L-1 briefing. We remain on track for the Artemis I wet dress rehearsal. Weather still looks favorable for tanking.-JP 6:31 PM · Apr 13, 2022·Twitter Web App
Zitat Final preparations on the umbilicals to ensure connectivity between the mobile launcher, the Space Launch System rocket and Orion spacecraft were completed this evening.
The umbilicals provide power, communications, coolant, and fuel to different parts of the rocket. Additional accessories provide access and stabilize the rocket and spacecraft. During launch, each umbilical releases from its connection point, allowing the rocket and spacecraft to lift off safely from the launch pad. ... The next update will be provided in the morning of April 14, prior to the mission management team’s pre-tanking briefing where they will review the status of operations and determine if they are “go” to proceed toward tanking operations.
Zitat NASA's Exploration Ground Systems @NASAGroundSys
Final checks on umbilicals are now completed. The umbilicals provide gases, propellants, power, and connectivity between the mobile launcher, @NASA_SLS and @NASA_Orion. All-day coverage starts tomorrow, April 14th.-JP
Zitat NASA's Exploration Ground Systems @NASAGroundSys
Tanking is delayed beyond the planned hold due to the GN2 pipeline issue. Additional time is needed to switch supply from air back to gaseous nitrogen. When the countdown resumes, it will pick up at T-6 hours, 40 minutes.-JP
1:49 PM · Apr 14, 2022·Twitter Web App
Zitat NASA's Exploration Ground Systems @NASAGroundSys
Artemis Launch Director, Charlie Blackwell-Thompson has given the "go to proceed" with cryo tanking for Artemis I wet dress rehearsal. GN2 issue has been resolved and the rocket has been switched to nitrogen. Teams are discussing when to resume the countdown clock.-JP
NASA reports a temperature limit was exceeded as teams began the "slow fill" process for pumping liquid oxygen into the core stage. "Teams believe they understand the issue and are working a solution that will allow operations to resume," NASA says. "These are all important aspects of test conditions in complex environments."
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
16:31 MESZ. Countdown läuft. Stand -6 h, 35 Min. 40 Minuten zum Beginn der Betankung. 4 Stunden sind dafür angesetzt. Updates im Folgenden.
Zitat 17:59 After resolving the liquid oxygen temperature issue, NASA confirms cryogenic oxidizer is now flowing into the Space Launch System core stage in “slow fill” mode. About 196,000 gallons of liquid oxygen will go into the core stage for this countdown test.
Zitat 18:33
NASA’s Artemis team at the Kennedy Space Center is now flowing super-cold liquid hydrogen fuel into the core stage of the Space Launch System. Today’s coundown rehearsal has now progressed beyond the point when officials scrubbed the test last week.
Zitat 19:27
NASA says a “surge in pressure” during the transition from liquid hydrogen slow fill to fast call triggered an automatic stop to fueling the Space Launch System core stage at the Kennedy Space Center. The launch team is reviewing a plan to resume tanking.
Countdown bei -3:31 & läuft.
Zitat 19:58
NASA says liquid oxygen loading into the core stage was paused while engineers resolved the liquid hydrogen issue. The liquid oxygen flow remains on hold.
Kühlung der Zuleitungen für den flüssigen Wasserstoff hat begonnen. 20:07: Beginn des Betankens des Startstufentanks mit Wasserstoff. Countdown exakt bei minus 3 Stunden. Das erste Mal, daß sowohl Sauerstoff wie Waserstoff zugeladen werden.
Zitat 20:23
It’s unclear whether the liquid hydrogen flow into the SLS core stage has actually resumed. At last report, NASA’s ground systems team tweeted engineers are “working through options” to resume fast fill.
Despite multiple requests from news organizations, NASA is not providing any real-time audio of the countdown dress rehearsal, citing "export control" concerns. NASA also declined to broadcast the Artemis countdown test on NASA TV.
Zitat Steven Young @stevenyoungsfn When NASA was more transparent with the news media they would have called this a leak.
Zitat NASA's Exploration Ground Systems @NASAGroundSys Teams have paused LH2 loading and are evaluating an out of limit hydrogen reading at the tail service mast umbilical. LOX is still paused.-JP 8:41 PM · Apr 14, 2022·Twitter Web App
21:20. Countdown wie vorgesehen beim Stand Minus 10:00 angehalten. In der Zuleitung für den Wasserstoff ist ein Leck aufgetreten; es ist noch unklar, ob das Leck selbst die Zuleitung betrifft oder die Stickstoffleitung, die das Entstehen von Knallgas im Fall eines Lecks in der Leitung verhindern soll.
Zitat NASA's Exploration Ground Systems @NASAGroundSys (1/2) Hydrogen is extremely hazardous, cold, and a small molecule that is known for leaking. All of these systems have been sealed, leak checked and tested to the highest extent possible prior to wet dress rehearsal. 9:38 PM · Apr 14, 2022·Twitter Web App
(2/2) Under the unique operating conditions with the rocket we are prepared and know leaks are a realistic possibility. We have amazing hazardous gas and leak detection systems that keep the rocket safe and alert us to conditions outside of normal parameters.-JP
22:08. NASA bestätigt, daß der Countdown bei -10 Min. angehalten bleibt und heute nicht zu Ende geführt wird. Es sollen nur noch einige Funktionstests der Kühlleitungen durchgeführt werden.
Zitat William Harwood @cbs_spacenews SLS/Artemis 1: It's worth recalling the SLS is the most powerful flight-ready (in theory) rocket ever built and that problems are not at all unusual in a first-time operation of this complexity; one wishes a competent commentator was on hand to explain things, but NASA declined 10:32 PM · Apr 14, 2022
NASA says the Artemis 1 wet dress rehearsal today won’t go into the terminal countdown as originally planned. Teams will soon run cryogenic propellant up lines to the SLS upper stage, but won’t load the tanks due to a valve failure previously reported.
Zitat NASA's Exploration Ground Systems @NASAGroundSys
NASA's Exploration Ground Systems @NASAGroundSys The leak is located in the purge can, which is on the exterior portion of the tail service mast umbilical (TSMU) and attached is to the TSMU plate itself. It is currently extended, and at T-0 the panel would retract into the TSMU main housing.-JP 10:22 PM · Apr 14, 2022·Twitter Web App
Teams have confirmed they have satisfied the test objectives for the ICPS LH2 chilldown and after gathering additional data, will work to drain propellant from the rocket. They will inspect the TSMU umbilical connection, review data, and establish a go-forward plan.-JP 10:55 PM · Apr 14, 2022·Twitter Web App
Zitat NASA managers called off a countdown rehearsal Thursday afternoon after hours of delays stemming from at least four technical problems. The final, and potentially most significant, issue was a hydrogen leak in the tail service mast umbilical on the mobile launch platform near the bottom of the SLS core stage. ... But the leak checks between the SLS core stage and the mobile launch platform have, until recent fueling tests, all occurred at warm ambient temperatures. Liquid hydrogen fuel is chilled to minus 423 degrees Fahrenheit (minus 253 degrees Celsius), and liquid oxygen is stored at minus 297 degrees Fahrenheit (minus 183 degrees Celsius).
At those temperatures, valves, seals, and gaskets can contract and change shape, revealing a leak that wasn’t apparent in warmer conditions. Hydrogen can find its way through seals that would contain other molecules.
Hydrogen leaks have cropped up in other rocket programs. NASA engineers spent months tracing hydrogen leaks that kept NASA’s space shuttles grounded in 1990.
“Having lived through ‘the summer of hydrogen leaks’ on the shuttle I can sympathize,” tweeted Wayne Hale, a former NASA flight director and former manager of the space shuttle program. “And that was after 35 or so launches. A leak the first time is almost to be expected. But not satisfactory.” ... Going into Thursday’s practice countdown, NASA managers already decided to forego loading cryogenic propellants into the upper stage of the Space Launch System. Engineers couldn’t tank that element of the rocket, made by United Launch Alliance, due to a failed helium valve.
The core stage, built by Boeing, contains the majority of the cryogenic propellants used by the rocket.
As part of Thursday’s test countdown, the NASA launch team at Kennedy flowed small amounts of cryogenic propellant up the transfer lines on the mobile launch tower to the connection with the upper stage tanks. The operation “chilled down” the propellant lines, allowing engineers to verify their readiness for launch day, but did not flow propellants into the upper stage tanks.
NASA officials said today the earliest they could try again to load propellants into the Space Launch System moon rocket is next Thursday, April 21. But that assumes technicians can locate and fix a hydrogen leak found during a fueling test yesterday.
Zitat von April 17, 2022NASA will move the Space Launch System moon rocket back into the Vehicle Assembly Building at the Kennedy Space Center to replace a failed valve and fix a hydrogen leak found during tests at the launch pad, the agency announced late Saturday.
It wasn’t known Saturday when the rollback might occur, or how long the unplanned return to the VAB might delay the eventual launch of the towering moon rocket on NASA’s Artemis 1 test flight. The mission was previously planned for launch some time in June, but the rollback will likely push back the oft-delayed test flight later in the summer.
NASA officials will brief reporters at 3 p.m. EDT (1900 GMT) Monday to discuss their plans for rolling the SLS moon rocket back to the assembly building. The 322-foot-tall (98-meter) rocket moved to Launch Complex 39B last month in preparation for a countdown rehearsal.
Liste der bislang aufgetretenen Probleme:
Zitat NASA’s launch team was unable to fully load the Space Launch System moon rocket with super-cold liquid hydrogen and liquid oxygen during three attempts this month. An issue with ventilation fans prevented teams from loading the rocket with propellant April 3, and a misconfigured valve at the launch pad cut short another tanking test April 4.
NASA also found a failed helium check valve on the rocket’s upper stage. Managers decided to forego loading of propellants into the upper stage during the third countdown rehearsal Thursday.
The launch team ran into an issue with a gaseous nitrogen supply from Air Liquide, a contractor that operates an off-site plant and routes gases into the space center through a pipeline. The gaseous nitrogen is used to purge parts of the rocket to reduce the risk of fire during propellant loading.
The gaseous nitrogen flow was restored, and NASA started loading propellants into the core stage Thursday afternoon. The core stage liquid oxygen tank was filled to about 49% full, but the liquid hydrogen flow was stopped at the 5% point after engineers detected a hydrogen leak.
The leak was located in the tail service mast umbilical, the connection where cryogenic propellants flow from the rocket’s mobile launch platform into the core stage.
Air Liquide’s nitrogen supply also had trouble during the April 4 countdown rehearsal, delaying the start of propellant loading on that day by several hours.
Zusammenfassung der Pressekonferenz der NASA von heute nachmittag.
Zitat Chris G - NSF @ChrisG_NSF SLS rollback and future timelines news conference updates. Thread 9:01 PM · Apr 18, 2022·Twitter Web App
2/x: "We are absolutely going back out and we are absolutely going to do a wet dress rehearsal," NASA says. The exact timing and which option to do that are under discussion. 3/x: Charlie (Launch Director): the rollback is not a result of the leak; could have been worked at pad. But the ability to roll back helps but wasn't required. 4/x: The Tail Service Mast (TSM) leak didn't reveal anything obvious. Ambient leak checks didn't show a leak. Plan going forward is same in VAB as it would have been at pad = remove purge can, leak check it more, inspection seals on forward ring... 5/x: Those additional steps will now take place in VAB. With rollback, will also fix the stuck Helium check valve on the Interim Cryogenic Propulsion Stage (ICPS) while back in VAB. 6/x: Getting out of wet dress configuration at the pad. Core Stage and booster deserving up next. Rollback is "around" Tuesday, April 26th. 7/x: 2 VAB options. Fast around - fix what you need and get back out as quickly as possible. Longer plan - get into a more launch-ready config, wet dress, rollback & get Flight Termination System ready for launch, roll out again and launch. Longer-er plan - Full launch config 8/x: Teams will know the minimum amount of time needed in VAB to fix both the tail service mast leak and the helium check valve issue. In the "weeks" timeframe, but firm-er timeline later in the week per Charlie. NASA: Early June window is challenging at best now according to NASA 10/x: NASA notes the late-June/early-July and late-July/early-August launch windows for #Atemis1. 11/x: Ha! "Mega Moon Rocket." Press thought NASA came up with it. They thought we came up with it. I love things like that. But NASA notes they feel it's a good way to talk about the rocket to the public to easily encapsulate what it is. 12/x: OH! A Shuttle era question from @SciGuySpace ... noting that most people who got Shuttle up and running in 1981 aren't here any more. NASA confirms these are new teams going through first-time ops. 13/x: Charlie notes that 2 folks are still here from that first Shuttle flight. NASA also notes that it took Saturn V and Shuttle multiple tries to get through wet dress rehearsal on the first stacks. (And took SpaceX 4 times for Falcon Heavy <-- I added that part) 14/x: For the Shuttle... 5 tanking attempts were needed for STS-1's test firing, not including the 17 to 19 tankings needed to get through test firings at Stennis of the Shuttle Main Propulsion System Test Article. (I add, took Saturn V 17 tries at wet dress) 15/x: Gaseous nitrogen issues were supplier-based and not specific to SLS/Artemis 1. But SLS is unique in that its volumetric requirements are much larger than other vehicles. So the supplier issues don't sound like they'll affect other upcoming missions. 16/x: Charlie noting data after Friday's briefing & a similar Gaseous Nitrogen failure during detanking... and that new data from that is what then drove the decision to change things up at supplier with more robust equipment and take that time to then rollback and fix issues. 17/x: And briefing lines suddenly cut off. Standing by for NASA to let us know what happened, etc. 18/x: And NASA confirming we'll be back at this in 5 minutes. Standby. 19/x: Per launch windows, constraints are: 1) launch vehicle's performance (which all LVs have) related to lunar position, 2) eclipse periods <90mins where Orion would be in shadow, 3) reentry and range from entry interface to day time landing site. 20/x: NASA noting it was a little surprising to need this more robust equipment for gaseous nitrogen, but right decision to step and get that in place now. 21/x: Charlie noting that the timeline for the gaseous nitrogen upgrades will in some ways give them the flexibility to maybe get some launch configurations done on SLS before going back out for wet dress rehearsal. 22/x: NASA notes late-June/early-July window has a cutout July 2-4 for an eclipse that would keep Orion in shadow for greater than 90mins, so no launches on those days. 23/x: Charlie notes that helium check valve first issue occurred after Run 2 on Wet Dress. Nominal performance before that. While in preps for Run 3, one of the regulators on the Mobile Launcher base was changed out and the check valve failed after the regulator was changed. 24/x: NASA notes that daylight is desirable for SLS's first launch, but they will launch at night if the window they're ready for is a night window. 25/25: And that's all for today.
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