The mission management team has polled "go" for loading more than 750,000 gallons of cryogenic propellants into the Space Launch System moon rocket. Launch director Charlie Blackwell-Thompson will poll her team in a few minutes for their approval to begin this next step in the Artemis 1 countdown.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
7:04. Zurzeit geht ein wüster Regenschauer über dem Cape nieder. Chancen für einen Blitzeinschlag innerhalb von 5 Meilen sind höher als 20%. Deshalb ist der Countdown weiter auf Standby.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat 08/29/2022 11:43 Graeber says the launch team is "moving forward" with the countdown after troubleshooting resolved concerns about a hydrogen leak in the tail service mast umbilical. After the leak stabilized, the launch team was able to fully load the core stage with 537,000 gallons of liquid hydrogen.
It's unlikely the launch will occur at the opening of today's two-hour window due to lost time at the start of tanking operations, caused by stormy weather, and then falling further behind schedule with the hydrogen leak troubleshooting.
Graeber said the team will reassess the timetable for launch after the countdown reaches the next planned hold at T-minus 10 minutes.
08/29/2022 11:48 There's also still an open issue regarding the communications link between ground teams and the Orion spacecraft. That has been under review throughout the countdown and is a constraint against proceeding with the launch.
08/29/2022 12:03 The engine bleed kickstart procedure has started to begin conditioning the Space Launch System's RS-25 core stage engines for ignition. The team is troubleshooting an issue they've encountered with the bleed for Engine No. 3.
08/29/2022 12:40 The launch control team is also evaluating a line of frost in the intertank section of the core stage, located between the liquid hydrogen tank at the bottom of the core stage and the liquid oxygen tank near the top of the core stage.
Zitat 08/29/2022 13:12 Launch director Charlie Blackwell-Thompson has asked her launch team to come up with options for next steps for this morning's countdown.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
13:23. Unplanmäßiger Halt des Countdowns bei Min. -40, um die Probleme mit der Herabkühlung für Brennkammer Nr. 3 zu lösen.
Zitat 08/29/2022 13:39 NASA says the issue with the crack found in the intertank section of the SLS core stage has been resolved. The crack, and associated frost accumulation, is in the foam insulation, and not in the core stage tank structure.
Zitat Eric Berger@SciGuySpace Rumor is that today's a scrub. No confirmation yet. 1:46 PM · Aug 29, 2022·TweetDeck
Zitat Jeff Foust @jeff_foust The T-40 minute hold, originally expected to last 10 minutes, has now lasted nearly a half-hour. 1:49 PM · Aug 29, 2022·Tweetbot for Mac
Zitat von Spaceflight Now feed08/29/2022 13:55 The countdown clock continues holding at T-minus 40 minutes. This hold was expected to last about 10 minutes, but the clock has now been stopped more than 25 minutes.
Zitat Unofficial SLS & Orion News @SLSNASA Engineers are asking for more time to resolve the engine issue.
NASA seems committed to resolving this issue.
Reminder we still have 3 hours left in NASA’s launch window today so there’s plenty of time to resolve issues if they can. 1:29 PM · Aug 29, 2022·Twitter for iPhone
Zitat Joey Roulette@joroulette I'm hearing mission management teams have opted to call off today's launch attempt. Nothing officially stated by NASA yet
This is according to a source who was told today's attempt has been scrubbed. 1:50 PM · Aug 29, 2022·Twitter Web App
14:33. Das heutige Startfenster hat sich gerade geöfffnet. Nur sieht es heute für einen Start schlecht auf. Das Problem mit der Herabkühlung von Brennkammer 3 auf Betriebstemperatur durch Durchleitung von flüssigem Wasserstoff besteht weiterhin, und zudem fängt eine Regenfront an, über das Cape hinwegzuziehen.
14:36: Flugdirektor Charlie Blackwell-Thompson hat gerade offiziell den Startabbruch mitgeteilt.
Zitat NASA@NASA The launch of #Artemis I is no longer happening today as teams work through an issue with an engine bleed. Teams will continue to gather data, and we will keep you posted on the timing of the next launch attempt. https://blogs.nasa.gov/artemis/ 2:44 PM · Aug 29, 2022·Twitter Media Studio - LiveCut
Zitat von August 29 2022 8:50 A.M.Launch Attempt Scrubbed
The launch director halted today’s Artemis I launch attempt at approximately 8:34 a.m. EDT. The Space Launch System rocket and Orion spacecraft remain in a safe and stable configuration. Launch controllers were continuing to evaluate why a bleed test to get the RS-25 engines on the bottom of the core stage to the proper temperature range for liftoff was not successful, and ran out of time in the two-hour launch window. Engineers are continuing to gather additional data.
Nächster Starttermin ist am Freitag, den 2. September, um 12:48 EDT/18:48 MESZ), für eine Dauer von zwei Stunden. Die widerborstige Brennkammer ist Nr. 2058, in der Graphik im Blogbeitrag rechts unten.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat William Harwood@cbs_spacenews SLS/Artemis 1: It's worth remembering that trouble with a 4-inch hydrogen QD in the engine cooling loop leaked during the most recent fueling test June 20; because of that, the system was bypassed and not exercised in the otherwise successful test 2:27 PM · Aug 29, 2022·Twitter for Mac
Zitat von Ulrich Elkmann im Beitrag Eine wirkliche Mondrakete. Update aus der EtappeBei 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.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat DutchSatellites @DutchSatellites Replying to @SciGuySpace After detanking the vehicle, engine nr. 3 will be inspected on the launch pad. If no obvious cause for the bleed issue is found, than the vehicle will be rolled back to the VAB to change out the engine.
Abort after engine start requires inspection and drying out the engines. Which is actually shorter in duration than changing out a engine. However both require rollback to the VAB. 3:28 PM · Aug 29, 2022·Twitter for Android
NASA officials are briefing the media on today's scrubbed launch attempt. Mike Sarafin, NASA's Artemis 1 mission manager, says engineers will rest tonight and reconvene at 3 p.m. EDT (1900 GMT) tomorrow for a mission management team meeting to assess their options for additional launch attempts moving forward.
"Friday is definitely in play," Sarafin said. The launch team will be postured to make another try for launch as soon as Friday, but that depends on the outcome of further reviews of the cause of today's scrub.
Zitat Jeff Foust@jeff_foust Sarafin: intertank vent valve issue came up when trying to increase tank pressure for engine bleed issue; vent valve not cooperating. Combination led to the scrub decision.
Free defends the decision of going for a launch attempt vs another WDR. Risks of another cycle of going out and back for just a WDR; learned a lot preparing for launch. 7:27 PM · Aug 29, 2022·Tweetbot for Mac
Zitat Andrew@Cosmic_Andrew1 They are changing the prop loading procedure to do the bleed earlier and some other stuff I can’t type fast enough. Anyway, Saturday September 3rd is what the targeted launch date now!!
The crane was out there to set up a work station to address an LH2 leak on the 8” QD pipe
Zitat Eric Berger@SciGuySpace·6m The launch window on Saturday, September 3, opens at 2:17 pm ET (16:17 UTC). Teams will start engine chill earlier in an attempt to have the RS-25 engines ready for ignition.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat Chris G - NSF @ChrisG_NSF NASA is about to host an #Artemis1 update on the status of engine and intertank vent valve issues and what the forward plan to a next launch attempt is. Thread: 1/x
2/x: There's a weather officer in this breifing, so we're clearly going to attempt on Friday.
3/x: Management Team agreed to change loading procedure and start engine chilldown earlier. Work at pad to address LH2 leak purge can, and moved launch to SATURDAY, Sept. 3rd! OK... one extra day to launch.
4/x: SLS manager says he's confident in the design of the rocket. Talking about "doing the same thing we did at Stennis." Honeycutt admitted that if they'd done a full Wet Dress Rehearsal, they'd have changed things. But NASA opted not to do a full WDR and press to launch.
5/x: 2 hr launch window on Saturday opens at 2:17pm EDT / 18:14 UTC.
6/x: They will open up the LH2 purge can, inspect, and re-torque and make a change to how things flow into the purge can.
/x: Weather for Saturday's attempt: No real information given.
12:05 AM · Aug 31, 2022·Twitter Web App
Nachtrag.
Zitat Jeff Foust@jeff_foust Long discussion from John Honeycutt, SLS program manager, about the temperature issue. Some possibility that the temperature sensor in the engine is faulty. 12:31 AM · Aug 31, 2022·Tweetbot for Mac
Zitat Eric Berger@SciGuySpace Per NASA's John Honeycutt, it sounds like the SLS rocket's engine no. 3 temperature issue may be due to a faulty sensor, rather than the engine not reaching its desired chilldown temperature.
"Replacing the sensor at the launch pad would be tricky. It’s not ideal," Honeycutt said. Sounds like they're going to look at all the other data, such as LH2 flowing into engine no. 3, and have a plan to go with a launch without absolutely knowing the temperature of the engine.
Zitat Jeff Foust@jeff_foust End of the briefing. Takeaway is that NASA is thinking the anomalous engine 3 temp may be a sensor issue: the way the sensor is behaving, Honeycutt said, doesn’t match the physics of the situation. Replacing the sensor now isn’t feasible, so developing flight rationale. 1:05 AM · Aug 31, 2022·Tweetbot for Mac
Zitat Eric Berger@SciGuySpace More on temperature unit madness. Turns out the chill-down temperature for the SLS main engines is 40 Rankine (not 500 as stated yesterday). That's -420 degrees Fahrenheit. NASA and temperature conversions: name a more iconic duo. 12:44 AM · Aug 31, 2022·TweetDeck
Theme from this briefing is that the temperature sensor is not critical for launch; have other means to ensure engine is chilled. Did not have time Monday to work through those issues since team was “off script” from earlier problems.
Asked about life-limited items on the SLS rocket, John Honeycutt said they have "high double digits" of propellant loading cycles left on the core stage. Biggest concern is rollbacks, don't want to do it too often as it stresses the vehicle.
Zitat Eric Berger @SciGuySpace Sarafin also provided an excellent overview of the reasons why the launch team scrubbed the countdown on Monday, in the heat of the moment, but now has confidence in proceeding if they face a similar issue with an engine chill down sensor.
"One of the worst things you can do, when you find yourself in a hazardous condition, is to go further off script," Sarafin said, noting the engine chill problem cropped up amid other issues. "The team did absolutely the right thing on the 29th." 12:53 AM · Sep 2, 2022·TweetDeck
Zitat Confident that out-of-bounds engine temperature readings during Monday’s Artemis 1 countdown came from a bad sensor, NASA officials gave the green light Thursday to move forward with another try Saturday afternoon to launch the agency’s giant new moon rocket on an unpiloted test flight from the Kennedy Space Center.
NASA engineers have also adjusted the timeline for loading super-cold propellants into the Space Launch System moon rocket, allowing more time to flow cryogenic liquid hydrogen through bleed lines to thermally condition the four main engines on the bottom of the core stage.
Several days of analyses and the revised countdown timeline gave NASA managers enough confidence to develop “flight rationale” to proceed into another countdown Saturday.
Liftoff of the SLS moon rocket is scheduled during a two-hour window opening at 2:17 p.m. EDT (1817 GMT) Saturday. The 322-foot-tall (98-meter) rocket — making its first-ever flight — is the most powerful ever built by NASA, and will produce 8.8 million pounds of ground-shaking thrust at liftoff, more than any launch vehicle ever flown from U.S. soil. ... The risks stem from the thermal conditioning of the rocket’s four main engines, which was the primary cause for scrubbing Monday morning’s countdown. The launch team also detected, and and then resolved, a hydrogen leak in a tail service mast umbilical near the connection between the rocket and its mobile launch platform. Since Monday, technicians at Launch Complex 39B have re-torqued a line believed to be the culprit for the leak.
Engineers want the RS-25 engines to be chilled to around minus 420 degrees Fahrenheit — about the same temperature as liquid hydrogen — to be at the proper temperature for the engine startup sequence. The temperature of Engine No. 3 on Monday was around minus 380 degrees, according to sensor data, giving engineers concern that not enough super-cold liquid hydrogen was was reaching the engine through a chilldown bleed line. ... “We have convinced ourselves, without a shadow of a doubt, that we have good quality liquid hydrogen going through the engines,” Honeycutt said. “There’s no fuzz on that.”
Honeycutt said engineers will look at five additional measurements on the engines during Saturday’s countdown to assure themselves that the engines are at the right temperature, specifically moving parts like fast-spinning turbines and pumps. There’s also data from the core stage itself indicating it was supplying the right amount of liquid hydrogen to the engines to chill them for ignition.
“We chill engines for numerous reasons, but the primary one is for the high pressure turbopump bearing,” said John Blevins, NASA’s chief engineer on the SLS moon rocket. “That high pressure turbopump bearing doesn’t have to be all the way as cold as the liquid, but it’s got to be cold. And if we know the liquid is going through, then we know it’s about that temperature.”
“We know we had a bad sensor,” Honeycutt said. “That was our challenge early in the week, where we could not make the physics of the system line up with what we were seeing with that one sensor.”
Zitat Even with the changes to the countdown and decent weather odds, there’s no guarantee the Artemis 1 mission will get off the ground this Labor Day weekend. That’s a risk with any space mission, but there are 489 launch commit criteria NASA needs to satisfy for the launch team to be “go” for liftoff of the first SLS moon rocket.
T -33 Stunden bis Sa, 20:17 MESZ.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Updated Mission profile. Die Daten des Orbits entsprechen denen, die ich im Posting genannt habe.
Zitat Mission Overview
Artemis I is the first integrated test of NASA’s deep space exploration systems: the Orion spacecraft, Space Launch System (SLS) rocket and the ground systems at the agency’s Kennedy Space Center in Florida. The first in a series of increasingly complex missions, Artemis I is an uncrewed flight test that will provide a foundation for human deep space exploration and demonstrate our commitment and capability to return humans to the Moon and extend beyond.
Launch site: Launch Pad 39B at NASA’s Kennedy Space Center in Florida Launch date: Sept. 3, 2022 Launch window: 2:17 p.m. EDT to 4:17 p.m. Mission Duration: 37 days, 23 hours, 53 minutes Destination: distant retrograde orbit around the Moon Total mission miles: approximately 1.3 million miles (2.1 million kilometers) Targeted splashdown site: Pacific Ocean, off the coast of San Diego Return speed: Up to 25,000 mph (40,000 kph) Splashdown: October 11, 2022
In Space Orion will separate from the ICPS approximately two hours after launch. The ICPS will then deploy ten small satellites, known as CubeSats, along the way to study the Moon or head father out to deep space destinations. As Orion continues on its path from Earth orbit to the Moon, it will be propelled by a service module provided by ESA (European Space Agency) that will course-correct as needed along the way. The service module supplies the spacecraft’s main propulsion system and power.
The outbound trip to the Moon will take several days, during which time engineers will evaluate the spacecraft’s systems. Orion will fly about 60 miles (97 kilometers) above the surface of the Moon at its closest approach, and then use the Moon’s gravitational force to propel Orion into a distant retrograde orbit, traveling about 40,000 miles (64,000 kilometers) past the Moon. This distance is 30,000 miles (48,000 kilometers) farther than the previous record set during Apollo 13 and the farthest in space any spacecraft built for humans has flown.
For its return trip to Earth, Orion will get another gravity assist from the Moon as it does a second close flyby, firing engines at precisely the right time to harness the Moon’s gravity and accelerate back toward Earth, setting itself on a trajectory to re-enter our planet’s atmosphere.
Landing The mission will end with a test of Orion’s capability to return safely to Earth. Orion will enter Earth’s atmosphere traveling at about 25,000 mph (40,000 kph). Earth’s atmosphere will slow the spacecraft down to a speed of about 300 mph (480 kph), producing temperatures of approximately 5,000 degrees Fahrenheit (2,800 degrees Celsius) and testing the heat shield’s performance.
Once the spacecraft has passed this extreme heating phase of flight, the forward bay cover that protects its parachutes will be jettisoned. Orion’s two drogue parachutes deploy first, at 25,000 feet (7,600 meters), and within a minute slow Orion to about 100 mph (160 kph) before being released. They are followed by three pilot parachutes that pull out the three main parachutes which will slow Orion’s descent to less than 20 mph (32 kph). The spacecraft will make a precise landing within eyesight of the recovery ship off the coast of San Diego.
L-9 hours, 40 minutes and counting Built in countdown hold begins (L-9H40M – L-7H10M) Launch team conducts a weather and tanking briefing (L-9H40M – L-8H50M) Launch team decides if they are “go” or “no-go” to begin tanking the rocket (L-8H40M) Core Stage LOX transfer line chilldown (L-8H15M – L-8H)
L-8 hours and counting Core stage LOX main propulsion system (MPS) chilldown (L-8H – L-7H20M) Core stage LOX slow fill (L-7H20M – L-7H5M) Core Stage LOX fast fill (L-7H5M – L-4H15M) Core Stage LH2 chilldown (L-7H15M – L-7H5M) Core Stage LH2 slow fill start (L-7H5M – L-6H15M) Core Stage LH2 fast fill (L-6H15M – L-5H5M) Engine bleed kick start (L-6H15M) Core Stage LH2 topping (L-5H5M – L-5H)
L-5 hours and counting Core Stage LH2 replenish (L-5H – Launch) ICPS LH2 ground support equipment (GSE) and tank chilldown (L-4H45M – L-4H30M) ICPS LH2 fast fill start (L-4H30M – L-3H30M) Orion communications system activated (RF to Mission Control) (L-4H20M – L-3H45M) Core stage LOX topping (L-4H15M– L-3H55M) Core Stage LOX replenish (L-3H55M – Launch) ICPS L0X MPS chilldown (L-3H55M– L-3H45M) ICPS L0X fast fill (L-3H45M– L-2H55M) ICPS LH2 validation and leak test (L-3H30M – L-3H15M) ICPS LH2 tank topping start (L-3H15M – L-2H55M)
L-3 hours and counting ICPS/Space Launch System (SLS) telemetry data verified with Mission Control and SLS Engineering Support Center (L-2H55M – L-2H45M) ICPS LOX validation and leak test (L-2H55M – L-2H30M) ICPS LH2 replenish (L-2H50M – Launch) ICPS LOX topping (L-2H30M – L-2H10M) ICPS LOX replenish (L-2H10M – Launch)
L-50 minutes and counting Final NASA Test Director briefing is held (L-50M)
L-40 minutes and holding Built in 30-miute countdown hold begins (L-40M)
L-15 minutes and holding The launch director polls the team to ensure they are “go” for launch
T-10 minutes and counting Ground Launch Sequencer (GLS) initiates terminal count (T-10M) GLS go for core stage tank pressurization (T-6M) Orion ascent pyros are armed (T-6M) Orion set to internal power (T-6M) Core Stage LH2 terminate replenish (T-5M57S) CS LH2 tank pre-pressurization (T-5M36S) GLS is go for FTS arm (T-5M) GLS is go for LH2 high flow bleed check (T-4M40S) GLS is go for core stage auxiliary power unit (APU) start (T-4M) Core Stage APU starts (T-4M) Core stage L0X terminate replenish (T-4M) ICPS LOX terminate replenish (T-3M30S) GLS is go for purge sequence 4 (T-3M10S) CS LOX Tank Pre-pressurization (T-2M50S) ICPS switches to internal battery power (T-1M56S) Core stage switches to internal power (T-1M30S) ICPS enters terminal countdown mode (T-1M20S) ICPS LH2 terminate replenish (T-50S) GLS sends “Go for automated launch sequencer” command (T-33S) Core stage flight computer to automated launching sequencer (T-30S) Hydrogen burn off igniters initiated (T-12S) GLS sends the command for core stage engine start (T-10S) RS-25 engines startup (T-6.36S)
T-0 Booster ignition, umbilical separation, and liftoff
Flight Day 2-5 - Outbound transit Flight day 6-9 - Transit to Distant Retrograde Orbit (DRO) around the Moon Flight Day 6 (9/8): Outbound Powered Fly-by (burn 8:26 p.m.), Lunar Closest Approach (~60 miles) Flight Day 10-26 - In DRO Flight Day 10 (9/12): DRO Insertion (burn 11:10 p.m.) Flight Day 10 (9/12): Orion passes Apollo 13 Record Flight Day 13: (9/15): Max distance from Earth Flight Day 27-32 - Exit DRO Flight Day 27 (9/29): DRO Departure (burn 9:45 p.m.) Flight Day 33-39 - Return transit Flight Day 33 (10/5): Return Flyby (burn 5:14 p.m.), Second Closest Approach Flight Day 39 (10/11)- Entry and splashdown (2:10 p.m)
Watch #Artemis I launch to the Moon! The broadcast will begin Saturday, Sept. 3, at 12:15pm ET (16:15 UTC) on our Twitter, YouTube, Twitch, Facebook, Daily Motion and https://go.nasa.gov/3B22Jlj.
Zitat Lunar demo mission to provide “stress test” for NASA’s Artemis moon program
It’s all designed to gather data and build confidence for NASA’s new 322-foot-tall (98-meter) Space Launch System moon rocket and Orion moonship before astronauts strap in on the next Artemis test flight. The first Artemis mission, Artemis 1, is set for liftoff Saturday from the Kennedy Space Center in Florida during a two-hour launch window opening at 2:17 p.m. EDT (1817 GMT).
“We are stressing and testing this thing in a way that you would never do it if we had humans on board, and that’s the point,” said NASA Administrator Bill Nelson. ... The planned 38-day duration of the Artemis 1 mission is nearly double the 21-day design life of an Orion spacecraft on standalone mission. The Orion spacecraft can spend up to six months in space when docked to a space station.
NASA has assessed there is a 1-in-125 probability that the Orion spacecraft could be lost on the Artemis 1 mission. That’s more risk than the agency would accept on a mission with humans on-board.
“On Artemis 1, we have a lean forward strategy to get our high priority objective, which is to demonstrate the heat shield at lunar re-entry conditions,” said Mike Sarafin, NASA’s Artemis 1 mission manager. “We are going to thrust to the point of trans-lunar injection unless we’re sure that we’re going to lose the vehicle.”
Even if there’s a problem deploying the Orion spacecraft’s four power-generating solar array wings, or a failure that leaves the capsule without a critical back-up system, NASA will proceed with the mission, Sarafin said.
“We would be ‘go’ on this flight for conditions that we would normally be ‘no go’ for on a crewed flight in the interests of crew safety, but because we want to buy down risk across the manifest, and to understand this system and the system design and its margins, we are going to press through the point of trans-lunar injection if at all possible,” Sarafin said.
NASA officials assessed the risk of losing the Orion spacecraft due to a failure during the Artemis 1 launch is 1-in-260, and the risk of a catastrophic failure during entry, descent, and landing is 1-in-890. There’s a 1-in-314 probability that a failure of the SLS moon rocket itself will lead to the destruction or loss of the Orion spacecraft on Artemis 1, according to Kathryn Hambleton, a NASA spokesperson.
Sarafin said the risk calculations are part of a probabilistic risk assessment that take into account known failure modes of different components and systems, levels of redundancy in the rocket and spacecraft, and “common cause failures” during the launch, in-space, and re-entry phases of the flight.
Zitat Avionics and software on the SLS moon rocket, which provide guidance, navigation and health monitoring of its engines, are also a “key driver” of the risk on the Artemis 1 mission, Sarafin said, as is the Orion spacecraft’s propulsion system required for maneuvers to enter orbit around the moon
“Those are the top risk drivers,” Sarafin said. “And thats what drove that 1-in-125 number.”
The launch abort motor on top of the Orion spacecraft for the first three minutes of the launch sequence is not active for the Artemis 1. The launch abort system’s jettison motor will fire the escape tower away from the Orion capsule as soon as it reaches space, when the core stage of the SLS moon rocket is still firing.
On the Artemis 2 mission and later crew flights, the launch abort motor will be active and armed to pull the astronauts and their Orion spacecraft from a catastrophic failure of the rocket. That won’t be possible in the first three minutes of the Artemis 1 launch.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat 09/03/2022 11:18 The Artemis 1 countdown clock entered a built-in hold at T-minus 6 hours, 40 minutes at 4:37 a.m. EDT (0837 GMT). This hold will last two-and-a-half hours, allowing time for the mission management team and the launch control team to confirm their readiness to proceed into cryogenic tanking operations.
09/03/2022 11:51 Launch director Charlie-Blackwell Thompson has given her "go" to begin propellant loading on the Artemis 1 moon rocket this morning.
09/03/2022 12:13 NASA has started chilldown of the liquid oxygen transfer line at pad 39B. This thermally conditions the ground systems for loading of cryogenic oxidizer into the core stage of the Artemis 1 moon rocket.
09/03/2022 12:25 Super-cold liquid hydrogen is now flowing into the Space Launch System moon rocket in slow fill mode. About 537,000 gallons of liquid hydrogen will be loaded into the core stage.
Zitat 09/03/2022 12:42 NASA briefly stopped flow of liquid hydrogen into the core stage due to an overpressure alarm, but the launch team reports fuel is again loading into the core stage of the Space Launch System moon rocket. There's a separate issue the launch team is discussing that involves the liquid oxygen system.
09/03/2022 12:53 NASA reports the liquid oxygen flow has resumed after a brief stoppage. The launch team believes the issue may have been caused to high liquid levels inside the ground liquid oxygen tank at pad 39B after it was replenished following Monday's scrubbed countdown.
13:06. Der Countdown zählt wieder herab.
Zitat NASA's Exploration Ground Systems@NASAGroundSys We are now in fastfill for liquid oxygen into @NASA_SLS core stage. 1:08 PM · Sep 3, 2022·Twitter Web App
Zitat 09/03/2022 13:12 The countdown clock resumed on schedule from its built-in hold at T-minus 6 hours, 40 minutes. The next pre-planned hold is at T-minus 10 minutes and will last a half-hour.
09/03/2022 13:20 Liquid oxygen is now being pumped into the core stage in "fast fill" mode.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat 09/03/2022 13:21 NASA has again stopped flow of liquid hydrogen due to a leak detected in the engine cavity on the Space Launch System core stage. The launch team will allow the leaky connector to warm up and then will again try to flow hydrogen through the lines.
This leaky quick-disconnect is not in the same area where the launch team has encountered hydrogen leaks during previous SLS countdowns.
NASA says the launch team will wait about 30 minutes to allow this connector to warm up before trying to flow hydrogen again.
Zitat Eric Berger@SciGuySpace Fueling operations of the SLS rocket were going well tis morning until a—you guessed it, hydrogen leak—was found in the engine cavity. Propellant loading of the liquid hydrogen tank has been stopped at 8 percent full while the launch team assesses. 1:24 PM · Sep 3, 2022·TweetDeck
13:33. LOX tank at 15%.
Zitat Marcia Smith@SpcPlcyOnline Leak was detected in engine section of core stage on LH2 side. It's a QD seal leak. Meanwhile core stage LOX is flowing, but at a slower rate. Can't be more than 50% full until LH2 is at 5%. LOX is15% full now.
Zitat Spaceflight Now@SpaceflightNow NASA is about to implement a troubleshooting plan after allowing the leaky quick-disconnect in the Space Launch System liquid hydrogen system to warm up. They will send manual commands to resume the flow of cryogenic fluid in hopes the seal reseats itself. https://spaceflightnow.com/2022/09/03/ar...ive-coverage-2/ 1:50 PM · Sep 3, 2022·TweetDeck
Zitat William Harwood @cbs_spacenews SLS/Artemis 1 (7:50am): Engineers are warming the hydrogen line connected to a quick-disconnect fitting where propellant enters the base of the core stage; after equalizing temperatures, a seal on the inner side of the fitting should re-seat when hydrogen begins flowing again 1:50 PM · Sep 3, 2022·Twitter for Mac
Zitat NASA's Exploration Ground Systems@NASAGroundSys Teams are performing a manual liquid hydrogen fill after warming up the liquid hydrogen line. 1:57 PM · Sep 3, 2022·Twitter Web App
Zitat Eric Berger@SciGuySpace After warming the hydrogen line leading to the rocket, the launch team has resumed slowly fueling the liquid hydrogen tank. No word yet from launch commentary on whether the 8-inch quick-disconnect has a better seal this time. 2:08 PM · Sep 3, 2022·TweetDeck
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
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