Blogarchiv
Raumfahrt - Startvorbereitung für SLS rocket Artemis 1 mission -Update-2

5.04.2022

artemis-logo-color-positive-cmyk-01-1024x954-1

Ground system problem halts Artemis 1 countdown dress rehearsal

sls-wdr-april3-2

NASA launch controllers called off plans to load super-cold liquid hydrogen and liquid oxygen into the first fully-assembled Space Launch System moon rocket Sunday for a countdown dress rehearsal, giving time for ground teams to troubleshoot problems with fans used to ventilate the giant rocket’s mobile launch structure at the Kennedy Space Center.

The practice countdown, known as a wet dress rehearsal, started Friday and was supposed to culminate in the pumping cryogenic propellants into the 322-foot-tall (98-meter) Space Launch System rocket Sunday on launch pad 39B.

But the SLS launch team scrubbed the simulated countdown shortly before noon EDT (1600 GMT), prior to the start of propellant loading. The countdown was paused much of Sunday morning while the launch team evaluated problems with fans needed to pressurize, or ventilate, the mobile launch tower.

The fans blow air into the mobile launcher to ensure hazardous gases don’t build up during tanking, reducing the risk of a fire or other emergency, according to Charlie Blackwell-Thompson, NASA’s Artemis launch director.

One of the fans ran into trouble early Sunday, so officials paused the countdown to allow a team to go back to the launch pad to troubleshoot the problem. The launch team switched to a backup fan and prepared to continue the countdown, but then the second fan encountered a different issue, Blackwell-Thompson told reporters Sunday afternoon.

“The purpose of that pressurization is to prevent hazardous gas intrusion during load, so it provides a positive pressure,” she said. “So in the event that you were to have a leak or have some sort of hazardous commodity out of at pad, that you didn’t have, those gases intrude into those areas and potentially cause a fire hazard.

“So we decided that we wanted to really understand (the fan problems), given it was the first-time loading of the vehicle, and we made the decision to stand down to get in a configuration to go troubleshoot that, and then to be ready to make another run at it tomorrow,” Blackwell-Thompson said.

The mobile launcher stands 370 feet (113 meters) tall, with retractable umbilical arms to route gases and propellants to the rocket, and a crew access arm to allow astronauts to board the Orion spacecraft for future Artemis moon missions.

The ventilation fans are located in a building along the perimeter of pad 39B, a few hundred feet away from the rocket and mobile launcher. Air from the fans is routed through ducting in the launch pad’s environmental control system.

Blackwell-Thompson said engineers do not believe the cause of the malfunctioning fans is related to four lightning strikes observed inside the perimeter of pad 39B during a thunderstorm late Saturday afternoon. However, ground teams were still troubleshooting the fans when she spoke with reporters Sunday, and NASA officials weren’t sure of the reason the fans ran into problems.

 

Engineers determine the lightning strikes did not impact the Space Launch System or ground facilities. Three of the strikes hit the launch pad’s lightning towers, and another struck the catenary wiring system used to route electricity away from the rocket while it is exposed at the pad.

NASA is testing the Space Launch System for its first test flight, known as Artemis 1. The countdown rehearsal at Kennedy is a full-up practice run for launch day. Once the countdown proceeds into the final steps before liftoff, the clock will stop at T-minus 9.3 seconds, just prior to main engine ignition.

If ground teams at Kennedy are able to resolve the fan problems overnight, NASA’s mission management team will meet at 6 a.m. EDT (1000 GMT) Monday to give a “go” or “no go” for the start of propellant loading.

That propellant loading should begin shortly after 7 a.m. EDT (1100 GMT) for the giant Boeing-built core stage, covered in orange foam insulation to prevent ice build-up on the rocket’s outer skin.

This view of the Space Launch System on pad 39B shows the rocket’s mobile launch tower (left) and platform. Credit: NASA/Joel Kowsky

Liquid oxygen, chilled to minus 297 degrees Fahrenheit (minus 183 degrees Celsius) will begin loading first into the core stage. Then liquid hydrogen, stored at minus 423 degrees Fahrenheit (minus 253 degrees Celsius), will start pumping into the rocket’s main stage at pad 39B.

It will take about three hours to load liquid oxygen into the core stage, and an hour-and-a-half for liquid hydrogen. In flight, the propellants will feed the rocket’s four RS-25 main engines, leftovers from the space shuttle program, for a burn lasting more than eight minutes.

Then the launch team will move on to loading hydrogen and oxygen into the rocket’s cryogenic upper stage, powered by a single Aerojet Rocketdyne RL10 engine. Here’s a breakdown of the propellants that will be loaded into the rocket Sunday:

• Core Stage liquid oxygen: 196,000 gallons

• Core Stage liquid hydrogen: 537,000 gallons

• Upper stage liquid oxygen: 5,000 gallons

• Upper stage liquid hydrogen: 17,000 gallons

Another 30-minute build-in hold is planned when the countdown reaches the T-minus 10 minute mark Sunday afternoon. After a final “go/no go” pre-launch readiness poll, NASA launch director Charlie Blackwell-Thompson will give approval for the countdown clock to resume.

If all goes according to plan, the countdown will target a simulated launch time of 2:40 p.m. EDT (1840 GMT) Monday. In the final 10 minutes of the countdown, the core stage and upper stage propellant tanks will be brought to flight pressure, the boosters will be armed, and the rocket will be switched to internal power.

The countdown will cut off at T-minus 33 minutes and recycle to the T-minus 10 minute hold. NASA’s launch team plans a second run through the terminal countdown later Sunday afternoon, culminating in a hold at T-minus 9.34 seconds, just prior to ignition of the main engines.

Then the core stage and upper stage will be drained of cryogenic propellants, and NASA engineers will evaluate the rocket’s performance during the dress rehearsal, before eventually rolling the rocket back to the Vehicle Assembly Building for final pre-launch testing and closeouts.

NASA plans to announce a target launch date for the Artemis 1 mission after the wet dress rehearsal is complete. The launch dates currently under consideration are in June.

The Artemis 1 mission will send an Orion crew capsule into orbit around the moon, where mission control will run the spacecraft through a series of demonstrations before astronauts fly on the next SLS/Orion flight, named Artemis 2, on a looping trajectory around the moon.

Future missions after Artemis 2 will attempt to land astronauts on the moon with a commercial lunar lander, and build out a mini-space station near the moon called the Gateway.

Quelle: SN

----

Update: 6.04.2022

.

After weather and hardware issues, NASA starts SLS moon rocket fueling test

48e73bd9-e6a8-4b2e-9393-50b212a45dcd-crb031822-artemis-17-

Update: NASA is now targeting sometime after Friday, April 8, to complete the SLS rocket's wet dress rehearsal. The shift makes way for SpaceX's Axiom-1 mission to fly from Kennedy Space Center at 11:17 a.m. ET Friday.

---

More technical issues forced NASA teams at Kennedy Space Center to delay a countdown rehearsal for the agency's Space Launch System moon rocket Monday, pushing critical fueling milestones to later in the week.

In an update posted at 5 p.m. Monday, NASA said a valve located on the 322-foot rocket's mobile launch tower failed to open properly, forcing managers to delay key portions of the practice countdown known as the "wet dress rehearsal." The 45-hour test that began Friday is designed to simulate a launch countdown and is called "wet" because it includes fueling the rocket with liquid propellants at pad 39B.

"Due the vent valve issue, the launch director has called off the test for the day," NASA said in an update. "The team is preparing to offload liquid oxygen and will begin discussing how quickly the vehicle can be turned around for the next attempt. A lot of great learning and progress today."

The SLS rocket's space shuttle-era RS-25 engines will not fire during the test. If all goes well, the rocket will be rolled back to the Vehicle Assembly Building for more work. An updated launch timeline is expected next week, though NASA will be unable to fly anytime before June.

"There is no substitute for testing with flight hardware versus models," NASA said in explaining why a wet dress rehearsal is needed.

The test originally designed to last about 45 hours began at 5 p.m. Friday and was scheduled to wrap up by Sunday, but a lightning strike within the pad 39B's perimeter and a fueling system issue forced teams to rework the timeline. Pad systems had to be inspected for damage after the lightning strike, too.

SLS is the NASA-branded rocket built for the Artemis program, which aims to put two astronauts on the lunar surface no earlier than 2025. The rocket is slated to fly an uncrewe Orion capsule on a multi-day trip to orbit the moon and return to Earth – a mission known as Artemis I. 

Artemis II plans to do the same but with astronauts in the Orion capsule; Artemis III, meanwhile, will go all the way down to the lunar surface with two yet-to-be-named astronauts.

The updates coming from NASA are limited only to text form via Twitter and the agency's website. Officials last week said national security concerns forced them to not allow media or the public to listen to mission managers conducting the test. The agency is also not offering commentary on NASA livestreams despite TV crews also rehearsing coverage of the event.

Quelle: Florida Today

----

Update: 7.04.2022

.

NASA further delays SLS moon rocket's big test to after SpaceX launch

48e73bd9-e6a8-4b2e-9393-50b212a45dcd-crb031822-artemis-17--1

NASA will wait until after Florida's next launch to resume a critical test of the Space Launch System rocket tasked with taking the agency back to the moon from Kennedy Space Center.

Teams last Friday kicked off what should have been a 45-hour launch countdown rehearsal, but had to delay some operations to Monday due to weather and hardware issues at pad 39B. The operation is called a "wet dress rehearsal" because it includes a detailed recreation of the real countdown and liquid propellant loading.

NASA officials said Monday's attempt to close out the remaining checklist items – loading the rocket's stages with liquid oxygen and hydrogen being chief among them – was also scrubbed due to a few technical issues. Teams are expected to work the issues while giving room for SpaceX to launch a Falcon 9 rocket and four private passengers to the International Space Station on Friday, April 8. Nearby pad 39A will host the 11:17 a.m. EDT liftoff.

A specific date for the next attempt at fueling the 322-foot rocket remains uncertain. It's tasked with launching Artemis I with an uncrewed Orion capsule around the moon, which should be followed by a crewed version called Artemis II no earlier than next year.

"We haven't run into any fundamental design flaws or design issues," Mike Sarafin, Artemis mission manager, told reporters Tuesday. "These are what I will characterize as nuisance or technical issues where we're learning features and systems."

Quelle: Florida Today

----

Update: 9.04.2022

.

Artemis I Wet Dress Rehearsal Update 

48e73bd9-e6a8-4b2e-9393-50b212a45dcd-crb031822-artemis-17--kopie

NASA is planning to proceed with a modified wet dress rehearsal, primarily focused on tanking the core stage, and minimal propellant operations on the interim cryogenic propulsion stage (ICPS) with the ground systems at Kennedy. Due to the changes in loading procedures required for the modified test, wet dress rehearsal testing is slated to resume with call to stations on Tuesday, April 12 and tanking on Thursday, April 14. Wet dress rehearsal is an opportunity to refine the countdown procedures and validate critical models and software interfaces. The modified test will enable engineers to achieve the test objectives critical to launch success.  

Engineers have identified a helium check valve that is not functioning as expected, requiring these changes to ensure safety of the flight hardware. Helium is used for several different operations, including purging the engine, or clearing the lines, prior to loading propellants during tanking, as well as draining propellant. A check valve is a type of valve that allows liquid or gas to flow in a particular direction and prevents backflow. The helium check valve is about three inches long and prevents the helium from flowing back out of the rocket. 

Following the modified test, the Space Launch System rocket and Orion spacecraft will return to the Vehicle Assembly Building (VAB) where engineers will evaluate the valve and replace if needed. Teams are confident in the ability to replace the valve once back in the VAB.   

NASA will host a teleconference to discuss details on Monday, April 11. Check back at this blog for an update on the countdown timeline prior to the modified wet dress rehearsal testing for the Artemis I mission. NASA is streaming live video of the rocket and spacecraft on the Kennedy Newsroom YouTube channel  

Quelle: NASA
----
Update: 11.04.2022
.

NASA to delay, modify SLS countdown rehearsal

sls-wdr-220409

NASA said April 9 it will delay a fueling test of the SLS until April 14 and modify it with "minimal propellant operations" on the upper stage because of a faulty valve. Credit: NASA/Joel Kowsky

 

After discovering a problem with a valve on the Space Launch System’s upper stage, NASA is delaying a countdown rehearsal and fueling test and modifying it to limit fueling of the upper stage.

NASA said in an April 9 blog post that it was delaying the wet dress rehearsal (WDR) for the SLS by another three days. NASA previously planned to restart the test with a “call to stations” for personnel April 9, leading up to the tanking test and practice countdown April 11. NASA said the call to stations is now set for April 12 and tanking on April 14.

The latest delay is linked to a faulty helium check valve in the Interim Cryogenic Propulsion Stage (ICPS), the upper stage of the SLS. The valve prevents helium, used to purge propellant lines and drain propellant, from escaping the rocket.

NASA said April 7 that engineers found a problem maintain helium purge pressure in the ICPS after changing out a regulator in the mobile launch platform. At that time, the agency said it was able to restore normal pressure but was still studying the source of the problem, now linked to the faulty valve in the ICPS itself.

Because that issue, NASA now plans to limit the amount of liquid oxygen and liquid hydrogen propellant loaded into the ICPS during the WDR. NASA said the countdown rehearsal will be modified with “minimal propellant operations” on the ICPS, but didn’t elaborate on how much propellant would be transferred into the upper stage.

“Wet dress rehearsal is an opportunity to refine the countdown procedures and validate critical models and software interfaces,” NASA said in the post. “The modified test will enable engineers to achieve the test objectives critical to launch success.”

The ICPS is based on the second stage of the Delta 4 launch vehicle and uses a single RL10 engine. This particular stage was one of the first components of the overall vehicle that was completed. It was delivered and placed into storage several years ago while the core stage and solid rocket boosters were still being manufactured.

The valve issue is the latest glitch in the WDR process that has delayed the full test of the vehicle by more than a week. NASA scrubbed the first countdown rehearsal April 3 after delays caused by severe weather the night before, followed by malfunctions of fans in the mobile launch platform designed to prevent the buildup of hazardous gases. A second attempt the next day resulted in filling the core stage’s liquid oxygen tank halfway, but several other problems, including a vent valve that failed to open, led controllers to halt the test before the start of liquid hydrogen loading.

The delays in the in the WDR and the need to replace the helium valve in the ICPS now put into doubt the ability of SLS to be ready for a launch window that runs from June 6 to 16. NASA said in its April 9 blog post that it is “confident in the ability to replace the valve” once the SLS returns to the Vehicle Assembly Building after the WDR, but didn’t estimate how long that would take and what additional testing might be required.

Quelle: SN

----

Update: 14.04.2022

.

NASA to restart fueling test of SLS rocket, with key modifications

"We’re very comfortable with the path forward."

hv-qblx4-800x534

Will the third time be the charm for a Space Launch System rocket fueling test? NASA will find out this week.

NASA will resume its efforts to complete a key fueling test of the Space Launch System rocket on Tuesday.

The space agency has decided to modify this test, however, due to a problem with a check valve on the rocket's upper stage that leads to a pressurized helium bottle. The valve was found to be stuck last week and will need to be replaced.

With the valve in this position, NASA does not feel it would be safe to load the upper stage with cryogenic oxygen and hydrogen during the "wet dress" test as originally planned. Therefore, Thursday's test will fuel only the core stage—the largest and least-proven part of the rocket—during tanking operations. As part of this test, the launch system will be brought into a terminal countdown before cutting off at T-10 seconds.

NASA plans to collect a trove of data from this test, and this information will inform the agency's plans going forward, officials said during a media teleconference with reporters on Monday. About 10 days after the test, NASA will roll the SLS rocket back into the Vehicle Assembly Building. There, technicians will remove the check valve, which is about 8 cm long, and inspect the part to understand why it malfunctioned. It can then be replaced, which should be a relatively simple operation, said John Blevins, the SLS chief engineer.

A path forward

"We’re very comfortable with the path forward," said Tom Whitmeyer, deputy associate administrator for common exploration systems development at the NASA Headquarters in Washington. "We think it’s a great path forward."

The officials on Monday's teleconference seemed confident that they could get a lot of good data from Thursday's test. For example, said launch director Charlie Blackwell-Thompson, during the terminal countdown from T-10 minutes to T-10 seconds, there are almost 25 "critical events" in the rocket's test objectives. Just two of those are specific to the upper stage, she said.

"There is a significant amount of testing and data and risk buy-down you get relative to the core stage, to the ground systems, and relative to the boosters," she said.

The upper stage, known as the Interim Cryogenic Propulsion Stage, was manufactured by United Launch Alliance and was delivered to Kennedy Space Center about four years ago. However, the chief SLS engineer, John Blevins, said he does not believe the valve issue was due to any shelf-life issues. The check valve in question, he said, is rated to function for 20 years or longer.

“Two days” becomes “two weeks”

The wet dress test was originally supposed to last two days when it began on Friday, April 1. But partly due to a problem with the fans on the Mobile Launch Tower, the first attempt at fueling the rocket had to be scrubbed on April 4. A second attempt last week saw NASA fill the core stage about halfway with liquid oxygen before the agency discovered that a core stage "vent valve," which is manually adjusted, was errantly left in the wrong position. Then NASA discovered the check valve issue on the upper stage.

Now, teams of NASA employees and contractors will be called to their stations again on Tuesday evening to prepare the vehicle and ground systems for propellant loading for the third time. The actual fueling of the vehicle is scheduled to commence on Thursday morning, with the terminal countdown reached at 2:40 pm ET (18:40 UTC). That precise timeline, of course, assumes no further delays, which seems unlikely for a two-day test that has expanded to two weeks.

Asked to assess next steps after this test in terms of readying the SLS rocket and Orion spacecraft for an uncrewed demonstration flight later this summer, NASA officials did not want to look too far beyond the conclusion of this core stage tanking. They declined to say whether the rocket might be subjected to a second wet dress test for the entire vehicle to ensure the flight readiness of the upper stage and its ground systems.

"I don't think we're ready to really state, one way or the other, what we think the next step is going to look like," Whitmeyer said. "I think we really do need to do the test Thursday and then look at the data."

Quelle: arsTechnica

Fuel leak thwarts NASA's dress rehearsal for moon rocket

NASA's latest attempt to fuel its huge moon rocket for a countdown test has been thwarted by a hazardous hydrogen leak

 

CAPE CANAVERAL, Fla. -- NASA's latest attempt to fuel its huge moon rocket for a countdown test was thwarted Thursday by a hazardous hydrogen leak, the latest in a series of vexing equipment trouble.

The launch team had just begun loading fuel into the core stage of the rocket when the leak cropped up. This was NASA's third shot at a dress rehearsal, a required step ahead of a test flight to the moon.

This time, the launch team managed to load some super-cold liquid hydrogen and oxygen into the core stage of the 30-story Space Launch System rocket, but fell far short of the full amount. Liquid hydrogen is extremely hazardous, with officials noting that the systems had been checked for leaks prior to the test.

Technicians deliberately left the smaller upper stage empty, after discovering a bad valve last week. The helium valve inside the upper stage cannot be replaced until the rocket is back in its hangar at Kennedy Space Center.

Two previous countdown attempts were marred by balky fans and a large hand-operated valve that workers mistakenly left closed at the pad last week.

Officials said via Twitter that they're assessing their next steps.

NASA had been targeting June for the launch debut of the 322-foot (98-meter) SLS rocket. The empty Orion capsule on top will be sent on a four- to six-week mission around the moon and back.

Astronauts will strap in for the second test flight around the moon, planned for 2024. That would be followed as early as 2025 with the first lunar landing by astronauts since 1972. NASA plans to announce the crews for these two missions this summer.

Quelle: abcNews

+++

Excitement palpable at Kennedy Space Center as NASA conducts last Artemis I moon rocket test

 

NASA teams at Kennedy Space Center are targeting this afternoon for the wrap-up of a series of tests and rehearsals for the agency's Space Launch System moon rocket, marking an end to their first time interacting with the massive vehicle on the launch pad.

But what might seem like a longer-than-planned test from the public's perspective continues to be a source of excitement for employees and officials, some of whom have waited more than a decade to see the 322-foot rocket at pad 39B. The test's timeline also reflects what NASA officials saw during the Apollo program and showcases differences in hardware development philosophies like those practiced by SpaceX.

"I've been seeing the excitement build with every milestone met and we especially feel it here in the firing room," Chance Belloise, a master console operator at KSC, told FLORIDA TODAY. "Things have been super busy lately. Subsystems have been working hard at their consoles, our (communications channels) are always buzzing, and it's even starting to get hard to find parking around here."

The "wet dress rehearsal," called that because it includes fueling the rocket with liquid propellants, was expected to take about 45 hours starting April 1 but had to be put on hold due to inclement weather and technical issues. Managers arrived at their consoles Tuesday afternoon and kicked off their third rehearsal countdown at 5:30 p.m. ET.

Excitement for the test and eventual launch of the rocket on Artemis I, now slated for its uncrewed flight around the moon no earlier than June, actually crystallized in March when the fully stacked rocket made its first public appearance. Thousands of officials, employees and their families, media, and others watched as the rocket exited the Vehicle Assembly Building on its slow trek to pad 39B. Some even hosted small picnics while others threw footballs to pass the time leading up to rollout.

"Standing there with family, friends, and co-workers who have been working on this years and years was a very sobering moment," Belloise, who works directly for ERC and joined the team last year, said. "It was truly a monument to all the years of work that have gone into it."

This afternoon, teams will keep a close eye on ground equipment as it pumps propellants into the first stage booster's tanks. Then, acting as if in a mock countdown, managers will command the process to stop just before the clock hits T-0.

Fueling of the rocket's second stage will not be part of the process due to a misbehaving check valve, which allows one-way flow for liquids or gases, but block backwards flow. Officials this week said that issue will need to be fixed once the WDR is complete and SLS is rolled back to the Vehicle Assembly Building. Whether or not that means another rehearsal will be necessary was not immediately clear.

The wet dress rehearsal has allowed teams to refine timelines; work together for the first time with the fully integrated rocket and ground equipment; troubleshoot hardware issues; work around inclement weather like lightning; and generally gain experience so as to not walk into the Launch Control Center on launch day without having practiced the process.

If all goes according to plan, this specific SLS rocket will fly from pad 39B without astronauts on a trip around the moon known as Artemis I. If successful, that will pave the way for Artemis II no earlier than 2023, which will be an identical mission but will carry astronauts. And if that goes well, Artemis III is expected to take two NASA astronauts to the lunar surface no earlier than late 2025.

"It will be almost like the night before Christmas," Belloise said of Artemis I's launch day. "And it honestly, it feels that way every time we come up to a major milestone like this."

Historical perspective

SLS isn't the first NASA-branded rocket to be put through its paces ahead of launch.

The first operational Saturn V moon rocket built for the Apollo program, for example, rolled out to nearby pad 39A – now leased by SpaceX for its vehicles – in August 1967, according to NASA. It was slated to go through a similar series of tests known as a Count Down Demonstration Test, or CDDT.

Just like with SLS, the Saturn V rocket was powered up and fueled at the pad. But the tests that were planned to take about six days actually needed 17 to be completed.

NASA archives credit the longer-than-anticipated testing phase as one of the key reasons behind the Apollo program's success. Rocco Petrone, director of launch operations at the time, said: "We learned a lot. The program came to fruition."

A few months later, Apollo 4 flew on a successful test flight without any crew onboard, just like SLS will do for its Artemis I mission no earlier than June.

Development philosophies

NASA's approach to rocket development stands in contrast to another organization that's gained worldwide popularity over the last two decades: SpaceX.

The company is famous for pushing the limits of its hardware, even as far as expecting explosive failures during first flights. Unlike NASA's approach, SpaceX puts fewer resources into prototypes and instead hopes to learn lessons along the way in a "fly-test-fix" approach.

NASA takes the opposite approach with SLS: the rocket must not fail, even during its two demonstration missions leading up to the lunar landing in 2025. The agency hopes to work out all the issues ahead of liftoff, which tends to front-load a lot of the work to earlier in the process.

NASA's approach also means the stakes are high for SLS' debut mission. Since everything has to go perfectly, the Artemis program could find itself in the crosshairs if a failure were to further push the already delayed timeline.

Quelle: Florida Today

----

Update: 17.04.2022

.

NASA to roll back SLS for repairs

Updated 10 p.m. Eastern after NASA decision to roll back SLS.

WASHINGTON — NASA announced late April 16 it will roll back the Space Launch System from the launch pad for various repairs, further delaying the rocket’s long-anticipated first launch.

In a statement late April 16, NASA announced it planned to roll back the SLS to the Vehicle Assembly Building (VAB) “due to upgrades required at an off-site supplier of gaseous nitrogen used for the test,” the agency said. Problems with the supply of gaseous nitrogen, used to support activities at the pad, had delayed two previous countdown rehearsals.

NASA did not state when the vehicle would go back from Launch Complex 39B, where it rolled out March 17, to the VAB. The agency said it will hold a briefing April 18 about its plans. The agency added it would use the time in the VAB to repair a faulty helium check valve in the SLS’s upper stage and a hydrogen leak detected shortly after starting to load liquid hydrogen into the rocket’s core stage during the April 14 attempt. It was the first time that controllers had reached that stage of the countdown after technical problems halted two previous attempts before liquid hydrogen could start loading.

The leak is on the ground side of an umbilical plate on the mobile launcher’s tail service mast, and not on the SLS itself. “The good news is that there’s only a few things in that purge enclosure and there’s a couple of discrete penetrations that could be the culprit,” said Charlie Blackwell-Thompson, Artemis launch director, during an April 15 briefing.

At that briefing, agency officials expressed some optimism about correcting the problem on the pad. Mike Sarafin, NASA Artemis mission manager, said those potential sources for the leak represented “low-hanging fruit” for fixing the problem and allowing another wet dress rehearsal as soon as April 21.

However, he suggested even then that rolling the SLS back the VAB was an option. “There are some more invasive options that require getting further into the hardware and potentially having to get into some extended troubleshooting,” he said, work he indicated might be best done in the VAB.

Sarafin said engineers also had to consider environmental issues of having the vehicle on the pad for an extended period, such as wind stresses on the towering vehicle. “The longer we stay at the pad, the more we stress the vehicle,” he explained. “Every time the wind blows against it, it creates a bending moment and, over time, that adds up.”

“We haven’t fully outlined all the options right now,” he said at the April 15 briefing. “The one that we’re pursuing with great vigor is the low-hanging fruit option and we’ll let the team come up with some other options.”

Blackwell-Thompson suggested one option would be to do another tanking test once the vehicle returns to the pad for the Artemis 1 launch. “You could certainly look at your schedule risk for launch countdown and make a decision whether or not you wanted to do a tanking prior to a launch countdown,” she said. In that scenario, the rocket would go through a tanking test and practice countdown and, if all went well, “some days later decide to go launch.”

Despite not getting through the countdown test in three attempts to date, and uncertainty about when the hydrogen leak will be fixed, Blackwell-Thompson said she was not particularly concerned. She noted there were five or six tanking tests before the first launch of the shuttle more than four decades ago. “Putting it into context, I would say we’re within family of our experience in the past for first-time ops,” she said.

Quelle: SN

+++

NASA to Discuss Status of Artemis I Moon Mission

NASA will hold a media teleconference at 3 p.m. EDT on Monday, April 18, to discuss the status of the next wet dress rehearsal test of the agency’s Space Launch System (SLS) rocket and Orion spacecraft at Launch Complex 39B at the agency’s Kennedy Space Center in Florida ahead of the uncrewed Artemis I lunar mission.

 

Due to upgrades required at an off-site supplier of gaseous nitrogen used for the test, NASA will take advantage of the opportunity to roll SLS and Orion back to the Vehicle Assembly Building to replace a faulty upper stage check valve and a small leak on the tail service mast umbilical. During that time, the agency also will review schedules and options to demonstrate propellant loading operations ahead of launch.

 

The teleconference will stream live on the agency’s website.

 

Teleconference participants include:

  • Tom Whitmeyer, deputy associate administrator for common exploration systems development, NASA Headquarters in Washington
  • Charlie Blackwell-Thompson, Artemis launch director, NASA Exploration Ground Systems program, Kennedy
  • Mike Sarafin, Artemis mission manager, NASA Headquarters

 

To participate by telephone, media must RSVP no later than two hours prior to the start of the event to: ksc-newsroom@mail.nasa.gov.  

 

Through Artemis missions, NASA will land the first woman and the first person of color on the Moon, paving the way for a long-term lunar presence and serving as a steppingstone to send astronauts to Mars.

Quelle: NASA

----

Update: 26.04.2022

.

NASA readies SLS moon rocket for return to Vehicle Assembly Building

sls-artemis1-b

Ground teams moved a diesel-powered crawler-transporter underneath the Space Launch System moon rocket Sunday on pad 39B at NASA’s Kennedy Space Center, preparing the towering launcher for a return to the Vehicle Assembly Building for repairs.

The rollback to the Vehicle Assembly Building is set to begin as soon as Monday afternoon, giving the SLS team plenty of time to bring the rocket back to the hangar before the scheduled launch of a SpaceX crew mission to the International Space Station early Wednesday.

The 4.2-mile (6.8-kilometer) journey along the dual-lane crawlerway is expected to last approximately 10 hours, but that could vary based on how many stops the crawler makes on the return trip to the assembly building.

NASA is moving the 322-foot-tall (98-meter) moon rocket off pad 39B after failing to fully load the vehicle with cryogenic propellants during testing earlier this month. On three fueling attempts, NASA’s launch team was blocked by ground equipment problems, a faulty helium valve, and finally a hydrogen leak in the interface between the rocket and its mobile launch platform.

The problems are expected to delay the first flight of the powerful new Space Launch System rocket — a vehicle NASA intends for future astronaut voyages to the moon — from the previous target schedule in early June. NASA has not identified a new timetable for the first SLS launch.

The launch will carry NASA’s Orion crew capsule on a multi-week journey into lunar orbit and back to Earth. The mission, known as Artemis 1, is a shakedown cruise before NASA aims to launch a crew around the moon on the second SLS/Orion flight.

Managers decided to return the Space Launch System to the Vehicle Assembly Building to replace the faulty helium check valve on the rocket’s upper stage, and to allow technicians an opportunity to locate and repair the hydrogen leak in the umbilical that leads into the core stage.

Meanwhile, teams from Air Liquide, which runs a plant just outside the gates of the Kennedy Space Center, will upgrade the gaseous nitrogen supply that leads into the spaceport through a pipeline. NASA found that the nitrogen gas supply was not sufficient for the high demands of the Space Launch System, a rocket larger than any other currently flying from the Florida spaceport.

The large size of the SLS moon rocket means it needs more propellants and other fluids, including nitrogen gas, than other rockets.

“We are upgrading the vaporization system to optimally manage the increased nitrogen requirements during launches,” said Alyson Bartol, a spokesperson for Air Liquide, which also supplies nitrogen gas for commercial launch operations in Florida, including SpaceX missions. “The nitrogen supplied to Kennedy Space Center is not restricted for use by NASA only, therefore other parties utilizing the supply will also benefit from the upgrades to Air Liquide’s system.

The upgrades are not expected to impact other launches from the Kennedy Space Center or Cape Canaveral Space Force Station, according to NASA.

NASA rolled the SLS moon rocket out to pad 39B on March 17 to prepare for the rocket’s first full-up countdown rehearsal and fueling test, culminating in a cutoff of the countdown clock at T-minus 9 seconds, just before main engine ignition.

NASA’s launch team attempted to pump propellants into the rocket April 3, April 4, and April 14. The final “wet dress rehearsal” test ended with the discovery of the hydrogen leak, when the core stage had been filled with about 5% of its liquid hydrogen load and about half of its liquid oxygen.

Once the SLS moon rocket is back in High Bay 3 inside the iconic Vehicle Assembly Building, ground teams will begin work to swap out the faulty helium valve and search for the source of a hydrogen leak in the tail service mast umbilical, where propellants flow from the mobile launch platform into the core stage.

Initial inspections at the launch pad revealed no sign of the leak, which appeared when NASA’s launch team began flowing liquid hydrogen — chilled to minus 423 degrees Fahrenheit (minus 253 degrees Celsius) — into the rocket in a “fast fill” mode.

Exposure to super-cold propellants contracts components in the mobile launch platform and the rocket itself, revealing leaks not apparent at ambient temperatures. Charlie Blackwell-Thompson, NASA’s Artemis 1 launch director, said last week engineers and technicians in the VAB will use probes and instrumentation to scan for a leak. They will also inspect seals, and re-torque flange connections in the umbilical, she said.

NASA officials originally planned to roll the SLS moon rocket back to the hangar after completing the wet dress rehearsal, allowing ground crews to complete closeouts on the rocket, test the vehicle’s flight termination system, and install final equipment into the Orion crew capsule.

Then the rocket would roll out again to pad 39B for launch preparations and the real countdown for the Artemis 1 mission.

Blackwell-Thompson said NASA managers are evaluating three options for how to complete the work required before clearing the Artemis 1 mission for liftoff.

One is a “VAB quick turn” option that would focus engineers on completing the minimum work to ready the rocket for another wet dress rehearsal run. That work would include replacing the upper stage helium valve and fixing the hydrogen leak, but the rocket would still need to come back to the VAB for final pre-flight preps.

“There’s a second option that looks at doing a great amount of work in the VAB, maybe getting closer to your rollout for flight configuration,” Blackwell-Thompson said. This option would also require another rollback to the hangar, but would involve a relatively shorter stay in the VAB focused on flight termination system testing.

The third option under consideration would keep the SLS moon rocket in the VAB for a longer period of time after rolling back from the pad next week, allowing teams to complete all the work needed to outfit the launcher for flight. Then the rocket would roll out again to pad 39B, allowing NASA to run through a wet dress rehearsal and then the real launch attempt during one campaign.

The third option would include a 20-day limit from the time the rocket rolls out of the VAB until the mission must launch. The restriction is associated with the flight termination system, which would be activated to destroy the rocket if it flew off course.

The U.S. Space Force’s Eastern Range, responsible for public safety, only certifies the SLS flight termination system for 20 days after it completes an end-to-end test inside the Vehicle Assembly Building.

The comprehensive flight termination system check can only be run inside the VAB, so the rocket would have to return to the hangar for another end-to-end test after 20 days, potentially leaving little margin for error to resolve problems during a wet dress rehearsal, and still proceed with the Artemis 1 launch.

Tom Whitmeyer, NASA’s exploration systems manager, said last week the agency is committed to completing the wet dress rehearsal before launching the SLS moon rocket.

“We will absolutely go back out,” he said. “We are absolutely going to do a dress rehearsal. We’ll demonstrate cryo loading, and we will also demonstrate terminal countdown.

“It’s just a matter of what’s the right time and what’s the right way to do that, and how that might fit in our forward scheduling.”

Quelle: SN

----

Update: 6.05.2022

.

NASA to Discuss Status of Artemis I Test, Launch

nhq202203170009-large

NASA’s Space Launch System (SLS) rocket with the Orion spacecraft aboard is seen through the windows of Firing Room One in the Rocco A. Petrone Launch Control Center atop a mobile launcher as it rolls out of High Bay 3 of the Vehicle Assembly Building for the first time to Launch Complex 39B, Thursday, March 17, 2022, at NASA’s Kennedy Space Center in Florida. Ahead of NASA’s Artemis I flight test, the rocket and spacecraft will undergo a wet dress rehearsal at Launch Complex 39B to verify systems and practice countdown procedures for the first launch.
Credits: NASA/Joel Kowsky

NASA will hold a media teleconference at 3:30 p.m. EDT Thursday, May 5, to discuss the status of the next wet dress rehearsal test of the agency’s Space Launch System (SLS) rocket and Orion spacecraft at the agency’s Kennedy Space Center in Florida. The teleconference will stream live on the agency’s website.

 

The agency plans to conduct another attempt of the wet dress rehearsal in early June to demonstrate the ability to load propellant into the tanks and conduct a full launch countdown ahead of the Artemis I launch this summer.

 

Teleconference participants include:

 

  • Jim Free, associate administrator, Exploration Systems Development Mission Directorate, NASA Headquarters in Washington
  • Cliff Lanham, senior vehicle operations manager, NASA Exploration Ground Systems Program, NASA Kennedy

 

To participate by telephone, media must RSVP no later than two hours prior to the start of the event to: ksc-newsroom@mail.nasa.gov.  

 

NASA’s SLS rocket and Orion spacecraft arrived back at Kennedy’s Vehicle Assembly Building April 26 after a 10-hour journey from launch pad 39B. Since their arrival, teams have worked to replace a faulty upper stage check valve and repair a small leak within the tail service mast umbilical ground plate housing. The teams also have been performing additional checkouts while the spaceport’s supplier of gaseous nitrogen makes upgrades to their pipeline configuration to support Artemis I activities.

 

Through Artemis missions, NASA will land the first woman and the first person of color on the Moon, paving the way for a long-term lunar presence and serving as a steppingstone to send astronauts to Mars.

Quelle: NASA                                                                                                                                                       ----                                                                                                                                                                     Update: 23.05.2022                                                                                                                                           .                                                                                                                                                                          

NASA plans early June rollout of SLS for next countdown test                                                                   sls-rollback-879x485           

 

WASHINGTON — NASA is gearing up to perform another practice countdown of the Space Launch System in mid-June as it completes repairs to the vehicle from previous tests.

NASA said May 20 it expects to roll out the SLS from the Vehicle Assembly Building at the Kennedy Space Center to Launch Complex 39B in early June for the next attempt at a wet dress rehearsal (WDR), where the vehicle is filled with liquid oxygen and liquid hydrogen propellants and goes through a countdown that stops just before ignition of the core stage’s four RS-25 engines.

NASA made three attempts at completing a WDR at the pad in April, but stopped all three early after a series of problems. The agency rolled the SLS back to the VAB April 26 to fix both issues with the vehicle and its ground systems as well as with the supply of nitrogen gas at the pad.

In the statement, NASA said workers have completed work on the vehicle, including replacing a helium check valve in the upper stage and fixing a hydrogen leak in an umbilical. Crews also modified “purge boots” on umbilical lines leading into the upper stage to protect them from the elements.

NASA confirmed that Air Liquide, the contractor who provides nitrogen gas for the launch pad and other facilities at KSC, had completed upgrades that will ensure there will be enough gas available to support SLS operations.

Janet Petro, director of KSC, said at a May 18 briefing that a test of the nitrogen gas system took place the previous night and went well. “We’re feeling really good about rolling out in early June and completing the wet dress.”

NASA did give a date for the next WDR attempt, other than about 14 days after rollout. At the May 18 briefing, though, NASA Associate Administrator Bob Cabana said he estimated the next attempt would be June 18 to 20.

NASA officials had previously said they would not set a launch date for the Artemis 1 uncrewed mission until after completion of the WDR and assessment of the work needed to get the vehicle ready for flight. However, NASA Administrator Bill Nelson told House appropriators May 17 he now expected it to launch in August.

An updated schedule released by NASA May 16 said the next launch window for the Artemis 1 mission is July 26 to Aug. 10, although with no launches possible on Aug. 1, 2 and 6. The following window opens Aug. 23 and runs through Sept. 6, but with no launches on Aug. 30 through Sept. 1. Launch windows are constrained by several factors, including availability of trajectories for the SLS to send the Orion spacecraft to the moon and return for a splashdown in daylight hours off the California coast.                                                                                           Quelle: SN

 

1797 Views
Raumfahrt+Astronomie-Blog von CENAP 0