Tag: SLS

Orion fires engines and is now on its way around the Moon

4:55 pm

After reviewing the operation of Orion capsule during its first day in orbit, the NASA Artemis-2 management team approved sending the spacecraft to the Moon.

The burn occurred at 7:49 Eastern. The live stream of that burn is embedded below.

At this moment NASA and the crew are committed. No matter what happens, they cannot return to Earth any earlier than about nine days from now. And when they return, they will have to do a direct dive into the atmosphere, heading to splashdown. The Orion heat shield at that point must work.
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SLS successfully puts Orion into orbit

3:46 pm

SLS less than a minute after launch
SLS less than a minute after launch

NASA’s SLS rocket today successfully launched the Orion capsule, carrying three Americans and Canadian on a planned ten-day mission swinging around the Moon and back to Earth.

During the countdown there were two minor issues, the second of which causes a slight ten-minute delay in the launch. Both were resolved very quickly, though one wonders if NASA can ever do a launch with this rocket without such issues during countdown.

The crew will remain in Earth orbit until tomorrow, checking out the capsule and its systems. Once they have confirmed these are working as expected, they will then fire their engines to head to the Moon.

The live stream can be viewed here.

As this was the first U.S. government launch this year (and the first since 2022), the leader board for the 2026 launch race remains unchanged:

40 SpaceX
16 China
5 Rocket Lab
3 Russia

SpaceX continues to lead the entire world combined in total launches, as it did in both ’24 and ’25.

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Watching the launch of the Artemis-2 mission

9:28 am

Artemis-2 mission flight path
The Artemis-2 flight path. Click for full animation.

The countdown for the launch of the 10-day Artemis-2 manned mission around the Moon continues, with the launch scheduled for 6:24 pm (Eastern) today.

For updates from NASA, go here. So far all is proceeding as planned. A step-by-step outline of the countdown itself can be found here.

A day-by-day detailed description of the planned mission can be found here. For the first day the crew will remain in Earth orbit in order to test the operation of their Orion capsule. To reiterate, the capsule’s life support system has not been flown in space previously, so this first day is critical. If there are any issues, the astronauts are still close to Earth and can return relatively quickly.

If no problems are detected during that first day, on day two the crew will fire the spacecraft’s engines and head to the Moon. At that point everything must function as planned for nine days as they travel out to the Moon, swing around it without going into orbit, and head back to Earth.

The return to Earth remains the most dangerous moment for this flight. During the 2022 unmanned test flight around the Moon, the heat shield design on Orion did not work as planned, with chunks breaking off in a manner that was unexpected and very concerning. NASA spent two years contemplating the issue, and decided to live with the same heat shield design for this mission, since replacing the shield would have delayed the launch at minimum two years. It has adjusted the return flight path in a way it thinks will mitigate the problem. As its engineers are only guessing at what caused the issue and could be wrong — having done no real life tests — we will not know if they are right until Orion splashes down.

We must pray that they are right.

I have embedded NASA’s live stream below.
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Countdown begins for the Artemis-2 mission around the Moon

11:57 pm

NASA this afternoon began the two-day long countdown leading up to the planned 6:24 pm (Eastern) launch of its Artemis-2 mission, sending three Americans and one Canadian around the Moon.

The onsite countdown clock started ticking down at 4:44 p.m. EDT to a targeted launch time of 6:24 p.m. on Wednesday, April 1. Artemis II is the first crewed launch of NASA’s SLS (Space Launch System) rocket and Orion spacecraft.

…NASA and weather officers with the U.S. Space Force’s Space Launch Delta 45 continue to pay close attention to weather conditions ahead of tanking operations. The weather forecast for launch day shows an 80% chance of favorable weather conditions with primary concerns being cloud coverage and the potential for high winds in the area. Teams will continue to monitor the weather in the coming days.

The ten-day mission will use the SLS rocket, which has only flown once previously, and has had repeated fueling issues prior to that 2022 launch as well as during dress rehearsal countdowns last month. It will also use an Orion capsule with a questionable heat shield and an untested life support system.

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SLS/Orion have begun 12-hour trip from VAB to launchpad

8:59 am

Artemis-2 mission flight path
The Artemis-2 flight path. Click for full animation.

NASA engineers today began the long and slow 12-hour trip of the SLS rocket from the Vehicle Assembly Building (VAB) to the launchpad in preparation for a targeted April 1, 2026 launch date of this Artemis-2 mission around the Moon.

NASA’s Artemis II SLS (Space Launch System) rocket and Orion spacecraft slated to send four astronauts around the Moon began rolling to Launch Pad 39B at 12:20 a.m. EDT on Friday, March 20. Rollout operations at the agency’s Kennedy Space Center in Florida were delayed earlier in the day due to high winds in the area.

The trek to the pad is expected to take up to 12 hours, as NASA’s crawler-transporter 2 carefully carries the rocket on top of the mobile launcher approximately 4 miles along the crawlerway.

The launch will send four astronauts on a ten-day mission swinging around the Moon and back to Earth, using a questionable heat shield and a life support system not yet been tested in space. On the first unmanned Artemis-1 mission around the Moon in 2022, the shield experienced far more damage than predicted, with large chunks breaking off. NASA engineers think they understand why this happened, and have decided that they can mitigate the problem by using a less stressful flight path upon return into Earth’s atmosphere.

They don’t really know if this is so, but they hope so. As for the life support system, the plan is to remain in a high Earth orbit for the mission’s first day to test it. If it has problems then, the crew will be able to return to Earth somewhat quickly. If it has problems after heading to the Moon, however, that won’t be possible.

If a private company tried to convince NASA to do this mission with these issues, the agency would say “Hell no!” It is proceeding because, like the Challenger and Columbia failures, it is a NASA-built project and politics and schedule have superseded safety and good engineering procedures

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A day-by-day description of the entire Artemis-2 manned mission

10:04 am

NASA today posted a detailed day-by-day description of the entire ten-day Artemis-2 manned mission around the Moon, outlining the tasks planned for the astronauts on each day.

The launch is now targeting April 1, 2026.

The description of their closest approach to the Moon is both interesting and underwhelming.

The Artemis II crew will come their closest to the Moon on flight day 6, while traveling the farthest from Earth. Artemis II could set a record for the farthest anyone has traveled from Earth depending on launch day, breaking the current record – 248,655 miles away – set in 1970 by the Apollo 13 crew. The distance the Artemis II crew will travel depends on their exact launch day and time.

Over the course of the day, the crew will come within 4,000 to 6,000 miles of the lunar surface as they swing around the far side of the Moon – it should look to them about the size of a basketball held at arm’s length. [emphasis mine]

In other words, Orion is not going to get very close, and in fact, the Moon will only be 2 to 3 times bigger than what we see here on Earth. I suspect the best photographs taken will be those showing both the Earth and Moon, both of which will be relatively small.

Overall, I remain highly concerned about this mission. The life support system has never been tested in space before, and they will spend the first day checking it out in Earth orbit. And the return to Earth will involve using a heat shield that did not perform well on the Artemis-1 mission in 2022, losing chunks during re-entry.

They hope a less stressful flight path will mitigate this issue, but then, they need to hit that flight path perfectly on their way back from the Moon. During yesterday’s briefing it was obvious this was a concern to NASA officials.

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NASA now targeting an April 1st launch of Artemis-2

3:54 pm

At a press briefing today, NASA officials said they are now targeting an April 1, 2026 launch date for the Artemis-2 mission, a ten-day manned mission sending four astronauts around the Moon.

NASA completed the agency’s Artemis II Flight Readiness Review on Thursday, March 12, and polled “go” to proceed toward launch. NASA is targeting Thursday, March 19, to roll the SLS (Space Launch System) rocket and Orion spacecraft to launch pad 39B in advance of a launch attempt Wednesday, April 1, pending close out of remaining open work.

The repair work involved replacing a helium seal that was preventing flow to and from the tanks and testing it to confirm the new seal worked. It also involved replacing batteries as well as some oxygen seals.

NASA officials also stated that they do not plan to do another wet dress rehearsal, that they are satisfied by the testing they did in the assembly building. Instead, they are go for full launch countdown, with the hope they can lift-off with no more fueling issues. They have also determined that if there is a scrub, they will also have several launch opportunities through April 6th.

To underline the risks of this mission, the Orion capsule in which they are sending four astronauts around the Moon has an uncertain heat shield and an untested life support system. To mitigate the shield uncertainties, they must hit a specific flight path through the atmosphere upon return.

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NASA awards ULA’s Centaur-5 upper stage for future SLS launches

4:30 pm

NASA yesterday awarded ULA the contract for providing SLS its upper stage after the Artemis-3 mission using the Centaur-5 upper stage that was developed for the company’s Vulcan rocket.

In its procurement statement, NASA said its intention is to issue a sole source contract to ULA, meaning it’s the only upper stage being considered for this new iteration of the SLS rocket. An eight-page supporting document from NASA’s Marshall Space Flight Center (MSFC) in Huntsville, Alabama, was published to document the reasoning for its decision.

Among the stated reasons are the decades-long heritage of the RL10 engine, which has matured over time; the ability of the Centaur 5 to use the interfaces available on the Mobile Launcher 1 (ML1) along with the propulsion commodities of liquid oxygen and liquid hydrogen; and the experience of ULA’s teams working with NASA’s Exploration Ground Systems (EGS) at the Kennedy Space Center and elsewhere in the country.

They also noted that with the Centaur 3 upper stage achieving certification to launch humans as part of the Commercial Crew Program, there are a lot of common features with the Centaur 5.

The decision relieves NASA from wasting more money on the Mobile Launcher-2, which has been a disaster. The contractor Bechtel has gone over budget — from $383 million to $2.7 billion — and is so behind schedule it is still unclear now whether it will be ready by 2029, a decade after the contract was awarded.

It also relieves NASA of spending more money on its own upper stage, which has been as much a disaster, from Boeing.

Instead, this deal is an example of Isaacman doing the right thing. Rather than have NASA design and build its own upper stage, he is buying the product — almost literally off-the-shelf — from a commercial rocket company. He should expand this effort, and consider other private rockets, such as Falcon Heavy, to replace SLS itself.

Now Isaacman should consider suing Bechtel for fraud and incompetence, to try to get back some of the money it wasted.

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Engineers locate helium flow issue on SLS upper stage

8:01 am

NASA last evening posted an update on the status of its SLS rocket, noting that engineers had located the seal that had caused the helium flow issue in the upper stage during unfueling after the wet dress rehearsal two weeks ago.

Engineers determined a seal in the quick disconnect, through which helium flows from the ground systems to the rocket, was obstructing the pathway. The team removed the quick disconnect, reassembled the system, and began validating the repairs to the upper stage by running a reduced flow rate of helium through the mechanism to ensure the issue was resolved. Engineers are assessing what allowed the seal to become dislodged to prevent the issue from recurring.

Though this information is somewhat vague, it strongly suggests the seal with the problem was in the upper stage, not the umbilical line that is part of the ground systems.

Before they can return the rocket to the launchpad, they need to make sure they identified the exact issue that caused the seal to not work properly. They also are replacing the batteries in the rocket’s self-destruct system as well as flight batteries in the upper stage, core stage, and two strap-on solid-fueled boosters. It also appears they are replacing another seal the oxygen feed line for the core stage.

Once this work is finished and confirmed, they will still need to roll SLS back to the launchpad and likely do another wet dress rehearsal countdown, though that rehearsal might be condensed to focus on these issues specifically.

The present launch window closes on April 6th, so the timeline is very tight. NASA management is reviewing later windows in late April as well as May and June.

Despite the major reshaping of the later missions in the Artemis program that NASA administrator Jared Isaacman announced last week, this upcoming Artemis-2 mission remains the same, a ten-mission carrying four astronauts around the Moon using an Orion capsule with a questionable heat shield and an untested life support system.

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SLS is back in the Vehicle Assembly Building

9:43 am

Last night NASA yesterday successfully completed the roll back of its SLS rocket back to the Vehicle Assembly Building (VAB).

The SLS (Space Launch System) rocket and Orion spacecraft for NASA’s Artemis II mission arrived at the Vehicle Assembly Building from Launch Pad 39B at approximately 8 p.m. EST Feb. 25, at NASA’s Kennedy Space Center in Florida. While in the assembly building, technicians will troubleshoot the helium flow issue to the rocket’s upper stage, replace batteries on the rocket’s upper stage, core stage, and solid rocket boosters as well as service its flight termination system.

NASA officials have not said what will happen next, once that helium flow problem is resolved. I suspect NASA administrator Jared Isaacman will insist on another wet dress rehearsal to not only test the rocket’s troublesome fueling system, but to also test the helium system used to drain the tanks afterward.

If so, it is very unlikely a launch can occur prior to April 6th, when the present launch window closes. The odds of there being no issues on the next dress rehearsal are slim, based on SLS’s past record, and even if all goes well, the time margins are very very tight, allowing for no delays of any kind.

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SLS begins trip back to Vehicle Assembly Building

9:12 am

NASA’s SLS rocket today began its long slow journey from the launchpad back to Vehicle Assembly Building (VAB) so that engineers can safely troubleshoot the failure of helium to properly flow into the tanks of the rocket’s upper stage following the dress rehearsal countdown last week.

NASA’s SLS (Space Launch System) rocket and Orion spacecraft for the Artemis II mission began rolling off the launch pad at 9:38 a.m. EST, Feb. 25, at NASA’s Kennedy Space Center in Florida.

Rolling from Launch Pad 39B to the Vehicle Assembly Building at NASA Kennedy is expected to take up to 12 hours.

At this time NASA officials have not yet determined whether they will need another wet dress rehearsal countdown. There are concerns however that the movement to and from the VAB might be contributing to the fuel leaks that have plagued previous rehearsals and countdowns, and if so, those concerns almost guarantee the need to do another countdown rehearsal once the helium issue is fixed and the rocket is back on the launchpad.

Officials are also reviewing potential future launch dates both in late April as well as May and June. The present window closes on April 6, though there is one launch opportunity on April 30th. Nothing has been decided as yet.

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NASA to return SLS to assembly building tomorrow Wednesday

9:10 am

UPDATE: Due to weather, the roll back to the VAB is now delayed until Wednesday, February 25, 2026.

Original post:
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According to its most recent update, NASA is now planning on rolling its SLS rocket back to the Vehicle Assembly Building (VAB) no sooner than tomorrow, February 24, 2026, in order to begin its investigation into the helium flow issue in the rocket’s upper stage that has now delayed any launch until April at the earliest.

Returning to the Vehicle Assembly Building at Kennedy is required to determine the cause of the issue and fix it.

Teams are reviewing the exact time to begin the approximately 4 mile, multi-hour trek. The quick work to begin preparations for rolling the rocket and spacecraft back to the VAB potentially preserves the April launch window, pending the outcome of data findings, repair efforts, and how the schedule comes to fruition in the coming days and weeks.

The present launch window closes on April 6, 2026. For a launch to occur, NASA engineers need to identify and fix the flow issue. They will also need to test it, which suggests they will have to do some form of fueling test once the rocket is returned to the launchpad.

All of this takes time. First we have one week to get back to the VAB. Then at least a full two weeks in the VAB to identify and fix the upper stage. Then another week to roll the rocket back to the launch pad. And then another week to do another fueling test on the launchpad. That brings us to the beginning of April.

In other words, NASA has no time margin at all. If anything takes just a little longer than planned, it will not make the April launch window.

None of this is a surprise. SLS in its first launch attempt in 2022 missed its spring launch window due to similar issues and ended up launching six months later (after more launch scrubs). I predicted it would happen again now. NASA at this moment has not revealed any later launch windows, so we don’t yet know how long a delay to expect if it misses this window. Based on 2022, I suspect the delay would be until the fall.

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Problem pops up during SLS roll back after wet dress rehearsal countdown

9:33 am

Not so fast! According to an update posted by NASA today, during the process to roll back the SLS rocket from the launchpad following the wet dress rehearsal countdown two days ago, crews suddenly detected “interrupted helium flow” in the upper stage that appears to be of some concern.

NASA is taking steps to potentially roll back the Artemis II rocket and Orion spacecraft to the Vehicle Assembly Building (VAB) at the agency’s Kennedy Space Center in Florida after overnight Feb. 21 observing interrupted flow of helium in the SLS (Space Launch System) rocket’s interim cryogenic propulsion stage. Helium flow is required for launch.

Teams are actively reviewing data, and taking steps to enable rollback positions for NASA to address the issue as soon as possible while engineers determine the best path forward. In order to protect for troubleshooting options at both Pad B and the VAB, teams are making preparations to remove the pad access platforms installed yesterday, which have wind-driven constraints and cannot be removed during high winds, which are forecasted for tomorrow. This will almost assuredly impact the March launch window. NASA will continue to provide updates. [emphasis mine]

The helium flow is likely used to fill the tanks as the actual and dangerous fuel is pumped out. They need to drain those tanks in order to roll the rocket from the launchpad. If it has stopped flowing, it means they can’t drain the tanks as planned.

During launch the helium is also likely pumped into the tanks to maintain pressure as the fuel burns. If during launch the helium stopped flowing it would almost certainly result in a failed launch.

This issue not only impacts the tentative March 6th launch date that NASA announced yesterday, if a fix is not found quickly it almost certainly means no launch can occur before this launch window closes on April 6th.

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NASA today completes SLS wet dress rehearsal with few problems

8:35 pm

NASA today successfully completed its SLS wet dress rehearsal countdown with few problems, fueling the rocket completely and then running the countdown down to T-33 seconds and then recycling back to T-10 minutes and running the countdown down again, this time to T-29 seconds.

During the day-long event there were only two minor issues, neither of significance. Early in the day there was “an issue with ground communications” that required mission control to shift to “backup communication methods” for about a half hour before the issue was resolved.

Then, during the first countdown to T-33 the count was paused and recycled once “due to a booster avionics system voltage anomaly.” This also appeared to be minor issue quickly resolved.

NASA will hold a press conference tomorrow at 11 am (Eastern) to discuss the results of the entire rehearsal.

NASA administrator Jared Isaacman had stated previously that he needed to see a perfect rehearsal before he would approve the launch of Artemis-2, carrying four astronauts on a ten-day mission around the Moon. While today’s rehearsal was not “perfect,” the issues were very minor. I suspect he will give the okay, with a tentative launch date of March 6, 2026 already being considered. The present launch window closes on April 6, 2026.

That mission, should it fly, still carries enormous risk. The Orion capsule will be using a life support system never tested in space before. It will also be using a heat shield that is questionable, having failed to behave as expected in the first Artemis mission in 2022.

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NASA now targeting February 19, 2026 for 2nd SLS wet dress rehearsal countdown

8:20 am

According to an announcement yesterday afternoon, NASA is now targeting February 19, 2026 for the second SLS wet dress rehearsal countdown.

During the rehearsal, the team will execute a detailed countdown sequence. Operators will conduct two runs of the last ten minutes of the countdown, known as terminal count. They will pause at T-1 minute and 30 seconds for up to three minutes, then resume until T-33 seconds before launch and pause again. After that, they will recycle the clock back to T-10 minutes and conduct a second terminal countdown to just inside of T-30 seconds before ending the sequence. This process simulates real-world conditions, including scenarios where a launch might be scrubbed due to technical or weather issues.

If this dress rehearsal goes off perfectly, NASA is considering the possibility of an actual launch attempt on March 6, 2026, though it admits that date is very preliminary That launch will carry four astronauts on a ten-day mission slingshot around the Moon and back to Earth, using an Orion capsule with untested life support system and a questionable heat shield.

The present launch window for this mission closes on April 6th, so NASA’s margins will shrink considerably if this second dress rehearsal has any further problems.

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NASA testing SLS fuel leak repairs; UPDATE: Problems!

10:33 am

UPDATE: NASA posted a late update today describing vaguely the results of this fueling test, and revealed that while the test of the replacement seals appeared to go well, there were other problems:

During the test, teams encountered an issue with ground support equipment that reduced the flow of liquid hydrogen into the rocket. … Engineers will purge the line over the weekend to ensure proper environmental conditions and inspect the ground support equipment before replacing a filter suspected to be the cause of the reduced flow.

In other words, the SLS fueling system is like playing whack-a-mole. You fix one problem, and others show up.

I predicted this. It remains entirely possible NASA will not be able to complete a perfect full wet-dress rehearsal countdown in time to launch before April 6th, when this present launch window closes.

Original post:
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NASA yesterday did an unannounced test fueling of its SLS rocket to check out the repairs in the fueling system.

NASA is loading liquid hydrogen aboard its Space Launch System moon rocket at the Kennedy Space Center on Thursday for an unpublicized but crucial test of the repairs made to a leaky umbilical that derailed a countdown rehearsal on Feb. 2.

The operation to load liquid hydrogen into the huge fuel tank on the rocket’s core stage was thought to be already underway at launch complex 39B on Thursday morning. The test will determine if new seals installed in the launch pad umbilical are working. “As part of our work to assess the repair we made in the area where we saw elevated hydrogen gas concentrations during the previous wet dress rehearsal, engineers are testing the new seals by running some liquid hydrogen across the interface and partially filling the core stage liquid hydrogen tank. The data will inform the timeline for our next wet dress rehearsal,” a NASA spokesperson said about the previously unannounced test.

If the new seals work on these fueling tests, another full dress rehearsal countdown could take place as early as next week.

Posting is going to very light for the rest of the day. I am fighting a bad head cold and just want to go back to bed.

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NASA provides update on Artemis-2 repairs for future dress rehearsal countdown

8:01 am

NASA late last night posted an update describing the fuel leak repair work taking place in advance of a second dress rehearsal countdown prior to the launch of the manned ten-day Artemis-2 mission around the Moon.

While teams continue evaluating the cause of the leak, reconnecting the interfaces is expected to be complete on Monday, Feb. 9. Testing is planned to occur at NASA’s Stennis Space Center in Bay St. Louis, Mississippi, to evaluate additional dynamics of the plates. Engineers are reviewing options to test the repair work prior to the next wet dress rehearsal to ensure the seals are performing as expected.

NASA also will update several operations for the next wet dress rehearsal to focus on fueling activities. The Orion crew module hatch will be closed prior to the test, and the closeout crew responsible on launch day for assisting the Artemis II crew into their seats and closing Orion’s two hatches will not be deployed to the launch pad. The crew access arm will not be retracted during the next rehearsal, after engineers successfully demonstrated the ground launch sequencer can retract it during the final phase of the countdown.

Additionally, NASA has added 30 minutes of extra time during each of two planned holds in the countdown before and after tanking operations to allow more time for troubleshooting, increasing the total time of the countdown by one hour. The additional time will not affect the crew’s timeline on launch day.

In other words, the next rehearsal will focus almost entirely on fueling to make sure these issues are resolved.

The agency however has not set a date for that countdown rehearsal. To launch in March, as presently planned, it must occur sometime in the next three weeks, and go perfectly. Otherwise that launch will slip again, and begin to bump up against the end of the launch window on April 6th.

Right now I am betting that second rehearsal will not go perfectly, as this was SLS’s track record leading up to November 2022 first launch. It took five countdowns before the agency was able to get the rocket off the ground without issues.

And if it does go perfectly and Artemis-2 is launched manned, it is essential to note again that it will be flying a manned capsule with a questionable heat shield and an untested life support system.

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Isaacman: SLS stands on very thin ice

2:46 pm

Though NASA administration Jared Isaacman continues to support unequivocally NASA’s planned Artemis-2 ten-day manned mission around the Moon — presently targeting a March launch date — in a statement today on X he revealed that he also recognizes the serious limitations of the SLS rocket.

And it takes two-plus years between launches
And it also takes two-plus years between launches

The Artemis vision began with President Trump, but the SLS architecture and its components long predate his administration, with much of the heritage clearly traced back to the Shuttle era. As I stated during my hearings, and will say again, this is the fastest path to return humans to the Moon and achieve our near-term objectives through at least Artemis V, but it is not the most economic path and certainly not the forever path.

The flight rate is the lowest of any NASA-designed vehicle, and that should be a topic of discussion. It is why we undertake wet dress rehearsals, Pre-FRR, and FRR, and why we will not press to launch until we are absolutely ready.

These comments were also in connection with the first wet dress rehearsal countdown that NASA performed with SLS/Orion in the past few days, a rehearsal that had to be terminated early because of fuel leaks. NASA now plans to do another wet dress rehearsal, requiring it to push back the Artemis-2 launch until March.

I think there is more going on here than meets the eye.
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NASA makes right decision and delays Artemis-2 launch to do a 2nd dress rehearsal countdown

8:53 am

Artemis Program logo

NASA management announced today that it has decided to postpone the launch of the manned Artemis-2 mission around the Moon until March in order to give it time to do a second wet dress rehearsal countdown of the rocket and fix the hydrogen fuel leaks that occurred in yesterday’s rehearsal.

Engineers pushed through several challenges during the two-day test and met many of the planned objectives. To allow teams to review data and conduct a second wet dress rehearsal, NASA now will target March as the earliest possible launch opportunity for the flight test.

Moving off a February launch window also means the Artemis II astronauts will be released from quarantine, which they entered in Houston on Jan. 21. As a result, they will not travel to NASA’s Kennedy Space Center in Florida Tuesday as tentatively planned. Crew will enter quarantine again about two weeks out from the next targeted launch opportunity.

It should be understood that these hydrogen leaks have been systemic to SLS’s core stage rocket engines, which come from the shuttle era. Shuttle launches were routinely delayed due to similar leaks. This was partly because hydrogen is extremely difficult to control, as its atom is so small and light, and partly because of the engine design. This was the first rocket system ever to use hydrogen as fuel, and was thus cutting edge, in the 1970s. We should not be surprised by such issues.

Newer hydrogen-fueled designs have apparently overcome the problem. For example, Blue Origin uses hydrogen as a fuel in the upper stage of its New Glenn rocket, and though it has only launched twice, it has not had such issues on either launch.

In its announcement NASA also noted a bunch of other issues that occurred during this first rehearsal, all of which suggest that a delay is called for. There was a valve issue in the Orion capsule, some audio communication channels kept dropping out, and the cold weather affected some equipment. Waiting until warmer weather will help alleviate some of this.

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Fuel leaks cause Artemis-2 dress rehearsal countdown to terminate at T-5:15, several minutes early

11:15 pm

Artemis Program logo

Two hydrogen fuel leaks during today’s Artemis-2 dress rehearsal countdown forced an early termination of the count as well as the cancellation of a second practice countdown.

The Artemis II wet dress rehearsal countdown was terminated at the T-5:15 minute mark due to a liquid hydrogen leak at the interface of the tail service mast umbilical, which had experienced high concentrations of liquid hydrogen earlier in the countdown, as well. The launch control team is working to ensure the SLS (Space Launch System) rocket is in a safe configuration and begin draining its tanks.

An earlier leak of hydrogen in the count forced a hold and a recycling of the count, though it did not stop the rehearsal.

The initial plan had been to do two terminal counts. First they would run the countdown down to T-33 seconds, hold for a few minutes, then recycle back to T-10 minutes and do it again. Because of that first leak delay the launch director canceled the second count. And because of the second leak they were unable to run that one count all the way to T-33 seconds.

The wise action would be for NASA to review their data, figure out what caused the leaks, correct it, and then do another dress rehearsal countdown. This being NASA, do not be surprised if they review the data, figure out what caused the leaks, and decide they can go ahead with the launch on February 8, 2026.

Why not? They are already launching this manned 10-day mission around the Moon with an untested life support system and a questionable heat shield. Might as well try a launch when you haven’t worked out all the fueling kinks.

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NASA delays Artemis-2 wet dress rehearsal countdown due to weather

9:30 am

NASA today announced it is delaying until February 2, 2026 the wet dress rehearsal countdown of its Artemis-2 mission due to weather concerns.

NASA is targeting Monday, Feb. 2, as the tanking day for the upcoming Artemis II wet dress rehearsal at the agency’s Kennedy Space Center in Florida, as a result of weather. With this change, the first potential opportunity to launch is no earlier than Sunday, Feb. 8.

Over the past several days, engineers have been closely monitoring conditions as cold weather and winds move through Florida. Managers have assessed hardware capabilities against the projected forecast given the rare arctic outbreak affecting the state and decided to change the timeline. Teams and preparations at the launch pad remain ready for the wet dress rehearsal. However, adjusting the timeline for the test will position NASA for success during the rehearsal, as the expected weather this weekend would violate launch conditions.

I had previously said this dress rehearsal countdown would include the astronauts inside Orion. This was incorrect. The astronauts are in quarantine in preparation for the actual mission. Orion will be unmanned during the rehearsal countdown.

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Artemis-2 proves NASA learned nothing from the Challenger and Columbia failures

9:56 am

NASA: an agency still avoiding reality
NASA: an agency that still avoids reality

Our bankrupt new media continues to fail us. NASA is about to send four astronauts on a ten-day mission around the Moon in a capsule with questionable engineering, and that media continues to ignore the problem. Mainstream news outlets continue to describe the mission in glowing terms, consistently ignoring that questionable engineering. In some cases the stories even make believe NASA has fixed the problem, when it has not.

The most ridiculous example is an article yesterday from an Orlando outlet, Spectrum New 13: “How the lessons learned from the Challenger disaster apply to Artemis rockets”. It focuses entirely on the O-ring problem that destroyed Challenger, noting repeatedly that NASA has fixed this issue in its SLS rocket.

Of course it has. That’s the last war, long over. Engineers fixed this issue almost four decades ago. The article however dismisses entirely the new engineering concern of today, Orion’s heat shield, which did not work as expected during its own test flight in space in 2022. It covers this issue with this single two-sentence paragraph:

However, during re-entry, it broke up into chunks instead of burning away. This issue pushed back the Artemis II and III missions, but NASA has stated it has resolved the problem.

NASA however has not resolved the problem. It is using the same heat shield now on this manned mission, and really has no reason to assume it will work any better, even if the agency has changed the re-entry flight path in an effort to mitigate the heat shield’s questionable design.

You see, NASA with Artemis-2 is doing the exact same thing it did prior to both the Challenger and Columbia accidents. » Read more

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NASA targeting January 31, 2026 for Artemis-2 dress rehearsal countdown

8:25 am

The flight plan for the Artemis-2 mission around the Moon
The flight plan for the Artemis-2 mission around the Moon. Click for original.

NASA engineers are now targeting January 31, 2026 for the manned dress rehearsal countdown of the Artemis-2 SLS rocket and Orion capsule.

The upcoming wet dress rehearsal is a prelaunch test to fuel the rocket. During the rehearsal, teams demonstrate the ability to load more than 700,000 gallons of cryogenic propellants into the rocket, conduct a launch countdown, and practice safely removing propellant from the rocket without astronauts inside the spacecraft.

During several “runs,” the wet dress rehearsal will test the launch team’s ability to hold, resume, and recycle to several different times in the final 10 minutes of the countdown, known as terminal count. The rehearsal will count down to a simulated launch at 9 p.m. EST, but could run to approximately 1 a.m. if needed.

This rehearsal will include the four-person crew inside the Orion capsule, which will once launched take them in a wide ten-day Earth orbit that will swing them past the Moon and then back to Earth. The crew entered quarantine at the end of last week to reduce the chance they will catch any illnesses prior to launch.

This mission carries great risk, as the capsule’s life support system has never been used in space before, while the viability of its heat shield remains questionable.

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Isaacman makes it official: Artemis-2 will fly manned around the Moon, despite Orion’s heat shield concerns

8:01 am

Orion's damage heat shield
Damage to Orion heat shield caused during re-entry in 2022,
including “cavities resulting from the loss of large chunks”

In a tweet yesterday afternoon, NASA administration Isaacman essentially endorsed the decision of the NASA managers and engineers in its Artemis program who decided they could live with the engineering issues of Orion’s heat shield (as shown in the image to the right) and fly the upcoming Artemis-2 mission around the Moon carrying four astronauts with that same heat shield design.

Isaacman’s statement however suggests to me that he is not looking at this issue as closely as he should.

Human spaceflight will always involve uncertainty. NASA’s standard engineering process is to identify it early, bound the risk through rigorous analysis and testing, and apply operational mitigations that preserve margin and protect the crew. That process works best when concerns are raised early and debated transparently.

I appreciate the willingness of participants to engage on this subject, including former NASA astronaut Danny Olivas, whose perspective reflects how serious technical questions can be addressed through data, analysis, testing, and decisions grounded in the best engineering judgment available. [emphasis mine]

The highlighted sentence is fundamentally incorrect. » Read more

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Former astronaut once again blasts NASA decision to fly Artemis-2 manned

10:13 am

Charles Camarda on the shuttle
Charles Camarda on the first shuttle flight
after the Columbia failure.

The opposition to NASA’s decision to fly humans in the Orion capsule around the Moon with a questionable heat shield continues. Charles Camarda, an engineer and former NASA astronaut who has repeatedly expressed concerns about that heat shield and had been invited to attend the review meeting that NASA administrator Isaacman had arranged to ease his concerns, has now revealed his concerns were not eased in the slightest by that meeting, and that the Ars Technica article by Eric Berger that suggested otherwise was wrong, and that he is still “outraged” at NASA’s bad engineering decisions.

The rage you witnessed was my observing the exact behaviors used to construct risk and flight rationale which caused both Challenger and Columbia Accidents. Using “tools” inappropriately and then claiming results to be “Conservative.” Not to mention the reliance on Monte Carlo simulations to predict failure probabilities which were also proven to be inaccurate by orders of magnitude in my book “Mission Out of Control” which you claim to have read.

I suggest, in the spirit of transparency, you should ask NASA to release just the “Findings” of NESC Report TI-23-01849 Volume I. Finding 1 states the analysis cannot accurately predict crack initiation and propagation at flight conditions. And there was so much more which was conveniently not presented.

In other words, he finds NASA’s engineering claims that Orion’s heat shield will work using a different less stressful return trajectory as it dives back into the atmosphere about 25,000 mph to be false and untrustworthy. Worse, he sees it as proof that this is a continuation of the same culture at NASA that resulted in the Columbia failure.

Some of the exact same people responsible for failing to understand the shortcomings of the Crater Analysis tool (used tiny pieces of foam impacts to Shuttle tiles to predict a strike from a piece of foam which was 6000 larger and which caused the Columbia Accident) were on the Artemis Tiger Team now claiming they could predict the outcome of the Orion heatshield using a tool (similar to CRATER) called the Crack Identification Tool (CIT) which was also not physics based and relied on predictions of the key paramenter, permeability, which they claim to be the “root” cause, pressure, to vary by three orders of magnitude (that’s over 1000x).

In defense of NASA, those engineers had also presented data that showed Orion’s hull was strong enough to survive re-entry, even if the heat shield failed entirely. It is unclear if Camarda’s objections here apply to that data as well.

Regardless, his strong public disagreement with NASA on this once again raises serious questions about the upcoming manned Artemis-2 mission, set to launch sometime in the February to March time frame.

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An outline of NASA’s present schedule leading up to the Artemis-2 manned lunar fly-by mission

8:11 am

Link here. The mission will slingshot four astronauts around the Moon and back to Earth. The update includes lots of details about the rollout, the dress rehearsal countdown, the follow-up, and finally the various launch windows and the requirements that determine them.

This paragraph however about those requirements struck me:

The launch day and time must allow SLS to be able to deliver Orion into a high Earth orbit where the crew and ground teams will evaluate the spacecraft’s life support systems before the crew ventures to the Moon.

That life support system will be making its first flight in space, with four humans as the guinea pigs. Though this is another example of NASA putting schedule ahead of safety (the system should have flown at least once unmanned), it does indicate the agency recognizes the risk it is taking, and has added this extra longer orbit to give engineers time to test the system.

There are three launch windows, within which there are only five available launch dates:

January 31 to February 14 (February 6, 7, 8, 10, and 11)
February 28 to March 13 (March 6, 7, 8, 9, 11)
March 27 to April 10 (April 1, 3, 4, 5, 6)

In 2022, once NASA managers chose their first launch window, they were able to get the rocket off on the first attempt. There were no scrubs or aborts, though prior to that attempt the launch date was delayed numerous time over five years. Based on that past history, it is likely the agency will succeed on its first attempt in February, barring weather issues.

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Isaacman okays flying Artemis-2 manned, despite heat shield questions

1:53 pm

According to an article posted today at Ars Technica, after a thorough review NASA administrator Jared Isaacman has decided to allow the Artemis-2 mission — set to launch sometime before April and slingshot around the Moon — to fly manned with four astronauts despite the serious questions that still exist about its heat shield.

The review involved a long meeting at NASA with NASA engineers, several outside but very qualified critics, as well as two reporters (for transparency).

Convened in a ninth-floor conference room at NASA Headquarters known as the Program Review Center, the meeting lasted for more than three hours. Isaacman attended much of it, though he stepped out from time to time to handle an ongoing crisis involving an unwell astronaut on orbit. He was flanked by the agency’s associate administrator, Amit Kshatriya; the agency’s chief of staff, Jackie Jester; and Lori Glaze, the acting associate administrator for NASA’s Exploration Systems Development Mission Directorate. The heat shield experts joined virtually from Houston, along with Orion Program Manager Howard Hu.

Isaacman made it clear at the outset that, after reviewing the data and discussing the matter with NASA engineers, he accepted the agency’s decision to fly Artemis II as planned. The team had his full confidence, and he hoped that by making the same experts available to Camarda and Olivas, it would ease some of their concerns.

My readers know that I have been strongly opposed to flying Artemis-2 manned, an opposition I expressed in an op-ed at PJMedia only yesterday. However, after reading this Ars Technica report, my fears are allayed somewhat by this quote:
» Read more

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Zimmerman Op-Ed at PJ Media

7:50 pm

Orion's damage heat shield
Damage to Orion heat shield caused during re-entry in 2022,
including “cavities resulting from the loss of large chunks”

PJ Media this evening published an op-ed I prepared this week in a last desperate effort to convince both President Trump and NASA administrator Jared Isaacman to rethink the manned nature of the Artemis-2 mission scheduled to launch sometime in the next three months.

President Trump and NASA Administrator Isaacman: Please Take the Crew Off of Artemis II

Nothing I say in this op-ed will be unfamiliar to my readers. I choose to farm it to PJ Media because I wanted it to get as much exposure as possible. As big as my audience is becoming, from 4 to 6 million hits per month, PJ Media has a wider reach.

I also decided in the op-ed to make no general arguments against SLS or Orion. Though my opposition to them is long standing and well known, this is not the time to fight that battle. My goal was simply to get NASA to put engineering ahead of schedule, so as to avoid the possibility of it repeating another Apollo 1 fire or Challenger accident.

I doubt at this point this op-ed will make a difference, but to paraphrase a quote written by Gordon Dickson in his wonderful science fiction book Way of the Pilgrim, there was a hand pushing me from behind, forcing me forward. I had no choice. The image of Orion’s heat shield to the right, after the 2022 return from the Moon, required action.

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New Trump executive order today guarantees major changes coming to NASA’s Moon program

4:51 pm

Change is coming to Artemis!
Change is coming to Artemis!

The White House today released a new executive order that has the typically grand title these type of orders usually have: “Ensuring American Space Superiority”. That it was released one day after Jared Isaacman was confirmed as NASA administrator by the Senate was no accident, as this executive order demands a lot of action by him, with a clear focus on reshaping and better structuring the entire manned exploration program of the space agency.

The order begins about outlining some basic goals. It demands that the U.S. return to the Moon by 2028, establish the “initial elements” a base there by 2030, and do so by “enhancing sustainability and cost-effectiveness of launch and exploration architectures, including enabling commercial launch services and prioritizing lunar exploration.” It also demands this commercial civilian exploration occur in the context of American security concerns.

Above all, the order demands that these goals focus on “growing a vibrant commercial space economy through the power of American free enterprise,” in order to attract “at least $50 billion of additional investment in American space markets by 2028, and increasing launch and reentry cadence through new and upgraded facilities, improved efficiency, and policy reforms.”

To achieve these goals, the order then outlines a number of actions required by the NASA administrator, the secretaries of Commerce, War, and State, as well as the Director of the Office of Management and Budget (OMB) and the Assistant to the President for Domestic Policy (APDP), all coordinated by the assistant to the President for Science and Technology (APST).

All of this is unsurprising. Much of it is not much different than the basic general space goals that every administration has touted for decades. Among this generality however was one very specific item, a demand to complete within 90 days the following review:
» Read more

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House hearing on Artemis yesterday signals strong doubts about the program in Congress

10:54 am

Artemis logo

The space subcommittee of the House Science, Space, and Technology Committee yesterday held a hearing on space, one day after the Senate held its own hearing on the nomination of Jared Isaacman as NASA administrator.

The House hearing however was not about Isaacman, but was apparently staged to highlight what appears to be strong reservations within Congress about NASA’s Artemis program, as presently structured. Its timing, just after the Isaacman hearing, was clearly aimed at garnering as much publicity as possible.

Video of the hearing can be seen here.

The focus of the hearing was also on China, and how there is real fear in Congress that its space program is outstripping NASA’s. Both the Republican committee chairman and the ranking Democrat stressed these concerns, and the need to beat China to the Moon and beyond.

More important, all four witnesses pushed the same point.

The rallying cry at this hearing as well as yesterday’s is the “race” with China.

…Foushee asked each of the witnesses for one-word answers to the question: is NASA on track to get back to the Moon before Chinese taikonauts arrive?

Not all succeeded with one word, but their sentiment was similar. Cheng replied “no, I am very pessimistic.” Swope: “worried.” Besha: “maybe.” Griffin: “no possible way…with the present plan.”

Former NASA administrator Mike Griffin was the most blunt in his criticism of NASA.
» Read more

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