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The fastest human spaceflight mission in history crawls closer to liftoff


After a remarkably smooth launch campaign, Artemis II reached its last stop before the Moon.

NASA’s Space Launch System rocket rolls to Launch Complex 39B on Saturday. Credit: Stephen Clark/Ars Technica

KENNEDY SPACE CENTER, Florida—Preparations for the first human spaceflight to the Moon in more than 50 years took a big step forward this weekend with the rollout of the Artemis II rocket to its launch pad.

The rocket reached a top speed of just 1 mph on the four-mile, 12-hour journey from the Vehicle Assembly Building to Launch Complex 39B at NASA’s Kennedy Space Center in Florida. At the end of its nearly 10-day tour through cislunar space, the Orion capsule on top of the rocket will exceed 25,000 mph as it plunges into the atmosphere to bring its four-person crew back to Earth.

“This is the start of a very long journey,” said NASA Administrator Jared Isaacman. “We ended our last human exploration of the moon on Apollo 17.”

The Artemis II mission will set several notable human spaceflight records. Astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen will travel farther from Earth than any human in history. They won’t land. That distinction will fall to the next mission in line in NASA’s Artemis program.

But the Artemis II astronauts will travel more than 4,000 miles beyond the far side of the Moon (the exact distance depends on the launch date), setting up for a human spaceflight speed record during their blazing reentry over the Pacific Ocean a few days later. Koch will become the first woman to fly to the vicinity of the Moon, and Hansen will be the first non-US astronaut to do the same.

“We really are ready to go,” said Wiseman, the Artemis II commander, during Saturday’s rollout to the launch pad. “We were in a sim [in Houston] for about 10 hours yesterday doing our final capstone entry and landing sim. We got in T-38s last night and we flew to the Cape to be here for this momentous occasion.”

The rollout began around sunrise Saturday, with NASA’s Space Launch System rocket and Orion capsule riding a mobile launch platform and a diesel-powered crawler transporter along a throughway paved with crushed Alabama river rock. Employees, VIPs, and guests gathered along the crawlerway to watch the 11 million-pound stack inch toward the launch pad. The rollout concluded about an hour after sunset, when the crawler transporter’s jacking system lowered the mobile launch platform onto pedestals at Pad 39B.

Hitting the launch window

The rollout keeps the Artemis II mission on track for liftoff as soon as next month, when NASA has a handful of launch opportunities on February 6, 7, 8, 10, and 11.

The big milestone leading up to launch day will be a practice countdown or Wet Dress Rehearsal (WDR), currently slated for around February 2, when NASA’s launch team will pump more than 750,000 gallons of super-cold liquid hydrogen and liquid oxygen into the rocket. NASA had trouble keeping the cryogenic fluids at the proper temperature, then encountered hydrogen leaks when the launch team first tried to fill the rocket for the unpiloted Artemis I mission in 2022. Engineers implemented the same fixes on Artemis II that they used to finally get over the hump with propellant loading on Artemis I.

So, what are the odds NASA can actually get the Artemis II mission off the ground next month?

“We’ll have to have things go right,” said Matt Ramsey, NASA’s Artemis II mission manager, in an interview with Ars on Saturday. “There’s a day of margin there for weather. There’s some time after WDR that we’ve got for data reviews and that sort of thing. It’s not unreasonable, but I do think it’s a success-oriented schedule.”

The Moon has to be in the right position in its orbit for the Artemis II launch to proceed. There are also restrictions on launch dates to ensure the Orion capsule returns to Earth and reenters the atmosphere at an angle safe for the ship’s heat shield. If the launch does not happen in February, NASA has a slate of backup launch dates in early March.

Ars was at Kennedy Space Center for the rocket’s move to the launch pad Saturday. The photo gallery below shows the launcher emerging from the Vehicle Assembly Building, the same facility once used to stack Saturn V rockets during the Apollo Moon program. The Artemis II astronauts were also on hand for a question and answer session with reporters.

Around the clock

The first flight of astronauts on the SLS rocket and Orion spacecraft is running at least five years late. The flight’s architecture, trajectory, and goals have changed multiple times, and technical snags discovered during manufacturing and testing repeatedly shifted the schedule. The program’s engineering and budgetary problems are well documented.

But the team readying the rocket and spacecraft for launch has hit a stride in recent months. Technicians inside the Vehicle Assembly Building started stacking the SLS rocket in late 2024, beginning with the vehicle’s twin solid-fueled boosters. Then ground teams added the core stage, upper stage, and finally installed the Orion spacecraft on top of the rocket last October.

Working nearly around the clock in three shifts, it took about 12 months for crews at Kennedy to assemble the rocket and prepare it for rollout. But the launch campaign inside the VAB was remarkably smooth. Ground teams shaved about two months off the time it took to integrate the SLS rocket and Orion spacecraft for the Artemis I mission, which launched on the program’s first full-up unpiloted test flight in 2022.

“About a year ago, I was down here and we set the rollout date, and we hit it within a day or two,” said Matt Ramsey, NASA’s mission manager for Artemis II. “Being able to stay on schedule, it was a daily grind to be able to do that.”

Engineers worked through a handful of technical problems last year, including an issue with a pressure-assisted device used to assist the astronauts in opening the Orion hatch in the event of an emergency. More recently, NASA teams cleared a concern with caps installed on the rocket’s upper stage, according to Ramsey.

The most significant engineering review focused on proving the Orion heat shield is safe to fly. That assessment occurred in the background from the perspective of the technicians working on Artemis II at Kennedy.

The Artemis II team is now focused on activities at the launch pad. This week, NASA plans to perform a series of tests extending and retracting the crew access mark. Next, the Artemis II astronauts will rehearse an emergency evacuation from the launch pad. That will be followed by servicing of the rocket’s hydraulic steering system.

The big question mark

All of this leads up to the crucial practice countdown early next month. The astronauts won’t be aboard the rocket for the test, but almost everything else will look like launch day. The countdown will halt around 30 seconds prior to the simulated liftoff.

It took repeated tries to get through the Wet Dress Rehearsal for the Artemis I mission. There were four attempts at the countdown practice run before the first actual Artemis I launch countdown. After encountering hydrogen leaks on two scrubbed launch attempts, NASA performed another fueling test before finally successfully launching Artemis I in November 2022.

The launch team repaired a leaky hydrogen seal and introduced a gentler hydrogen loading procedure to overcome the problem. Hydrogen is an extremely efficient fuel for rockets, but its super-cold temperature and the tiny size of hydrogen molecules make it prone to leakage. The hydrogen feeds the SLS rocket’s four core stage engines and single upper stage engine.

“Artemis I was a test flight, and we learned a lot during that campaign getting to launch,” said Charlie Blackwell-Thompson, NASA’s Artemis II launch director. “The things that we’ve learned relative to how to go load this vehicle, how to load LOX (liquid oxygen), how to load hydrogen, have all been rolled in to the way in which we intend to load the Artemis II vehicle.”

NASA is hesitant to publicly set a target launch date until the agency gets through the dress rehearsal, but agency officials say a February launch remains feasible.

“We’ve held schedule pretty well getting to rollout today,” Isaacman said. “We have zero intention of communicating an actual launch date until we get through wet dress. But look, that’s our first window, and if everything is tracking accordingly, I know the teams are prepared, I know this crew is prepared, we’ll take it.”

“Wet dress is the driver to launch,” Blackwell-Thompson said. “With a wet dress that is without significant issues, if everything goes to plan, then certainly there are opportunities within February that could be achievable.”

One constraint that threw a wrench into NASA’s Artemis I launch campaign is no longer a significant factor for Artemis II. On Artemis I, NASA had to roll the rocket back to the Vehicle Assembly Building (VAB) after the wet dress rehearsal to complete final installation and testing on its flight termination system, which consists of a series of pyrotechnic charges designed to destroy the rocket if it flies off course and threatens populated areas after liftoff.

The US Space Force’s Eastern Range, responsible for public safety for all launches from Florida’s Space Coast, requires the flight termination system be retested after 28 to 35 days, a clock that started ticking last week before rollout. During Artemis I, technicians could not access the parts of the rocket they needed to in order to perform the retest at the launch pad. NASA now has structural arms to give ground teams the ability to reach parts higher up the rocket for the retest without returning to the hangar.

With this new capability, Artemis II could remain at the pad for launch opportunities in February and March before officials need to bring it back to the VAB to replace the flight termination system’s batteries, which still can’t be accessed at the pad.

Photo of Stephen Clark

Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

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Managers on alert for “launch fever” as pressure builds for NASA’s Moon mission

“Putting crew on the rocket and taking the crew around the Moon, this is going be our first step toward a sustained lunar presence,” Honeycutt said. “It’s 10 days [and] four astronauts going farther from Earth than any other human has ever traveled. We’ll be validating the Orion spacecraft’s life support, navigation and crew systems in the really harsh environments of deep space, and that’s going to pave the way for future landings.”

NASA’s 322-foot-tall (98-meter) SLS rocket inside the Vehicle Assembly Building on the eve of rollout to Launch Complex 39B.

Credit: NASA/Joel Kowsky

NASA’s 322-foot-tall (98-meter) SLS rocket inside the Vehicle Assembly Building on the eve of rollout to Launch Complex 39B. Credit: NASA/Joel Kowsky

There is still much work ahead before NASA can clear Artemis II for launch. At the launch pad, technicians will complete final checkouts and closeouts before NASA’s launch team gathers in early February for a critical practice countdown. During this countdown, called a Wet Dress Rehearsal (WDR), Blackwell-Thompson and her team will oversee the loading of the SLS rocket’s core stage and upper stage with super-cold liquid hydrogen and liquid oxygen propellants.

The cryogenic fluids, particularly liquid hydrogen, gave fits to the Artemis launch team as NASA prepared to launch the Artemis I mission—without astronauts—on the SLS rocket’s first test flight in 2022. Engineers resolved the issues and successfully launched the Artemis I mission in November 2022, and officials will apply the lessons for the Artemis II countdown.

“Artemis I was a test flight, and we learned a lot during that campaign getting to launch,” Blackwell-Thompson said. “And the things that we’ve learned relative to how to go load this vehicle, how to load LOX (liquid oxygen), how to load hydrogen, have all been rolled in to the way in which we intend to do for the Artemis II vehicle.”

Finding the right time to fly

Assuming the countdown rehearsal goes according to plan, NASA could be in a position to launch the Artemis II mission as soon as February 6. But the schedule for February 6 is tight, with no margin for error. Officials typically have about five days per month when they can launch Artemis II, when the Moon is in the right position relative to Earth, and the Orion spacecraft can follow the proper trajectory toward reentry and splashdown to limit stress on the capsule’s heat shield.

In February, the available launch dates are February 6, 7, 8, 10, and 11, with launch windows in the overnight hours in Florida. If the mission isn’t off the ground by February 11, NASA will have to stand down until a new series of launch opportunities beginning March 6. The space agency has posted a document showing all available launch dates and times through the end of April.

John Honeycutt, chair NASA’s Mission Management Team for the Artemis II mission, speaks during a news conference at Kennedy Space Center in Florida on January 16, 2026.

Credit: Jim Watson/AFP via Getty Images

John Honeycutt, chair NASA’s Mission Management Team for the Artemis II mission, speaks during a news conference at Kennedy Space Center in Florida on January 16, 2026. Credit: Jim Watson/AFP via Getty Images

NASA’s leaders are eager for Artemis II to fly. NASA is not only racing China, a reality the agency’s former administrator acknowledged during the Biden administration. Now, the Trump administration is pushing NASA to accomplish a human landing on the Moon by the end of his presidential term on January 20, 2029.

One of Honeycutt’s jobs as chair of the Mission Management Team (MMT) is ensuring all the Is are dotted and Ts are crossed amid the frenzy of final launch preparations. While the hardware for Artemis II is on the move in Florida, the astronauts and flight controllers are wrapping up their final training and simulations at Johnson Space Center in Houston.

“I think I’ve got a good eye for launch fever,” he said Friday.

“As chair of the MMT, I’ve got one job, and it’s the safe return of Reid, Victor, Christina, and Jeremy. I consider that a duty and a trust, and it’s one I intend to see through.”

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Is Orion’s heat shield really safe? New NASA chief conducts final review on eve of flight.


“That level of openness and transparency is exactly what should be expected of NASA.”

The Orion heat shield as seen after the Artemis I flight. Credit: NASA

The Orion heat shield as seen after the Artemis I flight. Credit: NASA

WASHINGTON, DC—This week, NASA’s new administrator, Jared Isaacman, said he has “full confidence” in the space agency’s plans to use the existing heat shield to protect the Orion spacecraft during its upcoming lunar mission.

Isaacman made the determination after briefings with senior leaders at the agency and a half-day review of NASA’s findings with outside experts.

“We have full confidence in the Orion spacecraft and its heat shield, grounded in rigorous analysis and the work of exceptional engineers who followed the data throughout the process,” Isaacman said Thursday.

Isaacman has previously indicated that reviewing the heat shield issue early in his tenure, especially with the Artemis II mission due to launch in as few as four weeks, was a top priority. He met with senior agency officials about the matter within hours of being sworn in on December 18.

The private astronaut and billionaire entrepreneur has also said there should be more public transparency at NASA.

Following the Artemis I mission in November 2022, NASA was roundly criticized for its opaque handling of damage to Orion’s heat shield. The seriousness of the problem was not disclosed for nearly a year and a half after the Artemis I mission, when NASA’s Inspector General finally published close-up images of char loss—chunks of ablative material at Orion’s base that were intended to protect the spacecraft during its return but had fallen away.

To address these concerns, NASA tapped an “independent review team” in April 2024 to assess the agency’s investigation of the heat shield. This group’s findings were finalized in December 2024, at which time NASA formally decided to fly the Artemis II mission with the existing heat shield. Although NASA held a news conference to discuss its conclusions, a publicly released copy of the independent review team’s report was heavily redacted, creating further doubt about the integrity of the process. Some notable critics assailed NASA’s decision to fly on the heat shield as is and decried the ongoing lack of transparency.

That is more or less where the matter stood until a few days before Christmas, when Isaacman officially became NASA administrator.

Transparency for the taxpayer

After taking the job in Washington, DC, Isaacman asked the engineers who investigated the heat shield issue for NASA, as well as the chair of the independent review team and senior human spaceflight officials, to meet with a handful of outside experts. These included former NASA astronauts Charles Camarda and Danny Olivas, both of whom have expertise in heat shields and had expressed concerns about the agency’s decision-making.

For the sake of transparency, Isaacman also invited two reporters to sit in on the meeting, me and Micah Maidenberg of The Wall Street Journal. We were allowed to report on the discussions without directly quoting participants for the sake of a full and open discussion.

The inspector general’s report, released on May 1, 2024, included new images of Orion’s heat shield.

Credit: NASA Inspector General

The inspector general’s report, released on May 1, 2024, included new images of Orion’s heat shield. Credit: NASA Inspector General

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.

What followed was a spirited discussion, with Camarda sparring regularly with the presenters and Olivas asking questions more infrequently. The engineering team in Houston, led by Luis Saucedo, went through dozens of charts and presented reams of data that had not been made public before.

“That level of openness and transparency is exactly what should be expected of NASA,” Isaacman said after the meeting.

“What if we’re wrong?”

Perhaps the most striking revelation was what the NASA engineers called “what if we’re wrong” testing.

At the base of Orion, there are 186 blocks of a material called Avcoat, individually attached to provide a protective layer that allows the spacecraft to survive the heating of atmospheric reentry. Returning from the Moon, Orion encounters temperatures of up to 5,000° Fahrenheit (2,760° Celsius). A char layer that builds up on the outer skin of the Avcoat material is supposed to ablate, or erode, in a predictable manner during reentry. Instead, during Artemis I, fragments fell off the heat shield and left cavities in the Avcoat material.

Work by Saucedo and others—including substantial testing in ground facilities, wind tunnels, and high-temperature arc jet chambers—allowed engineers to find the cause of gases becoming trapped in the heat shield, leading to cracking. This was due to the Avcoat material being “impermeable,” essentially meaning it could not breathe.

After considering several options, including swapping the heat shield out for a newer one with more permeable Avcoat, NASA decided instead to change Orion’s reentry profile. For Artemis II, it would return through Earth’s atmosphere at a steeper angle, spending fewer minutes in the environment where this outgassing occurred during Artemis I. Much of Thursday’s meeting involved details about how the agency reached this conclusion and why the engineers deemed the approach safe.

A test block of Avcoat undergoes heat pulse testing inside an arc jet test chamber at NASA’s Ames Research Center in California. The test article, configured with both permeable (upper) and non-permeable (lower) Avcoat sections for comparison, helped to confirm an understanding of the root cause of the loss of charred Avcoat material on Artemis I.

Credit: NASA

A test block of Avcoat undergoes heat pulse testing inside an arc jet test chamber at NASA’s Ames Research Center in California. The test article, configured with both permeable (upper) and non-permeable (lower) Avcoat sections for comparison, helped to confirm an understanding of the root cause of the loss of charred Avcoat material on Artemis I. Credit: NASA

However, toward the end of the meeting, the NASA team agreed to discuss something that “no one really liked to talk about.” This was an analysis of what would happen to Orion if large sections of the heat shield failed completely during Artemis II. Formally, this is known as a “damage tolerance evaluation,” the engineers said. Informally, it’s known as “What if we’re wrong.”

The Avcoat blocks, which are about 1.5 inches thick, are laminated onto a thick composite base of the Orion spacecraft. Inside this is a titanium framework that carries the load of the vehicle. The NASA engineers wanted to understand what would happen if large chunks of the heat shield were stripped away entirely from the composite base of Orion. So they subjected this base material to high energies for periods of 10 seconds up to 10 minutes, which is longer than the period of heating Artemis II will experience during reentry.

What they found is that, in the event of such a failure, the structure of Orion would remain solid, the crew would be safe within, and the vehicle could still land in a water-tight manner in the Pacific Ocean.

“We have the data to say, on our worst day, we’re able to deal with that if we got to that point,” one of the NASA engineers said.

Getting to “flight rationale”

The composite layer beneath the heat shield is intended to withstand a maximum temperature of 500° F during reentry. During Artemis I, the maximum temperature recorded, despite the persistent cracking and char loss, was 160°. So any crew on board would have been safe. Even so, the heat shield damage was a serious concern because the agency’s modeling did not predict it.

After more than two years of testing and analysis of the char loss issue, the NASA engineers are convinced that, by increasing the angle of Orion’s descent during Artemis II, they can minimize damage to the heat shield. During Artemis I, as the vehicle descended from about 400,000 to 100,000 feet, it was under a “heat load” of various levels for 14 minutes. With Artemis II, this time will be reduced to eight minutes.

Orion’s entry profile will be similar for the first two and a half minutes, but afterward, the Artemis II entry will undertake a bit of a higher heat load than Artemis I for a couple of minutes. All of the agency’s modeling and extensive arc jet testing indicate this will produce significantly less cracking in the Avcoat material.

Much of the discussion Thursday delved into the technical minutiae of heat shields, tamp planes (the process of packing Avcoat into blocks), early char loss, spallation, and more. The discourse also revealed that one test in 2019, three years before Artemis I, indicated hints of the char loss later observed in flight. But this finding was not unequivocal, nor did it throw up a huge red flag at the time, the NASA officials said.

Technicians inspect the heat shield for the Artemis II launch.

Credit: NASA

Technicians inspect the heat shield for the Artemis II launch. Credit: NASA

The message from Isaacman, Kshatriya, and other NASA officials at the meeting was clear. This heat shield was not perfect. If NASA knew several years ago what it knows now, the heat shield would be designed differently. It would be permeable to prevent the outgassing problems. Those changes are being incorporated into the Artemis III mission’s heat shield. There will be other tweaks to increase reliability.

Nevertheless, the agency is confident that flying the Artemis II heat shield on the revised profile is perfectly safe. In NASA jargon, such a rigorous justification that a space mission is safe to fly is known as flight rationale.

But why get to flight rationale at all? About 18 months ago, as the agency was narrowing in on the root cause of the heat shield issues, NASA’s leaders at the time, including Kshatriya, considered their options. They mulled the possibility of flying Artemis II in low-Earth orbit to test its life support equipment but not overly stress the heat shield. They thought about flying a second robotic mission around the Moon.

Perhaps most seriously, they considered moving forward with the Orion spacecraft (or at least its heat shield) that will be flown in Artemis III, which has permeable Avcoat, to be used for this mission. I asked Kshatriya on Thursday why they had not simply done this.

“We had considered ‘let’s just pull forward CSM 3 (the Artemis III spacecraft),’” he said, in part. “and essentially turn CSM 2 (Artemis II) either into a test article or something else. Again, CSM 3 has unique capabilities, docking systems on it, right? We didn’t have a docking mode for that mission (Artemis II). CSM 2 could not be retrofitted with the docking system because of the uniqueness of the tunnel. Really, CSM 2 is kind of uniquely a free return vehicle because of the way it was designed initially. So the mods that would have had to be made for (Artemis) II and III to do that swap would have been too odious, and we wouldn’t have gotten the learnings. And, you know, we’re trying to get up hill as quickly as we can.”

Given all of this, how should we feel about this flight rationale, with Artemis II potentially launching in early February?

Over the last 18 months, I have had many discussions with experts about this, from mid-level engineers and current and former astronauts to senior leaders. I know definitively that the four Artemis II astronauts, Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen, are comfortable with the decision. They did not feel that way at the beginning of the process. Wiseman, in particular, was quite skeptical. But they’ve been won over. Like almost everyone else who has reviewed NASA’s data at length, they accept the plan. Indeed, they are ready and eager to fly.

But what of the outside critics? That was the whole point of Thursday’s session. Could the NASA engineers convince Olivas and Camarda?

Yes, and maybe

Olivas flew two Space Shuttle missions in 2007 and 2009 and has an advanced degree in materials science from Rice University. Before this week’s meeting, he had not gone public with his heat shield concerns. But he has been talking to me and another space reporter, Robert Pearlman, for about a month now.

Olivas is very credible on these issues. He was asked by the NASA leadership in late 2023, before the independent review team was formally named, to provide a second set of eyes on the space agency’s heat shield work. He saw all of the investigative data in real time. Although not formally a member, he sat in on the review team’s meetings through 2024 before that process ended. Afterward, he had some lingering questions he felt were unresolved by that process. A few weeks ago, he told Pearlman and me he would be reluctant to fly on Orion. It was a stunning admission.

Isaacman appeared to take these concerns seriously. In advance of Thursday’s meeting, he engaged with Olivas to hear him out and share information about what NASA’s engineers had done over the last 18 months to resolve some of the independent review team’s questions. These included char loss very early in Orion’s reentry.

After Thursday’s meeting, Olivas told me he had changed his mind, expressing appreciation and admiration for the in-depth engineering work done by the NASA team. He would now fly on Orion.

Camarda, another former shuttle astronaut, was less effusive. He has been very public with his criticism of NASA’s handling of the Orion heat shield. He told me in December 2024 that the space agency and its leadership team should be “ashamed.” Unlike Olivas, however, he has been on the outside the whole time. NASA had kept Camarda, 73, at arm’s length, and he felt disrespected. Given his credentials—the aerospace engineer spent two decades working on thermal protection for the space shuttle and hypersonic vehicles–Camarda could be a potent voice of skepticism leading up to the Artemis II launch.

After the meeting, I asked Camarda whether he felt any better about flying crew on the Artemis II heat shield.

“I would never be happy accepting a workaround and flying something that I know is the worst version of that heat shield we could possibly fly and hoping that the workaround is going to fix it,” Camarda said. “What I really hope he [Isaacman] gets is that if we don’t get back to doing research at NASA, we’re not going to be able to help Starship solve their problems. We’ve got to get back to doing research.”

But Camarda was no longer the firebrand he was at the outset of the meeting. Near its end, in fact, he even thanked the leadership team for being brought in, read in on the data, and allowed to have his say.

Photo of Eric Berger

Eric Berger is the senior space editor at Ars Technica, covering everything from astronomy to private space to NASA policy, and author of two books: Liftoff, about the rise of SpaceX; and Reentry, on the development of the Falcon 9 rocket and Dragon. A certified meteorologist, Eric lives in Houston.

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NASA’s next Moonship reaches last stop before launch pad

The Orion spacecraft, which will fly four people around the Moon, arrived inside the cavernous Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida late Thursday night, ready to be stacked on top of its rocket for launch early next year.

The late-night transfer covered about 6 miles (10 kilometers) from one facility to another at the Florida spaceport. NASA and its contractors are continuing preparations for the Artemis II mission after the White House approved the program as an exception to work through the ongoing government shutdown, which began on October 1.

The sustained work could set up Artemis II for a launch opportunity as soon as February 5 of next year. Astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen will be the first humans to fly on the Orion spacecraft, a vehicle that has been in development for nearly two decades. The Artemis II crew will make history on their 10-day flight by becoming the first people to travel to the vicinity of the Moon since 1972.

Where things stand

The Orion spacecraft, developed by Lockheed Martin, has made several stops at Kennedy over the last few months since leaving its factory in May.

First, the capsule moved to a fueling facility, where technicians filled it with hydrazine and nitrogen tetroxide propellants, which will feed Orion’s main engine and maneuvering thrusters on the flight to the Moon and back. In the same facility, teams loaded high-pressure helium and ammonia coolant into Orion propulsion and thermal control systems.

The next stop was a nearby building where the Launch Abort System was installed on the Orion spacecraft. The tower-like abort system would pull the capsule away from its rocket in the event of a launch failure. Orion stands roughly 67 feet (20 meters) tall with its service module, crew module, and abort tower integrated together.

Teams at Kennedy also installed four ogive panels to serve as an aerodynamic shield over the Orion crew capsule during the first few minutes of launch.

The Orion spacecraft, with its Launch Abort System and ogive panels installed, is seen last month inside the Launch Abort System Facility at Kennedy Space Center, Florida. Credit: NASA/Frank Michaux

It was then time to move Orion to the Vehicle Assembly Building (VAB), where a separate team has worked all year to stack the elements of NASA’s Space Launch System rocket. In the coming days, cranes will lift the spacecraft, weighing 78,000 pounds (35 metric tons), dozens of stories above the VAB’s center aisle, then up and over the transom into the building’s northeast high bay to be lowered atop the SLS heavy-lift rocket.

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Once unthinkable, NASA and Lockheed now consider launching Orion on other rockets


“We’re trying to crawl, then walk, then run into our reuse strategy.”

The Orion spacecraft for the Artemis II mission, seen here with its solar arrays installed for flight, just prior to their enclosure inside aerodynamic fairings to protect them during launch. Credit: NASA/Rad Sinyak

The Orion spacecraft and Space Launch System rocket have been attached at the hip for the better part of two decades. The big rocket lifts, the smaller spacecraft flies, and Congress keeps the money rolling in.

But now there are signs that the twain may, in the not too distant future, split.

This is because Lockheed Martin has begun to pivot toward a future in which the Orion spacecraft—thanks to increasing reusability, a focus on cost, and openness to flying on different rockets—fits into commercial space applications. In interviews, company officials said that if NASA wanted to buy Orion missions as a “service,” rather than owning and operating the spacecraft, they were ready to work with the space agency.

“Our message is we absolutely support it, and we’re starting that discussion now,” said Anthony Byers, director of Strategy and Business Development for Lockheed Martin, the principal contractor for Orion.

This represents a significant change. Since the US Congress called for the creation of the Space Launch System rocket a decade and a half ago, Orion and this rocket have been discussed in tandem, forming the backbone of an expendable architecture that would launch humans to the Moon and return them to Earth inside Orion. Through cost-plus contracts, NASA would pay for the rockets and spacecraft to be built, closely supervise all of this, and then operate the vehicles after delivery.

Moving to a ‘services’ model

But the landscape is shifting. In President Trump’s budget request for fiscal year 2026, the White House sought to terminate funding for Orion and the SLS rocket after the Artemis III mission, which would mean there are just two flights remaining. Congress countered by saying that NASA should continue flying the spacecraft and rocket through Artemis V.

Either way, the writing on the wall seems pretty clear.

“Given the President’s Budget Request guidance, and what we think NASA’s ultimate direction will be, they’re going to need to move to a commercial transportation option similar to commercial crew and cargo,” Byers said. “So when we talk about Orion services, we’re talking about taking Orion and flying that service-based mission, which means we provide a service, from boots on the ground on Earth, to wherever we’re going to go and dock to, and then bringing the crew home.”

By contrast, there has been little movement on an effort to commercialize the rocket.

In 2022, Boeing, the contractor for the SLS core stage, and Northrop Grumman, which manufactures the side boosters, created “Deep Space Transport LLC” to build the rockets and sell them to NASA on a more services-based approach. However, despite NASA’s stated intent to award a launch services contract to Deep Space Transport by the end of 2023, no such contract has been given out. It appears that the joint venture to commercialize the SLS rocket is defunct. Moreover, there are no plans to modify the rocket for reuse.

Wanted: a heavy lift rocket

This appears to be one reason Lockheed is exploring alternative launch vehicles for Orion. If the spacecraft is going to be competitive on price, it needs a rocket that does not cost in excess of $2 billion per launch.

Orion has a launch mass, including its abort system, of 35 metric tons. The company has looked at rockets that could launch that much mass and boost it to the Moon, as well as alternatives that might see one rocket launch Orion, and another provide a tug vehicle to push it out to the Moon. So far, the company has not advanced to performing detailed studies of vibrations, acoustics, thermal loads, and other assessments of compatibility, said Kirk Shireman, Lockheed Martin’s vice president and program manager for Orion.

“Could you create architectures to fly on other vehicles? Yes, we know we can,” Shireman said. “But when you start talking about those other environmental things, we have not done any of that work.”

So what else is being done to control Orion’s costs? Lockheed officials said incorporating reuse into Orion’s plans is “absolutely critical.” This is a philosophy that has evolved over time, especially after SpaceX began reflying its Dragon spacecraft.

NASA first contracted with Lockheed nearly two decades ago to start preliminary development work on Orion. At the outset, spacecraft reuse was not a priority. Byers, who has been involved with the Orion program at Lockheed on and off since its inception, said initially NASA asked Lockheed to assess the potential for reusing components of Orion.

“Whenever the vehicle would come back, NASA’s assumption was that we would disassemble the vehicle and harvest the components, and they would go into inventory,” Byers said. “Then they would go into a new structure for a future flight. Well, as the program progressed and we saw what others were doing, we really started to introduce the idea of reusing the crew module.”

How to reuse a spacecraft

The updated plan agreed to by NASA and Lockheed calls for a step-by-step approach.

“There’s a path forward,” said Howard Hu, NASA’s Orion program manager, in an interview. “We’re trying to crawl, then walk, then run into our reuse strategy. We want to make sure that we’re increasing our reusability, which we know is the path to sustainability and lower cost.”

The current plan is as follows:

Artemis II: A brand-new spacecraft, it will reuse 11 avionics components refurbished from the Artemis I Orion spacecraft; after landing, it will be used for testing purposes.

Artemis III: A brand-new spacecraft.

Artemis IV: A brand-new spacecraft.

Artemis V: Will reuse approximately 250 components, primarily life support and avionics equipment, from Artemis II.

Artemis VI: Will reuse primary structure (pressure vessel) and secondary structures (gussets, panels, brackets, plates) from Artemis III Orion, and approximately 3,000 components.

Lockheed plans to build a fleet of three largely reusable spacecraft, which will make their debuts on the Artemis III, IV, and V missions, respectively. Those three vehicles would then fly future missions, and if Lockheed needs to expand the fleet to meet demand, it could.

This photo, from 2023, shows the Orions for Artemis II, III, and IV all together.

Credit: Lockheed Martin

This photo, from 2023, shows the Orions for Artemis II, III, and IV all together. Credit: Lockheed Martin

Of course, Orion can never be made fully reusable. The service module, built by Europe-based Airbus and providing propulsion, separates from Orion before reentry into Earth’s atmosphere and burns up.

“We probably should call it maximum reuse, because there are some things that are consumed,” Shireman said. “For instance, the heat shield is consumed as the ablative material is ablated. But we are, ultimately, going to reuse the structure of the heat shield itself.”

Vectoring along a new path

Orion is always going to be relatively expensive. However, officials said they are on track to trim the cost of producing an Orion by 50 percent from the Artemis II to Artemis V vehicles and in follow-on missions to bring this down by 30 percent further or more. Minimizing refurbishment will be key to this.

Lockheed will never achieve “full and rapid reusability” for Orion like SpaceX is attempting with its Starship vehicle. That’s just not the way Orion was designed, nor what NASA wants. The space agency seeks a safe and reliable ride into deep space for its astronauts.

For the time being, only Orion can provide that. In the future, Starship may well provide that capability. Blue Origin and other providers may develop a deep space-capable human vehicle. But Orion is here and ready for its first astronauts in 2026. It will be years before any alternative becomes available.

It is nice to see that Lockheed recognizes this advantage won’t last forever and that it’s moving—or should we say, Vectoring—toward a more sustainable future.

Photo of Eric Berger

Eric Berger is the senior space editor at Ars Technica, covering everything from astronomy to private space to NASA policy, and author of two books: Liftoff, about the rise of SpaceX; and Reentry, on the development of the Falcon 9 rocket and Dragon. A certified meteorologist, Eric lives in Houston.

Once unthinkable, NASA and Lockheed now consider launching Orion on other rockets Read More »

nasa’s-acting-chief-“angry”-about-talk-that-china-will-beat-us-back-to-the-moon

NASA’s acting chief “angry” about talk that China will beat US back to the Moon

NASA’s interim administrator, Sean Duffy, said Thursday he has heard the recent talk about how some people are starting to believe that China will land humans on the Moon before NASA can return there with the Artemis Program.

“We had testimony that said NASA will not beat China to the Moon,” Duffy remarked during an all-hands meeting with NASA employees. “That was shade thrown on all of NASA. I heard it, and I gotta tell you what, maybe I am competitive, I was angry about it. I can tell you what, I’ll be damned if that is the story that we write. We are going to beat the Chinese to the Moon.”

Duffy’s remarks followed a Congressional hearing on Wednesday during which former Congressman Jim Bridenstine, who served as NASA administrator during President Trump’s first term, said China had pulled ahead of NASA and the United States in the second space race.

“Unless something changes, it is highly unlikely the United States will beat China’s projected timeline to the Moon’s surface,” said Bridenstine, who led the creation of the Artemis Program in 2019. China has said multiple times that it intends to land taikonuats on the Moon before the year 2030.

A lot of TV appearances

Duffy’s remarks were characteristic of his tenure since his appointment two months ago by Trump to serve as interim administrator of the space agency. He has made frequent appearances on Fox News and offered generally upbeat views of NASA’s position in its competition with China for supremacy in space. And on Friday, in a slickly produced video, he said, “I’m committed to getting us back to the Moon before President Trump leaves office.”

Sources have said Duffy, already a cabinet member as the secretary of transportation, is also angling to remove the “interim” from his NASA administrator title. Like Bridenstine, he has a capable political background and politics that align with the Trump administration. He is an excellent public speaker and knows the value of speaking to the president through Fox News. To date, however, he has shown limited recognition of the reality of the current competition with China.

NASA’s acting chief “angry” about talk that China will beat US back to the Moon Read More »

white-house-budget-seeks-to-end-sls,-orion,-and-lunar-gateway-programs

White House budget seeks to end SLS, Orion, and Lunar Gateway programs

Several sources in the space community, therefore, believe it is indeed plausible that SLS and Orion will be phased out over the next five years in favor of far less expensive commercial rockets and spacecraft. NASA will thus be asked to beat China to the Moon with the legacy systems and then identify more affordable options for future missions to the Moon.

Mars ambitions

One area that will see increased spending under the Trump administration’s proposed budget is human space exploration.

“By allocating over $7 billion for lunar exploration and introducing $1 billion in new investments for Mars-focused programs, the Budget ensures that America’s human space exploration efforts remain unparalleled, innovative, and efficient,” the document states.

Under the Trump administration, NASA will seek to reach both the Moon and Mars. The goal, stated in the document, is to refocus NASA “on beating China to the Moon and putting the first human on Mars.” Unfortunately, there is no information on what these “Mars-focused programs” will be. Some of this new funding would almost certainly go to SpaceX. The company, founded by Trump ally Elon Musk, explicitly focuses on establishing human settlements on Mars.

Although lunar and Mars exploration receive increases, the budget seeks to reduce the agency’s commitment to the International Space Station, while still flying it until 2030. “The Budget reduces the space station’s crew size and onboard research,” the document states. “Crew and cargo flights to the station would be significantly reduced. The station’s reduced research capacity would be focused on efforts critical to the Moon and Mars exploration programs.”

It is likely that Congress will oppose some of these changes, particularly the cuts to science programs and the reduction in activity on the International Space Station. But that story will play out in the coming months as the laborious budget process unfolds.

White House budget seeks to end SLS, Orion, and Lunar Gateway programs Read More »

nasa-says-orion’s-heat-shield-is-good-to-go-for-artemis-ii—but-does-it-matter?

NASA says Orion’s heat shield is good to go for Artemis II—but does it matter?

“We have since determined that while the capsule was dipping in and out of the atmosphere, as part of that planned skip entry, heat accumulated inside the heat shield outer layer, leading to gases forming and becoming trapped inside the heat shield,” said Pam Melroy, NASA’s deputy administrator. “This caused internal pressure to build up and led to cracking and uneven shedding of that outer layer.”

An independent team of experts concurred with NASA’s determination of the root cause, Melroy said.

NASA Administrator Bill Nelson, Deputy Administrator Pam Melroy, Associate Administrator Jim Free, and Artemis II Commander Reid Wiseman speak with reporters Thursday in Washington, DC. Credit: NASA/Bill Ingalls

Counterintuitively, this means NASA engineers are comfortable with the safety of the heat shield if the Orion spacecraft reenters the atmosphere at a slightly steeper angle than it did on Artemis I and spends more time subjected to higher temperatures.

When the Orion spacecraft climbed back out of the atmosphere during the Artemis I skip reentry, a period known as the skip dwell, NASA said heating rates decreased and thermal energy accumulated inside the heat shield’s Avcoat material. This generated gases inside the heat shield through a process known as pyrolysis. 

“Pyrolysis is just burning without oxygen,” said Amit Kshatriya, deputy associate administrator of NASA’s Moon to Mars program. “We learned that as part of that reaction, the permeability of the Avcoat material is essential.”

During the skip dwell, “the production of those gases was higher than the permeability could tolerate, so as a result, pressure differential was created. That pressure led to cracks in plane with the outer mold line of the vehicle,” Kshatriya said.

NASA didn’t know this could happen because engineers tested the heat shield on the ground at higher temperatures than the Orion spacecraft encountered in flight to prove the thermal barrier could withstand the most extreme possible heating during reentry.

“What we missed was this critical region in the middle, and we missed that region because we didn’t have the test facilities to produce the low-level energies that occur during skip and dwell,” Kshatriya said Thursday.

During the investigation, NASA replicated the charring and cracking after engineers devised a test procedure to expose Avcoat heat shield material to the actual conditions of the Artemis I reentry.

So, for Artemis II, NASA plans to modify the reentry trajectory to reduce the skip reentry’s dwell time. Let’s include some numbers to help illustrate the difference.

The distance traveled by Artemis I during the reentry phase of the mission was more than 3,000 nautical miles (3,452 miles; 5,556 kilometers), according to Kshatriya. This downrange distance will be limited to no more than 1,775 nautical miles (2,042 miles; 3,287 kilometers) on Artemis II, effectively reducing the dwell time the Orion spacecraft spends in the lower heating regime that led to the cracking on Artemis I.

NASA’s inspector general report in May included new images of Orion’s heat shield that the agency did not initially release after the Artemis I mission. Credit: NASA Inspector General

With this change, Kshatriya said NASA engineers don’t expect to see the heat shield erosion they saw on Artemis I. “The gas generation that occurs during that skip dwell is sufficiently low that the environment for crack generation is not going to overwhelm the structural integrity of the char layer.”

For future Orion spaceships, NASA and its Orion prime contractor, Lockheed Martin, will incorporate changes to address the heat shield’s permeability problem.

Waiting for what?

NASA officials discussed the heat shield issue, and broader plans for the Artemis program, in a press conference in Washington on Thursday. But the event’s timing added a coat of incredulity to much of what they said. President-elect Donald Trump, with SpaceX founder Elon Musk in his ear, has vowed to cut wasteful government spending.

NASA says Orion’s heat shield is good to go for Artemis II—but does it matter? Read More »

after-critics-decry-orion-heat-shield-decision,-nasa-reviewer-says-agency-is-correct

After critics decry Orion heat shield decision, NASA reviewer says agency is correct


“If this isn’t raising red flags out there, I don’t know what will.”

NASA’s Orion spacecraft, consisting of a US-built crew module and European service module, is lifted during prelaunch processing at Kennedy Space Center in 2021. Credit: NASA/Amanda Stevenson

Within hours of NASA announcing its decision to fly the Artemis II mission aboard an Orion spacecraft with an unmodified heat shield, critics assailed the space agency, saying it had made the wrong decision.

“Expediency won over safety and good materials science and engineering. Sad day for NASA,” Ed Pope, an expert in advanced materials and heat shields, wrote on LinkedIn.

There is a lot riding on NASA’s decision, as the Artemis II mission involves four astronauts and the space agency’s first crewed mission into deep space in more than 50 years.

A former NASA astronaut, Charles Camarda, also expressed his frustrations on LinkedIn, saying the space agency and its leadership team should be “ashamed.” In an interview on Friday, Camarda, an aerospace engineer who spent two decades working on thermal protection for the space shuttle and hypersonic vehicles, said NASA is relying on flawed probabilistic risk assessments and Monte Carlo simulations to determine the safety of Orion’s existing heat shield.

“I worked at NASA for 45 years,” Camarda said. “I love NASA. I do not love the way NASA has become. I do not like that we have lost our research culture.”

NASA makes a decision

Pope, Camarada, and others—an official expected to help set space policy for the Trump administration told Ars on background, “It’s difficult to trust any of their findings”—note that NASA has spent two years assessing the char damage incurred by the Orion spacecraft during its first lunar flight in late 2022, with almost no transparency. Initially, agency officials downplayed the severity of the issue, and the full scope of the problem was not revealed until a report this May by NASA’s inspector general, which included photos of a heavily pock-marked heat shield.

This year, from April to August, NASA convened an independent review team (IRT) to assess its internal findings about the root cause of the charring on the Orion heat shield and determine whether its plan to proceed without modifications to the heat shield was the correct one. However, though this review team wrapped up its work in August and began briefing NASA officials in September, the space agency kept mostly silent about the problem until a news conference on Thursday.

The inspector general’s report on May 1 included new images of Orion’s heat shield.

Credit: NASA Inspector General

The inspector general’s report on May 1 included new images of Orion’s heat shield. Credit: NASA Inspector General

“Based on the data, we have decided—NASA unanimously and our decision-makers—to move forward with the current Artemis II Orion capsule and heat shield, with a modified entry trajectory,” Bill Nelson, NASA’s administrator, said Thursday. The heat shield investigation and other issues with the Orion spacecraft will now delay the Artemis II launch until April 2026, a slip of seven months from the previous launch date in September 2025.

Notably the chair of the IRT, a former NASA flight director named Paul Hill, was not present at Thursday’s news conference. Nor did the space agency release the IRT’s report on its recommendations to NASA.

In an interview, Camarda said he knew two people on the IRT who dissented from its conclusions that NASA’s plan to fly the Orion heat shield, without modifications to address the charring problem, was acceptable. He also criticized the agency for not publicly releasing the independent report. “NASA did not post the results of the IRT,” he said. “Why wouldn’t they post the results of what the IRT said? If this isn’t raising red flags out there, I don’t know what will.”

The view from the IRT

Ars took these concerns to NASA on Friday, and the agency responded by offering an interview with Paul Hill, the review team’s chair. He strongly denied there were any dissenting views.

“Every one of our conclusions, every one of our recommendations, was unanimously agreed to by our team,” Hill said. “We went through a lot of effort, arguing sentence by sentence, to make sure the entire team agreed. To get there we definitely had some robust and energetic discussions.”

Hill did acknowledge that, at the outset of the review team’s discussions, two people were opposed to NASA’s plan to fly the heat shield as is. “There was, early on, definitely a difference of opinion with a couple of people who felt strongly that Orion’s heat shield was not good enough to fly as built,” he said.

However, Hill said the IRT was won over by the depth of NASA’s testing and the openness of agency engineers who worked with them. He singled out Luis Saucedo, a NASA engineer at NASA’s Johnson Space Center who led the agency’s internal char loss investigation.

“The work that was done by NASA, it was nothing short of eye-watering, it was incredible,” Hill said.

At the base of Orion, which has a titanium shell, there are 186 blocks of a material called Avcoat individually attached to provide a protective layer that allows the spacecraft to survive the heating of atmospheric reentry. Returning from the Moon, Orion encounters temperatures of up to 5,000° Fahrenheit (2,760° Celsius). A char layer that builds up on the outer skin of the Avcoat material is supposed to ablate, or erode, in a predictable manner during reentry. Instead, during Artemis I, fragments fell off the heat shield and left cavities in the Avcoat material.

Work by Saucedo and others, including substantial testing in ground facilities, wind tunnels, and high-temperature arc jet chambers, allowed engineers to find the root cause of gases getting trapped in the heat shield and leading to cracking. Hill said his team was convinced that NASA successfully recreated the conditions observed during reentry and were able to replicate during testing the Avcoat cracking that occurred during Artemis I.

When he worked at the agency, Hill played a leading role during the investigation into the cause of the loss of space shuttle Columbia, in 2003. He said he could understand if NASA officials “circled the wagons” in response to the IRT’s work, but he said the agency could not have been more forthcoming. Every time the review team wanted more data or information, it was made available. Eventually, this made the entire IRT comfortable with NASA’s findings.

Publicly, NASA could have been more transparent

The stickiest point during the review team’s discussions involved the permeability of the heat shield. Counter-intuitively, the heat shield was not permeable enough during Artemis I. This led to gas buildup, higher pressures, and the cracking ultimately observed. The IRT was concerned because, as designed, the heat shield for Artemis II is actually more impermeable than the Artemis I vehicle.

Why is this? It has to do with the ultrasound testing that verifies the strength of the bond between the Avcoat blocks and the titanium skin of Orion. With a more permeable heat shield, it was difficult to complete this testing with the Artemis I vehicle. So the shield for Artemis II was made more impermeable to accommodate ultrasound testing. “That was a technical mistake, and when they made that decision they did not understand the ramifications,” Hill said.

However, Hill said NASA’s data convinced the IRT that modifying the entry profile for Artemis II, to minimize the duration of passage through the atmosphere, would offset the impermeability of the heat shield.

Hill said he did not have the authority to release the IRT report, but he did agree that the space agency has not been forthcoming with public information about their analyses before this week.

“This is a complex story to tell, and if you want everybody to come along with you, you’ve got to keep them informed,” he said of NASA. “I think they unintentionally did themselves a disservice by holding their cards too close.”

Photo of Eric Berger

Eric Berger is the senior space editor at Ars Technica, covering everything from astronomy to private space to NASA policy, and author of two books: Liftoff, about the rise of SpaceX; and Reentry, on the development of the Falcon 9 rocket and Dragon. A certified meteorologist, Eric lives in Houston.

After critics decry Orion heat shield decision, NASA reviewer says agency is correct Read More »

nasa-is-stacking-the-artemis-ii-rocket,-implying-a-simple-heat-shield-fix

NASA is stacking the Artemis II rocket, implying a simple heat shield fix

A good sign

The readiness of the Orion crew capsule, where the four Artemis II astronauts will live during their voyage around the Moon, is driving NASA’s schedule for the mission. Officially, Artemis II is projected to launch in September of next year, but there’s little chance of meeting that schedule.

At the beginning of this year, NASA officials ruled out any opportunity to launch Artemis II in 2024 due to several technical issues with the Orion spacecraft. Several of these issues are now resolved, but NASA has not released any meaningful updates on the most significant problem.

This problem involves the Orion spacecraft’s heat shield. During atmospheric reentry at the end of the uncrewed Artemis I test flight in 2022, the Orion capsule’s heat shield eroded and cracked in unexpected ways, prompting investigations by NASA engineers and an independent panel.

NASA’s Orion heat shield inquiry ran for nearly two years. The investigation has wrapped up, two NASA officials said last month, but they declined to discuss any details of the root cause of the heat shield issue or the actions required to resolve the problem on Artemis II.

These corrective options ranged from doing nothing to changing the Orion spacecraft’s reentry angle to mitigate heating or physically modifying the Artemis II heat shield. In the latter scenario, NASA would have to disassemble the Orion spacecraft, which is already put together and is undergoing environmental testing at Kennedy Space Center. This would likely delay the Artemis II launch by a couple of years.

In August, NASA’s top human exploration official told Ars that the agency would hold off on stacking the SLS rocket until engineers had a good handle on the heat shield problem. There are limits to how long the solid rocket boosters can remain stacked vertically. The joints connecting each segment of the rocket motors are certified for one year. This clock doesn’t actually start ticking until NASA stacks the next booster segments on top of the lowermost segments.

However, NASA waived this rule on Artemis I when the boosters were stacked nearly two years before the successful launch.

A NASA spokesperson told Ars on Wednesday that the agency had nothing new to share on the Orion heat shield or what changes, if any, are required for the Artemis II mission. This information should be released before the end of the year, she said. At the same time, NASA could announce a new target launch date for Artemis II at the end of 2025, or more likely in 2026.

But because NASA gave the “go” for SLS stacking now, it seems safe to rule out any major hardware changes on the Orion heat shield for Artemis II.

NASA is stacking the Artemis II rocket, implying a simple heat shield fix Read More »

it’s-increasingly-unlikely-that-humans-will-fly-around-the-moon-next-year

It’s increasingly unlikely that humans will fly around the Moon next year

Don’t book your tickets for the launch of NASA’s Artemis II mission next year just yet.

We have had reason to doubt the official September 2025 launch date for the mission, the first crewed flight into deep space in more than five decades, for a while now. This is principally because NASA is continuing to mull the implications of damage to the Orion spacecraft’s heat shield from the Artemis I mission nearly two years ago.

However, it turns out that there are now other problems with holding to this date as well.

No schedule margin

A new report from the US Government Accountability Office found that NASA’s Exploration Ground Systems program—this is, essentially, the office at Kennedy Space Center in Florida responsible for building ground infrastructure to support the Space Launch System rocket and Orion—is in danger of missing its schedule for Artemis II.

During this flight a crew of four astronauts, commanded by NASA’s Reid Wiseman, will launch inside Orion on a 10-day mission out to the Moon and back. The spacecraft will follow a free-return trajectory, which is important, because if there is a significant problem with Orion spacecraft’s propulsion system, the trajectory of the vehicle will still carry it back to Earth. At their closest approach, the crew will come within about 6,500 miles (10,400 km) of the surface of the far side of the Moon.

The new report, published Thursday, finds that the Exploration Ground Systems program had several months of schedule margin in its work toward a September 2025 launch date at the beginning of the year. But now, the program has allocated all of that margin to technical issues experienced during work on the rocket’s mobile launcher and pad testing.

“Earlier in 2024, the program was reserving that time for technical issues that may arise during testing of the integrated SLS and Orion vehicle or if weather interferes with planned activities, among other things,” the report states. “Officials said it is likely that issues will arise because this is the first time testing many of these systems. Given the lack of margin, if further issues arise during testing or integration, there will likely be delays to the September 2025 Artemis II launch date.”

It’s increasingly unlikely that humans will fly around the Moon next year Read More »

nasa-confirms-“independent-review”-of-orion-heat-shield-issue

NASA confirms “independent review” of Orion heat shield issue

The Orion spacecraft after splashdown in the Pacific Ocean at the end of the Artemis I mission.

Enlarge / The Orion spacecraft after splashdown in the Pacific Ocean at the end of the Artemis I mission.

NASA has asked a panel of outside experts to review the agency’s investigation into the unexpected loss of material from the heat shield of the Orion spacecraft on a test flight in 2022.

Chunks of charred material cracked and chipped away from Orion’s heat shield during reentry at the end of the 25-day unpiloted Artemis I mission in December 2022. Engineers inspecting the capsule after the flight found more than 100 locations where the stresses of reentry stripped away pieces of the heat shield as temperatures built up to 5,000° Fahrenheit.

This was the most significant discovery on the Artemis I, an unpiloted test flight that took the Orion capsule around the Moon for the first time. The next mission in NASA’s Artemis program, Artemis II, is scheduled for launch late next year on a test flight to send four astronauts around the far side of the Moon.

Another set of eyes

The heat shield, made of a material called Avcoat, is attached to the base of the Orion spacecraft in 186 blocks. Avcoat is designed to ablate, or erode, in a controlled manner during reentry. Instead, fragments fell off the heat shield that left cavities resembling potholes.

Investigators are still looking for the root cause of the heat shield problem. Since the Artemis I mission, engineers conducted sub-scale tests of the Orion heat shield in wind tunnels and high-temperature arcjet facilities. NASA has recreated the phenomenon observed on Artemis I in these ground tests, according to Rachel Kraft, an agency spokesperson.

“The team is currently synthesizing results from a variety of tests and analyses that inform the leading theory for what caused the issues,” said Rachel Kraft, a NASA spokesperson.

Last week, nearly a year and a half after the Artemis I flight, the public got its first look at the condition of the Orion heat shield with post-flight photos released in a report from NASA’s inspector general. Cameras aboard the Orion capsule also recorded pieces of the heat shield breaking off the spacecraft during reentry.

NASA’s inspector general said the char loss issue “creates a risk that the heat shield may not sufficiently protect the capsule’s systems and crew from the extreme heat of reentry on future missions.”

“Those pictures, we’ve seen them since they were taken, but more importantly… we saw it,” said Victor Glover, pilot of the Artemis II mission, in a recent interview with Ars. “More than any picture or report, I’ve seen that heat shield, and that really set the bit for how interested I was in the details.”

NASA confirms “independent review” of Orion heat shield issue Read More »