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NASA confirms “independent review” of Orion heat shield issue

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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 »

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Rocket Report: Astroscale chases down dead rocket; Ariane 6 on the pad

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RIP B1060 —

Rocket Factory Augsburg, a German launch startup, nears a test-firing of its booster.

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This image captured by Astroscale's ADRAS-J satellite shows the discarded upper stage from a Japanese H-IIA rocket.

Enlarge / This image captured by Astroscale’s ADRAS-J satellite shows the discarded upper stage from a Japanese H-IIA rocket.

Welcome to Edition 6.42 of the Rocket Report! Several major missions are set for launch in the next few months. These include the first crew flight on Boeing’s Starliner spacecraft, set for liftoff on May 6, and the next test flight of SpaceX’s Starship rocket, which could happen before the end of May. Perhaps as soon as early summer, SpaceX could launch the Polaris Dawn mission with four private astronauts, who will perform the first fully commercial spacewalk in orbit. In June or July, Europe’s new Ariane 6 rocket is slated to launch for the first time. Rest assured, Ars will have it all covered.

As always, we welcome reader submissions, and if you don’t want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets as well as a quick look ahead at the next three launches on the calendar.

German rocket arrives at Scottish spaceport. Rocket Factory Augsburg has delivered a booster for its privately developed RFA One rocket to SaxaVord Spaceport in Scotland, the company announced on X. The first stage for the RFA One rocket was installed on its launch pad at SaxaVord to undergo preparations for a static fire test. The booster arrived at the Scottish launch site with five of its kerosene-fueled Helix engines. The remaining four Helix engines, for a total of nine, will be fitted to the RFA One booster at SaxaVord, the company said.

Aiming to fly this year… RFA hopes to launch its first orbital-class rocket by the end of 2024. The UK’s Civil Aviation Authority last month granted a range license to SaxaVord Spaceport to allow the spaceport operator to control the sea and airspace during a launch. RFA is primarily privately funded but has won financial support from the European Space Agency, the UK Space Agency, and the German space agency, known as DLR. The RFA One rocket will have three stages, stand nearly 100 feet (30 meters) tall, and can carry nearly 2,900 pounds (1,300 kilograms) of payload into a polar Sun-synchronous orbit.

Arianespace wins ESA launch contract. The European Space Agency has awarded Arianespace a contract to launch a joint European-Chinese space science satellite in late 2025, European Spaceflight reports. The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) is a 4,850-pound (2,200-kilogram) spacecraft that will study Earth’s magnetic environment on a global scale. The aim of the mission is to build a more complete understanding of the Sun-Earth connection. On Tuesday, ESA officially signed a contract for Arianespace to launch SMILE aboard a Vega C rocket, which is built by the Italian rocket-maker Avio.

But it may not keep it … In late 2023, ESA member states agreed to allow Avio to market and manage the launch of Vega C flights independent of Arianespace. When the deal was initially struck, 17 flights were contracted through Arianespace to be launched aboard Vega vehicles. While these missions are still managed by Arianespace, Avio is working with the launch provider to strike a deal that would allow the Italian rocket builder to assume the management of all Vega flights. The Vega C rocket has been grounded since a launch failure in 2022 forced Avio to redesign the nozzle of the rocket’s solid-fueled second-stage motor. Vega C is scheduled to return to flight before the end of 2024. (submitted by Ken the Bin)

The easiest way to keep up with Eric Berger’s space reporting is to sign up for his newsletter, we’ll collect his stories in your inbox.

Update on ABL’s second launch. ABL Space Systems expected to launch its second light-class RS1 rocket earlier this year, but the company encountered an anomaly during ground testing at the launch site in Alaska, according to Aria Alamalhodaei of TechCrunch. Kevin Sagis, ABL’s chief engineer, said there is “no significant delay” in the launch of the second RS1 rocket, but the company has not announced a firm schedule. “During ground testing designed to screen the vehicle for flight, an issue presented that caused us to roll back to the hangar,” Sagis said, according to Alamalhodaei. “We have since resolved and dispositioned the issue. There was no loss of hardware and we have validated vehicle health back out on the pad. We are continuing with preparations for static fire and launch.”

Nearly 16 months without a launch … ABL’s first RS1 test flight in January 2023 ended seconds after liftoff with the premature shutdown of its liquid-fueled engines. The rocket crashed back onto its launch pad in Alaska. An investigation revealed a fire in the aft end of the RS1 booster burned through wiring harnesses, causing the rocket to lose power and shut off its engines. Engineers believe the rocket’s mobile launch mount was too small, placing the rocket too close to the ground when it ignited its engines. This caused the hot engine exhaust to recirculate under the rocket and led to a fire in the engine compartment as it took off.

Rocket Report: Astroscale chases down dead rocket; Ariane 6 on the pad Read More »

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NASA still doesn’t understand root cause of Orion heat shield issue

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Flight rationale —

“When we stitch it all together, we’ll either have flight rationale or we won’t.”

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NASA's Orion spacecraft descends toward the Pacific Ocean on December 11, 2021, at the end of the Artemis I mission.

Enlarge / NASA’s Orion spacecraft descends toward the Pacific Ocean on December 11, 2021, at the end of the Artemis I mission.

NASA

NASA officials declared the Artemis I mission successful in late 2021, and it’s hard to argue with that assessment. The Space Launch System rocket and Orion spacecraft performed nearly flawlessly on an unpiloted flight that took it around the Moon and back to Earth, setting the stage for the Artemis II, the program’s first crew mission.

But one of the things engineers saw on Artemis I that didn’t quite match expectations was an issue with the Orion spacecraft’s heat shield. As the capsule streaked back into Earth’s atmosphere at the end of the mission, the heat shield ablated, or burned off, in a different manner than predicted by computer models.

More of the charred material than expected came off the heat shield during the Artemis I reentry, and the way it came off was somewhat uneven, NASA officials said. Orion’s heat shield is made of a material called Avcoat, which is designed to burn off as the spacecraft plunges into the atmosphere at 25,000 mph (40,000 km per hour). Coming back from the Moon, Orion encountered temperatures up to 5,000° Fahrenheit (2,760° Celsius), hotter than a spacecraft sees when it reenters the atmosphere from low-Earth orbit.

Despite heat shield issue, the Orion spacecraft safely splashed down in the Pacific Ocean. Engineers discovered the uneven charring during post-flight inspections.

No answers yet

Amit Kshatriya, who oversees development for the Artemis missions in NASA’s exploration division, said Friday that the agency is still looking for the root cause of the heat shield issue. Managers want to be sure they understand the cause before proceeding with Artemis II, which will send astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen on a 10-day flight around the far side of the Moon.

This will be the first time humans fly near the Moon since the last Apollo mission in 1972. In January, NASA announced a delay in the launch of Artemis II from late 2024 until September 2025, largely due to the unresolved investigation into the heat shield issue.

“We are still in the middle of our investigation on the performance of the heat shield from Artemis I,” Kshatriya said Friday in a meeting with a committee of the NASA Advisory Council.

Engineers have performed sub-scale heat shield tests in wind tunnels and arc jet facilities to better understand what led to the uneven charring on Artemis I. “We’re getting close to the final answer in terms of that cause,” Kshatriya said.

NASA officials previously said it is unlikely they will need to make changes to the heat shield already installed on the Orion spacecraft for Artemis II, but haven’t ruled it out. A redesign or modifications to the Orion heat shield on Artemis II would probably delay the mission by at least a year.

Instead, engineers are analyzing all of the possible trajectories the Orion spacecraft could fly when it reenters the atmosphere at the end of the Artemis II mission. On Artemis I, Orion flew a skip reentry profile, where it dipped into the atmosphere, skipped back into space, and then made a final descent into the atmosphere, sort of like a rock skipping across a pond. This profile allows Orion to make more precise splashdowns near recovery teams in the Pacific Ocean and reduces g-forces on the spacecraft and the crew riding inside. It also splits up the heat load on the spacecraft into two phases.

The Apollo missions flew a direct reentry profile. There is also a reentry mode available called a ballistic entry, in which the spacecraft would fly through the atmosphere unguided.

Ground teams at NASA's Kennedy Space Center in Florida moved the Orion spacecraft for the Artemis II mission into an altitude chamber earlier this month.

Enlarge / Ground teams at NASA’s Kennedy Space Center in Florida moved the Orion spacecraft for the Artemis II mission into an altitude chamber earlier this month.

The charred material began flying off the heat shield in the first phase of the skip reentry. Engineers are looking at how the skip reentry profile affected the performance of the Orion heat shield. NASA wants to understand how the Orion heat shield would perform during each of the possible reentry trajectories for Artemis II.

“What we have the analysis teams off doing is saying, ‘OK, independent of what the constraints are going to be, what can we tolerate?” Kshatriya said.

Once officials understand the cause of the heat shield charring, engineers will determine what kind of trajectory Artemis II needs to fly on reentry to minimize risk to the crew. Then, managers will look at building what NASA calls flight rationale. Essentially, this is a process of convincing themselves the spacecraft is safe to fly.

“When we stitch it all together, we’ll either have flight rationale or we won’t,” Kshatriya said.

Assuming NASA approves the flight rationale for Artemis II, there will be additional discussions about how to ensure Orion heat shields are safe to fly on downstream Artemis missions, which will have higher-speed reentry profiles as astronauts return from landings on the Moon.

In the meantime, preparations on the Orion spacecraft for Artemis II continue at NASA’s Kennedy Space Center. The crew and service modules for Artemis II were mated together earlier this year, and the entire Orion spacecraft is now inside a vacuum chamber for environmental testing.

NASA still doesn’t understand root cause of Orion heat shield issue Read More »