NASA discusses a surprise heat shield after the return of the Orion spacecraft from the Moon

During a media talk earlier today, NASA officials shared updates from the Artemis 1 flight as they explained the results of data analysis from the spacecraft and the way forward on the Artemis 2 mission. Artemis 1 took off from NASA’s Kennedy Space Center in Florida last year to test the Orion spacecraft. And the SLS missile on a manned mission is expected to take place next year. It included a critical test of the spaceship’s heat shield, which had not been fully tested on Earth due to insufficient equipment. NASA’s Orion Program Manager Howard Hu explained that his agency detected some variance in heat shield performance with more material burning than expected during the simulation.

Airbus and ESA will test faulty switches on Orion later this month

NASA is currently analyzing each clump of the heat shield that has behaved unexpectedly in that some of its material has opened up rather than melted. Heat shield testing was one of the main flight goals of the Artemis 1 mission since facilities that can simulate the extreme temperatures of a full structure do not exist on Earth.

NASA’s Orion Program Manager Howard Hu explained that some aspects of the heat shield’s performance did not match simulations running on Earth. The structure consists of 186 blocks and is a new design upgrade from a monolithic (or one-piece) design that was present in Orion’s Exploration Flight 1 (EFT-1) test in 2014 that orbited Earth. The upgrades were made after EFT-1 testing revealed that the previous heat-shield structure would not be strong enough to withstand higher temperatures on return and the harsh, cold space environment during lunar flight.

According to the master is:

Another interesting occurrence while returning the crew module and examining the heat shield, we noticed that there were more differences across the heat shield than we expected. Some of the predicted char materials we expect to return home have disappeared differently than our computer model and what our ground test predicted. So we had more char release during re-entry before our descent than we expected. So right now, we’re working hard on the investigation, taking the data that we’ve collected from the images and the videos, from the re-entry, and correlating that with the heat sensors, the heat shield sensors that we have on board.

And then also, of course, look at our computer models and look at how we understand this phenomenon that we experience upon re-entry. We have a dedicated investigation going on with a detailed analysis. We’ve extracted some samples from the heat shield, and we’re x-raying it against it. We also understand how much residual reel, or AVCOAT, was left on the heat shield and it was still quite a bit, so that was really good. But overall, there is a lot of work to be done on this investigation moving forward. We’re just beginning this effort where we’ve just collected all those bits of information, those samples, videos, images and data from the spacecraft itself and tied them together. And now we’re evaluating that data and moving forward with that evaluation.

Orion’s heat shield is made of polymer resin (AVOCAT) that is cut into smaller blocks that are mounted on a titanium and carbon fiber chassis. Since there are gaps between these blocks, the technicians measure the gaps between the blocks and fill them with adhesive. The heat shield design makes the gas generate through decomposition during atmospheric reentry, which then diverts heat away from the spacecraft. At the same time, part of the heat shield is also burned.

Mr. He added:

So you can imagine you know we have [an] The heat shield is abrasive so expect the material to wither. And part of that 5,000-degree Fahrenheit heating that you experience when you re-enter that temperature, you’ll see charring of that material. Kind of what you do when you grill yourself, like that. So that is expected to happen. That was planned. Now, what usually happens when you get charred, you’re going to experience a toll through a chemical reaction. We see some of it as bigger like, more like little bits that would come off, as opposed to excision. And I think that’s one of the things that was a little bit unexpected when we came back from the moon. As we review the data and look at what we saw visually, what our sensors told us in terms of temperatures and the profile of temperatures we experience upon re-entry.

During its voyage around the Moon, Orion also encountered some issues with its switches, which are responsible for sending power from the solar panels to various systems such as avionics and thrusters. These switches tripped without any command during flight, and Mr. Hu explained that the European Space Agency (ESA) and Airbus will test the system later this month to check if there is noise causing the problem. ESA and Airbus provided the service module for Orion, and the faulty switches are on that part of the spacecraft.

The Starship’s SpaceX moon lander was also discussed, with NASA officials emphasizing that the company must prove several milestones. This includes reducing the risk of transporting supercooled propellant in space from its fuel depot to the spacecraft by launching some missions.