Homecoming of Artemis II Will Include a Dangerous Ride Inside a Fireball
Today, April 10, 2026, the Artemis II Orion spacecraft will bring back to Earth four humans who reached farther than any human did. The reentry of Orion through the Earth’s atmosphere will start at 8:07 PM ET with a velocity measuring 30 times the speed of sound. Like a giant piston, it will push air supersonically and generate a fireball capped by a blast wave with a temperature of thousands of degrees. The safety of the astronauts during this dramatic phase relies on the successful isolation provided by the heat shield surrounding the Orion capsule. Meteoroids often burn up and disintegrate into fragments during a similar journey, but that is because their structure and material strength was not designed to survive it. As they break up into pieces, the surface area increases and the power generated by friction of air keeps growing, generating further fragmentation in an explosive process. We all pray for a safer fireball ride during the Artemis II reentry.
Below is a transcript of a new interview I had this morning in the company of former NASA Chief of Staff Gabriel (Gabe) Sherman, with the anchor Shannon Cake on Newsmax (accessible in video form here). Shannon’s questions are marked with SC, while my and Gabe’s answers are marked with AL and GS, respectively.
SC: I want to bring in the director of the Institute for Theory and Computation at Harvard
University this morning, Professor Avi Loeb, who has been walking us through this in recent days, and former NASA Chief of Staff Gabriel Sherman. Gentlemen: good morning to you.
Full eyes on California just off the coast of San Diego today. This will be, Dr. Loeb, a tricky reentry maneuver. It’s set for this afternoon. So, the astronauts are set to wake about 11:30 AM ET this morning. They were up late last night into the early morning hours. They are going to wake up, start stowing their gear for this plan. It is called a lofted reentry, kind of like skipping off the atmosphere like a stone across the water. How tricky is it? Walk us through it, if you will.
AL: Yes, the re-entry will start at around 8:07 PM ET. And the last time it was done was during the Artemis I mission where there was a skip. The capsule went down and then up again in order to go back down. And that created some problems for the heat shield. There were fragments from the heat shield that were lost. And that created a lot of concern. The hope is now to have much less of a skip, basically to go more smoothly down in a shorter path.
The biggest amount of heat will be generated initially. As this capsule is moving at 25,000 miles per hour, a very high speed that creates a lot of friction in the air because it’s about 30 times faster than the speed of sound. It creates a blast wave and a fireball surrounding the spacecraft, similar to the one around meteors, except the Orion capsule is protected by a heat shield. And we all pray that the heat shield will withstand the enormous amount of heat from the fireball. It involves a temperature of a few thousand degrees.
SC: Fiery hot. Gabriel: how serious are the concerns leading into the reentry today on this heat shield?
GS: I think anytime you’re doing this type of human exploration, there are concerns. But I
think what we heard the associate administrator from NASA say is they’ve looked at this, they’ve walked through the tests, they’ve done the appropriate work, and they’ve changed the trajectory to ensure that we return our astronauts home safely. And so, this mission would not have moved forward had the people at NASA not been very confident that we were going to bring these heroes home safely.
I look forward to that splashdown this evening. It’s going to be a historic day for us. We are all hoping and praying that everything goes according to plan today.
SC: I want to play a quick clip of the NASA Administrator giving us an update, talking about that splashdown, gentlemen. To your point, Dr. Loeb. We’ll be watching for it, 8:07 PM ET off the coast of San Diego.
“There’s no question that we’ll all be anxious. And, you know, but we’ll be with the families. We’ll be with them. We’ll all be together. You know, I have full confidence in the team. They do, too. You know, we’ve been with them the whole time. And so, you know, we’ve done the work. It’s impossible to say you don’t have irrational fears left, right? But I would tell you I don’t have any rational fears about what’s going to happen.”
So, before we get to the splashdown, there’s going to be this six-minute blackout, no communication. They say, Gabriel, it’ll be a plasma envelope that kind of forms around Orion. Why is this a critical time?
GS: I think it’s really interesting to think about just how quickly this process plays out, right? You go from releasing the service module to, you know, this atmospheric reentry and this plasma phase where you’re at 25,000 miles an hour. And then within just minutes, you’re all the way down to 17 miles an hour and landing safely in the ocean. And so that blackout, that’ll be a nervous time for everybody that’s watching because we want to maintain communications. But it’s expected, right? All of this stuff is expected. This whole process is planned out. The NASA engineers, the flight control team, the astronauts, they are ready for these moments. And so the six-minute blackout, totally normal. Of course, we want to regain communication as quickly as we can. And on the other side of that, we’ll
see the parachutes deploy and bring them home safely. A breathless six minutes, perhaps, for all of us here on Earth and certainly friends and families and loved ones and all of NASA.
SC: Dr. Loeb, can you explain a little bit more deeply this plasma envelope that will shield Orion? What is it? How does it deploy? And what are we looking for?
AL: Yes, the physics is really simple. What happens is that this object is moving through air at a very high speed, 30 times faster than the speed of sound. It creates hot gas around it. It shocks the gas. And that temperature, as we mentioned before, is several thousand degrees. And so, as a result of that all the atoms and molecules in air lose their electrons. They bump into each other and you create a cloud of free electrons around the spaceship. And those electrons block communication signals. That’s inevitable.
Of course, we can hope for better heat shields in the future, both in terms of having better technologies, but also artificial intelligence, AI, can allow us to design better materials.
I really hope that in the future missions, we will be much more secure in our assessments as to the effectiveness of the heat shield.
SC: Yeah, and of course, the Artemis I showed cracking in that heat shield. So, all of these steps and stages, the trajectory change and everything that you two have discussed, attempting to avoid all of that this time around. You’re looking at, meanwhile, some of these images that was captured by the crew.
In this debrief yesterday afternoon, the astronauts said that they are coming home with even more and better data than these images that they’re sharing here. What kind of data,
Gabriel, are you looking at? What are you most curious about?
GS: So, I think for me, it’s all about setting the stage for Artemis III, IV and V. Right. You want to test this Orion system out and ensure each one of the life support systems, propulsion systems, everything is working as it needs to to ensure that we can continue this adventure of lunar exploration because it is so critical at this point in history. And so, the most important information to me is the data that we gather on how all of these systems perform so that moving forward, we know we’re keeping our astronauts. safe as possible as we go even further and eventually move into a lunar landing.
SC: Yesterday, Senator Cruz was talking about the astronauts.
He basically said, you know, there’s a lot happening. He kind of walks it through. And they do make it look so easy, these astronauts, because they’ve backed up. They know each other’s roles and they can jump in at any time. Dr. Loeb, what are you looking for? What data are you most excited about unpacking? Basically, Senator Cruz was kind of walking us through what they do as they come back through and then they land and we grab them. It is very complicated and they back each other up. But what are you looking for this afternoon? In particular, in terms of duplication of roles, and also what are you most excited about unpacking when they finally do touchdown safely?
AL: There is a lot of interesting science that can be recovered from this new data. They had a limited level of the data, only several tens of gigabytes that was transmitted per day. They carry with them much more.
For example, if you look at the Moon, it started from a smooth surface of molten rock and now it’s scarred with all these impacts of asteroids and also interstellar objects — these are objects that came into the solar system from outside. We can learn a lot from these high-resolution images that the astronauts provide.
They also saw six flashes of micrometeorites. These are tiny objects that collided with the moon. The moon doesn’t have an atmosphere. And so, these objects do not burn up. When they collide with Earth, they burn up in the atmosphere. But there on the Moon, they just hit the surface and you see a crater for each of them.
The Moon is a museum of everything that impacted on it in the past 4.5 billion years. And I’m personally very interested to see if these are only rocks. Or maybe there are some technological artifacts, some objects that came from other civilizations that, you know, just by chance collided with the Moon. I calculated yesterday that an object like 3I/Atlas, which was the latest interstellar object, roughly the size of a city, two kilometers in diameter, has a 20% probability of colliding with the Moon over the Moon’s history.
So, there are lots of things that can be found by looking into the items on this museum that we can find. As complex as the data that you gentlemen will get excited about and our scientists will unpack for years to come, I think you really simplified it well.
SC: It is a museum of deep space. Professor Avi Loeb, director for the Institute of Theory and Computation at Harvard University and former NASA Chief of Staff Gabriel Sherman.
We’re excited right along with you today. The entire country, the entire world indeed cheering alongside you. Thank you for your time.
***
Let me close with a tidbit: reality is complicated because when a system is composed of N units, there could be N² interactions among these units, making a full census of these interactions challenging even for our most advanced AI systems.
ABOUT THE AUTHOR
Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, former director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics (2005–2026), and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024.
Professional website:
https://lweb.cfa.harvard.edu/~loeb/
Social media:
https://avi-loeb.medium.com/
https://www.youtube.com/@ProfessorAviLoeb
https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd
https://x.com/ProfAviLoeb
