**Jay Shaffer:** Welcome back to the StarCast for the week of April 5th, 2026. I'm your host, Jay Shaffer, and with me is my co-host, Mike Lewinski. Howdy, Mike.

**Mike Lewinski:** Good morning, Jay. How are you doing?

**Jay Shaffer:** Oh, good. Um… So it's been kind of an exciting week for space weather. What's it looking like over the next couple of days?

**Mike Lewinski:** Yeah, you know, last week, Jay, we said there was a 10% chance of an X-class flare for the 48 hours after our podcast, and it wasn't even about 10 hours after we finished recording that we got an X flare. So, that 10% chance is going to fire off right now. We've got 7 sunspot groups facing the earth, and one of them, 4409, has the Beta Gamma magnetic field that can produce M-class flares, and this one did produce an M 7.5 flare a couple days ago. We also have a narrow coronal hole facing the earth, and solar wind from that site could reach the Earth this coming Wednesday the 8th or Thursday the 9th. 

So NOAA forecast, we have a 55% chance of M-class flares over the next 48 hours, and a 20% chance of X-class flares in that same time window. Our geomagnetic storm outlook says that at mid-latitudes, we have a 30% chance of active conditions today, and 15% chance tomorrow. But at high latitudes there's a 40% chance of severe conditions today, dropping down to a 25% chance tomorrow. So what's happening in the night sky this week, Jay?

**Jay Shaffer:** Well, uh, the moon is now waning and heading toward its last quarter phase. The actual moment of the third quarter moon will fall at 4:52 UTC on April 10th, 2026, and that's about 11:52 p.m. Central Daylight Time on April 9th. And as always with the last quarter moon, it will rise shortly after midnight, your local time, and then set around noon in the daytime. So look for it high in the sky before dawn. 

And of course, the other thing that's happening in the night sky is the Orion spacecraft on its way to the moon. And a lot of people online have been asking the question whether or not you can see the spacecraft with a home telescope. And the answer is yes, amateur astrophotographers have successfully captured the Artemis 2 Orion spacecraft using home telescopes since its launch on April 1st. And because the spacecraft is currently on its four-day journey toward the moon, it is a challenging target that requires specialized techniques rather than just simple, uh, looking up in the sky and hoping that you see it. 

So the current observation details as of today is that it's about a 15 magnitude on the scale, so a plus magnitude, 15 magnitude. For context, that's significantly fainter than could be seen with the naked eye; the magnitude limit for the naked eye under perfect conditions might be approximately a plus 6 magnitude. So, uh, it requires using long exposure photography to actually detect this. In raw telescope images, the Orion spacecraft appears as a tiny moving point of light. To distinguish it from the background stars, photographers typically stack multiple short exposures, and so this results in the spacecraft appearing as kind of a streak or a dashed line across the star field, much the same way that asteroids and comets appear as streaks against the star field because they're not moving at sidereal speed like the rest of the star field. 

And so, uh, I've been seeing photographers reporting today that they've actually captured it, and since it's about 314,000 kilometers from Earth, that's pretty extraordinary. It's, uh, really challenging, um, and to track it, uh, unlike stars, which move at a predictable sidereal rate, the Orion capsule is moving on its own, uh, you know, course—topocentric coordinates—as it changes as it travels. So you can use some software; there's one called Project Pluto or Horizons, and you can get precise ephemeris data for the specific location. And so you would need a fairly large telescope, an 8-inch or larger would be ideal. I mean, with our little Seastars, they have a 50-millimeter aperture, and the Orion is kind of below their limiting magnitude at this point. Uh, and you may be able to catch it with a smaller telescope when it gets closer to Earth on its return. And also, there's the fact of the elevation of where the spacecraft is appearing right now. It's fairly close to the horizon and, uh, making it susceptible to atmospheric issues and obstructions like trees and buildings. 

But, if you have a tracking mount, and a camera, and you can look up at the current coordinates through NASA's JPL Horizon system—and search for the target Artemis II, or its COSPAR ID, which is 2026-069A—while it won't look like a ship through your backyard lens, it's more like a faint moving star. Capturing the craft with four humans on board headed to the moon would be a significant and rewarding feat for any amateur. So, Mike, what do you have for us in space news today?

**Mike Lewinski:** You know, Jay, that Artemis 2 mission is the big news, and the 4 humans are currently pushing our envelope for deep space travel. We're now officially on Flight Day 5. Commander Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen have now spent 114 hours aboard the Orion spacecraft, which they've officially named *Integrity*. They are currently in the Translunar Coast phase, having left Earth's orbit behind following a flawless engine burn on April 2nd. 

The crew is performing exceptionally well. Earlier today, they conducted critical checkouts of their Orion spacesuits and life support systems to ensure everything is green before they reach the main event. While they have been sending back stunning photos of a receding Earth, they haven't reached the moon just yet. The crew is currently closing the distance, and we expect them to perform their lunar flyby tomorrow, April 6th. They'll swing around the lunar farside at an altitude of about 4,700 miles, making them the first humans to see the moon up close in over five decades. Once they whip around the back, that free return trajectory will naturally point them back toward home for a splashdown later next week. 

But while those four astronauts are safely on their way to a lunar rendezvous, another traveler out there wasn't quite so lucky. In non-Artemis-related space news, we've been tracking comet C/2026 A1, better known as Comet MAPS. This one is a sungrazer, specifically a member of the Kreutz family, which are essentially the shrapnel of a giant comet that shattered centuries ago. MAPS was special because it was discovered further out than any other sungrazer in history, giving us a solid 81-day lead time to watch it scream toward the sun. For a while there, we were holding out hope it might pull a Comet Lovejoy and survive its pass to become a great comet in our evening skies this week. 

But the sun is a harsh mistress. On April 4th, MAPS made its perihelion pass, diving within just 100,000 miles of the solar surface. To put that in perspective, the sun is nearly 900,000 miles wide. This thing was basically skimming the fire of the photosphere. And latest data from SOHO and ground teams confirmed that the intense tidal forces and 2 million degree heat were just too much. Comet MAPS disintegrated shortly before it could emerge from the solar glare. 

Now, if you were planning on heading out tonight with your 8-inch Dobsonian to catch a glimpse, don't put the gear away just yet. While the head of the comet is gone, there's always a chance we'll see a ghostly tail—a leftover trail of dust and debris drifting near Venus in the western sky right after sunset over the next few days. It won't be the show of the century, but it's a rare look at the literal remains of a cosmic traveler. So pour one out for Comet MAPS. It flew too close to the sun, and this time the sun won. But Jay, that actually leads us right into our main topic tonight. We’re watching a comet get vaporized by solar heat, while back on Earth we’re trying to figure out how to pack that kind of power into a suitcase so we can actually stay on the moon for more than a weekend.

**Jay Shaffer:** Yeah, that's the ultimate irony, isn't it? We're terrified of the sun's heat when it's melting our comets, but the second the Artemis moon landing crew hits lunar night—which is 14 days of literally freezing darkness—suddenly we’re wishing we had a piece of it with us, and that's where the nuclear Renaissance comes in.

**Mike Lewinski:** Right? We're seeing some massive moves this week. NASA and the Department of Energy just put pen to paper on a new Memorandum of Understanding. They aren't just talking about batteries anymore; they're talking about fission surface power. Jay, walk us through the scale here. We aren't talking about the little plutonium heaters from the Voyager era, are we?

**Jay Shaffer:** Not even close. So we need to distinguish between the kind of the OG and the new wave. These older units that we put into space were **Radioisotope Thermoelectric Generators**, or **RTGs**. And they're basically like a… more like a battery than a reactor. They're basically passive batteries. They use a chunk of Plutonium-238, which is very highly reactive—radioactive, of course—and that naturally decays and gets hot. So they basically wrap that rock in thermocouples to turn that heat directly into electricity. It has no moving parts; it's incredibly reliable, but they're kind of low yield, and we're only talking like a few hundred watts. And so that's enough to keep a rover's computer awake, but it won't run a life support system for a crew of four.

**Mike Lewinski:** So that RTG is just a slow burning candle, and we're looking now at fission surface power—the old fireplace, right?

**Jay Shaffer:** Exactly. Fission is an entirely different beast. Instead of waiting for a rock to decay naturally, we're actively splitting Uranium-235 atoms in a controlled chain reaction, just like in the nuclear reactor in a submarine or in a power station. And this full-scale reactor, it's the difference between a campfire and a jet engine when we're talking the difference between RTGs and a reactor. So the efficiency leap that NASA is aiming for comes down to using, uh, old-fashioned **Stirling engines**.


**Mike Lewinski:** Wow. Well, Stirling engines are a bit of a throwback, right? That's 19th-century tech making a comeback now in the 21st.

**Jay Shaffer:** Yeah, I don't know if you ever did that experiment. I remember doing the experiment back in high school, where we had a Stirling engine and basically lit a candle underneath the heat exchanger, and then it would drive the piston and make it go around. So it's kind of like an old moving-part technology, as opposed to using turbines and water like you would in a typical nuclear reactor. And it's the perfect marriage. RTGs are notoriously inefficient; they only convert about 6 to 8% of their heat into power. But the **Free-Piston Stirling Engine** uses that fission heat to expand a gas, which then pushes the piston back and forth through a magnetic coil to generate the alternating current. And because it's a closed-loop system with almost no friction, it can hit efficiencies closer to 30 to 40%. And that's how you get the oomph that you need for a lunar colony.

**Mike Lewinski:** So the target for these first-gen lunar reactors is about 40 kilowatts. I know we said 10 houses earlier, but if you look at the math, where a typical American home consumes roughly 10 kilowatt-hours a day, 40 kilowatts of constant steady output is actually closer to powering 4 large modern homes running at peak capacity. That doesn't sound like much, but on the moon, every single watt is used for survival.

**Jay Shaffer:** Yeah, both you and I are really aware of our electricity usage since we were both off-grid and solar powered. So, you know, that 10 kilowatt-hours a day is about typically what my household would use. So in space, you aren't running a dishwasher; you’re running a CO2 scrubber and an oxygen recycler. You definitely want to make sure that you keep the power on. And unlike solar panels, which are basically useless for 350 hours at a time during the lunar night, the Stirling fission units don't care about where the sun is—they just keep on chugging.

**Mike Lewinski:** I noticed something in the budget. The **DRACO** program—the nuclear thermal rocket that was supposed to get us to Mars in half the time—that got the axe last year.

**Jay Shaffer:** Yeah, as part of the NASA budget cuts, and that was a heartbreaker for the propulsion nerds. DARPA pulled the plug because they basically figured out that SpaceX's Starship is making chemical launches so cheap that the R&D for a nuclear engine didn't look economical anymore. But—and that is a big 'but'—the tech didn't die. NASA is pivoting their research more toward **Nuclear Electric Propulsion**, or **NEP**. Instead of using a reactor to heat hydrogen for thrust, they're using it to power these massive ion engines, where it's heating plasma instead of hydrogen.

**Mike Lewinski:** So instead of a nuclear thermal explosion out the back, we're talking about a reactor-fed electric engine. It's slower to start, but we're talking about a marathon runner heading out into the solar system, right?

**Jay Shaffer:** Yeah, exactly. With NEP, you can keep a steady low-thrust acceleration going for months, and you're not running out of hydrogen fuel. And it's much safer to handle on the launch pad and potentially more sustainable for long-haul cargo runs to maybe even the Jovian moons later this century.

**Mike Lewinski:** Sounds like a total shift in strategy. Then we're moving from 'How do we get there fast?' to 'How do we survive once we arrive?' If we want a permanent footprint on the moon by 2030, we can't rely on solar panels that are going to take a nap for 2 weeks out of every month. We need the reliability of the atom, don't we?

**Jay Shaffer:** Yeah, and there are still, you know, the concerns of launching plutonium or uranium in the case of these fission reactors. But with companies like Rolls-Royce and BWXT now jumping into the supply chain, this isn't just a government science project anymore. It's becoming an industry, and they're basically trying to build a grid for the moon, or at least a microgrid. We're moving from the 'camping' phase of space exploration more towards the 'utility' phase.

**Mike Lewinski:** Yeah, and speaking of utilities, I see the private sector, including some of the AI tech giants, are suddenly reviving interest in nuclear as the only way to keep the lights on both here and on the lunar surface. I have a feeling that this is going to be the demand that drives us into the era of the small modular reactors.

**Jay Shaffer:** Yeah, and so, you know, traditionally, environmentalists have been totally opposed to nuclear power generation, mainly for the reasons of possibilities of meltdowns and what to do with nuclear waste. And all those issues still are there. But like we were saying, kind of downscaling these reactors kind of limits those risks to a lower level. Is that your perception, Mike?

**Mike Lewinski:** Yeah, it is. And with the 4th-gen tech, we're getting more 'laws of physics' fail-safes where you don't need an active power source to cool these reactors. They can deactivate on their own without interactions. That's what they mean by 'laws of physics'—so that if humans walk away or die off, the reactors will just stop.

**Jay Shaffer:** Yeah. And as we hopefully pivot away from fossil fuels as well, and we're kind of realizing that fossil fuels are as dangerous, if not more dangerous, to our continued existence than the possibility of having nuclear energy. And, uh, in particular, Bill Gates is one of the big proponents of using nuclear power to replace the fossil fuel power that we're so reliant on nowadays.

**Mike Lewinski:** Yeah, he's been an advocate of those fourth-gen reactors for decades now.

**Jay Shaffer:** So we'll see how that goes forward. So, uh, that was an interesting discussion. I want to thank all of our listeners for tuning in to the podcast today. And let us know what you think about nukes in space. Please be sure to comment, like, and subscribe. And you can also check out our websites. Mike's is *wildernessvagabonds.com*, and you can check out my cameras on *skylapser.com*. You can also look at our time-lapse videos on our YouTube channels—search for Mike Lewinski or Skylapser. Our intro music is 'Fanfare for Space' by Kevin MacLeod from the YouTube Audio Library. From the Deep Sage 9 Observatory, this is Jay Shaffer, and Mike Lewinski. wishing you all clear skies.