NEW: Valar Atomics announces its raised $1 Billion in funding from numerous companies including Sequoia Capital.

BREAKING: Google has rolled back its tool less than a day after it launched. Updated story coming soon.

NEW: Google adds AI to satellite images, raising fears of deepfakes in the sky. Full story here: www.npr.org/2026/07/31/n...

I will just point out that the Onion predicted this 18 years ago... www.youtube.com/watch?v=3q_i...

Wow. Somebody actually said it. #IranWar #HuntForRedOctober

GUYS! I'm going on vacation for a little bit, but I didn't want to leave you without quality content. So please enjoy this THERMONUCLEAR RAGEBAIT! 😘✈️🌴

Valar Atomic's nuclear powered website has been down since their demonstration event last week. That means the reactor isn't running at the moment...

What's the fuel's condition? "It's in good condition in terms of storage... But it is from a grade of fuel that was not the highest quality. So there's many different grades. This is definitely one of the lower grades of TRISO out there." (Image not of the actual fuel)

No surprise here: "We have what's called a Thermoelectric Generator, a TEG, and this is the type of system you'd find on satellites where you put nuclear reactors up in space." Basically it uses a thermal gradient to generate power. The Curiosity and Perseverance rovers use something similar.

NEW: After Valar Atomics produced the first electricity last week, I got a brief interview with Isaiah Taylor, their founder and CEO. I learned some interesting stuff that's probably a bit niche for NPR's audience, but #nukesky, you're going to love it.... Here we go! 😀☢️🧵

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Sayonara ALARA. The NRC is proposing removing the "As Low As Reasonably Achievable" standard from their rules for radiation exposure. The DOE removed the standard about six months ago. www.nrc.gov/docs/ML2618/...

NEW: @planet.com has lifted some, but not all of its restrictions on imagery from the Middle East.

AI: delivering the facts you want to hear. (Also a bit miffed they’re using the NPR badge to brand their errors).

Valar Atomics just dropped a video of their criticality test for the Ward 250 SMR, which is being run in a tent in Utah. Overheard "In accordance with the approval letter from Bob Boston, go to a step value of 20.5k" (Bob Boston is overseeing safety oversight of the RPP for DOE INL).

And I think it's likely to be a mission killer for Ukraine's new balloon missile too. The rocket appears to be a solid-fueled weapon with minimal guidance. The warhead is only 10 kg or so. That's pretty small. It's hard to imagine this will be a very accurate or dangerous weapon.

So first off, the idea of rockets on balloons goes all the way back to James Van Allen! He pursued the concept, which he hilariously called a "Rockoon", in the 1950s. But he abandoned it for the same reason most people abandon balloon-based explosives. The wind. airandspace.si.edu/stories/edit...

GUYS! Ukraine has dropped plans for a balloon launched rocket. According to this report, the DART rocket is designed to be EW resistant. But guess what? It's also a really bad idea! You know I can never let a balloon-weapon go uncommented on, so here we go... militarnyi.com/en/news/ukra...

OK for the real nerds, what I think is probably the newest thing in Hecla's paper is that it nearly completely rules out the possibility of an Indirect Cycle reactor. That would be a reactor with an isolated coolant and a heat exchanger. He concludes very likely too heavy/complex to work.

The reactor is operated using a ring of control rods that are half coated in Berylium Oxide and half in Boron-Carbon. To turn the reactor on, rotate the rods so the BeO side faces inward. Turn it off by rotating to B4C. INSANE! Also, the turbojet shaft goes STRAIGHT THROUGH THE CORE!

Jake told me a lot of his modelling of Burevestnik were built off that early work, specifically with the XNJ 140E design by General Electric. This is a B-A-N-A-N-A-S reactor design. Basically air is flowing straight through the core.... (OSTI source: www.osti.gov/biblio/12555...)

Now what I hadn't realized is that the U.S. actually did some work on direct-cycle nuclear engines in the 1950s. @whatisnuclear.com has posted a great video from that era which is worth a watch for a deep dive: youtu.be/V-8q8INxQEY?...

A DIRECT CYCLE NUCLEAR TURBOJET! And didn't my colleague Connie do a great job with this diagram? (Though she wouldn't let me label the control drums on the outer circumference of the reactor core.)

Quick H8RS break. I KNOW many people who follow me already knew it wasn't a ramjet. I KNOW most of you guys suspect what I'm going to say next. I KNOW there's a handful of diagrams out there that get it right. BUT this is the first really rigorous analysis I've seen showing Burevestnik is...

And like he mathed the whole Ramjet question. Basically a ramjet is far too heavy and has to move too fast to be feasible. Love this diagram.

He then used that to back out the aerodynamics and the thrust requirements for whatever reactor was onboard. His paper with R. Scott Kemp is here: spacenuclear.mit.edu/files/2026/0...

So if it wasn't a ramjet, what was it? Enter Jake Hecla. Jake's been wondering the same things I have about this missile. But unlike me, he has a joint appointment in aero/astro and nuclear engineering. Jake spent a lot of time doing photogrammetry to figure out Burevestnik's dimensions....

Now many people thought this, but it was basically confirmed in October, after a successful flight test. Russian Chief of the General Staff Valery Gerasimov confirmed that the missile flew 14000 km in a little under 15 hours. Math tells you that's very much subsonic.

But the ramjet concept didn't make all that much sense. Ramjets can only operate at supersonic speeds, and Burevestnik didn't look like a supersonic missile. Left: a design for the Supersonic Low Altitude Missile or SLAM. Right: A fuzzy photo of Burevestnik.