A data point on decoupling. The Soviet Union did an experiment back in 1976. 36-meter cavity (from another explosion), 10 kt, 15-fold signal reduction. (Russian Strategic Nuclear Forces, p. 477)

Taught about the "decision to use the atomic bomb" a bit today, and the thing the students were audibly the most surprised by was Nagasaki being written in, by hand, on the penultimate draft of the strike order, after Kyoto had been definitely removed from the list for the final time.

The difference between zero enrichment in Iran and a couple of thousand centrifuges in Iran is quite modest, since Iran has shown the ability to install almost that many in a month. Some compromise there would be better than going back to military strikes, with all their risks and uncertainties.

Nine ministry of defense satellites launched from Plesetsk on Feb 5. The missions are not yet clear. One, Cosmos-2600, is on sun-synchronous orbit with altitude about 325 km. Others are at about 500 km orbits. Website: russianforces.org/blog/2026/02... Substack: open.substack.com/pub/russianf...

Those of you who are lucky to be in Paris, don't miss the chance to see Martin Parr's photos at Jeu de Paume. He is really good.

Russia takes back the commitment to stay within New START limits for one year, but leaves some room for doing it de facto (or together with the US). However, Putin's September initiative seemed only conditioned on the US response after a year, so maybe we'll see it again. mid.ru/ru/press_ser...

The Soviet Union, of course, had no weapons or delivery systems to do anything like this in 1954

@russianforces.org is pretty spot-on here. New START's probable expiry reflects the broader state of relations between Russia, the US, and China. Those poor relations are the fundamental source of nuclear risk, rather than the existence or not of a specific treaty. www.ft.com/content/fd1d...

What to expect when New START expires on 5 February 2026? Russia is likely to stick to its offer to stay within the limits. The US is likely to go for upload, but there are options about when and how. Links to the post below. 1/2

NUKEMAP is apparently making guest appearances on the London metro, to the surprise of many (including me — but I explicitly make it clear people can use its imagery for whatever without asking me!)

Back to Greenland and early-warning radars. As it turned out, a few things have changed. All radars got an upgrade to AN/FPS-132 (UEWR). Here is an updated Goole Earth file russianforces.org/US-Early-War.... The image shows Pituffik/Thule. Note that ranges are notional

All eyes on Greenland... Yes, the US has an early-warning radar there. And in many other places too. Here is a Google Earth file with US radar fans russianforces.org/US-Early-War... It's from 2018, but I don't think much has changed. Maybe the name - it's still Thule in the file.

65 years ago today, President Dwight D. Eisenhower delivered his Farewell Address, warning—inter alia—“against the acquisition of unwarranted influence, whether sought or unsought, by the military-industrial complex. The potential for the disastrous rise of misplaced power exists and will persist.”

"Wellerstein presents his story in clear, direct prose, ... 'The Most Awful Responsibility' is a well-written opus unpacking Truman’s—and America’s—complicated relationship with nuclear weapons." www.wsj.com/arts-culture...

That's a good milestone: "January 14, 2026 marks a milestone in world history. The world has gone eight years, four months, and 11 days without a nuclear test—the longest period since the Trinity test without a nuclear explosion" blog.ucs.org/dylan-spauld...

Those opposed to extending New START limits feel that it's their moment. If the limits are extended now, even for one year, it would be much more difficult to upload and do other things a year later. 1/

Forty years ago, on 15 January 1986, Mikhail Gorbachev announced a plan to eliminate all nuclear weapons by 2000. Here is the original poster and the English version. More details on the website russianforces.org/blog/2026/01... and Subtack open.substack.com/pub/russianf...

I tried to put together an update of the status of the Russian strategic forces. My estimate is 575 launchers/1530 warheads (can "upload" to about 2100). It appears that R-36M2/SS-18 has been withdrawn. Website: russianforces.org/blog/2026/01... Substack: open.substack.com/pub/russianf...

First Yars missiles deployed at Tatishchevo. Not clear if they are replacing Topol-M deployed there since 1997. Website: russianforces.org/blog/2025/12.... Substack: open.substack.com/pub/russianf...

A nice video by DTRA on inspections. They are optimists and still maintain the program to train linguists and inspectors. Don't tell me that verification is hard or even impossible. There is a lot of expertise there. youtu.be/FNtV2-0QFzg?... (Image: R-39 removed for inspection?)

I am thrilled the newest "Russia's Nuclear Signaling" Chronology is published! Really glad @smetanamichal.bsky.social came onboard 15 months ago to continue this important work. A big thank you to all @swp-berlin.org @swp-intsecurity.bsky.social #STAND & @prcp.cuni.cz for making this possible! 1/7

My annual report, Space Activities in 2025, is now available at planet4589.org/space/papers...

Well, Russian early-warning satellites may not be dead yet. Thanks to @planet4589.bsky.social and @coastal8049.bsky.social for pointing out that it may be too early to write these satellites off. I still think the constellation is not quite well, but we'll see in a few months. Links below 1/

This is a nice addition to the "bad Cold War ideas" file — nukes that would detonate themselves at full yield "in the event the carrier and/or crew fell prey to the enemy defense." Never adopted as far as I know... from a Sandia study of nuclear safety issues, 1959.

The space segment of the Russian early-warning system is not in good shape. Only one satellite appears to be operational. The image shows mean motion of Cosmos-2563, launched in November 2022. Links to posts below 1/2

It's now clear that the Yars test launch in early December was postponed. Russia made another attempt on Dec 25-26, unclear if successful (probably not). russianforces.org/blog/2025/12... (The early December attempt is here russianforces.org/blog/2025/12...)

Oreshnik in Belarus? Something is definitely happening but there are reasons to be skeptical. I tried to put various bits together russianforces.org/blog/2025/12... Krichev-6 on the map below is the site identified by Jeffrey Lewis' team (seems rather close to the Russian border) 1/2

Missile defense was, of course, a big topic as well. Here is Putin in 2008 (I'd disagree with this logic, but it's a standard argument). What's interesting, the "barbaric" stuff was indeed under development. There is a photo of Status-6/Poseidon from 2009 russianforces.org/blog/2016/04...

Here is an interesting exchange between Bush and Putin in 2005. Uranium of Pakistani origin in Iran? And who are "they" who found it (if Iran didn't tell the IAEA)? nsarchive.gwu.edu/sites/defaul... (I must say I don't know Iran all that well, so maybe this is not something new at all)

Deployment of Yars missiles in Kozelsk completed russianforces.org/blog/2025/12... The decision to keep silos for Yars was made in 2008, first two missiles deployed in 2014. The total number of Yars missiles in Kozelsk silos is now 30. Post on Substack: russianforces.substack.com/p/deployment...

I'm excited about this — expect lots of interesting things in the new year! thebulletin.org/2025/12/alex...

Missile defense works perfectly ... against missiles that don't exist. Documents from the Katayev archive show how the Soviet Union concluded that it can come up with missile designs to defeat SDI. I'm sure it will be the same with the Golden Dome. Links to full posts below 1/2

In early December Russia released NOTAMs for the 3-7 December window covering Plesetsk and Kura. By all indications it was a Yars launch. The test was either cancelled or postponed - NOTAMs were cancelled on 2 December (h/t @thelookout.bsky.social) russianforces.org/blog/2025/12...

Oh no. This is a very sad news. Bill was great.

Knyaz Pozharsky submarine was accepted for service in July 2025, but it's not clear if it test-launched its missile, Bulava. NOTAMs suggest that the launch was planned (h/t @m514ever.bsky.social) and it's likely it was scrubbed. But hard to say this with certainty. Links below. 1/

I am going to be holding a talk and discussion of my NEW BOOK about Truman and the atomic bomb on December 16, 2025 at 12-2pm ET. The event will be in Paris (free to anyone who is local — 18:00-20:00 CET), but also streamed on Zoom. Here is the event description: www.sciencespo.fr/ceri/fr/even...

Oh and TOMORROW, FRIDAY, December 5th, I will be doing an AMA about the book on Reddit's AskHistorians forum. Exact time TBD but it will probably start around 10am ET and go for a few hours.

By all indications, the event in Yasnyy/Dombarovskiy was a failed Sarmat test (links to the full post below). So much for the promise to deploy the first Sarmat in 2025. I wouldn't overdramatize this - stuff happens. And it's not like Russia needs Sarmat. 1/

Full video of the launch t.me/militaryruss.... Colleagues are positive it's SS-18 or Sarmat (they are quite similar). My guess is that Sarmat is more likely. A launch from Yasnyy logical after last year failure in Plesetsk. As for SS-18, it hasn't been tested for a while (2014?) so why do it now?

For comparison, here is a failed Proton launch in 2013. It's a bigger rocket, but it's UDMH/NOx too www.youtube.com/watch?v=ycRV...

Something happened in Yasnyy/Dombarovskiy. There is also a video and some NOTAMs t.me/militaryruss.... Looks like a failed ICBM launch. The color of this cloud doesn't look good. Not clear if it's Sarmat. There are other options: SS-18 or SS-19. Wait for more information.

Excellent stuff here from Tatiana Stanovaya. x.com/Stanovaya/st...

Apparently, it's the first document of this kind in quite a while (since 2005?). Here is the link www.fmprc.gov.cn/mfa_eng/xw/w...

Three Rodnik communication satellites launched from Plesetsk by Angara 1.2 launcher. Will be designated Cosmos-2597, -2598, and -2599. This is second Rodnik launch in 2025 (previous in March). Links in the next post. 1/

This post by @wellerstein.bsky.social doomsdaymachines.net/p/nuclear-we... reminded me of an interesting observation by a colleague based on her interviews about attitudes toward nuclear weapons: Older generation experts are quite emotional about nuclear weapons. The younger folks, not so much.

By the way, my old take on "strategic stability" thebulletin.org/2012/10/the-...

Looks like an interesting book - “Strange Stability: How Cold War Scientists Set Out to Control the Arms Race and Ended Up Serving the Military-Industrial Complex.” Author's interview to Harvard Gazette share.google/saasRud8lxHm...

Niels Bohr writing to Carlsberg Foundation: "I respectfully request a travel grant of 2500 Kr for a one-year study stay at foreign universities." That's it. That's the entire proposal. He received approval the next day...

I'm not an economist, so don't shoot me. One idea shows up in many places in @johncassidysays.bsky.social Capitalism & its Critics: Capitalism is truly effective in amassing wealth, which must be spent (it creates problems otherwise). But the system cannot spend it on citizens' welfare... 1/

There seems to be a new date for Sarmat deployment: "experimental combat duty" in 2025 and "combat duty" in 2026. The former seems plausible: Rocket Forces can put it into one of the Uzhur silos (like the one below). The latter is unlikely w/o tests. Links to posts in reply 1/