Jeffrey LewisNuclear Test Sites Are Too Damn Busy

This is the written summary accompanying the satellite images we provided to CNN about the worrisome levels of activity we see at Russian, Chinese and US nuclear test sites.

See also: Exclusive: Satellite images show increased activity at nuclear test sites in Russia, China and US, September 23, 2023.


Satellite images taken by Planet Labs show that Russia, China and the United States are all increasing levels of activity at their nuclear tests sites.  This heightened activity includes significant construction at all three locations, raising the prospect that one or all three may resume nuclear explosive testing for the first time since the 1990s.

The activity at Novaya Zemlya and Lop Nor is raising concern that Russia and China are either preparing to resume underground nuclear explosions or secretly conducting low-yield explosions already.  However, the reasons for the construction at sites in Russia and China are unclear. Construction could be related to so-called subcritical nuclear experiments or preparing to respond to a nuclear test if the United States were to conduct one. 

Mutual suspicions are being used by advocates in all three countries who would wish to resume the explosive testing of nuclear weapons. If one country explodes a nuclear weapon, the other two are likely to follow suit.  A resumption of nuclear explosive testing by the three big nuclear powers would allow all three to resume development of new nuclear weapons and accelerate the arms race among the three.

Russia, China and the United States stopped explosive testing of nuclear weapons in the 1990s. There has been a moratorium among the three on nuclear explosive testing ever since. All three countries signed the Comprehensive Nuclear Test Ban Treaty, which prohibits all nuclear explosions in 1996 – although neither China nor the United States have ratified this treaty and more than twenty-five years later the treaty has not entered into force. In the absence of nuclear explosive testing, all three countries are limited in the new nuclear weapons they develop as the three countries have been traditionally reluctant to deploy untested nuclear weapons designs.

At the same time, all three countries have continued to conduct so-called subcritical nuclear experiments and maintained readiness to resume conducting nuclear explosions if the others do. Satellite images show that in 2022 and especially 2023, the activity levels at all three sites have increased substantially.

At Russia’s nuclear test site on the archipelago of Novaya Zemlya, there is significant construction ongoing not seen since the end of nuclear testing in the 1990s.  There are significant numbers of large trucks, construction cranes, shipping containers and building supplies supporting the construction of at least two new buildings, including what will be the largest building at the site.  This construction is occurring in Severny, which is the main administrative and residential area at the nuclear test site.  Russia may be planning to station more personnel at the facility or operate it year round.

At China’s Lop Nor nuclear test site, there is also significant activity.  The main administrative and support area at Lop Nor has a number of ongoing construction projects.  One facility appears to be a set of bunkers for storing explosives.  At the site with horizontal tunnels, excavation at a large underground tunnel has continued in recent years – either to support subcritical nuclear experiments or to maintain readiness to resume nuclear testing.  Other new stories have documented activities at the area containing vertical shafts that were used for nuclear testing.

In recent years, the U.S. State Department has raised concerns about the possibility that both Russia and China are conducting low-yield nuclear explosions that are difficult to detect at these sites.  These concerns are probably based in part on analysis of satellite imagery.

Russia, and likely China, appear to harbor suspicions about the United States that mirror American concerns, particularly after press reports indicated that the Trump Administration seriously considered resuming nuclear testing in 2020. In February, Vladimir Putin accused the United States of preparing to break the moratorium on testing, adding that “… if the United States conducts tests, then we will. No one should have dangerous illusions that global strategic parity can be destroyed.”  

Russian and Chinese analysts looking at satellite images of the US nuclear test site would also see extremely high levels of activity.  The United States recently completed one of a pair of around the clock underground mining operations that added more than 1,000 square feet of underground laboratory space to its U1a Complex for conducting subcritical nuclear experiments.  

In general, the United States has been relatively transparent about both the experiments conducted at U1a, as well as the rationale for expansion. At the same, from the perspective of Russian and Chinese analysts, satellite images show the same kinds of high levels of construction activity at U1a that, when seen at Novaya Zemlya and Lop Nor, raise concerns among American analysts.

The activities detected in satellite images are giving rise to mutual suspicion. The solution, if there is one, is likely to require expanded on-the-ground transparency.  Recently, the US Administrator for the National Nuclear Security Administration, proposed “hosting international observers for monitoring and verification research and development on our subcritical experiments” to help dispel suspicions.