“For half a century, ACA has been providing the world … with advocacy, analysis, and awareness on some of the most critical topics of international peace and security, including on how to achieve our common, shared goal of a world free of nuclear weapons.”

– Izumi Nakamitsu
UN High Representative for Disarmament Affairs
June 2, 2022
Daryl Kimball

Keeping Outer Space Nuclear Weapons Free

March 2024
By Daryl G. Kimball

Fifty-seven years ago, through the Outer Space Treaty, the United States and the Soviet Union agreed to codify a fundamental nuclear taboo: nuclear weapons shall not be stationed in orbit or elsewhere in outer space. But there is growing concern that Russia is working on an orbiting anti-satellite (ASAT) weapons system involving a nuclear explosive device that would, if deployed, violate the treaty, undermine space security, and worsen the technological and nuclear arms race.

The flash created by the Starfish Prime high-altitude nuclear test on July 9,1962 as seen from Honolulu, 900 miles away. (Wikimedia Commons) The White House confirmed on Feb. 15 that U.S. intelligence uncovered evidence that Russia is developing an ASAT weapon that “would be a violation of the Outer Space Treaty, to which more than 130 countries have signed up to, including Russia.” Russian President Vladimir Putin issued a nondenial denial, claiming on Feb. 20 that Russia remains “categorically against…the placement of nuclear weapons in space.”

An ASAT system involving a nuclear explosive device could produce a massive surge of radiation and a powerful electromagnetic pulse that, depending on the altitude of the explosion and the size of the warhead, could indiscriminately destroy, blind, or disable many of the 9,500 commercial and military space satellites now in orbit.

Russia’s reported pursuit of a nuclear-armed ASAT system is another troubling attempt by the Kremlin to challenge the fundamental norms against nuclear weapons and to use nuclear weapons to intimidate and coerce. But it would not be a “Sputnik moment” requiring parallel ASAT weapons system development or radical new countermeasures by the United States.

As with the exotic nuclear delivery systems that Putin first announced in 2018, including a long-range, underwater torpedo and a nuclear-powered cruise missile, a nuclear-capable ASAT weapons system would add a dangerous capability. But it would not alter the existing military balance of terror.

Russia already fields a range of ASAT system capabilities, including co-orbital systems that can launch cyberattacks and engage in electronic jamming of specific adversary satellites. As with China, India, and the United States, Russia has already demonstrated a capability to use a ground-based missile to hit and destroy an orbiting satellite. All nations with nuclear-armed ballistic missiles also have the latent ability to detonate a nuclear explosive device in space. From 1958 to 1962, the United States and the Soviet Union conducted nuclear explosive tests in the outer atmosphere.

The United States, which has the largest number of satellites in orbit, is already working to improve the resilience of its military communications, early-warning, and surveillance assets. A new Pentagon program soon will put constellations of smaller, cheaper satellites into orbit to counter space-based threats. Any corresponding U.S. nuclear-armed ASAT system effort would put U.S. and other satellites at even greater risk and do nothing to protect U.S. capabilities in space.

Off-and-on talks designed to maintain the peaceful use of space, including restrictions on ASAT weapons systems, have been stymied for years. A long-standing Chinese-Russian treaty proposal would ban objects placed into orbit with the intent of harming other space objects. It also would ban the “threat or use of force against outer space objects,” which would still allow suborbital and ground-based ASAT weapons capabilities.

Until recently, the United States has been wary of any legally binding restrictions on ASAT weapons systems in part because they might restrict U.S. ground-based missile defense capabilities or a possible space-based, kinetic anti-missile system that could involve a number of orbiting interceptors that provide a thin defense against ground-based missiles. More recently, the Biden administration proposed and rallied support for a ban on direct-ascent ASAT missile tests, which create debris fields that pose a major hazard to orbiting objects.

In the coming weeks, Washington, Beijing, and other capitals need to pressure Putin to abandon any ideas about putting nuclear weapons in orbit. As President Joe Biden noted on Feb. 16, that deployment “hasn’t happened yet, and my hope is it will not.”

The possibility of a Russian nuclear-armed ASAT system should also spur Washington, Moscow, Beijing, and other space-faring nations to get serious finally about additional measures to protect space security. They need to implement effective limits on ASAT weapons systems, including direct-ascent ASAT weapons and space-based systems that can destroy satellites and other objects traveling through space.

Russian ASAT weapons systems are not the only destabilizing factor in the dangerous nuclear and deterrence equation. In the absence of new, agreed constraints on Russian and U.S. strategic nuclear arsenals and measures to halt the growth of China’s arsenal, a costly three-way nuclear arms race could accelerate after the New Strategic Arms Reduction Treaty expires in 2026. In response, Biden needs to rally international pressure on Russia to support his proposals for talks on a new nuclear arms control framework and separate, regular dialogues with Moscow and Beijing on reducing nuclear dangers. Space and global security depend on it.

Fifty-seven years ago, through the Outer Space Treaty, the United States and the Soviet Union agreed to codify a fundamental nuclear taboo: nuclear weapons shall not be stationed in orbit or elsewhere in outer space.

U.S. Warns of New Russian ASAT Program

March 2024
By Daryl G. Kimball

Russia is pursuing a new and more advanced anti-satellite (ASAT) weapons system that would violate the Outer Space Treaty, according to Biden administration officials.

U.S. intelligence reports that Russia is pursuing a new and more advanced anti-satellite weapons system have raised new concerns about an arms race in space. But Russian satellites, such as the one pictured, also would be vulnerable. (Photo by NASA)National Security Advisor Jake Sullivan briefed select members of Congress on new U.S. intelligence about the system on Feb. 15, and later that day, White House spokesperson John Kirby confirmed to reporters that the system is “related to an anti-satellite weapon that Russia is developing.”

Although it is not an “active capability that has been deployed,” Kirby said that the new system “would be a violation of the Outer Space Treaty, to which more than 130 countries have signed up to, including Russia.”

Article IV of the treaty expressly prohibits countries from deploying “in orbit around the Earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install[ing] such weapons on celestial bodies, or station[ing] such weapons in outer space in any other manner.”

Kirby said that “our general knowledge of Russian pursuit of this kind of capability goes back many, many months, if not a few years. But only in recent weeks has the intelligence community been able to assess with a higher sense of confidence exactly how Russia continues to pursue it.”

“We found out there was a capacity to launch a system into space that could theoretically do something that was damaging,” President Joe Biden told reporters at the White House on Feb. 16. “Hasn’t happened yet, and my hope is it will not.”

According to a CNN report that same day, officials familiar with the intelligence assessment confirmed that the Russian ASAT system under development involves a nuclear explosive device that would produce not only a massive nuclear-driven blast wave and a surge of radiation, but also a powerful electromagnetic pulse that could destroy, blind, or disable other satellites in orbit over a wide zone.

Such a weapon could pose a threat to U.S. and allied military communications, early-warning, and intelligence-gathering satellites if it were to become operational. It also would pose a threat to thousands of other space-based assets in orbit operated by dozens of other countries and commercial entities.

During the Cold War, the Soviet Union and the United States experimented with various types of ASAT weapons systems concepts, including the use of nuclear explosions to destroy objects in space and the production of beams of directed energy to destroy or disable enemy satellites.

Between 1958 and 1962, the United States carried out a handful of very high-altitude nuclear detonations, including the massive 1.4-megaton Starfish Prime test that occurred 250 miles above the Pacific Ocean and demonstrated the potential of nuclear detonations as ASAT weapons. The Soviets conducted a series of high-altitude nuclear test explosions over Kazakhstan between 1961 and 1962.

These test explosions produced a surge of free electrons that created X-rays capable of severely damaging electronic components and computer systems on the ground and in low earth orbit, an electromagnetic pulse that can disable unprotected electrical components on satellites, and a nuclear flash that can blind optical sensors on reconnaissance satellites. The Starfish Prime nuclear test explosion also produced radiation belts that lingered for months, disabling eight of the 24 satellites that were in orbit at that time, according to a 2022 report by the American Physical Society.

In 1963, U.S. and Soviet negotiators concluded the Limited Test Ban Treaty, which prohibits nuclear test explosions in the atmosphere, and in 1967 the Outer Space Treaty.

As Jaganath Sankaran wrote in Arms Control Today in 2022, Russia has been pursuing a range of ASAT system capabilities for more than a decade, including co-orbital ASAT weapons capabilities in the geostationary orbit where most military command-and-control satellites operate, as well as ground-based lasers and a range of satellite jamming systems to deny and degrade the capacity of weapons that rely on satellite-enabled information.

In 2021, Russia conducted an ASAT weapons test on one of its own satellites, breaking it into more than 1,500 pieces of debris, which can pose a serious threat to other objects in orbit. China, India, and the United States also have demonstrated ASAT missile capabilities.

But none of these systems involved nuclear explosive devices. Today, there are approximately 9,500 active satellites in orbit and two crewed, orbiting space stations. One or more nuclear weapons explosions in orbit would create far more indiscriminate damage than the 1962 Starfish Prime nuclear test, and the loss of satellite services would affect significant commercial, military, communications, and navigations systems on Earth.

On Feb. 15, Kremlin spokesperson Dmitry Peskov dismissed the claim that Russia was pursuing a nuclear-armed ASAT weapons capability as a “malicious fabrication," but on Feb. 16 he told RIA Novosti that Russia is ready to discuss the issue “if there are such initiatives from the American side.”

On Feb. 15, Kirby said, “We are in the process with engaging with Russia about this.” He said that Biden “has directed a series of initial actions, including additional briefings to congressional leaders, direct diplomatic engagement with Russia, with our allies and our partners as well, and with other countries around the world who have interests at stake.”

On Feb. 20, Russian President Vladimir Putin commented on the topic of nuclear weapons in space during a working meeting in Moscow with Russian Defense Minister Sergei Shoigu.

“Our position is clear and transparent: we have always been categorically against, and are now against, the placement of nuclear weapons in space,” Putin said, according to Kommersant. “On the contrary, we call for compliance with all agreements that exist in this area and proposed to strengthen this joint work many times over.”

The anti-satellite weapons system would violate the Outer Space Treaty.

Russia Rejects New Nuclear Arms Talks

March 2024
By Libby Flatoff and Daryl G. Kimball

Russian leaders have rejected a formal U.S. proposal to resume talks “without preconditions” on a new arms control framework to succeed the New Strategic Arms Reduction Treaty (New START) that expires in two years.

A Russian Topol-M intercontinental ballistic missile on display in Red Square  in Moscow in 2009. (Photo by Dmitry Kostyukov/AFP via Getty Images)If the decision holds, it means that the only remaining bilateral nuclear arms control agreement limiting the world’s largest nuclear weapons arsenals will expire on Feb. 5, 2026, along with its strict verification provisions.

In a written response to the United States on Dec. 2 obtained by Arms Control Today, the Russian Foreign Ministry said, “The proposal of the U.S. Side to launch a bilateral dialogue ‘to manage nuclear risks and develop a post-2026 arms control framework’ is unacceptable to us. Such ideas are completely inappropriate and absolutely untimely for they cannot be considered adequate to today’s realities and to the state of Russia-U.S. relations.”

Citing NATO and the “acute conflict around Ukraine,” the Russian diplomatic note also said, “At the moment, the U.S. Side does not demonstrate any interest in a mutually acceptable settlement of the current crisis [Ukraine], does not show readiness to take into account Russia’s security concerns…. Thus, there is no visible basis for a constructive and fruitful dialogue with the United States on strategic stability and arms control.”

The U.S. proposal was first announced by National Security Advisor Jake Sullivan at the annual meeting of the Arms Control Association last June. Sullivan said that the United States is ready to engage in nuclear arms control diplomacy with Russia and with other nuclear-armed members of the nuclear Nonproliferation Treaty (NPT) “without preconditions.”

“Rather than waiting to resolve all of our bilateral differences, the United States is ready to engage Russia now to manage nuclear risks and develop a post-2026 arms control framework,” he said. Three days later, Kremlin spokesperson Dmitry Peskov described Sullivan’s comments as “important and positive.” (See ACT, July/August 2023.)

But by August, Russian officials at the preparatory committee for the 11th NPT Review Conference had already started signaling that, in their view, nuclear arms control talks “cannot be isolated from the general geopolitical and military-strategic context,” which includes the full-scale Russian invasion of Ukraine.

The United States followed up Sullivan’s June speech with a written proposal to Russia that was transmitted in September. (See ACT, December 2023.)

On Jan. 17, Russian Foreign Minister Sergey Lavrov elaborated on Russia’s written response to the U.S. proposal, saying that “amid a ‘hybrid war’ waged by Washington against Russia, we aren’t seeing any basis, not only for any additional joint measures in the sphere of arms control and reduction of strategic risks, but for any discussion of strategic stability issues with the United States.”

Pranay Vaddi, senior director for arms control at the U.S. National Security Council, said at an event hosted by Center for Strategic and International Studies on Jan. 18 that the rejection “linked other politics to arms control in a way that has not been done in the post-Cold War era…[and] as a result, we don’t have a conversation to be had.”

Vaddi expressed disappointment that Russia had not even offered a counterproposal on nuclear arms control and disarmament. In failing to do so, “Russia is minimizing their obligations under the NPT” and not even attempting “to pursue negotiations in good faith” as required by Article VI of that treaty.

Shortly after Russia’s rejection of the U.S. proposal became public, the U.S. State Department on Jan. 31 released its annual report to Congress on the implementation of New START. It said that the United States had 1,419 warheads on deployed intercontinental ballistic missiles, submarine-launched ballistic missiles, and heavy bombers, below the limit of 1,550 deployed warheads permitted by the treaty.

The report said that Russia’s decision to pause New START inspections in 2022 and its failure to provide data on its strategic nuclear forces since it suspended implementation of the treaty in early 2023 “negatively affects the ability of the United States to verify Russia’s compliance” with the New START deployed-warhead limit.

Despite the verification obstacles, the report assesses that Russia “likely did not exceed” the treaty’s deployed-warhead limit in 2023 and “that there is not a strategic imbalance between the [United States] and [Russia] that endangers the national security interest of the United States.”

But the report noted that “due to the uncertainty generated by Russia’s failure to fulfill its obligations with respect to the [t]reaty’s verification regime, the United States was unable to verify that [Russia] remained in compliance throughout 2023 with its obligation to limit its [number of] deployed warheads…to 1,550” on delivery vehicles subject to the treaty.

Deputy Russian Foreign Minister Sergei Ryabkov said in an interview with RIA Novosti on Jan. 22 that, “for now, we are focusing on the task of maintaining the quantitative indicators of strategic offensive weapons at the levels established by the treaty on the condition that further destabilizing steps by Washington will not make such a task meaningless for us.”

The decision means that the remaining Russia-U.S. nuclear arms control treaty limiting the world’s largest nuclear arsenals will expire in 2026.

Nuclear Arms Control Remains at Risk

In early 2021, ACA successfully encouraged the White House to work quickly on a deal with the Kremlin to extend the last remaining treaty limiting U.S. and Russian strategic nuclear weapons for another five years. In 2023, we encouraged the White House to outline a practical strategy for advancing nuclear arms control diplomacy with Russia and China. At ACA’s annual meeting in June, President Biden’s national security advisor proposed renewing a dialogue with Russia on a new nuclear arms control framework and a separate nuclear risk reduction dialogue with China “without preconditions.” At...

2023 Arms Control Person(s) of the Year Winner Announced



For Immediate Release: Jan. 12, 2024

Media Contacts: Daryl G. Kimball, executive director, (202) 463-8270 ext. 107; Tony Fleming, director for communications, (202) 463-8270 ext. 110

(Washington, D.C.)—Workers and technicians at the U.S. Army’s Pueblo Chemical Depot in Colorado and the Blue Grass Army Depot in Kentucky were selected as the 2023 Arms Control Persons of the Year through a recent online contest that engaged thousands of participants from dozens of countries.  

The annual contest is organized by the independent, nongovernmental Arms Control Association. The contest has been held each year since 2007.

Workers at the Blue Grass Army Depot in KentuckyThe workers and technicians at the two chemical stockpile depots were nominated for their successful and safe completion of eliminating the last vestiges of the United States' once-enormous declared stockpile of lethal chemical munitions as required by the 1997 Chemical Weapons Convention.

Under the supervision of the U.S. Army's Office of Assembled Chemical Weapons Alternatives, the last mustard gas munition was destroyed in June at Pueblo; Blue Grass destroyed the last missile loaded with Sarin nerve agent in July. The elimination program cost an estimated $13.5 billion.

“We applaud the highly professional work of all the people involved in the difficult destruction of the last remnants of the U.S. chemical weapons stockpile," remarked Daryl Kimball, executive director of the Arms Control Association.

"Their efforts bring to close an important chapter in the decades long global disarmament struggle to verifiably eliminate an entire class of weapons considered so inhumane that their use was condemned more than a century ago," he said.

"The successful work of the people and community watchdogs in and around the Pueblo Chemical Depot and the Blue Grass Army Depot is an important reminder that even after a major treaty, like the 1997 Chemical Weapons Convention, is concluded, there is hard, behind-the-scenes work to be done in order to ensure full implementation and ongoing compliance,” Kimball added.

A total of nine individuals and groups were nominated by the Arms Control Association staff and board of directors for the annual Arms Control Person(s) of the Year honor. 

"This contest is a reminder of the positive initiatives—some at the grassroots level, some on the international scale—designed to advance disarmament, nuclear security, and international peace, security, and justice,” Kimball said.

Worker and technicians at the U.S. Army’s Pueblo Chemical Depot in Colorado

The runners-up in this year’s contest were the governments of Austria and 27 co-sponsoring states that secured approval in the United Nations' First Committee of the first-ever resolution on lethal autonomous weapons systems (LAWS), advancing the possibility of binding international regulations on such weapons systems. In response to its adoption, UN Secretary-General António Guterres and International Committee of the Red Cross president Mirjana Spoljaric issued a joint call urging world leaders to launch negotiations on a new legally binding instrument to set clear prohibitions and restrictions for LAWS and to conclude these negotiations by 2026.

Online voting for the 2023 Arms Control Person(s) of the Year contest was open from Dec. 8, 2023, until Jan. 11, 2024.  A list of all of this year's nominees is available at ArmsControl.org/ACPOY/2023.

Previous recent winners of the "Arms Control Person of the Year" include: the Energoatom staff working at Ukraine’s Zaporizhzhia Nuclear Power Plant (2022) and Foreign Minister Marcelo Ebrard and the Government of Mexico (2021). A complete list of previous winners from previous years is available here.


Workers and technicians at the U.S. Army’s Pueblo Chemical Depot in Colorado and the Blue Grass Army Depot in Kentucky were selected as the 2023 Arms Control Persons of the Year.


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