The Future of U.S. Intercontinental Ballistic Missiles
Lead author: Frank von Hippel, January 2020
U.S. Strategic Command plans to replace its 400 single-warhead Minuteman III Intercontinental Ballistic Missiles (ICBMs) with new missiles (the “Ground Based Strategic Deterrent,” GBSD) between 2029 and 2036 in the same missile silos for an estimated cost of $85-150 billion in “then-year” dollars. This is in the context of a larger “modernization” plan that includes replacing the the two other components of the strategic “triad:” ballistic missile submarines and long-range bombers, each for a similar cost.
The U.S. Strategic “Triad”
The warheads on the ICBMs represent about one quarter of the U.S. deployed strategic warheads. More than half of U.S. strategic warheads are carried by ballistic missile submarines and the remainder are nuclear bombs and on nuclear-armed air-launched cruise missiles deployed at three U.S. strategic bomber bases.
Strategic Command argues that each “leg” of the triad has its own strengths and weaknesses. Originally, one strength of the ICBMs was their high accuracy and thereby their ability to destroy hardened targets, specifically Russian missile silos and command bunkers. Another strength is that they have multiple communication links with U.S. national command posts and can launch quickly if ordered (hence the name “Minuteman”). Their perceived weakness is that their locations are known and therefore they can be targeted. However, it would take more than one Russian warhead to destroy the single warhead currently on U.S. Minuteman III missiles. (They were originally deployed with three warheads each and presumably could be restored to that loading if the Trump Administration maintains its expressed disinterest in extending the New START Treaty by another five years beyond February 2021.)
Ballistic Missile Submarines. The missiles on U.S. ballistic-missile submarines are now as accurate as the ICBMs and about half of those at sea are in deployment areas within range of their targets, cruising slowly near the surface with their missiles launch ready and their Very Low Frequency (VLF) antenna and satellite signal receivers deployed so that they they can receive launch orders as quickly as the ICBMs. The other half of the submarines at sea are in transit at higher speeds to or from their deployment areas with their missiles not launch ready and not in constant touch with the national command posts.
At any one time, eight to ten of the 14 U.S. Ohio-class ballistic missile submarines are at sea, two are in overhaul and the other two to four are in port for supplies and a change of crews. They are carefully designed to emit very little sound and travel deeply enough at transit speed so there is no evidence of their presence on the surface. Measures are employed to prevent trailing from their ports. Currently no threat to their survivability is foreseen that cannot be countermeasured with decoys and other means. It could be argued that they are all the United States requires. Indeed, both France and the United Kingdom have decided that having one ballistic-missile submarine at sea at all times is sufficient for their independent deterrents. (In a crisis, they could increase the number to two or three.)
The Navy plans to replace these 14 submarines between 2028 and 2042 with 12 new Columbia-class submarines at a currently estimated cost of about $100 billion in Fiscal Year (FY) 2019 dollars). The Navy argues that, because the new submarines will have lifetime cores in their reactor, they will not spend an extra two years in drydock undergoing mid-life refueling and it will be possible to keep about the same minimum number of submarines at sea.
In addition, the Trident II ballistic missiles must be replaced as they are expended in tests at a rate of about six per year, including by the United Kingdom, which deploys Trident II missiles on its four ballistic-missile submarines. Thus far, according to one estimate, the program has cost about $70 million per missile. The U.S. Navy says $31 million – perhaps this is the marginal cost. At this price, replacing the 242 missiles tested over the 42-year lifetime of the Columbia-class fleet would cost $8 billion.
Each new submarine will have sixteen launch tubes for Trident II missiles. The missiles can carry up to eight warheads each. Each submarine therefore could carry up to 128 warheads. The 20 Trident missiles on each Ohio-class submarine actually carry about four warheads each on average because of New START limits on total deployed warheads.
Bombers. Long-range bombers were the first U.S. “nuclear delivery vehicles.” In the 1960s, with the advent of Soviet ICBMs, the Strategic Air Command (subsequently merged into Strategic Command) became concerned about the vulnerability of these bombers on the ground. It therefore kept some, loaded with multimegaton bombs, aloft at all times. After a few crashes of nuclear-armed bombers, this practice was abandoned in 1968 as too dangerous. For the rest of the Cold War, a fraction of the bombers were kept loaded and ready to take off within ten minutes of warning. Unlike the ballistic missiles, the bombers can be called back in case of false alarm. With the end of Cold War, the bombers were taken off alert but they could be returned to alert in a crisis.
Starting in the mid to late 2020s, the DOD proposes to buy at least one hundred new B-21 bombers and a new generation of air-launched cruise missiles with improved capabilities for penetrating Russian and Chinese air defenses. Like the current B-2A and B52H nuclear bombers, the new bombers also would be available for conventional missions. Indeed, hopefully, conventional missions would be their only use. Curiously, the B-21 would replace the B-1 bomber, which is now considered a non-nuclear bomber, and the B-2 stealth bomber but not the older B-52s, which were built during 1952-62 but have had most of their parts replaced in cycles of refurbishment. The Air Force has declared the cost of the B-21 a secret but has declared that its goal is an “average procurement cost of $0.564 billion” in FY16 dollars plus $11 billion for about 1,000 new nuclear cruise missiles (the Long-Range Standoff, LRSO) weapon and perhaps as much more for refurbishing the W-80 cruise missile warhead to become the W-80-4.
Concerns about a possible Russian first strike
Strategic Command is both deeply concerned about the possibility of a Russian first strike on its nuclear forces and their command and control system, and fascinated by the possibility of a disarming strike on Russia’s nuclear forces and their command and control system. Russia is very concerned about the possibility of a U.S. first strike on its strategic forces. Given the very low probability that either side could accomplish a first strike without some nuclear retaliation involving at least tens of nuclear weapons, the idea that either side would mount a first strike seems implausible. But that idea exists and has put large parts of each country’s nuclear forces in a very dangerous launch-on-warning posture that sometimes is described as a “hair-trigger” posture because of fears that it could lead to an accidental nuclear war.
Any first strike on U.S. nuclear forces would have to be massive and, in the case of U.S. ICBMs, would reduce the attacker’s nuclear arsenal by perhaps two warheads for every U.S. warhead destroyed. Also, the lethal fallout from such a massive attack would extend many hundreds of miles downwind, killing millions. Russia would have to assume that the United States would retaliate with nuclear weapons and, even if the United States unalerted bombers where destroyed in the same first strike, about 800 U.S. nuclear warheads at sea would be available for such a retaliation. Even with a maximal attack on US command and control – which would kill additional millions – Russia could not assume no retaliation. Only a deranged leader would launch such an attack. Or, Russia could launch because of false warning of a U.S. attack.
Launch under attack and the danger of mistaken launch
Because the ICBM silos are targetable, Strategic Command insists on maintaining the option of launching them on warning of attack. Indeed, according to one former Commander in Chief of Strategic Command, launch under attack is Strategic Command’s preferred option, which would put an inadequately prepared President under great pressure to make within minutes a decision that would result in the deaths of at least millions and perhaps over a billion.
The flight time of a Russian ICBM would be about 30 minutes. Of this time, perhaps 15 minutes would be devoted to confirming and assessing the launch with data from U.S. early-warning satellites and radars and seven minutes would be required to transmit and implement the launch order for the ICBMs including two minutes for the missiles to get out of range of damage by the incoming warheads. This would leave the president with a very short decision time and raises the possibility of a launch on a false warning due to an equipment or personnel failure – both of which were publicly reported in1980 – or, a more recent concern: a computer hack.
Indeed, given the number of false warnings that have occurred and irrationality of starting a war of mutual nuclear annihilation, many analysts worry more about the possibility of accidental nuclear war than a deliberate first strike. Because of concerns about a hostile power’s hackers, operational U.S. ICBMs do not have safety systems that could destroy the missile if the launch were discovered to be mistaken. This is unmistakable evidence that the U.S. government worries more about a hostile attack than it does about a mistaken launch.
A launch-on-warning posture has been debated within the U.S. government since the Kennedy Administration but apparently had been adopted by the 1970s. Because of his concern about accidental nuclear war, President Reagan wanted to negotiate an agreement with the Soviet Union to eliminate ballistic missiles in favor of bombers. Both Presidents G.W. Bush and Obama came into office proposing to take the ICBMs off “hair trigger.” Once in office President Obama pursued the issue but retreated in the face of opposition from Strategic Command and Russian disinterest in doing so reciprocally. This history of intransigence has convinced some, including former Secretary of Defense William Perry, to propose the elimination of the ICBMs. General Mattis expressed this view in 2015, two years before he was nominated to be the Trump Administration’s first Secretary of Defense, “Is it time to reduce the Triad to a Diad, removing the land‐based missiles? This would reduce the false alarm danger.” But abandoned that position in his confirmation hearing.
Given that Strategic Command insists that “de-alerted” ICBMs are not worth keeping, the risk of mistaken launch on warning of ICBMs vastly exceeds the benefit of their contribution to deterrence and Secretary Perry’s recommendation that they be eliminated becomes persuasive. A recent public-opinion survey found 70% of the public, including 62 percent of Republicans, open-minded on this issue.
The Congressional “ICBM caucus” sees ICBM-related bases as important to the economies of their five states. However, the economic benefits are relatively small – an average of about 1000 families at the one missile base each in Montana, North Dakota and Wyoming, with a median family income of about $30,000. The foregone combined income for the three states would therefore be on the order of $0.1 billion per year for all three states – much less than the $5 to $10 billion per year over about 15 years proposed to be spent on the new Ground-based Deterrent.
Life-extend the Minuteman III as an interim measure?
Given the talismatic significance the triad has developed within the U.S. nuclear-weapons policy community, it may take years to reach a consensus on elimination of U.S. ICBMs. It is important not to preempt this debate by making an $85-150 billion commitment to a new ICBM with subcontracts deliberately spread over many states to make the commitment politically irreversible.
Fortunately, the time necessary for debate can be made available by refurbishing some or all of the Minuteman III missiles instead of replacing them. The lifetime of the Minuteman III ICBM is determined primarily by its solid fuel and its guidance system both of which can be replaced. This has already been done once. The missiles were first deployed around 1970 and were refurbished around 2000. They could be refurbished again around 2030 for another 30 years for a small fraction of the cost of an equivalent new system. A 2014 RAND analysis estimated the refurbishment cost for 420 Minuteman III’s at $20-40 billion. In 2017, the Congressional Budget Office estimated the savings from delaying the launch of the ICBM modernization program till 2036 at $37 billion FY2017 dollars.
Minuteman IIIs are being expended by testing at a rate of 4.5 launches per year, up from the past level of three per year. There were 500 missiles in inventory in 2017. If the current testing rate were maintained, the number of remaining missiles would fall below the currently deployed number of 400 in 2040 and below 300 in 2060. If the testing rate were returned to 3 per year, these dates would be deferred to about 2050 and 2080.
Recommendation
The U.S. Minuteman III ICBMs should not be replaced. Eight U.S. ballistic-missile submarines at sea, each carrying up to 128 warheads – backed up if need be by a re-alerted strategic bomber force – would constitute a more than adequate U.S. nuclear deterrent. If Congress cannot bring itself to a decision on this matter in a timely manner, it could give itself more time by authorizing planning for the refurbishment of the current Minuteman ICBMs.