Avangard, Dark Eagle, or Dongfeng 17 – more and more countries are developing their own hypersonic weapons, or more precisely, hypersonic boost-glide vehicles. In an Issue Brief for the Deep Cuts Project, the authors Steve Fetter, Tim Thies, and Victor Mizin examine how these new weapon systems affect stability between nuclear states in crisis situations. They find that much of the alarm around these weapons is unwarranted. While the new systems are fast and accurate, they do not fundamentally surpass already existing delivery vehicles, such as ballistic missiles with a separately maneuverable reentry vehicle, in either category. However, their maneuverability during flight and detection by radar systems are different. For a long time after initial detection, it remains unclear which exact targets the warhead is attacking, and a launch can no longer be verified by two independent technical systems through its heat and radar signature. Both factors increase the risk that a strike against a tactical target could be perceived as an attack on a much more valuable target, triggering inappropriate countermeasures or retaliation.
To reduce these risks, states have several options available, known from classical strategic arms control. Military commanders should have means of contact with the opposing side. States should clarify which target sets they intend to use hypersonic weapons against, and weapon systems that can target the other side's strategic nuclear weapons should be under the control of the highest political level.
You can read the full article "Evaluating inadvertent escalation risks of hypersonic boost-glide vehicles" here.