The first stage necessarily involves rockets with extreme levels of thrust. Typically, the final stage is carried out before the warhead has completed its first orbit of the Earth, hence ‘fractional orbit’. The final stage involves the use of a retrograde rocket to reduce the warhead’s speed and de-orbit it for its final approach to the target. A primary rocket and second-stage booster is used to accelerate the warhead into orbit, at which point the warhead coasts and reorients itself to the target. The underlying technology of an FOBS is simple, but mastering the design presents complicated material challenges. The lower accuracy and yield of the FOBS compared with an ICBM would make it better suited to pre-emptive strikes against ‘time-urgent, soft targets, such as SAC bases…and key governmental and control centres’. The Soviet design was estimated to be capable of flying via the South Pole, which would minimise the time available for the US Ballistic Missile Early Warning System to detect the incoming threat. The concept of a FOBS was pursued by the Soviet Union during the 1960s and led to the fielding of the R-36-0 Orbital Bombardment Missile in 1969. This reflects the fact that the old Chinese nuclear doctrine of living with uncertain second-strike capabilities is giving way to an approach emphasising assured retaliation.Ĭurrent reports suggest that China has tested a fractional orbit bombardment system (FOBS). This is, in many ways, positive as it suggests these capabilities exist to reinforce China’s second-strike capability rather than enable first strikes. Details of the report are consistent with prior evidence regarding the accuracy of such systems and implies that they have a primarily countervalue (city targeting) role. The HGV then re-entered the earth’s atmosphere, landing ‘about two-dozen miles’ from its intended target. In August 2021, China launched a Long March rocket carrying a hypersonic glide vehicle (HGV) into low earth orbit.