From Wikipedia
11-28-24

A  kinetic bombardment  or a  kinetic orbital strike  is the hypothetical act of attacking a planetary surface with an inert  kinetic projectile  from  orbit  ( orbital bombardment ), where the destructive power comes from the  kinetic energy  of the projectile impacting at very high speeds. The concept originated during the  Cold War .

Typical depictions of the tactic are of a  satellite  containing a magazine of  tungsten  rods and a directional  thrust  system. When a strike is ordered, the launch vehicle  brakes [ 1 ]  one of the rods out of its orbit and into a  suborbital  trajectory that intersects the target. The rods would typically be shaped to minimize  air resistance  and thus maximize velocity upon impact.

The kinetic bombardment has the advantage of being able to deliver projectiles from a very high angle at a very high speed, making them extremely difficult to defend against. In addition, projectiles would not require explosive warheads, and—in the simplest designs—would consist entirely of solid metal rods, giving rise to the common nickname " rods from God ". [ 2 ]  Disadvantages include the technical difficulties of ensuring accuracy and the high costs of positioning ammunition in orbit.

Real life concepts and theories

Predecessors and early concepts

During the  Korean  and  Vietnam  Wars, there was limited use of the  Lazy Dog  bomb, a kinetic projectile shaped like a conventional bomb but only about  1 + 3 / 4  inches (44 mm) long and  1 / 2  inch (13 mm) in diameter. A piece of sheet metal was folded to make the fins and welded to the rear of the projectile. These were dumped from aircraft onto enemy troops and had the same effect as a machine gun fired vertically. [ 3 ] [ self-published source? ] [ 4 ] [ self-published source? ]  Similar  flechette proj ectiles have been used since  World War I . [ 5 ]

In the 1980s, another kinetic swarm system was conceptualized as a potential part of the  Strategic Defense Initiative , there codenamed  Brilliant Pebbles . [ 6 ] [ 7 ]

Project Thor  was an idea for a weapons system that launches  telephone pole -sized kinetic  projectiles  made from  tungsten from Earth's orbit to damage targets on the ground.  Jerry Pournelle  created the concept while working in operations research at  Boeing  in the 1950s before becoming a science-fiction writer. [ 8 ] [ 9 ]

2003 United States Air Force proposal

A system described in the 2003  United States Air Force  report called  Hypervelocity Rod Bundles [ 10 ]  was that of 20-foot-long (6.1 m), 1-foot-diameter (0.30 m) tungsten rods that are satellite-controlled and have global strike capability, with impact speeds of  Mach  10. [ 11 ] [ 12 ] [ 13 ]

The bomb would naturally contain large kinetic energy because it moves at  orbital velocities , around 8  kilometres per second  (26,000  ft/s ;  Mach  24) in orbit and 3  kilometres per second  (9,800  ft/s ;  Mach  8.8) at impact. As the rod reenters Earth's  atmosphere , it would lose most of its velocity, but the remaining energy would cause considerable damage. Some systems are quoted as having the yield of a small tactical nuclear bomb. [ 13 ]  These designs are envisioned as a  bunker buster . [ 12 ] [ 14 ]  As the name suggests, the 'bunker buster' is powerful enough to destroy a nuclear bunker. With 6-8 satellites on a given orbit, a target could be hit within 12-15 minutes from any given time, less than half the time taken by an  ICBM  and without the launch warning. Such a system could also be equipped with sensors to detect incoming  anti-ballistic missile -type threats and relatively light protective measures to use against them (e.g. hit-to-kill missiles or megawatt-class  chemical laser ). The time between deorbit and impact would only be a few minutes, and depending on the orbits and positions in the orbits, the system would have a worldwide range. There would be no need to deploy missiles, aircraft, or other vehicles.

In the case of the system mentioned in the 2003 Air Force report above, a 6.1 by 0.3 metres (20 ft × 1 ft) tungsten cylinder impacting at Mach 10 (11,200 ft/s; 3,400 m/s) has kinetic energy equivalent to approximately 11.5  tons of TNT (48  GJ ). [ 15 ]  The mass of such a cylinder is itself greater than 9 short tons (8.2 t), so the practical applications of such a system are limited to those situations where its other characteristics provide a clear and decisive advantage—a conventional bomb/warhead of similar weight to the tungsten rod, delivered by conventional means, provides similar destructive capability and is far more practical and cost-effective. [ 16 ] [ 17 ] [ 18 ] [ fu ll citation needed ]

The highly elongated shape and high mass of the projectiles are intended to enhance  sectional density  (and therefore minimize kinetic energy loss due to air friction) and maximize penetration of hard or buried targets. The larger device is expected to be quite effective at penetrating deeply buried bunkers and other command and control targets. [ 19 ]

The weapon would be very hard to defend against. It has a very high closing velocity and a small radar cross-section. The launch is difficult to detect. Any  infrared  launch signature occurs in orbit, at no fixed position. The infrared launch signature also has a much smaller magnitude compared to a ballistic missile launch. The system would also have to cope with atmospheric heating from re-entry, which could melt non-tungsten components of the weapon. [ 20 ]

The phrase "rods from God" is used to describe the same concept. [ 21 ]  An Air Force report called them "hypervelocity rod bundles". [ 2 ]