Lucifer's Hammer is a post-apocalyptic science fiction novel by Larry Niven and Jerry Pournelle, first published in 1977.
Political lobbying by California Senator Arthur Jellison eventually gets a joint Apollo-Soyuz (docking with the second flight-worthy Skylab) mission into space to study the comet, dubbed "The Hammer" by popular media, which is expected to pass close to the Earth. Despite assurances by the scientific community that a collision with Earth is extremely unlikely, the public, fueled with religious fervor by the evangelist Henry Armitage, begins to hoard food and supplies in anticipation.
Eventually, to the shock of scientists at JPL in Pasadena, who could not track the trajectory accurately enough because of the comet's constant outgassing, the Hammer does fall, breaking up into several smaller comets that impact around the world with devastating results, striking parts of Europe, Africa, the Gulf of Mexico, and both the Pacific and Atlantic Oceans.
The strikes trigger several volcanoes and earthquakes around the world, including the San Andreas fault, heavily damaging the Southern California region and the rest of California, causing millions of casualties. Several of the fragments land in the ocean, causing further damage by the resulting tsunamis (which destroy several major coastal cities around the world, including Los Angeles, killing millions) and long-term climate problems due to the massive quantities of vaporized seawater.
Rods from God Space-launched darts that strike like meteors
This technology is very far out—in miles and years. A pair of satellites orbiting several hundred miles above the Earth would serve as a weapons system. One functions as the targeting and communications platform while the other carries numerous tungsten rods—up to 20 feet in length and a foot in diameter—that it can drop on targets with less than 15 minutes’ notice. When instructed from the ground, the targeting satellite commands its partner to drop one of its darts. The guided rods enter the atmosphere, protected by a thermal coating, traveling at 36,000 feet per second—comparable to the speed of a meteor. The result: complete devastation of the target, even if it’s buried deep underground. (The two-platform configuration permits the weapon to be “reloaded” by just launching a new set of rods, rather than replacing the entire system.)
The concept of kinetic-energy weapons has been around ever since the RAND Corporation proposed placing rods on the tips of ICBMs in the 1950s; the satellite twist was popularized by sci-fi writer Jerry Pournelle.