In war, one should seek to take and hold the high ground. From there, the enemy's movements are clearly visible, and he will struggle just to reach you, let alone fight you. High orbit is the highest ground there is.
When it absolutely, positively, has to be destroyed on time, nothing beats your own remote-controlled, satellite-mounted laser cannon.
A variation of the Wave Motion Gun, Kill Sats have the added advantage that you don't need to be anywhere near either the weapon or the target. Instead, you can fire it from the safety of your headquarters: your satellite will move into position and unleash a shiny descending Pillar of Light on your unsuspecting target. Power/accuracy on Kill Sats vary, ranging from "lone vehicle" to "entire building" to (rarely) "town or small city." Planet busters are another category entirely, as firing them remotely from anywhere on the surface is inadvisable.
Since it's considered poor form to snipe your opponent from such a risk-free distance, Kill Sats are generally the realm of villains. So-called good guys who resort to these will, at best, fail miserably. If Everything Is Online in their world (and you know it is), there is always the risk of control falling into the wrong hands.
In video games, Kill Sats are frequently used by the good guys (ie the player) but usually requiring some sort of targeting system on the ground in the vicinity of the target (distance varies from a few meters to a few miles). If the good guys do have one, its precision and accuracy are emphasized, often by providing the bad guys with a less precise weapon of equivalent power (such as a nuclear missile).
Of course, in the hands of either side, it would end the story in a hurry if these could be used repeatedly — none of the opposing side could poke their nose into the open without risking vaporization. Therefore:
It's prohibitively expensive, time-intensive, and/or just plain difficult to get it moved over the target and charged, making it something that can't be used regularly or that can be avoided.
It Only Works Once, because there was only enough power/ammo to fire it the one time, or because the heroes sabotage it or its control system before the villains can shoot again.
Some combination of the above two, the former giving the opportunity for the heroes to do the latter.
Its firepower is limited and slow, you can pick off soldiers or armored vehicles one at a time, but you can't use it to turn back a full-scale invasion. Thus, usage is reserved for important high-value targets. Or the exact opposite, it's a Weapon of Mass Destruction that can't even be considered until the Godzilla Threshold is reached.
Alternatively, it's not active at all yet, in which case the story centers around making sure it never gets off its first shot. In these cases it generally leans toward the powerful end of the scale.
Kill Sats sometimes display the orbital properties of their more benign counterparts, the Spy Satellites, able to move themselves over any target in record time and then park themselves there to get off as many shots as they please. More often, thankfully, the writers actually pay attention to how satellites work and incorporate that into the plot ("we've got two hours to destroy the control center before the satellite is in position over our headquarters!")
Any villain seeking to get their private space program off the ground (pun most definitely intended) is probably doing so to put one of these bad boys in orbit (never mind what it actually gets used for). Spy villains love these things. The Ancient Conspiracy may already have a full network of Death Ray Sats secretly in orbit, but they're careful about using it regularly, lest someone catch on.
The Standard Sci-Fi Fleet can and will take this Up to Eleven, with the heavier ships turning their guns on a helpless planet below.
An early test fire of these may create the Doomed Hometown.
The trope name is a parody of "TelSat", the TV satellite system.
A popular way to rain Death from Above.
Orbital Bombardment is similar but involves a manned space ship or station
Compare Wave Motion Gun, BFG, Big Bulky Bomb, There Is No Kill Like Overkill.
This item is available in the Trope Co. Catalog.
Although only Floyd makes an actual appearance, it is perhaps worth noting that it was introduced as "the only one currently in range of Neo-Tokyo"... so, just how many ARE there...?
Battle Programmer Shirase has a technique called "Three Sisters Deathblow", where three scrapped Cosmos satellites are programmed for re-entry. The first two serve to shield the third from atmospheric heat, so that it can enter the atmosphere intact and precisely hit a target on the ground (or sea).
One of the major subplots in the original Bubblegum Crisis revolved around a MacGuffin which would allow a Boomer to gain control of the military's network of Kill Sats.
Space Battleship Yamato had a few of these. The first series had a series of Gamilon mirror satellites working in conjunction with a planet-based BFG, and the second had a proper kill sat in Earth orbit.
The Damocles from Code Geass. Technically not a satellite but a floating fortress armed with a cannon that shoots FLEIA warheads, but since it was supposed to be flown out of the atmosphere and placed on a geosynchronous orbit, it fulfills all the criteria for a Kill Sat (it's in space, it rains doom on people).
Mikawa Kai uses a NASA Kill Sat in an effort to destroy the "Terminator" in Seto no Hanayome.
In Great Mazinger -the sequel of Mazinger Z-, Great Marshall of Hell fabricated a massive lens of ice orbited around Earth and worked like a Kill Sat by focusing sunrays in one single point and blasting it with a massive, hot-melting heat ray. It appeared only in one of the manga continuities, though.
Used in Nadia: The Secret of Blue Water. Especially impressive considering the series takes place in the 19th century (the satellite was Atlantean technology).
Jiro from Hajimete No A Ku has one, on top of that it has ridiculously accurate aim, able to shoot glasses of the heroines face without hurting her.
The original Sol Bianca OAV cheats a little, when Feb hides herself on an orbiting Space Ring with a very long-ranged laser sniper rifle to help her friends escape from their own execution on the planet below.
A different Angel started out dropping bits of itself on the city, gradually target-tracking onto the geofront, at which point the whole thing came crashing down and the Evas have to run up and catch it.
Surely Tengen Toppa Gurren Lagann's Anti-Spiral-controlled Cathedral Terra counts? Okay, the heroes nip its firing sequence in the bud, but it had several hundred (if not thousand) massive death rays trained on the planet, and it was (disguised as) the planet's natural satellite at the time.
The AMP in Silent Möbius has access to a Kill Sat, which seems to be privately owned by member Lebia Maverick. It also acts as her second brain, providing a ridiculous amount of extra data storage. Its name is Donald.
Fairy Tail features the Aetherion, a magical version of this. It takes about an hour for the Council, an organization of the strongest wizards in the land, to charge up, and then it blasts down with the power of more than two billion, seven hundred million ideas of magical energy, which is about equivalent to the combined magical energies of all the wizards on the continent. According to one member of the Council, its destructive power is sufficient to wipe an entire country off the face of the planet. Naturally, the arc's villain absorbs the magical energy so he can use it as a power battery for his spell to resurrect history's most infamous black mage.
Later we learn that the true purpose of the Evil Plan behind the events of this Story Arc was to provoke the Council into such extreme action as firing the Aetherion, then reveal that they were fooled by the villain, thus undermining their authority.
Utawarerumono. You won't know where it is though... Until episode 24, when Mikoto/Kamyu uses a powerful magic to obliterate a country. The next episode, we are given a glimpse on how it actually works... arrays of satellite-mounted beam cannons.
Kill Sats show up in many Gundam series, although they aren't quite as common as the Colony Drop.
According to the backstory given in the original Gundam novels, the reason space colonization was needed was due to the Federation bombarding the Earth with kill sats entirely by accident. They tried to solve the world's energy problems with solar power satellites, but miscalculated the power of the microwave beams used to transmit the energy to the surface and almost burned off the entire atmosphere.
Getter Robo features two of these, in Humongous Mecha form. The first, from the Shin Getter Robo vs. Neo Getter Robo OVA dispenses countless meteorites over North America, some of which are so large that they function as drop pods for otherHumongous Mecha. The second is in the Getter Robo Go manga, and is of the laser variety. Though it can apparently fire multiple times in succession.
Macross Plus reveals that, decades after Space War I, Earth has upgraded its defenses with a network of hundreds of thousands of densely-packed, automated Kill Sats that serve a dual purpose: vaporize orbital debris before it falls into the atmosphere, and discouraging invasion from external forces. When Isamu has to navigate this network and force his way into Earth, his only hope is to shoot down a couple of communication sats, hide among the falling debris, and pray. His companion has so little faith in their chances he just shuts himself off into hibernation.
On that subject, the conclusion to Space War I: the Main Zentraedi Fleet folds in and the first thing they do is shoot the Earth with several million (Not Hyperbole) Wave Motion Guns, turning most the surface into an arid wasteland and exterminating 90% of the human population.
Dancougar handles this differently; the Kill Sat hits the sword of the titular machine, creating a gigantic laser sword for it to use.
Yu-Gi-Oh! GX — Securing the two keys of one of these was plot for the last third of the second season. Coincidentally, its owner duels with a deck built around his veritable love for Kill Sats.
In the Yu-Gi-Oh! Cyber World filler arc, the guy who takes the form of Jinzo summons a monster called Satellite Cannon, which is quite a a pain to Kaiba until he finally summons BEWD and destroys it. (Satellite Cannon, being a Kill Sat in itself, was capable of fusing in GX, making it an even bigger version of itself.)
In Eureka Seven, Dewey Novak fires one called "Oratorio #8" once at the Scab Coral to make a hole for TheEND to fly through, and again to target the beacon TheEND placed on the Control Cluster. After the second shot, the thing self-destructed and STILL rained death down on the poor planet with its highly explosive debris.
Shaman King has one of these which is used against the main villain Hao Asakura, but he is unhurt by it.
It was also detrimental for the other shaman as it caused the world to become aware of their presence on the island.
Zoids has one in the New Century Zero series, as a side function of the Judge satellite. While it doesn't usually come up because the enemy uses Dark Judges, which skew the battle in their favor, in one specific instance there's a regular Judge on the battlefield and the bad guys ignore him completely, prompting him to call down a barrage that completely frags the remaining enemies and their Airborne Aircraft Carrier.
Near the end of the series during a tournament, the Backdraft Group calls down a whole bunch of different Dark Judges. As they're defeated on the ground, the real judging authority has a very large satellite covered in gun turrets that blows the satellites out of the sky.
Wormhole Driver from The Third: The Girl with the Blue Eye is an old (but still fully operational) Kill Sat capable of creating Black Holes on top of the targeted area (which means that depending on the power used in such attack it can most likely destroy anything up to the entire planet)
The GHQ's satellite laser "Leucocyte" in Guilty Crown. All 256 of them. Or rather, all three of them, and two of them were destroyed in episode 6. The 256 number was a bluff pulled by a guy with massive steel balls, and the U.N. bought it. The last remaining satellite was not in a position to deal any damage.
Fate Prototype brings us Archer: his twin swords join to form a bow, yet the arrow fired from the bow itself is nothing more than a targeting beacon for a magical version of this trope.
Legend of Galactic Heroes featured two variants of Kill Sat, both of which are designed as space-based defences: the giant Iserlohn Fortress occupying an important choke-point in the Imperial frontier and the Artemis Necklace network of battle-satellites orbiting around the Alliance capital planet.
Saya from Onidere has access to a Kill Sat that strikes her father every time she says a phrase. However her father is so tough that despite destroying his house he doesn't even notice it.
The final issue of the Global Frequency comic is based around a preset plan by the US government to cause a population reduction by blasting a few major cities with Kill Sats. These are kinetic harpoons, a single shot weapon mostly by virtue of being a fancy orbiting crossbow that fires an artificial diamond at enough speed that the kinetic energy goes off like a nuke when it strikes the ground.
A kinetic harpoon also appears in Blackhawks, though this one is armed with bunches of tungsten rods. Wildman is in love with the concept — "Why spend all the money and resources building a laser or a missile when an inert object traveling at Mach Ten does the same amount of damage?"
The last Story Arc of the original Grendel series features the Sun-Disk, a superweapon used only once (to level Japan and and a future cold war), before its creator disables it and dies.
Zodon's 'modifications' to the lunar lander in PS238.
An orbital particle beam cannon shows up in Planetary.
The Marvel Comics version of G.I. Joe had a kill sat with the command centre hidden in the Chrysler Building. The IDW series that carries on the Marvel continuity also uses it.
Batman: The rogue Brother Eye satellite that Batman built can be used as a kill sat, it even has the A.I necessary to use and control all of it's functions(yes, even the really deadly ones) on it's own, which sucks for Earth.
In Antz, a kid with a magnifying glass functions as the insect-sized version of this. He vaporizes one soldier ant before chasing the protagonists down with a beam of sunlight. They get away, but end up hopelessly lost in the process.
In the straight-to-video Megamind: The Buttom of Doom, the villain-turned-hero Megamind tries to sell off all his "evil" inventions at a garage sale, including the Kill Sat, which he markets as a barbeque starter. This is the only item he fails to sell. Of course, it turns out to be useful in the end when he has to destroy a Humongous Mecha he built a long time ago programmed to kill heroes, who he now happens to be.
Films — Live-Action
The Death Star from Star Wars. It's a space station filled with millions of staff, stuffed to the bursting point with weaponry, and has a planet shattering superlaser built right into it!
The Death Star is mobile and in fact there would be no point to it if it wasn't. It is basically a giant starship that is called a space station.
Dr. Evil's "Alan Parsons Project" in Austin Powers: The Spy Who Shagged Me. He cheated a little by putting it on the Moon, but that's still in orbit.
Diabolical Mastermind Ernst Stavro Blofeld helped pioneer this trope in Diamonds Are Forever. Willard Whyte, a faintly disguised version of Howard Hughes, is a reclusive billionaire who supposedly put a satellite into orbit as part of his Aerospace operations, only to discover it was actually Blofeld, impersonating Whyte, who went on to use the satellite's ability to focus the sun's light into a coherent beam and thus fire a laser anywhere on earth to attack important locations such as nuclear missile launch facilities or nuclear submarines.
Moonraker had a slight twist on it: Hugo Drax's Kill Sat was also an inhabited space station, where his master race would remain safe and sound while nerve gas wiped out the rest of humanity.
The titular weapons in Goldeneye were single-shot EMP-based Kill Sats. The first one is used to cover up the theft of the satellite control codes by destroying the operations base. The Big Bad plotted to use the second one to knock out London (and all evidence of a grand electronic bank raid to be completed first), but was stopped by Bond and his Girl of the Movie, Natalya.
The villain in Die Another Day makes an orbital mirror that doubles as a Kill Sat. Much like Blofeld's version, the weapon used diamonds to focus the energy.
In Real Genius, the lead characters are duped by their college professor into building a laser which is intended as the main weapon for a Kill Sat. They retaliate by sabotaging the test to have it destroy the duplicitous professor's home. With popcorn.
Technically, the weapon would be mounted on a shuttle, not on a satellite, as shown by the demo video at the start of the movie. It's still insta-death from orbit for anyone it hits though.
More bonus points are awarded for being a Kill Sat that shoots earthquakes. Extreme bonus points are awarded for being a Kill Sat that shoots earthquakes but still manages to destroy ostensibly high-flying bomber planes.
In Godzilla vs. Megaguirus a satellite is used to attack Godzilla and barely manages to get off a shot on target before it burns up. The fact that it fired a solid projectile which took almost a minute to get to the ground against a notably fast-moving target makes one wonder why they bothered to put it orbit.
The disaster movie Meteor features two satellites armed with over a dozen nuclear weapons. It turns out Sean Connery designed one to be a defense against asteroids, but they thought it would be better used against Russia.
The protagonists in Space Cowboys go into space to fix what they're told is a communications satellite, only to find out it's an old Soviet Kill Sat armed with nuclear missiles and in danger of activating.
The Narada's drill from Star Trek. It seems to blast some kind of epic fire rather than an actual laser, but it can punch straight to the core of a planet. This turns out to be problematic for Vulcan, as it allows the Romulans to drop a ball of black-hole-creating matter to the core and literally make it implode. Something like that in the hands of angry and "particularly troubled" Romulans? Oh sure, they get kinda woobie with the backstory, but that still ain't a happy situation.
In Transformers: Revenge of The Fallen, Soundwave's alt mode is that of a satellite. Instead of normal projectiles, however, he fires other Decepticons, notably his minion Ravage. And if his toy bio has any credence, he's hacked so many satellites that he could pretty much destroy human civilization if he got bored.
Want to know something scary? That appears to be a very accurate depiction of how such a system would function in reality.
The fusion-powered microwave satellites in Duumvirate can burn and melt a building.
The Cardinal of the Kremlin by Tom Clancy had as a major plot point the simultaneous development of anti-satellite weapons by the US and the USSR. As the lasers were ground-located, they weren't technically Kill Sats, but the US system included the ability to bounce the laser beam off of multiple orbiting mirrors, thus hitting any target on the planet. It worked, too, except that the laser was too weak to do much more than give the target a mild sunburn.
In Dan Simmons' Hyperion Cantos, Fedmahn Kassad uses these to resolve a planet-wide hostage situation—by simultaneously attacking all of the terrorist ringleaders at once. The leader of the terrorists is even killed on live television mid-Sedgwick Speech, for bonus points.
A Kill Sat named ODIN ( Orbital Defense INitiative) appears in Philip Reeve's Mortal Engines Quartet, especially in Infernal Devices and A Darkling Plain. A semi-sentient one no less. You might even feel sorry for it after it's mini-BSOD.
The Night's Dawn Trilogy by Peter F. Hamilton has planets surrounded by swarms of these, known as "Strategic Defense satellites". They usually are pointed outward to defend against attacks from space, but can be used against surface targets with devastating effects.
Powersat by Ben Bova: a microwave power satellite is turned into a Kill Sat by a bunch of terrorists.
In Quicksilver by Judith and Garfield Reeves-Stevens, the titular satellite was intended to be a relatively harmless (to biological material) EMP blast, but instead caused some sort of chain reaction which charged the air around the target to such a degree that hugely powerful bolts of lightning would strike the target instead.
David Weber's Safehold series: the planet Safehold's prohibition on advanced technology is enforced by orbital platforms that, if they detect power sources, will unleash a kinetic bombardment capable of devastating a small continent. Merlin is running extensive tests to determine what counts as a "power source". So far, no solution has been found to the main problem, but we're up to steam engines with no response.
Silver Tower by Dale Brown. The title space station has a high energy laser weapon called Skybolt that's used to wipe out a swarm of Soviet cruise missiles and save an American naval fleet from destruction. It reappears in later books, but the Skybolt is eventually removed. Executive Intent has the Mjölnir/Thor's Hammer kinetic kill vehicles, transparently based on the Real Life "Rods from God".
Flight of the Old Dog, which involved the Russians with a nuclear powered laser in Siberia. Later, they deploy a mirror sat, and the Americans deploy their own Kill Sat with X-Ray warheads in response.
Wedge's Gamble, Rogue Squadron remote-control-hijacks a solar mirror orbiting Imperial Center. The mirrors are used to redirect sunlight, but this one was focused on one of the water reclamation plants in order to raise the local humidity to create a massive thunderstorm and knock out the power at a shield generator. Nothing exploded, but there was quite a bit of steam and melting going on.
In Rebel Dream, the New Republic pulls this off for the first time with Operation Emperor's Hammer, using the Lusankya to bombard the Yuuzhan Vong warriors assaulting the Borleias base.
Wedge: "We're going to face them with an enemy they've never had the displeasure of fighting. We're going to hit them with the Empire."
Tycho: "They're not going to like the Empire."
The novel Shatterpoint features a De-Orbiting Kinetic Anti-emplacement Weapon, or DOKAW, that essentially drops a chunk of metal from orbit at 30,000 kilometers per hour.
One of the ultimate examples of this trope: Larry Niven's Ringworld is defended by a magnetically controlled X-Ray laser made by the forced-fluorescing of sunspots. The beam of this weapon is the width of Earth's moon. Sort of makes the Death Star seem wimpy in comparison.
In the book "Milan last stop" of Simone Farè, in a soft dystopic world, the city of Milan, Italy, has a secret Pure Energy and Deflector Shields and use it, among things, to create and launch such a satellite called "Giudecca", controlled by the same physicist who controls the city and created these technologies.
In the Riverworld series by Philip Jose Farmer, human history (as represented by the population of the Riverworld) ends when a fumbled first contact triggers a counterattack by an orbiting alien satellite that methodically lases every square mile of Earth into ash.
The Dean Koontz novel Dark Rivers of the Heart has a rare heroic use of one. One of the protagonists uses a back door to commandeer a Japanese laser satellite, using it to help make a getaway. The satellite is named Godzilla.
In Vernor Vinge's story, "True Names", the Eye of God laser satellites are are the first military installations taken over during the climactic in-computer battle between the Big Bad and Mr. Slippery/Erythina. Suddenly, things get real, and the danger of dying the True Death raises its head.
Live Action TV
Babylon 5, "Endgame"; When Sheridan's forces arrive at Earth and easily overwhelm most of the remnants of EarthForce fleet, President Clarke kills himself, after programming the planet's orbital defense system to take all of Earth with him. This means Sheridan's fleet must destroy the satellites before they fire.
In the Stargate SG-1 episode "Ethon", the Ori supply one of these to the Rand Protectorate, one of two feuding governments on the world of Tegalus. It ends up destroying Earth's first starship, the Prometheus.
Also, before the Ori, a network of Kill Sats is deployed ostensibly as a defense against external threats, but gets turned on terrestrial targets anyway as a scheme to Take Over the World. By a main character. But it was All Just a Dream, intended to show him that You Are Not Ready.
The Asurans use a Kill Sat against Atlantis on Stargate Atlantis. The Kill Sat itself is a big ship with a stargate embedded in it. The beam is fired on the Asuran homeworld through a stargate, and out the other onto Atlantis. The Expedition also uses one (though it's actually a space station, not a satellite) in order to destroy a Wraith hive ship while a fleet of Wraith is on its way to Atlantis in in the finale of the first season.
The 1978 Quatermass series (aka Quatermass IV or The Quatermass Conclusion) featured an alien device that lured people into small areas and then engulfed them in a column of light. True Believers assumed that the light was transporting them to a better planet. No such luck. It was actually a kind of nasty and insidious form of Kill Sat, only just to make things worse there wasn't an actual satellite that could be shot down. There was something that the Russians launched nuclear missiles at, but it didn't work.
In the novelisation (by the scriptwriter) Quatermass theorises that it's a kind of energy field surrounding the Earth like a huge soap bubble. When it needs to fire it just concentrates its energy on one spot.
An early First Wave episode has the protagonist investigate the death of a college student who is revealed to have been working on a government project to deploy a series of nuclear missile-armed satellites in Earth's orbit. While he initially assumes they're there to attack other nations, the fact that they're pointing away from Earth tips him off that the government is aware of (some sort of) an alien threat and are taking precautions. Unfortunately, the aliens find out about this and send their agent to set the satellites to self-destruct, showing Earth with radioactive material. Since Cade foils this plot, the satellites are assumes to still be up there. Of course, none if this is ever mentioned again.
The M-BUS is capable of acting as one, though it mostly serves as a Transform Sat instead.
Religion And Mythology
There is a Kill Sat greater than all others on this page and His name is the LORD.
Although He deals out punishment from Heaven several times throughout the Bible, special points go to the story of Elijah. The prophet is sitting on a hill when a captain leading fifty soldiers approaches and calls out, "Man of God, the king orders you to come down." Elijah responds, "If I am a man of God, may fire from heaven consume you and you fifty men." A second captain leading fifty men suffers the same fate, and the third one appears begging for his life. An angel tells Elijah that this one is safe to go with.
In Conspiracy X, the secret organization "Project Rasputin" has a psychic Kill Sat. It's a gigantic amplifier for a crew of psychic characters, letting them use their powers on anything from one building to several square kilometers. In that area it can do things like read minds, alter memories, or yes, kill people.
More directly, NASA also had "Gun Stars" that would fire hockey-puck sized chunks of metal really fast at ground targets.
In the Old World of Darkness, the Technocracy had secret orbital satellites for spying, defense against alien incursions, you name it (as well as various research stations on Luna and some moons of Jupiter and at Lagrange points throughout the solar system, a defense parameter around Earth and Moon, a Dyson Sphere in Deep Space...). As revealed in the supplement Time of Thin Blood, when an ancient vampire arose from slumber in India during the End Times and laid waste to Bangladesh the Technocracy executed "Code Ragnarök"; they finally managed to destroy the vampire by first stunning him with fusion bombs and then incinerating him with the help of a network of mirror satellites and a concentrated ray of sunlight from heaven.
In Warhammer 40,000, Exterminatus is the command used by the Inquisition when demons or heresy spread too far across the planet to be contained by covert or even overt military action. All possible (or at least important) Imperial forces pull out, and the orbiting fleet blows the hell out of the planet in any of a wide variety of ways, ranging from glassing the surface with hundreds of multi-gigaton warheads and ship-based beam weapons, to bombs filled with viruses that turn all organic matter into sludge, and "cyclonic torpedoes" that light the atmosphere on fire in a rather Homeworld-esque way. All of these methods aim for one thing: rendering life on the planet impossible.
Even when you don't need to destroy the entire planet, the various factions aren't above shelling the battlefield from orbit.
There is a giant defense system in Terra's solar system meant to defend it against enemy fleets thousands strong. It includes Kill Sats, moons that were hollowed out and made into bases, and a whole space fleet to name a few items.
This being Warhammer 40k, sometimes setting the atmosphere on fire, rendering organic matter into its constituent molecules or just plain old turning everything into molten slag just is not enough.. for this, there are two stage torpedoes which will actually blow a planet up.
Lampshaded in the Ciaphis Cain novels, with Cain admitting that occasionally a planet is too far gone even for bombardment, as it won't work and merely "gives them ideas".
In Shadowrun, "Thor shots" are Kill Sats that fire space junk at the target. It has similar power to a nuclear device and is treated as such. Orbital lasers also exist, and one was used on the dragon Alamais. He survived.
The Fist of Shiva from the Feng Shui supplement "Seed of the New Flesh" is a Buro weather control satellite that doubles as a Kill Sat. In the adventure that features it, the players have to forge an alliance between all the other factions in order to commandeer a space shuttle, take over the Fist of Shiva, and use it to destroy the Buro-controlled 2056-era Vatican in order to wipe out not only a powerful Buro feng shui site, but also to stop the Buro from using their new Transworld Maglev Network to make the site the most powerful in the world and warping the world's chi to an unimaginable degree.
Dungeons & Dragons has a spell called "Apocalypse from the Sky". No points for guessing what it does, considering it's not summoning kitties.
Also, in 4e Warlocks with a Starpact learn an spell that calls down an ice beam from the stars. Sustaining it drains the Warlock's life but continually ramps up the power. With Actions and a paladin sustaining him a Warlock could do several dozen D10's of damage over the course of the spell.
In the d20 Modern Urban Arcana setting, the Swiss Juncture of Gnome (a bunch of gnomes dropped in Switzerland using their "out of the box" though process to form their technical consulting company) made plans for a kill sat, that was never built because of cost concerns.
In the post-apocalyptic world of Eclipse Phase, the Earth has been ravaged by nuclear weaponry, bio- and nanovirii, and rampaging TITAN technology. The planet is under interdiction by a number of Kill Sats - they shoot down anything attempting to reach or leave the surface. Who put them there? Nobody's quite sure...
In Heavy Gear, there's even a new term to describe kill sats - ortillery, a portmanteau of orbital artillery.
In Genius: The Transgression, "Orbital Gun" is a modification one can make to Katastrofi Wonders. It allows the Wonder in question to deal out hellish amounts of damage, but makes it difficult to successfully hit any target smaller than an Navy destroyer.
A miniature variant (Romanov Attack Satellite) appears as a regular enemy in Heavy Weapon. It will fire a death ray downwards, which will instantly fry your tank if it hits, regardless of your shielding. To avoid such a fate, you have to shoot at it to push it away from you. It's also the game's signature enemy.
Since the protagonist in inFAMOUS has attacks that mimic Standard FPS Guns, one these attacks is this in the form of lightning.
In Phantom Dust, this is one of the many psychic powers you can obtain. Where exactly the laser comes from is never explained.
Advance Wars Dual Strike features a Kill Sat called the Black Onyx on the level Crystal Calamity. Its primary purpose is to create a barrier around Kindle's main source of power — a large crystal that turns the land into desert while creating energy. The Black Onyx also features a potent laser beam.
Spin-off Battalion Wars features a good guy version — the Doomsday Weapon used by the Solar Empire to put an end to the Iron Legion in the game's backstory.
Belcrant in Tales of Destiny It was used to fire on the earth to absorb pieces of it to create the Aethersphere
In what is one of the (probably) few unintentional uses of a Kill Sat, the game Freelancer makes mention of a winter world attempting to use a vast array of orbital mirrors to gradually thaw out the world, or at least the settled parts of it. Evidently, someone didn't carry the one, because the in-game article basically states that it focused the refracted light into a single coherent beam and described the results as being akin to a superlaser bombardment on the colony.
Just before The End of the World as We Know It, the North American Strategic Defense Agency also had access to satellites stuffed with thermonuclear missiles, which NEXUS, of course, used to nuke most of humanity all the way to the afterlife.
Final Fantasy VII has two. One was the "Bahamut ZERO" summon (though it was less a satellite and more a giant dragon blasting the enemy from orbit), and the other was one of Barret's level three limit breaks called "Satellite Beam", which does exactly what the name suggests (even underground).
Crisis Core had Bahamut Fury turn the Moon into a Kill Sat.
Final Fantasy IX has another summons that seems to do much the same thing, Ark, complete with mystical targeting electronics readouts.
Final Fantasy XII has yet another in the form of the Holy summon Ultima, who fires a beam from space via a cannon mounted below herself from space, as a finishing move.
Ultima did it again in Final Fantasy Tactics Advance. However, this version only did MP damage. Watching a gigantic lance of energy smash into the enemy from above with an explosion of magical force, only to see nobody at all physically harmed, let alone reduced to a pair of smouldering boots... a case could be made for subversion, there.
Duodecim gives access to one of these to Laguna as one of his HP attacks.
Breath of Fire IV has it's 2 Dragon protagonist and antagonist, Ryu and Fou-Lu have their ultimate dragon forms, Kaiser and Tyrant respectively. The method of attack is eerily similar to the Final Fantasy VII Bahamut Zero example above, they both transform, fly high into space, and then Tyrant blasts the entire battlefield with a massive dark ball of power, while Kaiser beam spams the area.
The GDI Ion Cannon in Tiberium is a by-the-book kind — used and abused against the Brotherhood of Nod. It has a humble start killing small targets but eventually moves to levelling military bases. As of Tiberian Twilight, it even has adjustable power settings, and there are even some foot-soldiers that can call down a strike (first seen in Renegade). Compare this to Nod's excessive use of tactical nukes.
In the Command & Conquer 3: Kane's Wrath expansion, GDI have an additional orbital attack protocol: Thor's Hammer orbital attack satellites that fire Mjölnir rods at the surface, decimating Kane's little armor divisions with impunity.
The Scrin, having a bunch of support starships beyond Neptune's Orbit, as well aswormhole capabilities, can deploy a Tiberium-laced asteroid against ground targets, as well as call down a Tiberium-seeding beam from orbit. None of these are superweapon-grade, however.
The Soviet Union also uses a sort of Kill Sat in the form of the Magnetic Satellite, which is capable of sucking any vehicle up into space. This, coupled with their Krasna-45 Orbital Drop protocol enables them to not only de-orbit space stations at you, but also send back the same vehicles they've previously captured.
Neverwinter Nights of all things added one in the second Expansion Pack with the Epic Spell "Greater Ruin" (though no mention is made of a "Ruin" spell) that includes a beam of earth-shaking golden light striking from above, then tracking across the ground onto target.
There is also the "Hammer of the Gods" spell, which causes a large yellow column of holy light to strike the target. "Greater Ruin" also causes holy energy damage. It is likely an upgraded version of "Hammer of the Gods".
Unreal Tournament 2k3 and 2k4 have the Ion Cannon, which deals lots of damage in a wide radius.
Gears of War - The Hammer of Dawn, controlled by the good guys, and somewhat more limited than usual for this trope as it requires a grunt on the ground to 'paint' the target using a handheld laser gun from close range; getting into a position it can reach while it's overhead plays a part in the stages where it's used.
The Kill Sat only works in certain weather conditions — it's how they explain it only being used occasionally. The Government in Gears deliberately Kill Satted most of the planet to stem the Locust invasion, which is the major reason for all the Scenery Gorn.
Mega Man X4, the Final Weapon satellite was such a Kill Sat that Sigma was trying to use to destroy the Earth.
Zero's Tenshouha and Optic Sunflower's 'Earth Crush' presumably come from the same satellite.
SearchMan.exe can summmon a small one as his most damaging attack in the Mega Man Battle Network series. Unfortunately for him, it's also the easiest of his attacks to avoid, as it'll only fire if its targeting cursor touches you, and even if it does, it can still be sidestepped.
In Sonic Adventure 2, the bad guys take control of the Space Colony ARK and threaten to use the planet-piercing Eclipse Cannon on the populace, demonstrating its power by using it to destroy half of the moon. Fortunately, the heroes managed to short-circuit the system in time to prevent the planet's destruction (what happened afterwards is a different story).
Shadow the Hedgehog also featured a "Satellite Laser" weapon as one of several rewards for beating the game; this was a targeting beam for what was presumably an orbital laser satellite. There's a significant delay before firing, during which the target often moves away, which is probably why the laser doesn't see more use by the heroes.
The heroes in Time Crisis II are fighting to foil a plot to launch a nuclear equipped military satellite. A prototype copy of the satellite features as the final boss, and is equipped with rockets, a laser and a guy in glasses perching on top with a pistol.
The Satellite Rain weapon in Syndicate Wars drops a tungsten-uranium alloy rod which melts into ten "raindrops", each a couple of seconds apart. While it can level buildings, so does a regular land mine. Just not with half the style.
The Armored Core series has the Justice cannon, a space-based laser cannon which, to this writer's knowledge, fired once, charring the surface of Earth and forcing humanity underground and to Mars in order to survive. Later, someone attempts to fire it again, and the player must take the fight down the barrel of the cannon to stop it from annihilating the planet.
This fight, by the way, is between robots that are at least fifty, and probably closer to one hundred feet tall. And they fight down the barrel of a space gun that takes a full three seconds of flight to reach the top of. That is a big f**king gun.
In Armored Core: Silent Line, a Kill Sat takes out anything that crosses the titular boundary. In Armored Core: For Answer, its revealed that there are so goddamn many of these cannons in Earth Orbit that its become impossible to reach space.
Subverted in Another Centurys Episode 2, a spinoff of Super Robot Wars. The rival's Humongous Mecha has access to a network of Kill Sats, but curiously never uses its full force just to wipe out the player's characters. That's because the rival is actually the main character's partner/love interest, who faked her death to pilot said mecha in order to prevent an alien invasion (here, the Zentraedi from Super Dimension Fortress Macross)). She tries to prevent the hero from using the Kill Sats because they run off the pilot's life force; the amount of power required to stop the Zentraedi would cost one pilot his/her life. Eventually the main character's mecha unlocks access to the Kill Sats by accident, and he convinces his partner that they should fight the Zentraedi together, so neither one of them has to die, which of course causes her to switch back to your side.
As an added bonus linked to the storyline aspect of the Guardian Kill Sat, using the full power of the attack did damage to the user, making the Gunark and Buster Ark the only units in the game that could kill themselves.
The Space Marine Force Commander's special ability in Dawn of War allows him to call in supporting fire from his Battle Barge in orbit. In Dark Crusade onward, the Tau Ethereal can also call down an Orbital Bombardment.
Warhammer 40,000: Dawn of War: Soulstorm has the Tau turn a natural satellite into a Kill Sat. As in, they built a cannon capable of firing across the system's interplanetary distances on a moon. (Flee not, spoilerphobes! This is told to you in the very first campaign cinematic!)
In Dawn of War 2, the Orbital Bombardment ability for Space Marine players is essentially three lasers hitting the area of your target. Devastating to anything that gets hit.
The last few missions of the first Crusader game involve striking at an orbital defense platform which controls a network of nuclear-armed satellites.
Dino Crisis 2 has one of the protagonists activating a satellite to vaporize a gigantic dinosaur.
Street Fighter Alpha 3 had this as one use of the Psycho Drive, apparently. Also, Karin Kanzuki's ending has her calling in a family favour and using their own Kill Sat to blow up the Shadaloo base.
The Golden Sun games had a fair few summons that did this — and, being summons, they could naturally target anywhere you happened to be battling, even inside caves or buildings — but only Eclipse (a dragon) and Isis were in space at the time.
In Snatcher, the Snatchers' final stronghold is destroyed by one of these in the game's climax.
As a affectionate parody of Bond villains, it shouldn't be too surprising that your goal in Evil Genius is to launch one of three Kill Sats to blackmail world leaders into total surrender. It works.
In the RTS Tom Clancy's End War, both the American Joint Strike Force and the European Enforcers Corps have access to Kill Sat technology. The latter have your usual laser satellite tech, while the former have kinetic impactors, aka "Rods from God."
In Star Wars: Jedi Starfighter, one of the protagonists gains access to a giant space laser (actually designed to be fired from the ground at orbiting capital ships, like the ion cannon on Hoth), described by some as a "mini-Death Star" which can be targeted to vaporize, well, just about anything.
The BFG of Ratchet: Deadlocked is the Harbinger, which scatters targets all over the battlefield, which are then quickly followed by beams of light blasting those spots.
Civilization: Call to Power was a Civilization-style game that included the ability to build space-based weapons and cities. One of these weapons was, for all intents and purposes, a high-powered Kill Sat that could hit anything on the ground with near impunity. It's a shame that the game was never completely debugged....
Top-down shmupSonic Wings features a barrage of orbital lasers presumably from satellites as the special weapon of one of the playable characters. Video games seem to like to give these to good guys and bad in equal measure.
In the anime-style fighting game Evil Zone, Metal Heroes parody Danzaiver's Limit Break has him calling upon a Kill Sat to strike at his enemy from orbit, complete with cutaway to the satellite itself. It's not as painful as it sounds. It should be noted, however, that this technique is actually a grappling maneuver, which takes the concept to an unforeseen level of ridiculous.
The 3rd Birthday features another one, although scaled down, that you get to use several times.
The GULF satellite in Win Back.
In Jack's ending in Tekken 2, he is destroyed by a Kill Sat in front of young Jane. In his Tekken 3 ending, he is carrying adult Jane on his shoulder, when Dr. Abel tries to do the same thing, but he protects her and himself with a Beehive Barrier.
In Sengoku Basara, Nohime has this as her Limit Break, summoning the Oda Mon as beacons with pillars of lights coming from the sky.
The expansion pack for Supreme Commander gives these to the UEF. They aren't particularly powerful, but given enough resources, you can use a group of them to pick off enemies with impunity.
As a nice touch, if the control station is destroyed, the satellite de-orbits. Straight down at whatever it was targeting. With all the ready-to-explode mass and energy of any experimental. Did we mention wreckage ignores shields?
In Zone of the Enders, BARAM turns Mars' moon, Deimos, into a Kill Sat based on the Urenbeck Catapult, a form of space-compression power slingshot. 'Course, then it turns out the real use is to not fire it, and let the overload blow a hole in space/time three times the size of the solar system.
Gunbound has two. First, the mobile E. Sate has a Kill Sat as its normal attack, though it doesn't as much fly through space as hover above it's head. However, there's the giant Kill Sat named Thor that hovers above the stage, adding damage to attacks on certain turns, and becoming stronger as it deals more damage. The two of them together is a sight to see.
Then there's the Aduka, whose secondary weapon is specifically designed to call down the Thor. A 4v4 match where everyone is piloting an Aduka... things aren't so bad in the beginning, but the pain really starts once Thor hits 3 or 4.
LARS from the car combat game Interstate '82 which is possibly the first video game weapon that's more effective in the hands of the player than the AI.
King of Fighters 2000 has the Zero Cannon, a Kill Sat created by the NESTS group, powered by fight energy, but stolen by the renegade Clone Zero, who desires to use it against them. While it fails to destroy NESTS, it does succeed in nuking Southtown. Its later destroyed by Kula Diamond.
That system is talked about in the Halo 2 announcement trailer, where there is a debate between a general on the ground wanting those platforms to be used as Kill Sats against the already-landed invasion forces, and the admiral in orbit trying to hold off the Covenant fleet:
"I'm asking you to re-target the orbitals!" "And let more of them sweep the kill zone? That's insanity! There's nothing more I can do!"
In Halo Wars, the smaller MAC Gun of the Cool ShipSpirit of Fire can be used as a more conventional, if ad hoc, Kill Sat. On the other hand, Covenant ground forces can call upon their own ships in orbit to deliver plasma bombardment or 'glassing' on their enemy.
The fourth boss in the SNES game The Ninja Warriors Again wields a pimp cane that can direct an unseen Kill Sat to fire on your position.
In Spore, you get the "Uber Turret", a fast moving low-orbit satellite missile platform. It is an inversion in that instead of attacking ground targets (you deploy on your own colonies; not exactly the thing you'd want to blow), it is used to destroy (in a matter of seconds) squadrons of alien invaders that enter your planet's atmosphere.
There is such a weapon in the game Uprising. And it is called Ksat. If only the SP enemy didn't use it....
If you built a Microwave power station in SimCity 2000, it could occasionally "miss" and rain Kill Sat-like destruction on your helpless citizens.
In World of Warcraft, Azeroth has 4 Kill Sats in orbit, used by the Titans as orbital defense weapons and named after the Keepers of Ulduar.
The final quest in the current starting area for gnomes suggest the gnomes have some themselves.
In Razing Storm, your allies have one, aimed by firing a laser cannon at the target to transmit its location to the satellite. It's used in Stage 3 to destroy the Big Bad and his headquarters, as well as to finish off the Giant SpiderTank boss.
The scrapped Fallout: Van Buren project revolved around the B.O.M.B., one of two nuke-throwing death stations, still in orbit after 200 years, and still with its payload intact.
Machines: Wired For War has a ion cannon that can wipe out almost anything in its (small) blast radius and set fire to anything just out side it. Taking over an enemy base can gain access to their ion cannon.
Ace Combat 5: The Unsung War has the SOLG (Strategic Orbital Linear Gun), a satellite-based railgun capable of firing MIRV-type nuclear warheads and wiping out half the major cities in the game's two main countries, not to mention it's programmed to crash down into Earth if control from the surface is cut off. There's also the Arkbird, which is actually a huge spaceship rather than a satellite, but can still kick some ass down there when equipped with a laser system.
The Belkan laser-based superweapon Excalibur in Ace Combat Zero: The Belkan War, while not a satellite, can still use mirror-like structures in orbit in order to increase its effective range and change its angle of attack.
In Target Terror, the player can acquire a one-use "Smart Bomb" by firing at a miniature Kill Sat that quickly scrolls across the screen at regular intervals. When used, a cutscene shows a satellite charging and firing into the earth, immediately killing all hostile targets with individual lasers while leaving friendly NPCs unharmed, even indoors.
The 8-bit game Dark Side takes place on a moon where terrorists have built a superweapon. It continuously collects energy from the Sun; guess what will happen if you fail to disable it.
In XGRA, you can use the Death Strike for a One-Hit Kill. It's an orbital laser operated by the sponsors.
BlazBlue has the magical satellite Nox Nyctores Gigant: Take Mikazuchi, complete with digital monster in a coffin that shoots the beam. It has a four-year "cooldown" period, and the firing sequence is breathtaking to behold.
Ruins of Japan: The shot from Take-Mikazuchi was the finishing blow to the Black Beast.
Ibukido: The entire city was annihilated. In one timeline, only Number 12 (aka Noel) survived.
X-Men Legends gives you super moves for each character. Beast's is "Orbital Bombardment", wherein he magicks a holographic computer from nowhere, presses some buttons and multiple lasers rain down and wipe out all onscreen enemies.
It appears in the third game as well - though instead of a summon for Natalie, it's a Limit Break for Lance. And it's safer to use. And then in the fourth one, one of the bosses hacks it to use it on you, though you can use it as well if you find the right chest.
Note that it apparently has a two shot limit, after the second time, if you don't finish him off before the third, he just yanks it out of orbit.
Champions Online actually has the "Orbital Cannon" power available for player characters (and some NPC's) to use. Normally a single, vehicle-sized blast, one optional advantage allows it to fire continuously - and select new targets on its own (always an enemy)as it does so.
Star Wars: The Old Republic. Imperial Agents have the Orbital Strike skill, calling in a strike from some of the Imperial ships orbiting the planet.
The most destructive spell in Black & White is called Mega-blast, in his basic form consist in one powerful beam of turning a building into scraps and in his most powerful form consist in many powerful beams capable of turning an entire village into scraps.
In the sequel, activating a Wonder initially manifests as a beam from the sky, quickly followed by anything from a localized hurricane to a volcanic eruption at ground zero.
City of Heroes features a few examples at higher levels - the powerful War Walkers have access to an Orbital Cannon, while Mad Scientist Anti-Matter can launch an Obliteration Beam from his space station which not only deals massive damage but also holds players helplessly in the beam.
Digimon World 3 has Gunslinger, the location and last boss, sort of, of the final boss battle for the main part of the game. It's infested with powerful Digimon and at the end Snatchmon merges itself with its master and then with the station itself. Then it plans to merge with Earth to make the most powerful Digimon EVER to have existed.
Crusader: No Remorse last mission consists in the player destroying an enemy space station (with a kill sat goal) before it becomes fully operational.
War Wind's human scientist faction can build armed satellites.
The EA version of Battleship for iOS has a one-shot satellite-based superweapon that can devastate a fairly-large area of the game grid. Naturally, it ends up being Too Awesome to Use.
One of the oldest examples of this trope in video games was Shin Megami Tensei II's Megiddo Arc - a massive superlaser designed to all but eradicate humanity's last strongholds. The guy who had it constructed? YHVH. And he's intent on using it - even against cities explicitly confirmed to be aligned with Him.
Predating even that is the Missile Command-inspired Ashes to Ashes from the early Macintosh days, which had a satellite-based ion cannon as one of the three weapons in the player's defensive arsenal. It strikes the target area instantly and has unlimited uses, but has a 2 second cool-down delay and a smaller blast radius than ground-based missiles. Still, skilled players can survive for quite a while after exhausting their other weapons.
The X-Universe series features lasertowers and orbital defense stations, which operate like Halo's Super MACs in that they're defensive in nature, blowing hostile ships out of the sky. In X3: Terran Conflict the lasertower is a Useless Useful Spell since out-of-sector combat mechanicsnote used when the player is in another sector negate its main advantage over its targets (superior range). Even in-sector, it can take dozens to bring down a capital ship. Lasertowers got a major buff in Albion Prelude, making them effective defenses.
In The Elder Scrolls V: Skyrim, the Dawnguard expansion features Auriel's bow, a weapon forged by a God. Whenever this weapon is used to fire Sun-Hallowed Elven Arrows directly at the Sun, cue the magical equivalent of a powerful Kill Sat being unleashed onto nearby enemies.
In Star Control II, this is how the Ur-Quan appears to enslave alien races. Once an alien civilization's starfleet is destroyed, they will send ships into near-orbit as Kill-Sats over the major capitals of their homeworld and threaten death unless they surrender. Except...they still destroy some capitals as a message. As the Earth commander states: "you won't find Buenos Aires" on any new maps...
Call of Duty: Ghosts takes place after the United States has been devastated by strikes from its own Kinetic Impactors ("Rods from God") after the space stations containing the weapons were hijaked by astronauts from a hostile nation.
The graphic novel-esque flash series Broken Saints features a fanatical Corrupt Corporate Executive who sets up a Kill Sat network in order to broadcast a signal triggering his vision of Judgment Day. It also has the ability to lock on to anywhere on the planet and emit highly-focused EM pulses.
In Megatokyo, the Tokyo Police Cataclysm Division used "a high-intensity satellite-based laser" to "neutralize" Ed and his plasma cannon, in this strip.
In Drive, it is revealed the Tesskans used some kind of Kill Sat on Berlin, Beijing, and New York City.
Exterminatus Now, being a combination of Sonic the Hedgehog and Warhammer 40,000, is named after the command that field agents of the Mobian Inquisition can use in times of imminent defeat or upon discovering a massive demon incursion to request a direct strike from an orbital weapons platform on their current position — which means if they don't manage to get far away quickly enough, they too will go out with a bang. Note that this is a toned down version of the W40K Exterminatus...
User Friendly is also fond of this trope, in the form of "Crowbar Satellites", which... well, drop crowbars from orbit. When the User Friendly crew were visiting Antarctica, one of the techs living there used a satellite to drop a crowbar on the unfortunate Predator wandering around outside with a soldering iron stuck in his eye (it's a long story), exploding him quite satisfactorily. Pitr (resident evil-genius wannabe) eventually got his own Crowbar Satellite... at least until one of the other techs found the remote and mistook it for a handheld game, wasting all the ammo.
NSTA revolves around the operations of the titular National Satellite Tracking Agency, which manages orbital satellites used for both techno-telepathic brain-borrowing computation and orbital laser strikes. The first strip to introduce the latter functionality involved precision brain surgery by thought-controlled orbital laser.
The Tower of Babel in S.S.D.D is an odd variation in that the satellite is only a mirror designed to redirect the lasers fired from a very large, very phallic looking tower. Apparently previous attempts at orbital weapons were either really large and easy to shoot down, or underpowered.
In Sequential Art Jack launched an orbital laser cannon and used it to destroy a couple buildings, then Art accidentally made it target the tank Jack was driving, and (intentionally) pinned him to it. Later OZBASIC attempted to upload into that satellite.
Gilgamesh Wulfenbach of Girl Genius made it look like he was directing a Kill Sat with a handheld scepter. Subverted when the power source is six large crystals positioned around the city, which fried right before the enemy surrendered.
The SCP Foundation has SCP-923, a Memetic Kill Sat. It makes people Ax-Crazy, and the effect 'splashes' at higher settings. It reports a maximum output of 238, which gets converted to 'keter' intensity - and apparently causes effects that screw with reality itself. More worryingly, using it causes wear (and results in lower-intensity settings slowly becoming unavailable). What really worries the Foundation, though, is the fact that the Kill Sat says it was built to help protect a site that they never built.
Futurama included an unintentional satellite of doom. In an effort to defeat global warming, a scientist creates a giant mirror to reflect the sun's rays. When the giant mirror is knocked off course, it focuses a beam of sunlight on the Earth that incinerates everything in its path. Epic Fail.
Later in the episode, the same scientist converted the same mirror into a more traditional Kill Sat at the request of the President of Earth, Richard Nixon. The plan was to use it to destroy the Galapagos Islands, where Nixon had tricked all of Earth's robots into going with a massive party, when it was discovered that robots were the cause of global warming. It Makes Sense in Context.
The second Watchtower in Justice League Unlimited had one of these, which caused the heroes no end of grief when it got hijacked for villainous purposes. They eventually decided it was too much power for anyone to have and decommissioned the gun. It was called the "Binary Fusion Generator", which (while never spoken as such in the show) has a convenient acronym.
In the Justice League episode Maid of Honor, villain Vandal Savage takes control of a mass driver equipped Kill Sat owned by the kingdom of his intended bride...and is promptly crushed (but not killed, thanks to his regenerative powers) by a shot from the weapon after his plans are foiled.
In an episode of Galactic Guardians, Darkseid tries to turn the peaceful Star City into a Kill Sat. When the heroes foil his plan, he is forced to settle for a Colony Drop.
In the 1981 Spider-Man cartoon, Doctor Doom introduced us to a satellite-mounted laser — the laser part of which was actually a holdover from an earlier episode — and used it to play with the Pacific Ring of Fire. As far as the "kill" part, the satellite turns out to have a surprisingly localized effect when it gets knocked off course, burns a path to his castle and bodily vaporizes him.
Johnny Bravo was once fried by one when he started hitting on a random nerd girl.
Invader Zim parodies this. When Dib discovers that Zim is weak against water, naturally a water fight ensues. This escalates until Zim builds a giant, orbital water balloon launcher.
In the Dilbert series, Dogbert causes some havoc with one of these.
Ronald Reagan in Celebrity Deathmatch tried to kill Ayatollah Khomeini with the Star Wars satellite defense system. The first attempt failed and killed a random audience member instead, but the second attempt succeeded.
Transformers Prime has established that before he founded MECH, leader Silas was involved in the development of these as part of "Project Damocles". Which was believed to be cancelled, but it turned out the prototype had been built, and when Silas gets transplanted into Breakdown's chassis and joins the Decepticons, it gets put to use with great effect by Soundwave.
In Spliced, Octocat controls a Kill Sat that she uses on people who annoy her.
A Kill Sat made a short appearance in an episode of Kim Possible. The series Arch-Enemy tried to obtain the controls for it, but failed.
The actual deployment of nukes in space is prohibited by the 1969 Outer Space Treaty.
One of the best-known real life examples (although it never passed the experimental stages) was the US "Strategic Defense Initiative" or "Star Wars" program which was shelved in the closing years of the Cold War. Principally a system to intercept intercontinental missiles from space, it also included "Rods from God" and "Brilliant Pebbles", anti-fortification weapons which (in laymen's terms) were meant to drop big rods or lumps of metal from orbit at underground bunkers, using the kinetic energy of the weapon rather than explosives or nukes to do the damage.
Another SDI idea was the pop-up one-shot X-Ray laser satellite. They would be powered by a nuke and theoretically they would toast an area as wide as a football field. The single test towards this design proved inconclusive, though serendipitously fueled the development of plenty of other (often civil) technologies. Still, it may have been the inspiration for Goldeneye, above.
Rods from God is supposedly back on the drawing board now, as a possible way of discreetly dealing with hardened targets belonging to terrorists or rogue states.
In the decades since it was abandoned, many of the engineers and scientists who were involved in SDI have openly admitted that they'd never expected their projects to work: to them, it was just a handy way to get funding for pure physics research under the guise of applied military R&D.
The scary thing? With the current technology, Rods from God could be built, launched and deployed right now. You Can Panic Now.
The Russian Almaz-class military space station OPS-2/Salyut 3 sported a self-defense gun that was tested successfully on a target-satellite (probably one of their own obsolete ones, since shooting down a US satellite would have been considered an act of war). The intent here was probably taking out potential US killer satellites.
The Russians also had the Polyus project, an advanced weapons satellite that would have sported particle weaponry, orbital mines, and an anti-observance shroud (read: cloaking device, or rather very dark cover). Would have — it was launched upside down, executed a 360-degree spin instead of a 180, and crashed into the ocean.
During the late 1990s, the Russian government announced plans for building a network of mirror satellites to capture and collect sunlight and direct it onto subpolar regions (i.e. Siberia) during winter, to improve agriculture or cut down on electrical lighting during the polar winter. The project seems to have been dropped quietly, due to costs.
That's also a proposed alternative for terraforming Mars: since the planet doesn't have enough gravity to retain an atmosphere with significant greenhouse effect (for dummies: the little heat that makes it to Mars escapes too quickly as opposed to Earth where the much thicker atmosphere keeps some of said heat for months; without this, Earth's average surface temperature would be around -18°C), they'd build several orbital mirrors and focus them onto a relatively small area. Even a few sats could heat the target area enough that a human could stroll around with a simple oxygen mask and street clothing. And since Humans Are Warriors, it's only a matter of time before someone gets the idea to weaponize the tech.
Older Than They Think: Sputnik 1, the first artificial satellite, freaked a lot of people out when it went up, although they were afraid of the possibility of the launch vehicles the Russians now had being used to launch nuclear warheads rather than the satellite itself.
Even Older Than They Think: The Nazi's called theirs the Sonnengewehr or "Sun Gun", which in turn was based on a 1929 design. A giant space-borne parabolic mirror, it would have been used to burn down cities from space. Let me repeat: The Nazis were planning a giant space-borne sun laser. More info here.
The ultimate proposed kill-sat is the Nicoll-Dyson Laser. Using a shell of satellites in orbit around the sun (the original proposal for a Dyson Sphere, not a solid shell) which collect solar energy and convert it into a laser beam, James Nicoll calculated that one could use the satellites to create a phased array laser which would have an initial beam width equal to the size of the satellites' orbits and an effective range of millions of light years. Talk about "leading your target". However, it should be pointed out that the guy who 'designed' it is a SF blogger and fan-writer, not a scientist or engineer. It's technically feasible, maybe, but in the end, just a plot point idea.
The inversion is more common: Anti-satellite weapon, or ASAT. These range from nuclear explosions (IN SPACE!) to contemporary missiles. In this age of information, these have incredible destructive potential to infrastructure (compare the 2006 internet slowdown when some undersea cables were destroyed by an earthquake in Taiwan). It's not entirely ominous though, as there are few ways to safelynote hey, it's either this or risk flaming debris falling on your head and economically dispose of unused old satellites.
So far, the US and China have successfully demonstrated ASAT weapons. (The US in 1985, China in 2007, and the US again in 2008, probably to remind China they could do it, too.) The Chinese gained some negative international reputation because they destroyed their satellite in high orbit, leaving over 2,000 potentially-dangerous chunks of debris out there. (The International Space Station is often moved to avoid orbital debris; at least two moves since the Chinese test have been done specifically to avoid its debris.)
One drawback of proposals for the use of orbiting solar-power satellites as an environmentally-friendly form of energy generation is that any means of delivering the energy to the Earth's surface in useful quantities could potentially be used as one of these if someone hacked the controls.