I'm very much in favour of destroying places and things players may think are sacrosanct or safe. Any key location is going to have serious defences against plausible threats. Dropping an asteroid on a Mars habitat is for example unlikely to work, since it would be detected by all the sensors in the Martian system and plenty of killsats, antimatter missiles and other things could be aimed at it while it was slowly dropping towards the target. Even a ship trying to do a 911 would likely have problems. But plenty of places are inherently vulnerable. Any space habitat can be vented by a fairly small detonation. Sabotage the lift of a Venusian city and it drops like a stone. Cut the counterweight of a beanstalk and it will start falling, winding its way around the planet. Of course they have been designed against this possibility which makes it a challenge for would-be megaterrorists. They will have to sabotage the fail-safes and make sure no emergency procedures function. Antimatter is one of my favourite nasties. It can be hard to detect (although this depends a lot on how much people scan for it and how well it is shielded), and a fridge-sized container can contain many, many megatons. Spaceships can also be stealthed and accelerated to pretty high speed, hitting something like a kinetic missile. There are also subtle ways of destroying places like reprogramming the repair hives to start making disassembler nano or introduce the security AI to a little program that makes it want to maximize human suffering. But blunt force is often more reliable. Personally I would suggest downing a Venusian sky city. Have some infiltrator nano enter the buoyancy system and suddenly corrode the balloons open while bombs go off in the emergency thrusters (I assume there are some systems intended to keep the place aloft long enough for an evacuation - although this might be old and under-sized in some cities anyway). The city will start falling, possibly at some serious tilt and with pieces breaking off. If it starts at a height of 100 km (forgot what the canon altitude is) it would take around 150 seconds to hit the ground (disregarding air resistance, which might buy you a minute or two) - plenty of time for desperate egocasts, jammed bandwidth (oops, did somebody sabotage the encryption or communications infrastructure to make escape impossible?) and recordings from people desperately trying to flee, tell their loved ones they love them or shoot their way to the remaining escape pods before the superheated sulphuric acid mist gets them... By the way, I wonder if cortical stacks are resilient enough to survive crashing onto the Venus surface? 460 degree heat, lots of sulphuric acid, the kinetic energy of megatons of city dropping on top of it, and potentially a giant metal fire as a sky city starts to burn into carbonates.

I would go for one of two paths: the simple, almost elegant, would be to take control of the life support-center and simply open all the hatches and stop air recicling and all that. A slow and painful death that reminds them of the power technology has. The brutal one only works for Mons Olympus, and would consist on dropping the space elevator on top of the city.

Yes, security on the elevator is going to be tight. That is why it is easier to blow up the city below, or use the aquifer method. If the terraformers of the PC have done their work properly there shouldn't be any risk for massive outflows near any inhabited places. But that assumes they have done their work properly - incompetence can happen. Or that somebody spoofs geological data, deliberately mislaid a report or similarly hides the information. Still, getting a massive outflow to kill lots of people would be tricky - first you need to trigger it, likely by nukes or antimatters that causes the aquifer to break through. As it flows, it will destroy everything in its path - but the flow speeds are only fast on a human level. Very shortly satellite images will make it clear what is going on and Mesh signals will warn everybody in its path. Might still not save everyone, and finding stacks buried in cubic kilometres of silt is going to be hard. To get the beanstalk to fall down you need to sever it near the top, since it is held up by the centrifugal force from its outer half and counterweight. I'm not sure it would do enormous damage: yes, it will be falling at orbital speed, but it will also interact with the atmosphere. I suspect that it will simply burn (it is mainly carbon) and break into small pieces. A sensible security precation for the builders would also have been to integrate scrapping charges: if a disaster happens, it will be blown apart into low-mass pieces that cannot hurt the transhuman infrastructure. Similarly the total mass is pretty low; if the cable diameter is a centimeter and the length on the order of 20,000 km, then for carbon nanotube densities the total weight is just 2600 tons - not enough to make earthquakes. The big question is what kind of terrorists we are talking about. Real terrorists make very odd but kind-of-rational choices of targets and methods: soft targets are preferred to hard targets, but prestige seems to be a major factor, and they generally chose conventional means rather than new methods. The exceptions are the dangerous ones, of course.

Arenamontanus wrote:

A sensible security precation for the builders would also have been to integrate scrapping charges: if a disaster happens, it will be blown apart into low-mass pieces that cannot hurt the transhuman infrastructure.

Hack the charges, bye-bye bean stalk? Also, loved the image I got of a Venusian aerostat going down.

King Shere wrote:

false labling (Habitat is regarded as a dangerous space debree...)

I love that one! Suddenly all the automated meteor interceptors of the Mars system aim at the innocent space habitat, blasting it into pieces. Afterwards an examination shows that someone had entered it into the orbital tracking system as a piece of small industrial production debris with unusually large radar cross-section. Since it was small none of the usual "check with the boss AGI" failsafes activated and auto-fire was allowed (big debris can produce dangerous secondary debris when blasted) and since it was labelled as ultra-dangerous everything fired. One attack that almost succeeded in one of my games was genetically altered yeast (found in the spaceship environment) programmed to start to produce bacteriophages to kill off soil bacteria when given a chemical trigger. Had it actually been triggered the space mission would have failed, all the plants in the greenhouse dying (and the hydroponics failing due to the breakdown of a particular recycling pathway). A nastier version: someone has created a version of the Aspergillus mold that can also synthesize a potent neurotoxin. The trigger of the gene is either an obscure chemical or the neurotoxin itself: once the mold starts making it other mold in the vicinity will begin too. This gene is also placed next to a new gene giving it a slight fitness advantage by allowing it to grow in certain modern plastic bathroom fittings. If the terrorists want to leave a message they can write it in the mold genome. The mold is introduced into a habitat by contaminated cargo, spreads quietly and becomes part of the normal ecosystem (Aspergillus is *everywhere* in transhuman environments with oxygen and water). One day another contaminated cargo arrives, this one containing an obscure chemical. Over the span of hours the habitat fills with neurotoxin. The best thing (from a mold perspective, at least) is that as people start dying and things breaking down there will be a lot more places for mold to grow... [... and this is why I constantly fully sequence samples of all cells in my immediate environment and run them past safety checkers. Paranoid, you say?! It is not just nanites that are dangerous! ]

jackgraham wrote:

Massive, massive gamma ray emissions, for one thing.

Once the initial reaction releases a sizeable fraction of the total energy and turns the bomb and vicinity into a plasma fireball (just like a nuke) there will still be a lot of antimatter that just got vaporized mixed with the plasma, producing an "ambiplasma". The mean free path of these particles will be quite long due to the high temperature and low density so they will all have a high chance to get to the fireball surface where they encounter compressed matter from the surroundings and annihilate. This will heat up the surface even more. The same process occurs with x-rays and gamma rays (this is how ordinary nuclear fireballs first form). I haven't done the calculations for this, but I suspect antimatter produces larger fireballs than equivalent nukes because there is more energy production at the surface. A nuclear detonation has a double flash pattern: a first flash from the fireball shell formed when radiation from the detonation itself turns the air into an opaque plasma and then a second, slower flash from when the expanding contents reach the fireball surface. An antimatter detonation would make the second flash much bigger for the above reason. Since the main thermal pulse is from this second flash, I would suspect the heat damage of antimatter weapons would be significantly higher than equivalent nukes. High altitude detonations would likely grow very large and might produce long-lived plasma clouds giving off massive IR radiation for a long while. The gammas would be more of a direct flash. Generally, gamma rays have a halving distance in air of about 150 meters. Not that much gammas are going to reach the ground. However, there would be plenty of radionuclides produced. I'm not entirely sure what is left if an oxygen atom is hit by a high energy antiproton; it might break into individual particles, there is certainly enough energy in the annihilation to overcome the binding energy. But in any case, there will be plenty of radioactivity.

Going back to the original thread, task and goal. [I have edit this post, for better clarification and grammar reasons] [B]Goal is to blow up a habitat, destroying a habitat/city on Mars[/B] Villains goal or GMs goal ^^ [B]"the terrorists goal isn't to kill the people, there is something they desperately want to destroy and are going about it in a similar way to a firewall erasure squad." [/B] Dont kill civilians, dont reveal or implicate your orginisation, erase the problem with extreme prejudice & ensure it is gone. . [B]"The perpetrators are a small group of highly-skilled specialists, not an army."[/B] [B]"the villains don't necessarily want the attention but I want the whole system to hate these guys"[/B] What Villains wants & what they get are two different things. Perhaps what you (as GM) want is a attack that results in the destruction of the habitat/city & also system wide dislike of the perpetrators. The villains doesn't seem to have desired destroying the entire habitat city, but things got out of hand. like a player party on its less successful sessions. Fun solution is to have another player party play the highly-skilled (but unlucky) erasure squad in a session. [B]Example turn of events:[/B] A simple burglary, against some incriminating evidence (that needs erasing) Burgles disables the security system to make intrusion possible. When welding the security safe; significantly less Thermite was needed. (turns out the safe wasn't built according to specs) The unstoppable thermite fire results in a spreading building fire. The earlier disabled security system hampers proper fire containment. "Villain player session" participants Exit Stage Left. The large spreading fire itself could pose a threat to the entire habitat, but to those that like Fireworks ^^ The fire spreads down the building block into a factory & igniting its stockpiles of antimatter. Habitat/city had some sentimental & historical value. Many will mourn its loss. [B]Result:[/B]Destroyed habitat, system wide outrage & a big mess.

Drive home how fragile humanity's position is. Some idiot kid is messing around with a Nanohive, and produces a Protean Nanoswarm that makes more Protean Nanoswarms. Grey Goo ensues.