I believe that the capsule will only be the command center/cockpit/bridge of the spacecraft that is planned to go to Mars. The rest of the craft will be assembled in orbit from various Ares V launches.
While APCP will not detonate, it will deflagrate (which is what it is designed to do).
APCP when burning produces large amounts of gases quickly, which if confined, will cause the container to burst (dry ice also bombs work on this principle). For safety reasons (more than fear of terrorism), the US Department of Transportation regulates shipping materials that strongly deflagrate as explosives under the HAZMAT cateogory of Class 1.3 explosives.
There is a large misconcetption between a detonation and explosion. All conventional military bombs desgined to explode use a detonation as the mechanism because it is easier to control, more powerful, and more precise, but explosions can be caused by other mechanisms as well.
Rockets are powered by materials that will explode under confinement (like gunpowder), but will usually not detonate.
It may be that this isn't a big deal to the various assortments of petty dictators, but they will often gang up on unpopular countries. Witness how the UN commission on racism is consistently and ironically hijacked by antisemitic agenda. It is worth noting that censorship is a universal concern for dictators and other autocrats and totalitarians. Control over the internet would likely inspire the various anti-freedom forces which make up the majority of the UN to work together for their individual benefit.