The defensive capabilities of the Nivenian Empire are quite high since they have a huge population and a very small territory to protect. Unlike relativistic kinetic missiles (R.K.M.s), which are discussed on the main page, the systems here are limited to the Nivenia system only.
Defense Rings Edit
The most iconic component of the Nivenian Empire is the Niven ring or ringworld, a rotating actively supported structure wrapping all the way around a star. Defending ringworlds is very tricky, as any random shot fired more or less toward the star has a serious chance of hitting the ringworld, and even one exploding fusion bomb has a chance to severely damaging it since it is so thin. Their defense is left up to the defense rings, bands 100 km across and 2 km thick, spinning at orbital velocity at 3 times the distance of the ringworlds. These mainly contain space for fusion missiles and coilgun ammunition, and these missiles and coilguns are their main weapons, although fusion-powered gamma-ray lasers are also sometimes used. The defense rings are outfitted with toroidal quantum chromodynamic shields (at a strength of 250 TJ/mol quarks) and auxiliary cold fusion generators for powering them and the weapons systems in emergencies. Each kilometer of defense ring is manned by 5,000 Nivenians, mainly controllers and overseers for the weapons. Each kilometer also contains hundreds of thousands of 20-Exajoule fusion missiles and trillions of rounds of coilgun shells for kinetic attacks at close range. Around 200 of these exist around the primary, and around 150 exist around the secondary, although these are much smaller in radius. Rotating habitats inside the rings provide crew quarters and artificial gravity. The active support structures on the ringworlds also contain some fusion missiles. The defense rings are also 99% reflective to all forms of light (except gamma rays) due to several layers of chemical coating.
Nicoll-Dyson Beam Edit
There is a set of mirrors and lenses orbiting the primary, that, if focused properly, can fire out 24.7 Yottawatts of energy, mainly in the form of UV light. The power can be focused either in one giant beam, or in tens of thousands of smaller beams. Of course, this device has a lot of blind spots due to the ringworlds being opaque and fragile. However, it is very good for accelerating ships, R.K.M.s, and random debris to extremely high speeds (usually up to 0.95c).
The Nivenian Navy's composition is shown below. All Nivenian ships' main weapon is their narrow-beam protium-protium fusion rocket, which outputs an energy proportional to the mass of the ship at a certain acceleration level. Secondary weapons include thermonuclear missiles and coilguns that launch thermonuclear warheads.
All ships have a total delta V of 0.055c.
|Number (Old fleet)*||0||50,000,000||0||0|
|Number (New fleet)**||30,000,000||700,000,000||900,000,000||1,500,000,000|
|Crew per ship||750,000||60,000||25,000||8,000|
|Mass of Ship (Tg)||75.0||6.0||2.5||0.8|
*Before 21 NE**After 21 NE