Planet crackers done dirt cheap

Though one could avoid that cost by roleplaying out finding a suitable asteroid and strapping engines onto it, etc.

Keep in mind Yamatai System's defense network could stop these as far as 20 LY out (using wormholes, quantum detonators, and/or anti-FTL fields), and anywhere there's one of the new Scopio-class stations, they could do the same for 10 LY. Basically, places inside the circles on the map are protected (including Elysia Novus and all of Nepleslia.

Rules say nothing about mass costs

That doesn't mean you can ignore logic.

You have a point, they don't discuss "mass." But that's because the rules weren't designed to handle a giant bullet.

I suppose..... But yeah, It's not like I want to use it myself, I just want it to be avalible

While this system could theoretically work, it would be incredibly easy to intercept (keep in mind sensors in this setting are extremely good) by any reasonably defended force these devices could be intercepted well before they hit there target (remember, even at the speed of light, it will take dozens of minutes if not hours to go from the outer reach of a system to the target. To me, this means that such a weapon is pretty much weapon only really of use to terrorists (who lack the resources of a national or corporate military), as a legitimate navy could sterilize the planet in question in a much shorter span of time.

P.S. to La Blue Dude & Kel: Engineering/Physics Majors heck yeah!! (I am one myself).

Actualy that's who I saw using it. Terrorist orginisations.... Also once it's within several light-hours of the target you can't stop it by blowing it up, it's chunks will still damage the planet's surface/atm

You needn't blow it up, just take out its propulsion and slightly nudge it and it would miss by tens of thousands of km, if not millions.

Also, you're forgetting that the tech level of Star Army allows them to blow it up, and then blow up the pieces, within a space of two point one seconds or less.

This is why all of my RKVs have a cloaking device.

A few thousand KM? Earth is a few thousand KM in diameter. It's gravity field is much larger. Once it's in system it would require an outragious amount of energy to do anything about it... Except warp it the crap away. That's about the only solution.

Actually, vesper is right on this one. If it was nudged a little bit then it would miss earth entirely. 9.8m/s of gravity isn't going to change that.

NASA even has a plan to deploy a poor man's tractor beam to knock doomsday asteroids away from earth. Technically this would happen at much slower speeds but it is essentially the same idea.

The following asteroid is sufficient to produce an Earth-shattering impact:

Projectile Diameter: 36000.00 m = 118080.00 ft = 22.36 miles
Projectile Density: 8000 kg/m3
Impact Velocity: 299700.00 km/s = 186113.70 miles/s (Your chosen velocity is higher than the maximum for an object orbiting the sun)
Impact Angle: 45 degrees

Click to expand...

A grazing hit by the same projectile at impact angle of 0.9 degrees - nearly tangent to the Earth's surface, would melt a volume of rock slightly greater than Earth's volume. Earth is a little more complicated internally than a big, cold homogeneous ball of rock, but suffice it to say that the "before" and "after" photos would nonetheless look quite different.

The density is consistent with that of a mostly-iron asteroid. Incidentally, many terrestrial (i.e. not "gas giant") planets. such as Earth, have iron-rich cores...

If our terrorists have access to a wormhole generator, they can deliver their 36km-wide greeting card to well within a light-second of its target from over twenty light-years away. The wormhole itself will be unusually large, but nobody will notice the cloaked asteroid emerging from it. The first warning sign would be the asteroid decloaking (if necessary to actually hit the planet without passing through it, as tends to occur with some types of cloaking technology) at a mere 100km from the planet's surface.

There is the matter of planetary shields.