[jere]

Sure. It's commonly called dead reckoning as I understand it: http://en.wikipedia.org/wiki/Dead_reckoning#Dead_reckoning_f...

But even if you only send a "real" update once a second, I still don't see how this thing scales (that still leaves 1 PB in the above calculation). And if you send it less than that, I imagine things would start to look rather jittery. The "occasional discrepancy form reality" would be awful.

[stingraycharles]

It depends. If you have 3000 clients and a full sync of all visible ships occurs every second, you get 3000 * 48 = approx 150kb/sec/client. Yes, that means that the server must be able to handle 3000 times that speed, but that still leaves us at about 0.5gbit. Yes, it's a very high load, but then again, these types of situations are extraordinary.

Last but not least, compression is your friend.