From The TimeSplitters Wiki

Rocket Launcher (FP)
Ammo	6/6
Fire Rate bullets per sec/cartridge time	single/auto
Reload Time	4 sec
Damage (per Single Shot) Head/Body/Leg	100% (if it hits target)
Type	Rocket
Zoom	None
Primary Fire	A rocket
Secondary Fire	Automatic rocket shots
Games	TS & TS2 & TSFP

The Rocket Launcher has appeared in every game so far. It has very powerful explosive shots that can kill in one shot, though robots can endure more damage from rockets. The secondary fire shoots three rockets at the same time, which can dispatch robots faster.
In TimeSplitters: Future Perfect the secrondary fire mode of the rocket launcher underwent a change, in that you can now set it to automatic, this will cause it to discharge all the rocket left in the clip in a very short space of time.This is effective at blanketing an area in explosives and forcing opposing player to keep their head down. The downside of using this is that it entails a long reload time.