Editing MESSENGER (section)

===Attitude control and propulsion===
Main propulsion was provided by the 645&nbsp;[[Newton (unit)|N]], 317 sec. [[Specific impulse|I<sub>sp</sub>]] [[bipropellant rocket|bipropellant]] ([[hydrazine]] and [[nitrogen tetroxide]]) large velocity assist (LVA) thruster. The model used was the [[LEROS|LEROS 1b]], developed and manufactured at AMPAC‐ISP's Westcott works, in the United Kingdom. The spacecraft was designed to carry {{convert|607.8|kg|lb}} of propellant and [[helium]] pressurizer for the LVA.<ref name="MESSENGERLaunch"/>

Four {{convert|22|N|abbr=on}} [[monopropellant rocket|monopropellant]] thrusters provided spacecraft steering during main thruster burns, and twelve {{convert|4.4|N|1|abbr=on}} monopropellant thrusters were used for [[Spacecraft attitude control|attitude control]]. For precision attitude control, a [[reaction wheel]] [[attitude control system]] was also included.<ref name="MESSENGERLaunch"/> Information for attitude control was provided by [[star tracker]]s, an [[Attitude control (spacecraft)#Gyroscopes|inertial measurement unit]] and six [[Sun sensor]]s.<ref name="MESSENGERLaunch"/>