11. Another method is to use an oxidizer that can also be used as a monopropellant . 12. When mixed with a fuel and stored before use, it becomes a mixed monopropellant . 13. Attitude control and ullage are provided by means of hydrazine monopropellant thrusters located around the stage. 14. The "'Pegasus "'is an stages and an optional monopropellant fourth stage. 15. The HAPS ( Hydrazine Auxiliary Propulsion System ) is powered by three restartable, monopropellant hydrazine thrusters. 16. Propulsion is by a hydrazine monopropellant system, containing 544 kg of fuel in four exposed tanks. 17. Engineers choose monopropellant systems when the need for simplicity and reliability outweigh the need for high delivered impulse. 18. LMP-103S has 6 % higher specific impulse and 30 % higher impulse density than hydrazine monopropellant . 19. Propulsion for midcourse maneuvers was supplied by a monopropellant ( anhydrous hydrazine ) 225 N retro-rocket. 20. Their lunar rover was named European Lunar Lander and used a monopropellant rocket engine for landing and hovering.
