In the focus of attention of every space agency with plans of deep space exploration is developing new types of engines. New propulsion, less limited with amount of fuel, is necessary if any kind of human Mars mission is concerned.
Aerojet Rocketdyne announced today that won NASA contract, worth $2.5 million, for developing program of new electric propulsion characterized with high output power (more about space electric propulsion You can read in this post). NASA seriously considers it as important step in reducing time needed for reaching Mars by manned spacecraft. It is second contract for electric propulsion recently - on 6 February 2016 it was announced that Busek Co. Inc. was granted with contract for electrospray thrusters for Cubesat satellites. It shows general tendency and increasing role of electric propulsion in far perspective of NASA space exploration.
Objective for Aerojet Rocketdyne, especially for team responsible for developing Hall Thruster System, is not easy. First of all Aerojet will develop 100 kW Hall Thruster System and 250 kW thruster based on Nested Hall Thruster technology. Key element of the conception of Aerojet Rocketdyne is Power Processing Unit (PPU) which will convert solar energy from solar arrays of spacecraft into electric power for Hall Thrusters. Whole system will be tested for 100 hours in NASA Glenn Research Center in Cleveland, Ohio. It will be final confirmation for NASA if Aerojet managed to meet demands. It is worth to remind that present electric thrusters are mainly used for final maneuvers of satellites. They are powered mainly with electricity, using very small amount of fuel, operating without any vibrations and they are easy to control (they have capability of multiple on/off cycles). Their main disadvantage is very low power comparing to ordinary rocket engine. At the present most electric thrusters are generating less than 5 kW of output power. It is far less then power needed for any serious maneuvers of large spacecraft. Even if consider only as main propulsion for satellite it is too low for providing enough power for reaching orbit in reasonable short time. Although perspectives are very promising; ten years ago NASA was developing technology with high power electric propulsion. Project was called High Power Electric Propulsion (HiPEP) and was part of the Jupiter Icy Moons Orbiter program, which was canceled in 2005. HiPEP was developed as pre-prototype with achieved power level of 39.3 kW. It is almost eight times more than present thrusters and it is worth to remind that technology is more advanced than ten years ago. NASA is still looking for alternative propulsion for future deep space exploration and this contract proves that NASA did not resign from ambitious plans.