Today, satellites have become an indispensable part of our everyday life. Our mobile phones, TV sets, offices, the internet and smart devices cannot work without satellites. Bellatrix Aerospace is a key supplier of electric propulsion systems for satellites. These thrusters mark a revolution in the field of nano and micro satellite propulsion as the power requirement for these thrusters is relatively low. Electric Propulsion Systems are the prime mover for affordable access to space .
All satellites need a means of moving through space, and their usual way of travelling resembles that of skaters: a short push and a long glide. All satellites move along orbits, as they revolve around a celestial body. Once rocket take satellites to their parking orbits, the satellites need to find their way to their nominal orbit. It needs to overcome gravitational pulls and keep itself in the orbit. It also needs to maintain its orientation as required by its function. To do this, the satellite needs its own propulsion system.
Traditionally chemical propulsion systems were used for satellite propulsion. Now, electric propulsion (EP) systems have evolved and are revolutionizing the satellite industry. An electrically powered spacecraft propulsion system uses electrical energy to change the velocity of a spacecraft. Most of these kinds of spacecraft propulsion systems work by electrically expelling propellant at high speed. Electric thrusters typically use much less propellant than chemical rockets because they have a higher exhaust speed (operate at a higher specific impulse) than chemical rockets.
ADVANTAGES OF Electric Propulsion
Electric propulsion offers several advantages. Electric Propulsion is safe and these engines are more efficient than chemical ones, in the sense that they require much less propellant to produce the same overall effect, i.e. a particular increase in spacecraft velocity. The propellant is ejected up to twenty times faster than from classical thrusters and therefore the same propelling force is obtained with twenty times less propellant. Electric propulsion can produce force for a very long time as compared to chemical propulsion.
HALL EFFECT TRUSTERS
Hall Effect Thruster or Stationary Plasma Thruster (SPT) is a type of advanced ion propulsion system. They work by trapping electrons in a magnetic field and then use the electrons to ionize propellant, efficiently accelerate the ions to produce thrust. At Bellatrix SPT's with 40mN and 90mN thrust output is under development. The developmental process is expected to be completed in second half of 2018.
MAGNETO PLASMA DYANMIC THRUSTER
Magnetoplasmadynamic Thruster (MPDT's) or Lorentz Force Accelerators (LFA) is an advanced type of electric propulsion system, capable of generating high thrust(~200N) with very high specific impulses (>20,000 seconds). Presently they are unrealistic to be operated in space owing to its requirement of power in the range of 50-200MW. This type of thruster, however has the potential for efficient interplanetary exploration in the future when such power is made available in Space. Bellatrix is independently carrying out R&D on MPDT's since June 2013 to understand its physics and operationalise it in the future.