DS4G thruster firing during tests
DS4G thruster firing during tests

Why is Propulsion and Aerothermodynamics important?

The domain of Propulsion and Aerothermodynamics is important for maintaining and widening our gateway to space. It takes extreme speed to reach orbit and precisely controlled thrust firing to get a mission where it needs to be. Landing on Earth or other planetary surfaces is just as challenging – particularly because the high velocity that carried the spacecraft into space needs to be bled away to ensure a survivable touchdown.

Chemical propulsion remains state-of-the-art for the large thrust generated by current launch vehicles as well as on-orbit spacecraft manoeuvres, usually employing liquid propellants which are so-called because they are stored aboard the rocket or spacecraft fuel tank in a cooled liquid state.

There are exceptions however: solid rocket motors can be used for 'kick' stages that put payloads into their final orbit while cold gas systems which simply emit pressurised gas through a nozzle are well suited to small spacecraft or low thrust applications.

Electric propulsion systems, which accelerate their fuel to high velocities taking advantage of electrical energy, are proving increasingly significant to spaceflight. Electrostatic engines in particular are prized for their ability to deliver sustained thrust over prolonged periods of time with limited masses of fuel.

Last update: 30 September 2009

Copyright 2000 - 2015 © European Space Agency. All rights reserved.