Stephen Withers
Wednesday, 11 March 2009 08:33
Science -
Space
Page 1 of 2
The European Space Agency (ESA) is set to test a tiny space engine that's so finely controllable it can balance the pressure of sunlight.
The ESA's Field Emission Electric Propulsion (FEEP) engine has been designed to hold a future probe stationary in space.
Measuring just 10 centimetres across, it works by emitting charged atoms (ions) and so gives off that blue glow loved by science fiction movies and TV shows.
But unlike the ion propulsion systems already in use, FEEP produces an average thrust equivalent to the force of a single falling hair, ESA officials explained.
FEEP is intended for use in the joint NASA-ESA LISA Pathfinder mission which will observe the behaviour of objects freed from the influence of gravity. It is also being developed with the requirements of the planned French Microscope mission.
LISA Pathfinder will travel to the Lagrange Point 1 (L1) where the pull of the Earth's gravity is exactly balanced by that of the Sun.
The main remaining force on the probe will be the pressure of sunlight. Slight as that is, it must be allowed for in the LISA Pathfinder experiments.
Exactly how slight is the thrust developed by FEEP? Find out on
page 2.
