aberration of light


ECSS-E-ST-60-20C Rev. 2


Error on the position of a measured star due to the time of propagation of light, and the linear motion of the STR in an inertial coordinate system


  • NOTE 1 The Newtonian first order expression of the rotation error for one star direction is: where: V is the magnitude of the absolute linear velocity of the spacecraft w.r.t. to an inertial frame c is the light velocity (299 792 458 m/s) is the angle between the vector and the star direction
  • NOTE 2 For a satellite on an orbit around the Earth, the absolute velocity is the vector sum of the relative velocity of the spacecraft w.r.t the Earth and of the velocity of the Earth w.r.t the Sun.
  • NOTE 3 For an Earth orbit, the magnitude of this effect is around 25 arcsec (max). For an interplanetary spacecraft the absolute velocity is simply the absolute velocity w.r.t. the sun.
  • NOTE 4 The detailed contributors to the relativistic error are given in Annex G.
Glossary app image

ECSS Glossary mobile applications

ECSS Glossary mobile apps available from iOS and Android store and ECSS Glossary Plugin for MS Word available from Microsoft Appstore
Search the online Glossary