Transportation requirements for the Horizon 2000 programme

The European Space Agency (ESA) has laid the foundations for a long term plan for space activity in Europe. A series of missions to study the planet Earth are planned, the next mission will be the ERS-1 satellite and also there is a long term plan for space science. This is essentially the study of the solar system and the study of the universe by all possible means and is known as the Horizon 2000 programme. Propulsion is a key element in all programmes since it often accounts for half the mass of the spacecraft and a significant part of its life limitation and reliability budgets. The paper addresses the propulsion options for the Horizon 2000 missions and, where choices have to be made, the reasons behind the choices. The UK is also featuring prominently in the propulsion programmes so emphasis is placed on this involvement