The overall development of ESA’s Space Transportation Programme can be perceived in two major phases. The first phase finished with the transfer of the ARIANE 1-4 launch systems to Arianespace for utilisation and commercialization. The second phase was started after the success of the ARIANE launcher programme had created a sound basis for Europe’s space industry in the evolving commercial space transportation market. This has lead to the definition of a second phase of the launcher development program which is expected to fulfil the needs for transport into space for many years to come. The wide objectives of the program makes it not only suitable for commercial applications but can also be expected to cover the launching needs for future Space Astrophysics missions.
Market studies of the future commercial space transportation needs show growing satellite masses and an increased worldwide competition. Europe therefore needs a powerful launcher with improved cost-effectiveness and improved reliability for geostationary missions. On the other hand the discussion about the optimum launcher, spacecraft size and orbits for Astronomy missions, as well as for Space Science missions in general, is still a matter under debate, as explained by Dyson elsewhere in these Proceedings. The experience obtained with IUE and EXOSAT-Observatory satellites which, due to their general user nature, do not have a rigidly preplanned observing program - seem to suggest that, at least for operational motives, high orbits appear preferable for such satellites. This is especially true as compared to the operational and planning difficulties foreseen with the recently launched Hubble Space Telescope, which is in low earth orbit (LEO). Of course, for firmly pre-scheduled observatories with a predetermined Science program, such as COBE and HIPPARCOS, this choice may not be obvious.