Within the next five years five cometary space missions are planned to be launched to visit seven different target comets. These missions vary significantly in objectives and expected scientific outcome. Nevertheless, it is clear that each of them will increase our knowledge of cometary nuclei. They will for instance all provide images of the comet nucleus, of which we so far have only one single example, namely, comet 1P/Halley. The seven targets chosen for the missions are 76P/West-Kohoutek-Ikemura (DS1), 81P/Wild 2 (Stardust), 2P/Encke, 6P/d'Arrest, 73P/Schwassmann-Wachmann 3 (CONTOUR), 46P/Wirtanen (ROSETTA), and 9P/Tempel 1 (DS4). They are all short-period comets and may appear to be similar on first glance. However, a closer look reveals that they are quite different in their orbital evolution and physical properties. Comet 81P/Wild 2 for instance was only recently (1974) deflected into the inner Solar System from an orbit lying much further out and comet 73P/Schwassmann-Wachmann 3 split during its apparition in 1995. The diversity of the targets promises for the future that properties of cometary nuclei can be analysed and interpreted with resonably high statistical significance.

The available information on all targets will be reviewed in a comparative overview. In addition, I will give a summary of the observations still needed to support the space missions and optimize the return from each of them.