Berndt Feuerbacher

Materials sciences in space

A summary is presented of recent theoretical and experimental examinations of materials processing methods in microgravity conditions. The discussion covers Skylab and Spacelab flights, rocket and parabolic flights, and drop tube experiments. Attention is given to crystal growth, fluid physics, metallurgical and electrophoresis experiments.

Binary Systems with Miscibility Gap in the Liquid State

Systems with miscibility gap in the liquid state, “immiscibles”, are of fundamental interest and have potential for the preparation of dispersions. The study of these systems and their application has, thus far, been very limited. Under terrestrial conditions the liquid components separate quickly due to sedimentation and buoyancy. Component separation due to nucleation and growth of nuclei and spinodal decomposition can, therefore, not be studied under defined conditions and fine dispersions cannot be prepared. Research under microgravity conditions in orbiting laboratories or under free fall conditions opens new avenues for the study of these systems. This paper summarizes the underlying thermodynamic and physical principles and mechanismes and reviews results of recent experimental investigations.

Chapter 46 – Strategies of Modern Solar System Exploration

The exploration of the solar system is a continuous challenge for humanity. Its benefits include innovation, culture and inspiration, and peaceful global cooperation. Ambitious future goals such as the human exploration of Mars are very demanding and require international cooperation on a global scale. Long-term strategies to implement solar system exploration missions rely on a suitable cooperation framework between participating nations and on an agreement on common goals and objectives. This is followed by an exploration road map defining the mission scenario, suitable design reference missions, and finally detailed long-term work plans for the partners. An increasing number of nations is getting interested in space and may be part of a future global exploration effort. In addition, commercial companies develop business in deep space. Judged from the present world spending in civil space programs, and compared to the cost implications of the Apollo program, a human flight to Mars can be considered affordable. A first cooperation initiative by 14 national space agencies has been established to jointly develop a global exploration road map with the objective of an affordable and sustainable human mission to Mars.

Rosetta: Landing on a comet

The European Space Agency will launch in January 2003 a mission called “Rosetta” to visit a comet. This space-craft will rendezvous with comet Wirtanen, follow it on its way to the sun in a close orbit and observe the comet core from this position. As part of the mission, a small package is carried, the “Rosetta Lander”, which separates and lands softly on the surface of the comet, where it will carry out a sequence of scientific investigations.Comets are amongst the most interesting bodies in our near space environment. They can be regarded as messengers from the time of formation of our planetary system, 4.5 billion years ago. A concise view on the origin and properties of comets in the context of the development history of our solar system is presented. The only direct information on comets available so far stems from the GIOTTO mission carried out during the last encounter with comet Halley in 1986. From the results obtained there, rough estimates are possible on the local environment near a comet and thus on the design requirements for a landing probe.The Rosetta mission follows a complicated flight path, which will reach the comet after a number of swing-by manoeuvres that use Mars and Earth to gain momentum. The information we have on comet 64P/Wirtanen is very limited. Therefore the final parameters for separation, descent and landing will be set after close observation of the target object by the Orbiter instruments.An overview will be given on the main components of the Lander, and short animations will be used to illustrate the Orbiter separation, descent and landing. The payload will be described, consisting of nine scientific instruments, chosen to complement each other in the fulfilment of the scientific objectives, which are discussed in some detail.