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Science & Exploration

N° 56–1995: Full load of ESA experiments on Maxus-2 sounding rocket

24 November 1995

The Maxus-2 sounding rocket is scheduled for launch on Monday 27 November 1995 from the Esrange launch site in Kiruna, Sweden. The launch window opens at 09:30 hrs and closes at 11:30hrs. The sounding-rocket will reach an apogee of 710 km and will provide 121/2 minutes of microgravity (virtual absence of gravity) for the experiments on board.

Maxus sounding rockets are built and commercialised by an industrial joint venture, a team comprising of the Swedish Space Corporation (SSC) and DASA of Germany. ESA is fully funding the scientific payload for this mission.

The payload comprises 8 experiments spanning the fields of fluid physics, electrophoresis and cell biology. Scientists from Belgium, France, Germany and Switzerland designed these experiments and the hardware was built by Swedish, German and Italian firms. The experiments are accommodated in 5 autonomous experiment modules and account for an overall mass of about 500 kg out of a total payload of about 800 kg.

The first module contains an experiment which aims to check the static and dynamic behaviour of liquids at corners and edges. The second contains a biological experiment on two unicellular organisms (loxodes and paramecium). In their natural habitat (lakes), these organisms make use of the gravity vector for their orientation. Their swimming behaviour in microgravity will be observed on Earth in real time.

The third module houses two other biology experiments. One examines the effect of microgravity on particle ingestion of gold beads by human macrophage cells (a type of white blood cell). Macrophage cells digest foreign particles, such as bacteria and viruses, thereby performing an important function in our immune system. The other experiment investigates the influence of weightlessness on the structure of lymphocytes (white blood cells).

The fourth module accommodates three different experiments all dealing with convection phenomena due to surface-tension instabilities (Marangoni convection). Surface tension is that property of liquids which makes raindrops nearly spherical and allows insects to move on water surfaces. These phenomena, which are masked by the effect of gravity on Earth, can be easily studied in microgravity conditions.

The fifth module contains an experiment that deals with electrophoresis, i.e. a process which is used to separate biological products in solution by application of a strong electric field. A highly concentrated solution with two proteins will be separated into its fractions and collected in a set of 59 syringes.