Formation and vesiculation of biomembranes during spaceflight.

Shuttle flight, sounding rocket flight, and parabolic flight experiments demonstrate the formation of bilayer membrane vesicles (liposomes) in reduced gravity, following the dilution of detergent from detergent-phospholipid mixed micelles. The reduction in detergent concentration initiates assembly of bilayer membrane sheets, which are sensitive to solution disturbances. An increase in disturbances by forced dilution results in small diameter liposomes (< 150 nm), in both ground and flight samples. In the absence of forced dilution, liposomes remain small at 1-g, but exhibit much larger diameters at 0-g (1000-2000 nm). Our spaceflight data reveal that membrane assembly and vesiculation are strongly influenced by gravity-induced solution disturbances (e.g., convection currents), which limit vesicle diameter.     

A compact body mass measuring device for space flight applications.

During spaceflights, it is important to measure an astronaut's body mass ('weight'), both for investigating the influence of the space environment on the human body and for monitoring the physical (health) condition of the astronaut. This paper reports the development of a mass measuring device that is compact, user friendly, and has an absolute measuring accuracy better than 60 gram. The measurement accuracy turns out to be restricted by the way a human body is configured by nature and not by the instrument itself, that has an accuracy much better than required.