Space processing

(engineering) The carrying out of various processes aboard orbiting spacecraft, utilizing the low-gravity, high-vacuum environment associated with these vehicles.

Experiments conducted in space in order to take advantage of the reduced gravity in studies of the growth, behavior, and properties of materials. Spacelab, developed by the European Space Agency (ESA), is a laboratory module that flies in the space shuttle payload bay. First launched in 1983 on the Columbia, the module has become the workhorse for United States and international science missions emphasizing low gravity. The experiments in fluids, combustion, materials science, and biotechnology conducted on these missions, together with their related ground-based research, have resulted in more than 2200 scientific publications.

Since biotechnology experiments generally have modest space and power requirements, they were able to be accommodated by middeck lockers in other shuttle missions as well as on the Spacelab microgravity emphasis missions, which provided them with many more flight opportunities. Even though the microgravity environment on some of these missions was not ideal, biomolecular crystal growth experiments for structural analysis as well as cell and tissue culturing experiments produced many interesting results, some of which could have commercial applications.

There are two compelling reasons for the study of combustion in microgravity. One is the issue of fire safety in the design and operation procedures of orbiting laboratories; the other is to take advantage of the weightless state to study certain combustion phenomena in more detail and to test various models in which convection has been ignored in order to be mathematically tractable. Examples of the latter are a number of droplet combustion experiments in which the burning of free-floating or tethered droplets was studied. The absence of gravity allowed the droplet size to be increased to as much as 5 mm (0.2 in.) so that more detailed observation could be made. The objective is to test theories of droplet combustion and soot formation that are of importance to improving the efficiency of internal combustion engines, gas turbine engines, and home and industrial oil-burning heating systems. See also Combustion; Gas turbine; Internal combustion engine.

In materials science, the processing of metallic alloys and composites has been carried out in space in order to study their microstructure, thermal properties, and crystal growth.