STS -73 (English Space Transportation System) is a mission name for the U.S. Space Shuttle Columbia ( OV -102) from NASA. The launch took place on 20 October 1995. It was the 72th Space Shuttle mission and the 18th flight of the Space Shuttle Columbia.

  • 2.1 Physics
  • 2.2 Materials Science
  • 2.3 biotechnology
  • 2.4 combustion studies
  • 2.5 Space Technology


Home team

  • Kenneth Bowersox ( third space flight), Commander
  • Kent Rominger ( first space flight), Pilot
  • Kathryn Thornton ( fourth space flight ), Mission Specialist
  • Catherine Coleman ( first space flight ), Mission Specialist
  • Michael López- Alegría ( first space flight), Mission Specialist
  • Fred Leslie ( first space flight), Payload Specialist, Space Science Laboratory
  • Albert Sacco ( first space flight), Payload Specialist, Worcester Polytechnic Institute


  • Ray Holt and David Matthiesen for Leslie and Sacco

Mission Description

For the second time flew the United States Microgravity Laboratory USML, a specially equipped Spacelab module, are studied in the effects that can be observed only under conditions of microgravity. The 14 major experiments related to physics, materials science, biotechnology, combustion research and space technology.


In weightlessness effects come to the fore, which are covered on the ground by gravity in whole or in part. This includes the dynamics of floating drops. In various experiments, droplets were manipulated aware of water and silicone oil. So they were transferred by means of sound waves in rotation or braked, shared and observed their movements. We investigated the behavior of air bubbles in water drops and water bubbles in silicon oil.

Between two stainless steel balls or sapphire silicone oil has been exposed to specific temperature and pressure conditions. The gravity was simulated here by electric fields, the pressure exerted by the rotation of the ball. More than 150 hours, simulating conditions were similar to those in our oceans, in the atmosphere, in the atmospheres of giant planets and in the sun's atmosphere. It was investigated what laws obeyed the flow of the liquid. This conclusions for global currents in the oceans and in the atmosphere of the earth should be considered.

In both experiments was to investigate when thermal convection currents are irregular, turbulent. In polarized light, certain patterns are discernible. If these patterns are chaotic, so regular flow in turmoil, known as thermocapillary oscillations goes on. To prevent these irregularities was the main concern of the experiments. Was also used here silicone oil was heated with a laser. In the chemical industry is used a lot of fluids. The surface tension of droplets plays a major role. In another experiment, this voltage has been decreased by the addition of various chemical substances, such as soap. This also the convection behavior at the surface changed.

One theory is that during an explosion liberated dust and particle clouds form clumps due to the electrostatic attraction. With various fine - or coarse-grained quartz-containing dusts, this theory has been verified. It proved to be correct. Thus, even sandstorms on Mars and the formation of new stars can be explained in planetary nebulae.

As colloids are called mixtures of gases in liquids floating or floating in a liquid medium solids. When CDO experiment microscopically small plastic spheres moving in a liquid. This froze it, the freezing point was measured with high precision. There was a stable, disk-shaped crystal with dendritenartigen foothills. The movement of the beads in the fluid should be a model for the interactions between the atoms in a substance. On Earth, such interaction processes are very slow and therefore can not be effectively studied.

Here, the movements of liquids were examined as a function of the shape of the container. In half-empty tanks, for example, the liquid longer time sloshing back and forth and can disturb sensitive measurements. Now Man looking for a cheap form in which the effects on the environment are minimal.

Materials Science

In this furnace various semiconductor crystals of highest purity were prepared. The semiconductor material was evaporated to and stored directly from the gas phase on a support from. The rate of crystal growth depended on the temperature and vapor pressure. To avoid irregularities in the crystal lattice largely, the crystal growth was very slow. Overall, only eight crystals were grown. On the one hand it was Galliumarsenidkristalle for electronics, further to cadmium zinc telluride and mercury cadmium telluride crystals for infrared sensors, and finally to gallium -doped germanium crystals (II -VI semiconductors ). At the last melting experiment, the apparatus was aligned so that the crystal along the expected preferred direction of force grew. This should be achieved even lower number of defects. Of note are a five -centimeter-long CdZnTe crystal whose production lasted 30 hours and a nearly 13 cm long germanium crystal, which was created in nine hours.

Zeolites are inorganic compounds of aluminum, silicon and oxygen. Due to their porous structure, they are particularly well suited for catalysts and filters in the chemical industry. With this experiment, we examined what factors promote uniform crystal structure the most.


In a special mini greenhouse ten potato plants were grown. The most favorable values ​​for temperature, humidity, water and nutrient intake were determined. The plants grew in fact, what was regarded as evidence that a production plant foods in zero gravity is possible.

The unit had 132 chambers in which different samples were located. These were prepared by an astronaut with a glove and then deposited in a range of normal room temperature or in an incubator. After the designated time the samples were then frozen. The evaluation of the experiments was carried out on the Earth. The experiments were the manufacture of medicines, biomedical research and environmental tests. The samples ranged from proteins by cultures of plant and animal cells to small animals (cold water crabs).

During the flight of the Columbia a total of 1500 different protein crystals were produced. This was a multiple of the usual amounts. The structure of the crystals was after returning to Earth thoroughly investigated ( X-ray). Knowing the spatial structure of a protein, one can draw conclusions about its function. In the human body, millions of different proteins for various life processes are responsible. Pathogens we viruses and bacteria use the signaling effect of proteins. The research in this area therefore has a size significance for medicine. On this flight, for example, RNA molecules, ribosomes, the epidermal growth factor EGF, the vegetable protein complex Photosystem I, beet mosaic virus proteins and the bacteriophage lambda lysozymes were synthesized. These is also the light-induced charge transfer in bacteriorhodopsin.

Combustion studies

Here small fuel droplets were placed between thin fibers of a temperature resistant material and ignited with a hot wire with needles. Were filmed the sequence and duration of combustion. It was found that hydrocarbon mixtures burn more slowly than alcohol mixtures. A particularly large drop burned 40 Seconds considerably longer than expected. Could be varied the fuel mixture, the drop size and the flow rate of air ( oxygen ). Be used knowledge of the combustion of the atomized liquid, especially in the development of improved systems for example for combustion engines.

Space technology

The braking effect of the 300 kilometers in height, although very thin, but still existing earth's atmosphere, the movements of the astronauts and thruster firings cause many small forces that affect the whole spaceship and all is running experiments. These small forces ensure that in a spacecraft not an ideal weightlessness but only a so-called micro-gravity prevails. To filter out this interference, STABLE has been developed. It is a small platform that floats in an electromagnetic field. All the forces were balanced by altering the electromagnetic field. The platform was therefore completely decoupled from the space ship for some time. The data for the variation of the field strength was the system of different instruments, which measured the accelerations on board as accurately as possible.

3DMA is a measuring complex. He identified in all three dimensions, the accelerations and sent them to various devices. In addition, the data were recorded.

Also SAMS and OARE determined acceleration values ​​. These were recorded and could be evaluated after the flight. If during an experiment particularly strong disturbances were measured, one can determine in retrospect, what the consequences of this. SAMS is used for most Shuttle missions.

About the Hi- Pack TV experimenters in space and developers were constantly connected to each other on the ground. Thus, the development team could directly influence the interpretation of experimental results, where they watched the events live on television. Up to 6 video channels could be transmitted in compressed form simultaneously.

During the flight, there were few technical problems. In order not to let the air pressure in the wheels of the landing gear to fall below a critical value, the Columbia was four times as oriented in space that the sun was shining directly on the underside of the shuttle and thus also heated the suspension spaces. With the landing at the Kennedy Space Center was on November 5, until then second longest shuttle flight to a successful end.