STS-73

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Mission emblem
Mission emblem STS-73
Mission dates
Mission: STS-73
COSPAR-ID : 1995-056A
Crew: 7th
Begin: October 20, 1995, 13:53:00  UTC
Starting place: Kennedy Space Center , LC-39B
Landing: November 5, 1995, 11:45:21 UTC
Landing place: Kennedy Space Center, Lane 33
Flight duration: 15d 21h 53m 16s
Earth orbits: 255
Rotation time : 90.0 min
Track height: 267 km
Orbit inclination : 39.0 °
Covered track: 10.5 million km
Payload: Spacelab
Team photo
v. l. No. Catherine Coleman, Albert Sacco, Kenneth Bowersox, Kent Rominger, Fred Leslie, Michael López-Alegría, Kathryn Thornton
v. l. No. Catherine Coleman, Albert Sacco, Kenneth Bowersox, Kent Rominger, Fred Leslie, Michael López-Alegría, Kathryn Thornton
◄ Before / After ►
STS-69 STS-74

STS-73 ( english S pace T ransportation S ystem) is a mission designation for the US Space Shuttle Columbia (OV-102) NASA . The launch took place on October 20, 1995. It was the 72nd space shuttle mission and the 18th flight of the Columbia space shuttle.

team

Main team

replacement

Mission description

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

physics

Drop Physics Module

In weightlessness, effects come to the fore that are completely or partially covered by gravity on earth. This includes the dynamics of floating drops. Drops of water and silicone oil were deliberately manipulated in various experiments. They were set in rotation or braked by means of sound waves, divided and their movements observed. The behavior of air bubbles in water droplets and of water bubbles in silicone oil was also examined.

Geophysical Fluid Flow Cell Experiment

Silicone oil was exposed to certain temperature and pressure conditions between two balls made of stainless steel or sapphire. The gravitation was simulated by electric fields, the pressure by the rotation of the ball. For more than 150 hours, conditions were simulated that correspond to those in our oceans, in the earth's atmosphere , in the atmospheres of gas planets and in the atmosphere of the sun. It was investigated which regularities the flow of the liquid obeys. Conclusions should be drawn from this for global currents in the oceans and in the earth's atmosphere.

Surface Tension Driven Convection Experiment and Oscillatory Thermocapillary Flow Experiment

Both experiments examined when thermal convection currents become irregular and turbulent. Certain patterns can be seen in polarized light. When these patterns become chaotic, the regular flow turns into turbulence, so-called thermocapillary oscillations. Preventing these irregularities was the main aim of the experiments. Here, too, silicone oil was used and a laser was used for heating . Liquids are used a lot in the chemical industry. The surface tension of drops plays a major role in this. In another experiment, this voltage was increased by adding various chemical substances, e.g. B. Soap, reduced. This also changed the convection behavior on the surface.

Particle dispersion experiment

One theory is that clouds of dust and particles released during an explosion form clumps due to electrostatic attraction. This theory was tested with various fine or coarse-grained quartz-containing dusts. It turned out to be correct. This can also explain sandstorms on Mars and the formation of new stars in planetary nebulae.

Colloidal Disorder-Order Experiment

Colloids are mixtures of liquids suspended in gases or solid bodies floating in a liquid medium. In the CDO experiment, microscopic plastic spheres moved in a liquid. This was allowed to solidify, the solidification point being measured with the highest precision. A stable, disk-shaped crystal with dendrite-like extensions resulted. The movement of the spheres in the liquid should be a model for the interactions between atoms in a substance. Such interaction processes take place very slowly on earth and can therefore not be effectively investigated.

Interface configuration experiment

Here the movements of liquids depending on the shape of the container were examined. In half-empty tanks, for example, the liquid sloshes back and forth for a long time and can interfere with sensitive measurements. One is now looking for a favorable form in which the effects on the environment are minimal.

Materials science

Crystal Growth Furnace

Various semiconductor crystals of the highest purity were produced in this melting furnace . The semiconductor material was evaporated and deposited directly from the gas phase on a carrier. The rate of crystal growth depends on temperature and vapor pressure. In order to largely avoid irregularities in the crystal lattice , the crystal growth took place very slowly. In total, only eight crystals were grown. On the one hand there were gallium arsenide crystals for electronics, furthermore cadmium-zinc-telluride and mercury-cadmium-telluride crystals for infrared sensors and finally gallium-doped germanium crystals (II-VI semiconductors). In the last melting experiment, the apparatus was aligned in such a way that the crystal grew along the expected preferred direction of force. This should result in an even lower number of imperfections. Noteworthy are a five centimeter long CdZnTe crystal, which took 30 hours to produce, and a nearly 13 cm long germanium crystal that took nine hours.

Zeolite Crystal Growth

Zeolites are inorganic compounds of aluminum, silicon and oxygen. Due to their porous structure, they are particularly suitable for catalysts and filters in the chemical industry. This experiment investigated which factors promote a uniform crystal structure the most.

biotechnology

Astroculture Plant Growth Facility

Ten potato plants were grown in a special mini greenhouse. The most favorable values ​​for temperature, humidity, water and nutrient intake were determined. The plants actually grew, which was seen as evidence that it was possible to produce plant-based foods in weightlessness.

Commertial Generic Bioprocessing Apparatus

The device had 132 chambers in which various samples were located. These were prepared by an astronaut using a glove box and then deposited in an area with normal room temperature or in an incubator. After the allotted time, the samples were then frozen. The experiments were evaluated on earth. The experiments were used for drug production, biomedical examinations and ecological tests. The samples ranged from proteins and cultures of plant and animal cells to small animals (cold-water crabs).

Protein Crystal Growth

A total of 1500 different protein crystals were produced during the flight of the Columbia . This was a multiple of the usual amounts. The structure of the crystals was examined in detail after their return to Earth ( X-ray structure analysis ). If you know the spatial structure of a protein, you can draw conclusions about its function. Millions of different proteins are responsible for different life processes in the human body. Pathogens such as viruses and bacteria also use the signaling effect of proteins. Research in this area is therefore of great importance for medicine. On this flight z. B. RNA molecules, ribosomes , the epidermal growth factor EGF, the plant protein complex Photosystem I, proteins of the beet mosaic virus and the bacteriophage lambda lysozymes are synthesized. The charge shift in bacteriorhodopsin caused by light should also be emphasized.

Burn examinations

Fiber Supported Droplet Combustion Experiment

Here, small fuel droplets were placed between thin fibers of a temperature-resistant material with needles and ignited with a glow wire. The process and duration of the burn were filmed. It was found that hydrocarbon mixtures burn more slowly than alcohol mixtures. A particularly large drop burned for 40 seconds, considerably longer than expected. The fuel mixture, the droplet size and the flow rate of the air (oxygen supply) could be varied. Knowledge about the combustion of atomized liquids is needed, especially in the development of better combustion systems, e.g. B. for engines.

Space technology

Suppression of Transient Acceleration By Levitation Evaluation

The braking effect of the Earth's atmosphere, which is very thin at an altitude of 300 kilometers, but still there, the movements of the astronauts and the engine ignitions cause many small forces that affect the entire spaceship and all experiments taking place in it. These small forces ensure that there is no ideal weightlessness in a spacecraft, but only what is known as microgravity. STABLE was developed to filter out this interference. It is a small platform that floats in an electromagnetic field. All forces were balanced by changing the electromagnetic field. So the platform was completely decoupled from the spaceship for some time. The system received the data for varying the field strength from various measuring devices, which determined the accelerations on board as precisely as possible.

Three Dimensional Microgravity Accelerometer

3DMA is a measurement complex. It determined the accelerations in all three dimensions and transmitted them to various devices. The data was also recorded.

Space Acceleration Measurement System / Orbital Acceleration Research Experiment

SAMS and OARE also determined acceleration values. These were recorded and could be evaluated after the flight. If particularly strong disturbances were measured during an experiment, it was possible to determine afterwards what effects they had. SAMS was used on most of the shuttle missions.

High-Packet Digital Television Technical Demonstration System

The experimenters in space and the developers on the ground were constantly connected to each other via the Hi-Pack TV. In this way, the development teams were able to directly influence the execution of their experiments, following the action live on the screen. Up to 6 video channels could be transmitted simultaneously in compressed form.

There were hardly any technical problems during the flight. In order not to let the air pressure in the wheels of the undercarriage fall below a critical value, the Columbia was oriented four times in such a way that the sun shone directly on the underside of the shuttle and thus also warmed the undercarriage rooms. With the landing at the Kennedy Space Center on November 5th, the second longest shuttle flight to date came to a successful end.

See also

Web links

Commons : STS-73  - album with pictures, videos and audio files