STS -75 (English Space Transportation System) is a mission name for the U.S. Space Shuttle Columbia ( OV -102) from NASA. The launch took place on 22 February 1996. It was the 75th Space Shuttle mission and the 19th flight of the Space Shuttle Columbia.
- Andrew Allen ( third space flight), Commander
- Scott Horowitz ( first space flight), Pilot
- Franklin Chang- Diaz ( 5 space flight), Mission Specialist
- Maurizio Cheli ( first space flight), Mission Specialist (ESA / Italy)
- Jeffrey Hoffman ( 5 space flight), Mission Specialist
- Claude Nicollier ( third space flight), Mission Specialist (ESA / Switzerland )
- Guidoni ( first space flight ), Payload Specialist (Italy )
The focus of the mission of the second test of the Tethered Satellite TSS were ( Tethered Satellite System, mass about 700 kg) to develop new energy sources and new methods to study the Earth's upper atmosphere, as well as work to acquire new materials and a better understanding of certain physical phenomena.
With the Tethered Satellite should be examined primarily whether and how much electrical energy can be produced with this new method. Shuttle and satellite moved, connected by a 20 km long cable, with great speed through the Earth's magnetic field. A high voltage is induced. Through the cable, an electrical current to flow to the shuttle, where its energy can be used ( study complexes DCORE / SCORE ). Subsequently, the excess charges will be transported back by so-called electron guns in the ionosphere. With TSS many side effects of this process have been examined more closely. So current and voltage were measured (Experiment SETS ), the behavior of charged particles in the vicinity of the satellite studied ( ROPE ), found the electric potential at the satellite and low-frequency waves produced there identified ( RETE ). Strength and fluctuations of the magnetic field were also object of investigation ( TEMAG ) as the density of charged particles (electrons and ions) to the shuttle ( SPREE ) and oscillations of the support cable, or satellite ( IMDN / TEID ). This theoretical models were electro- dynamic processes in the ionosphere checked ( TMST ). Additionally, you can also use as an antenna for longwave radiation such a long line, of course. Therefore, instruments for quantification of radio signals from space and from the ground components of TSS ( EMET / Oesse ) were. Finally, the whole process was taken with a special camera (TOS). In the analysis here, especially the interaction of the satellite with the upper atmosphere and the vibrations of the support cable were considered.
After the start of the Columbia various plants of the tethered satellite experiment were first put into operation on a trial basis. It appeared serious computer problems that could be reversed by the replacement of a cable and several reboots of the systems involved. A day later than planned, the mounted on a Spacelab pallet 11.3 meter high retaining mast was erected and fired the satellite from the cargo bay. Here, a plastic-coated copper wire was unrolled. The satellite had its own nitrogen - drive with which he was maneuvered away from the Shuttle. The plan was a roll-out on 20.7 km for 22 hours and then a gradual rolling multi-stop for long plasma measurements. The retaining cord ripped but after about 5 hours just before reaching the maximum length. Until then, the measurements had shown a maximum voltage of 3500 volts and a maximum current of 480 milliamperes. The returned electrons reached by 10 keV ten times the output power, the acceleration values on board the satellite was less than one thousandth of the gravitational acceleration ( 0.0009 g). After emerging from the metal tips of the electron gun, the electron cloud stretched depending on the potential of the orbiter, from the local Ionosphärendichte and the beam direction from a cylinder. On the 6th day of flying more appliances were activated, so that data on the upper atmosphere could be collected by radio command. These included ion and electron density measurements as well as measurements of the electric and magnetic field strengths. The measurement results were as long as transmitted until the batteries of the satellite were exhausted. Despite the loss, TSS brought a lot of valuable data. It was found that the energy was far more effective by a Tethered Satellite, had predicted as theoretical models.
Then the Columbia crew dedicated as planned microgravity and combustion experiments. So crystals were made of lead -selenium telluride in a special furnace ( AADSF ). Simultaneously, the minimum acceleration have been measured and are caused by the braking action of the atmosphere and movements of the astronauts ( SAMS / OARE ). The purpose of the study was to determine the influence of these minimal interference to a directional crystal growth. The solidification process then occurs very slowly. The apparatus has a plurality of zones in which the temperature can be varied from 340 to 870 ° C. Lead -selenium telluride is a semiconductor material that is used for the production of infrared detectors and lasers.
MEPHISTO was the name given to an apparatus, were studied with the interesting solidification phenomena in parallel on the earth and in weightlessness. It was about the influence of gravity- dependent convection and sedimentation in the manufacture of metals and metal alloys. During the STS - 75 mission three tin-bismuth crystals were pulled. The shape of the solidification interface was visualized by current pulses. Also for Solid State Research Isothermal Dendrite Growth was the experiment ( Idge ). A material ( SCN = Succinonitrile ), which on solidifying a similar behavior as metals, but is transparent, was solidified by cooling. This tree-like outgrowths called dendrites created. Their shape allows statements about the progress of solidification, which were recorded with video and film cameras.
Was also filmed the behavior of small xenon clouds at the critical point. The critical point is a state in which the boundary between liquid and gas will disappear. Xenon is in a gaseous state and transparent as whitish liquid. With the help of reflected laser light size and shape of the liquid sub-areas could be monitored closely. When Critical Fluid Light Scattering Experiment, which was called after a Greek philosopher Zeno of antiquity, statements regarding the course of changes of state and change of magnetic properties were clarified.
In the middle deck also three experiments for the investigation of combustion processes in the microgravity were conducted. They were in a so-called glove box and were hermetically sealed from the environment. Has been studied the propagation of flames in response to air flow and temperature ( FFFT ), the ignition of an ashless filter paper by heat radiation ( Ritsi ) and the formation of carbon black, its distribution and movement in the quasi-steady flame. These various sources of fire were examined, from a normal candle flame on paper and insulation material to Teflon and Kapton (CSD ). As with almost every shuttle flight a plant was also on this mission for the production of pure protein crystals for medical research on board ( CPCG ). With nine samples of new therapeutic agents against infections, cancer and hormonal disorders, a new vapor -diffusion apparatus was inaugurated for protein crystallization.
For the first time the crew worked in three shifts. In addition, each crew member had a half day off. The flight was initially extended for additional experiments and later due to bad weather at the intended landing site each by one day. On March 9, the Columbia ended up with tons of data in Cape Canaveral.