Thursday, January 28, 2010

ISS experiments

Did you ever wonder what goes on at the ISS. ScienceDaily offers three examples.

"Space Shuttle Brings New Experiments To Space Station"

March 15th, 2008

The space shuttle Endeavour is carrying with it a set of experiments designed and constructed in the laboratory of Dennis Jacobs, a University of Notre Dame professor of chemistry and biochemistry who also serves as a vice president and associate provost.

The experiments are part of the Materials International Space Station Experiment (MISSE), a multi-institutional collaboration to explore how materials degrade in the low-earth orbit spacecraft environment.

The 16-day mission will be NASA's longest space station trip and will include five space walks by the crew of seven, the most ever while a shuttle is docked to a station. The Notre Dame experiments occupy a prized spot, alongside the installation of a Japanese research module and the delivery of a two-armed Canadian robot to the orbiting International Space Station.

Appropriately for a research effort from the home of the Fighting Irish, astronauts will perform a space walk on St. Patrick's Day (March 17) to install the MISSE-6 experiment outside the space station, where it will fly for approximately one year. Every 20 minutes during the next year, the experiment will gather important data on a variety of materials involved in the experiment.

On a later shuttle mission, a different team of astronauts will retrieve the MISSE-6 experiment and bring it back to earth for further analysis. Jacobs and other researchers will then be able to examine closely the kind of degradation that transpired in space.

"Contrary to popular belief, the low-earth orbit spacecraft environment is a hostile one where energetic atoms, ions, electrons, and radiation bombard the surfaces of a satellite," Jacobs said. "Over time, these corrosive components will degrade and erode most materials.

"We have devised a set of knock-out experiments that remove different portions of the flux of energetic particles that irradiate the external surfaces of a spacecraft. This will allow us to isolate how each component of the low-earth orbit environment contributes to the overall degradation of each material specimen. By understanding the detailed mechanistic pathway through which a variety of materials are eroded in space, we hope to guide the development of next-generation satellite materials that will be durable in space."

Jacobs' laboratory research involves the study of non-thermal processes at the gas/solid interface. He previously had a one-year experiment conducted on the International Space Station in 2005-06.

"Pioneering Space Station Experiment Keeps Reactions In Suspense"

December 12th, 2008

A revolutionary container-less chemical reactor, pioneered by the space research team at Guigné International Ltd (GIL) in Canada with scientists at the University of Bath, has been installed on the International Space Station. The reactor, named Space-DRUMS, uses beams of sound to position chemicals in mid-air so they don’t come into contact with the walls of the container.

Space-DRUMS is based on the DRUMS device (Dynamically Responding Ultrasonic Matrix System), originally developed by Professor Jacques Yves Guigné, Chief Scientist of GIL (now with PanGeo Subsea Inc) to survey the sea floor using sonar.

With participation from Professor Nick Pace from the University of Bath’s Department of Physics, and aerospace industrial associates of GIL, Professor Guigné has adapted the system to enable scientists to produce new materials in zero-gravity without using a container.

Professor Guigné, who gained his PhD at Bath and is now a Visiting Professor in the University’s Department of Physics, explained: “Space-DRUMS uses beams of sound energy to position solids or liquids which are floating in zero-gravity.

“If you’ve ever been to a really loud rock concert and stood in front of the speakers, you can actually feel the force of the sound when they turn up the volume. Space-DRUMS works like this but on a much gentler scale – the beams of sound energy work like invisible fingers that gently push the sample into the centre of the container so that it doesn’t touch the walls.

“Space-DRUMS uses 20 of these ‘fingers of sound’ arranged within a dodecahedron configured reactor such that the positions of the samples can be adjusted accurately.

“This method of acoustic levitation means there is no chemical contamination from the container, which is vital for making ultra-pure materials such as temperature-resistant ceramics used in coatings for planes and engines.”

The equipment was initially tested in a low-gravity environment created by the vertical climbing and nose-diving flight path of a KC135 aeroplane, nick-named the vomit comet, similar to that used to train astronauts.

Space-DRUMS was launched into space in partnership with NASA and installed on the International Space Station on 14 November, coinciding with the International Space Station’s 10th anniversary celebrations. The final components will be sent into orbit in July 2009, with experiments starting shortly afterwards.

Professor Nick Pace said: “We are delighted that this key step has been achieved; we have waited several years to witness this milestone.

“The most exciting thing is that we can control the experiments from Earth. Our physics students will be able to use it as part of their final year projects – there aren’t many universities that can offer their students a chance to conduct experiments in space!”

In addition to making new materials, Space-DRUMS will also be used to study the physics of turbulence, which has diverse applications such as predicting the paths of hurricanes and helping biopharmaceutical studies.

Deputy Director of the Centre for Space, Atmospheric & Oceanic Sciences at Bath, Dr Philippe Blondel explained: “Even with large computer clusters, the understanding of complex weather patterns is still limited. Using Space-DRUMS will help us to better understand the behaviour of complex systems like hurricanes, their interaction with the atmosphere and hopefully anticipate where a hurricane can go next.

“Bath is at the forefront of this pioneering technology and we are really privileged by this opportunity to do these ground-breaking experiments in space.”

"Plasma Experiments Aboard International Space Station Yielding Better Picture of Liquids and Solids"

January 27th, 2010

On 27th January 2010, the 25th series of experiments studying complex plasmas will start on board the international space station ISS. Physicists from the Max-Planck-Institute for extraterrestrial Physics in Garching, Germany, will use them to study fundamental structure forming processes to better understand what happens in liquids and solids.

That matter exists in three states is widely known: as solid, liquid or gas. Our Universe, however, is dominated by a fourth state of matter: plasma. This forms, if a gas is heated to very high temperatures, so that its molecules dissociate in ions and free electrons. A plasma is regarded as the most disorganised state of matter. Researchers at the Max-Planck-Institute for extraterrestrial Physics, however, have found that under certain conditions plasmas can become liquid or may even crystallise. These are called "complex plasmas" and allow new insights into the physics of liquids and solids. Plasma physicists use them to study melting and crystallisation, motion of lattice defects in crystals, or liquid effects and other processes by looking at single atoms.

Complex plasmas consist of tiny particles (about one thousandth of a millimetre) that are suspended in a plasma and carry a highly negative electric charge. Due to the strong interaction between the particles, they can form regular structures, either liquid or solid. Since Earth´s gravitational field interferes with these processes, experiments with complex plasmas are carried out in space.

Research on complex plasmas with the PKE-Nefedov laboratory in 2001 was the first science project on board the international space station ISS and the most successful one during the first years. Its successor PK-3 Plus has already been running for four years and provides again unique results. The new series of experiments, carried out from 27th to 29th January is already the 25th mission to study complex plasmas in the absence of gravity. Moreover, PK-3 Plus has now been installed permanently in the new ISS module MIM-2, and will be its first scientific experiment.

One of the experiments in the PK-3 Plus laboratory will deal with "binary" complex plasmas: if two kinds of particles with different sizes are suspended in a homogeneous plasma, one could expect them to mix due to mutual repulsion. Previous experiments on board the ISS, however, have shown a clear phase separation of the two particles clouds (see 2).

"This phenomenon is well known from many different systems, such as molecular liquids or colloidal suspensions, and has been studied for a long time," says Hubertus Thomas, MPE-scientist and coordinator of the PK-3 Plus experiments. "In complex plasmas, for the first time we can now study these processes looking at the movement of individual particles and we hope that our latest experiments will lead to new insights into the physics of phase separation."

The study of complex plasmas is interdisciplinary, fundamental research. As in other fundamental research before, however, this work initiated a new approach in applied research: the results and experience gained with the plasma experiments on board the ISS and in the lab led to a new medical field, the so-called plasma medicine. Currently a clinical trial is carried out to study how plasmas can be employed for contact-free sterilisation of wounds, hand disinfection in clinical environments or treatment of gingivitis.

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