Microgravity facilities

The term 'Microgravity facilities' is quite open ended and encompasses many areas of science; the list below gives an overview of some of the important facilites, avaliable to researchers. The titles of each section are hotlinked to pages containing website links that give more detailed information about the each facility. The links are very varied with some containing very technical information and others providing good introductions to areas of microgravity research. People with an existing knowledge of microgravity facilites may like to look at the following link which is principally designed for researchers

The International Space Station and shuttle flights.

The International Space Station (ISS) represents the largest and most complex international science collaboration ever; drawing on scientific and technological resources of 16 nations: Canada, Japan, Russia, 11 nations of the European Space Agency and Brazil. When it is completed it will have a mass of about 471700 kg and will measure 356 feet (108.5m) across by 290 feet (88.3m) long.The ISS orbits the Earth at approximately 250 miles (410km), this near earth orbit gives the ISS excellent Earth observations with coverage of 85 percent of the globe and over flight of 95 percent of the worlds population!

The Zarya Control module was the first part of the ISS to go into orbit and was launched on the 20th of November 1998 from Cosmodrome in Kazakhstan. A few weeks after the launch of Zarya, the shuttle Endeavour was launched carrying the Unity connecting module in its cargo bay. The shuttle captured Zarya with its mechanical arm and attached it to Unity. On the 29th of May 1999, the shuttle Discovery performed the first docking with the ISS, delivering nearly two tons of equipment and supplies to the ISS. Since then a third Module (The Zvezda module) has been added on 26th July 2000 and on the 10th Feb 2001 the $1.4 billion dollar Destiny Lab became the fourth part of the station. Starting in 2005, Europe will have at its disposal the unique facilities of the Columbus laboratory on board the ISS.

Work on the station is expected to go on for the next 4 years or so, and once the station is complete (currently planned for 2006) it will provide a comprehensive microgravity research platform, that will give both the life and physical sciences the facilities required to carry out experiments in microgravity. As well as allowing a longer period of microgravity, the ISS differs from shuttle flights and other microgravity platforms in the sense that it is a dedicated laboratory containing state -of-the-art equipment not avaliable on shuttle flights. This combination of a highly skilled crew and the facilities, make the ISS a far more powerful microgravity research platform than anything preceding it and will hope fully help to recapture some of the space fervour seen during the first moon landings.

A space shuttle is a reusable launch vehicle that can maintain a consistent orbit and provide up to 17 days of high quality microgravity conditions. The shuttle can accommodate a wide range of experiment apparatus and a laboratory environment in which scientists can conduct long-term investigations.

Sounding rockets and parabolic flight.

Sounding Rockets take their name from the nautical term "to sound" which means to take measurements. They have the advantage of being relatively low cost and their payload can be developed and flown in as little as six months, allowing scientists to con-duct investigations at specified times and altitudes. The flight profile of a sounding rocket follows a parabolic trajectory it goes up and comes back down. Flight time is less than 30 minutes. Sounding rockets are a relatively cheap way of obta-ining microgravity opportunities with a longer duration (typically 5-7 mins) and higher quality of microgravity than airplanes.

A typical parabolic flight currently consists of four parabolic trajectories that have a total dur ation of about 45 minutes. Each parabola lasts approximately 75 seconds, of which 15 to 20s are at 0.02 g or less, followed by a 1.8 g pull-out. Although these flights attain less free-fall microgravity time than sounding rockets they have many advantages, including: The capacity to fly, many experiments on one flight, to fly human subjects and allow the researchers to be on hand allowing more complex reading to be obtained, in addition to this flight costs relative to the weight of experiments that can be carried make these flights very cost effecient, and several repetitons of each experiment can be carried out on one flight.

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Drop towers and terrestrial studies such as the ESA bed rest study.

Drop towers and other terrestial studies represent the cheapest form of microgravity research tool, and whilst having their problems; provide a useful tool for looking at simulated microgravity on large numbers of subjects, over a long period of time and with a relatively low cost.

A drop tower is a long vertical shaft from which air is evacuated. When experiments are dropped into the shaft, they exp-erience microgravity conditions. Drop towers typically achieve microgravity qualities of 10-4g from 2.2 to 10 seconds. Although the microgravity time provided by the drop is shorter than that of parabolic aircrafts (15 to 20 seconds), experi-ments dropped down towers and tubes undergo less disturbance than those flown in an aircraft. Drop towers and tubes have been used for a variety of experiments such as liquid crystal diffusion and containerless processing of metallic mat-erials. Drop towers represent some of the most accessible microgravity facilities; the diagram on the right shows the ZARM drop tower in Bremmen Germany, please follow the highlighted link at the top of this section to see other related links.

Bed rest studies (such as the recent ESA short term bed rest study) and other terrestrial immobilisation techniques used to simulate the effects of microgravity/disuse on living tissue is a controversial microgravity simulation technique. Although the participants are never in a state of free fall and therefore do not experience microgravity per se; they do experience many of the symptoms classically see in astronauts and cosmonauts returning from time in space. These techniques can only really be applied in the field of physiology to investigate such phenomenon as orthostatics intolerance, bone-remodelling and muscle wasting. However the fact that these type of studies can look at huge numbers of subjects in highly controlled conditions for long periods of time at a low cost has made them an invaluable tool in microgravity investigations into the effects of microgravity on the body. Results from these studies have also been cited as having the potential to help improve treatment of many debilitating terrestrial pathologies such as osteoporosis, muscle wasting due to bed rest, an many other problems associated with aging.

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