On 6 April 1984, the crew of Space Shuttle Challenger moved a 10-ton cylinder out from the shuttle's cargo hold and left it in space. It was brought back to Earth by Space Shuttle Columbia in January 1990 after being over 2000 days in space.
This beast, called Long Duration Exposure Facility, or LDEF in short, was a unique material science mission that had 57 experiments gathering data on the long-term effects of space exposure on materials, components, and systems.
Originally the idea emerged in early 1970 when the scientists and engineers needed information about the applicability of many materials, coatings, components, and bigger systems in space. How they cope with the vacuum, hard solar radiation, temperature changes, and micrometeoroid bombardment.
NASA approved the project in 1974 as one of the uses of the Space Shuttle that was under development then. At that time the plan was to fly shuttles quite often to space and back, so a bus-sized structure with many samples could be left to space and recovered easily after a year or 18 months to be launched again with new samples.
Finally, the shuttle operations were slightly different, but the basic idea stayed. LDEF was intended to be reused, but it was left in space for a longer time. Now the structure of the facility and its systems became also experiments and were intensively studied.
In addition to materials, coatings, technological items and systems, optical fibers and crystals, tomato seeds and bacterial spores were also aboard.
WISA Woodsat is smaller and more targeted to plywood, but the purpose is the same: studying how a material copes with the space conditions.
Our little satellite can't be recovered from space, but during the mission, we take photos from inside and outside, measure the compounds possibly outgassing from the wood with a mini-laboratory provided by the European Space Agency, and study the internal changes in plywood with an experiment from Captain Corrosion of Estonia.
In addition, we test for the first time 3D printed metal in a primary structure (made by Huld) and also fly aboard a test of memory membrane (4D plastic) – a first in a European satellite.