Discovery of vacuum was a revolution, its helping someway or other the poor souls like ours, but life moves on. Once we have vacuum we can do lots of model experiments, that will gives us a clue of what can happen in the space above us, but, hold on, you can not get rid of the gravity so easily until you cross the field and go in to space. The amount of effort that goes in behind the space research is huge but now research in space invoked a great deal of interests among the researchers. Presently NASA and ESA has carried out quite a few experiments in space and believe me they are really fascinating.
Experiments in space were started probably through sputnik-3 in 1969, which sent mostly some geophysical information. Until very recently, experiments were concentrated mostly on the atmospheric or geophysical studies but the scenario has changed quite rapidly. Experimental research had leap when Mir was placed in space in the year 1986, and from year 1989 till it was abandoned in 1999, there was always a human being in space. The Venture, International Space Station, took the lead there after. Scientists from all over the world including Russia are participating in this program.
The idea of carrying out experiments in a space station appears bizarre to many people, mostly because of the cost and the futuristic nature as we can not see the application. The fact is someway different; these experiments are mostly carried out for advanced technology. I found one nice example; an experiment on flame. The flames coming out of some nozzle appears like a fluid drop due to the gravitational force resulting in an air flow. Now if these experiments are carried out in space under microgravity atmosphere the flame breaks in to balls, the experiment is known as Lwis SOFTBALL experiments. For this combustion the fuel required is extremely low, which is a process all automotive engine companies will look for, as the hydrogen or hydrocarbon based combustion engines requires these informations. This was an example for a direct application to technology. However, the fundamentals for the basic science are getting major benefits from the zero gravity experiments. Imagine a human brain, which has been modeled to function under gravity, when it is exposed to the microgravity condition, the systems response to this change. It is therefore an interesting area for study. Again we know the plants grows in the direction of light, its roots also grows in the direction of gravitational force, hence it is interesting to know how the plants grow in such conditions.
Materials research did achieve much scope to carry out experiment although levitation experiments for solidification of metals have drawn interest. The constraints are mostly forming the experimental module and control over the experiments, the results is unknown till the specimens come back to earth. Among the other materials research semiconductor crystal growth has been quite a revelation. Near perfect crystals can be grown under microgravity, under surface tension driven flow in the melt. A control in the defect concentration in the crystal is also possible, but its is not so straight forward as the density driven flow and surface tension driven flow complicates the process. The container free melt will have hardly a site for defect nucleation hence these processes are really useful.
Every scientific advance comes with a price tag and we had to pay it through the lives of astronauts who were killed the Columbia explosions. These were the part of NASA’s STS -107 program, more than 70 experiments were carried out in space. We have lost Kalpana Chawla, the only Indian female astronaut.
Efforts are on as many other countries are coming up with ideas and launch vehicles for carrying out experiments. Indian space research also as an individual progressed a lot and one day we will also be able to carry out our own experiments in space.
I found infornation from the following places
Future Materials Science Research on the International Space Station (1997), National Academy publishers
European Space Agency
News about ISRO