By Jonathan Amos
Science reporter, BBC News, Kennedy Space Center
It has been a long wait but Europe's space lab is finally about to take up station.
COLUMBUS SCIENCE MODULE
Columbus is taken into space by the shuttle Atlantis
Total length - 6.8m
Diameter - 4.5m
Volume - 75 cu m
Launch mass - 12.8t
Operation - 3 crew
Cabin temp - 16-27C
Total power - 20kW
Columbus would have been in orbit in October of 2004 had it not been for the enforced delay resulting from the 2003 shuttle disaster and the grounding of the US orbiter fleet.
The module is intended to be the "productive cornerstone" of Europe's space station activities - the major reason for it being involved in the 27,000km/h flying outpost.
Come the middle of the next decade, Europe will have spent something in the region of nine billion euros on the International Space Station (ISS) project; and that kind of investment demands Columbus deliver some very special science.
But researchers say don't expect astronauts to suddenly shout "eureka" inside the module as they find a cure for cancer or make the energy breakthrough that rescues us from our addiction to oil.
Rather, expect Columbus to deliver a steady stream of knowledge that feeds into the gradual improvement in processes and products.
"You shouldn't dream about making too much up there," explains Dr Martin Zell, who heads up the microgravity programme at the European Space Agency (Esa). "What you do is learn a lot about processes in space and then you apply that intelligently on Earth."
During its 10 year projected lifespan, Earth-based researchers - with a little help from the ISS crew - will conduct hundreds of experiments in life sciences, materials science, fluid physics and a whole host of other disciplines.
Biolab - supports experiments on microbes, cell and tissue cultures, small plants and insects.
European Physiology Modules Facility (EPM) - a set of experiments to investigate the effects of long-duration spaceflight on the human body
Fluid Science Laboratory (FSL) - will be used to study how fluids behave in microgravity
European Drawer Rack (EDR) - a carrier system designed to house experimental modules in drawers and lockers
European Transport Carrier (ETC) - will serve as a workbench and stowage facility
The key to science on Columbus is the "weightless" conditions - "zero g".
In an Earth laboratory, gravity pulls hard on everything; but in space, there is no "up" and "down" as such. When gases and liquids are heated, they don't rise and sink as they do at the planet's surface. Suspended particles don't settle out into neat layers like they would in an Earth river.
In the permanent state of free-fall experienced on the space station, the "mask" of gravity is lifted and other forces come to the fore - with surprising effects.
"For example, consider our immune system which plays a vital role fighting disease," says Dr Thomas Reiter, a past ISS resident who has worked on the Columbus development programme.
"We find that certain aspects of our immune system are activated or deactivated as soon as we pass particular gravity levels. So from this research, we may derive some information which will help us fight disease."
European Technology Exposure Facility (EuTEF) - carries experiments requiring exposure to the space environment
SOLAR - a platform with three scientific instruments to study Sun-related phenomena
Chemical reactions behave differently without the influence of gravity and this means that molecules can be blended and substances created that would be impossible on Earth.
Crickets in space
Columbus science will be nothing if not diverse - from helping to develop new lightweight alloys for manufacturing to the development of tiny, perfectly formed crystals that will form the basis of future pharmaceuticals.
Its experiments will test some of the fundamentals in atmospheric circulation that underpin climate models.
Columbus will investigate the idea that life spread throughout the Solar System on meteorites.
It will check out the next generation of space-based atomic clock that will soon feature in global positioning satellites.
A German control room will monitor events inside Columbus
And there is even a group of crickets booked to fly on Columbus later this year to help scientists understand the effects of long-duration spaceflight.
The list goes on. There are currently some 2,000 scientists working on the European Space Agency's microgravity programme. About 200 experiments have so far been scheduled for the module; 50 will be flying this year.
Much past microgravity research has been done in drop towers or on sounding rockets; and even on the "vomit comet" aircraft that fly steep curves to reproduce the conditions of being in orbit.
But these approaches only give seconds to hours of useable research time.
On Columbus, experiments can run for months; or be repeated many times with different parameters. And the advanced instrumentation installed in the module's racks will afford unprecedented levels of scrutiny.
Dr Rainer Hollerbach, from Leeds University, UK, is involved in a fluid science experiment that will heat and cool silicon oils inside concentric spheres whilst applying an artificial gravity field that pulls towards the centre of the set-up.
GeoFlow, as it is known, will be used to model the convection systems operating in the interiors of planets and stars.
"Columbus is very impressive," he told BBC News. "We go with a shoebox-sized set-up; and we can basically do what we like inside our box given certain parameters. Obviously if we were to raise the temperature too much, that would become a safety issue but by and large they let us get on with it.
GeoFlow will help model what happens inside planets and stars
"In our particular experiment, we have an optics system that takes pictures which first get recorded on to a hard drive and then get beamed down to us."
Indeed, a lot of Columbus is automated. The astronauts need have no input other than to set the science going. Data is passed to a control centre in Oberpfaffenhofen in southern Germany, and then on to nine distribution centres across Europe where researchers can pick up the results.
"But don't neglect the importance of the astronauts," stresses Dr Zell. "In the mid-90s, there was an attempt to do a lot of robotics in Columbus with a robot standing in front of the racks. It proved to be totally inefficient.
"You need these guys, especially if something fails. And often, they observe some things which may be missed on video on the ground. The astronauts' intelligence is a real asset."
As is their blood - because one of their prime roles in Columbus will be to act as guinea pigs, providing samples that will allow a detailed study of the effects on the human body of long duration spaceflight.
Astronaut health and well being is an important focus of Columbus. A big part of what space agencies need to know if they are ever to send astronauts to the Moon, or beyond, for long periods will be learned in the module.
Microgravity changes the way the human body behaves, and accelerates degeneration. The classic examples are bone calcium loss (osteoporosis) and muscle wasting.
Other changes are more subtle, such as visual-perception. To an astronaut's eyes, objects do not always appear to be where the hand reaches out. A head-worn "computer game" in Columbus will investigate why this is so.
Work inside Columbus will be gradually ramped up over the coming year. Some experimental racks currently stored in the US Destiny lab will be moved into the European sector.
Future shuttle, and Progress and ATV supply ships, will take up further experiments.
And once the crew of the space station rises to six in mid-2009 (and the Japanese have their Kibo lab on station), orbital science will be full-on.
10 Esa member-states contribute to the ISS project. Their investment to date since the inauguration of the European programme is about five billion euros.
Alan Thirkettle, the agency's space station programme manger, believes that represents good value in comparison to other major infrastructure projects: "The money has been spent in the member states over 12 years. That amount of money would build approximately one kilometre of motorway, or autoroute, in each of the member states for each of those years."
Time then for Columbus to start to return on that investment.