Wednesday, 03 September 2014
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Carry on Columbus

As the Columbus laboratory, the European Space Agency’s section of the International Space Station, reaches its fifth birthday, ESA and one of its main suppliers, Astrium, is looking forward to a future beyond low Earth orbit.

The International Space Station is many things, some of them concrete, others symbolic. A permanent outpost for humanity away from the Earth’s surface; a flagship for peaceful international cooperation; a laboratory for human biology; the best viewpoint humans have ever had. But the way it earns its keep is as a scientific and engineering research outpost, and the European branch of its experimental facilities is celebrating its fifth birthday.

Columbus

The Columbus module carries experiments on its exterior as well as its interior

Columbus, the European Space Agency’s section of the ISS, was taken into orbit by the Space Shuttle Atlantis in 2008. Built in Italy by Alcatel Alenia Space (now part of Thales Alenia Space) and fitted out by Astrium in Bremen, Germany, Columbus is about 7m long, 4.5m in diameter, and houses experimental equipment both on its inside and outside. ‘Columbus is the flagship of European scientific engineering and a key contribution of ESA member states to the ISS success story,’ commented Jean-Jacques Dourdain, ESA director-general, at an event to mark the module’s anniversary.

“Columbus is the flagship of European scientific engineering and a key contribution of ESA member states to the ISS success story

Jean-Jacques Dourdain, ESA director-general

Originally designed for a ten-year lifespan, Columbus has now had an extra two years added to its operational period, along with the rest of the ISS; subsequent increases are also possible, and the structure of the laboratory and its facilities are subject to constant review, said the head of Astrium’s manned space flight activities and director of the Bremen facility, Bart Reijnen.

The interior of Columbus is fitted out with removable racks which hold the various experiments being run by the ISS crew. Experiments can be swapped in and out of these racks, with new equipment supplied by the various transport vehicles used to supply the station. ‘Astrium’s task is to prepare everything for these experiments,’ explained Helmut Luttmann, Astrium’s head of ISS operations. ‘That includes the integration of the experimental equipment, and preparation of the astronauts’ training packages for them to operate the equipment, and that has to be delivered to whichever site is used to launch the packages.’ Resupply vessels are launched from Cape Canaveral, ESA’s spaceport in Kourou in Equatorial Guinea, and from the Russian spaceport at Baikonur Cosmodrome in Kazakhstan, and as many as 40 separate companies and institutions can be involved in preparation of equipment, Luttmann said.

columbusrack

The experiments on Columbus are loaded into removable rack modules that line the spacecraft

Over 400 experiments have been performed on Columbus since it entered service, and many have been extended well beyond their original planned duration. An experiment to observe the interaction between solar radiation and Earth’s atmosphere, appropriately called SOLAR, was one of the first to begin, with equipment mounted on a rack on the exterior of the laboratory back in February of 2008. It was originally planned to last for 18 months, Luttmann said, but is in fact still running. The data gathered by SOLAR are used for several purposes, including climate modelling, studies of the activity of the Sun, and for insights into stellar evolution.

SOLAR uses three instruments to cover almost the entire electromagnetic spectrum of solar radiation, and late last year was the cause of the first repositioning of ISS for entirely scientific reasons. The experiment only works when it has a clear view of the solar disc, but in its standard orbit, the bulk of the station blocked its view for two weeks out of every month. The experimental teams which run the instruments, in Germany, France and Belgium, wanted to observe the sun over an entire cycle of solar rotation, which takes 29 days, so in November the ISS’s thrusters turned the Station through 7 degrees. ‘That took a long time to organise and to work out how to do it,’ Reijnen said. ‘We count it as a major achievement.’

One of the most interesting experiments on Columbus in engineering terms is Geoflow, an attempt to model the way that the liquid layers of molten rock inside the Earth behave as the planet rotates. The experimental equipment consists of two solid concentric spheres, enclosing between them an incompressible liquid hydrocarbon, with the consistency of runny honey. The innermost sphere is heated while the outer one is cooled, and a strong electric field is applied across the two spheres to mimic the action of gravity, creating a uniform force acting towards the centre of the spheres. The two spheres spin on a common axis to create a flow within the liquid.

Geoflow

The Geoflow experiment aims to mimic the flow of molten materials within the Earth

The equipment includes sensors to measure the liquid flows and cameras to record images, and represents the first attempt to prove models proposed by computer simulations of the activity inside the Earth. This could only be done in space, because it eliminates the effect of gravity, which would impose a constant force in one direction across the equipment.

The experiment is designed to give insights into several terrestrial processes, including the planet’s magnetic field (which is generated by the movement of the molten iron core) and the currents which influence plate tectonics, whose mechanisms are still largely unknown.

Geoflow has recently completed its second phase; its first, which looked at convection currents with and without rotation, used a silicone oil as a working fluid, while the second, which looked at changes in viscosity and volume as the liquid was heated and cooled, used a hydrocarbon oil.

Among the results of Geoflow is the observation of plumes of hot liquid moving from the inner sphere to the outer one, which were predicted by numerical simulation of the Earth’s core. This, according to ESA’s head of manned spaceflight, Thomas Reiter, will feed into a planned vulcanology research stream on the ISS. It is also expected to provide insights into the design of other rotating assemblies, such as spherical gyroscopes, bearings and centrifugal pumps, and in situations where ions are injected into spinning fluids, such as tokomak nuclear fusion reactors. Preparations are now underway for a third phase of Geoflow, which will look at atmospheric flows from the poles to the equator.

Other research is attempting to make life in space easier for astronauts. The CRUISE experiment, for example, is testing voice control of the computers used to run procedures on the station, allowing crew to advance instructions or select diagrams, for example, without having to constantly go back to the laptop or tablet and use manual controls. ‘It means that you don’t have to “swim” around the module so much, which reduces crew fatigue and saves time,’ explained Jasminka Matevska, a software systems engineer at Astrium Bremen and one of the CRUISE system designers, ‘and, of course, it means that hands are kept free for work.’

The system could also be useful for terrestrial activities where operators need to refer to instruction screens, such as subsea engineering, oil and gas exploration and so on, she added, as well as one of ESA’s most prized goals: participation in manned missions outside Low Earth Orbit, particularly a return to the Moon and other planetary exploration. ESA hopes that this could be a fruit of participation with NASA’s MPCV (multi-purpose crewed vehicle) project, for which it is developing the service module: this, Jean-Jacques Dourdain indicated, was discussed at the last ministerial council meeting of 2012. Also discussed were updates to Europe’s launcher, Ariane, which will be developed with a new upper stage for Ariane 5-ME, set for its first launches in 2017 or 2018, and further towards a new version, Ariane 6, for which studies will be carried out during this year. Dourdain indicated that he has been in preliminary talks with NASA director Charles Bolden for ESA to contribute to the development of the US’s next-generation heavy launcher, the SLS, which will carry Orion and the service module into orbit and beyond.

MPCV

The MPCV — multipurpose crewed vehicle — will consist of the Orion command module and a service module based on ESA’s ATV

‘The Orion MPCV is very significant,’ said Thomas Reiter. ‘It’s the first time has involved ESA in the safety-critical path of crewed spaceflight, which marks an exciting new chapter for us.’ Developing the service module is a tight schedule, he added; the first (unmanned) flight is scheduled for 2017.

The basis for the service module, the Automated Transfer Vehicle (ATV), is now reaching the end of its programme. The fourth ATV, named after Albert Einstein, is now in Kourou being fitted out for a launch this summer, while the fifth and last, named for Belgian astronomer/physicist Georges Lemaître, is being built in the Bremen facility’s cavernous clean rooms.

‘The Orion MPCV is the first time NASA has involved ESA in the safety-critical path of crewed spaceflight

Thomas Reiter, head of manned spaceflight, ESA

ATV wasn’t officially crew-rated but has turned out to be very much a manned module; while it is docked to the ISS, some of the crew use it as sleeping quarters, its isolated position on the end of the Russian modules making it quieter than the rest of the station. The MPCV service modules will have to meet more demanding standards, however; experience gained during the building of Columbus and its predecessor experimental facility, Spacelab, which flew inside the Space Shuttle’s cargo bay, will go into its design, indicated Bart Reijner.

This will involve extensive cooperation with the manufacturer of the Orion command module itself, Lockheed-Martin, as the two modules will have to interface extensively, with air, water and power flowing between them.

‘We’re still actually waiting on the contract to go ahead with the service module; we expect it in late summer to early autumn,’ he told The Engineer. ‘But we are going ahead with our preliminary work.’ UK involvement in the service module will include propulsion systems and life support.


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