Europe on board the space station
This is the year when Europe is gaining a real foothold in the International Space Station, with the docking of its Columbus research laboratory and the inauguration of its unmanned resupply spacecraft, the Automated Transfer Vehicle, both happening in 2008. This dual achievement places European aeronautics on par with the United States and Russia.
The idea of an International Space Station dates back to the Cold War in the early 1980s. The Americans wanted to build their own space station, Freedom, to compete with the Russian Salyut, and especially Mir, space stations. However, after the collapse of the Communist bloc, this was no longer justified. In the early 1990s, the United States, Russia, Japan, Canada and the member states of the European Space Agency (ESA) started negotiations for the construction of a space station, this time an international one, initially called Alpha but later renamed International Space Station (ISS). “This project has enabled ESA to develop a real policy of collaboration by getting 17 European Union Member States to work together and by helping to build bridges between the Russians and Americans,” explains Franco Bonacino, spokesperson for the ESA Director General. And to all those who think that NASA has taken all the credit, he replies, “international cooperation is never easy; the right balance has to be found to ensure that everybody gets something out of it.”
NASA could not go it alone and welcomed Europe’s participation in the ISS. “With two key elements, Europe has made a significant contribution. The first is the Columbus laboratory, which has formed part of the ISS since 11 February 2008, and the second is a resupply spacecraft, the Automated Transfer Vehicle (ATV), which will provide the space station with food, fuel and supplies and whose first model, Jules Verne, successfully completed its mission on 3 April this year.”
Columbus, a long gestation
“Columbus and ATV are the cornerstones of Europe’s manned space programme,” explains Markus Bauer, ESA Communication Officer. The Columbus story began in Rome in January 1985, when ESA approved the eponymous Columbus programme. The plan then was to build three modules: an Attached Pressurized Module (APM) to dock with the space station, a Man-Tended Free-Flyer (MTFF) to float freely in space and conduct microgravity experiments away from the mass of the space station, and an autonomous platform in polar orbit for Earth observation. In the end, only the APM module, now called Columbus, has been confirmed.The construction of Columbus is now in the hands of a number of European partners. The Italian aeronautics constructor Alenia is responsible, among other things, for the mechanical, thermal and life-support systems. European Aerospace Defence Systems (EADS) Astrium Space Transportation is the company responsible for designing Columbus and its avionics systems. The launch of this cylindrical pressurised laboratory, measuring 4.5 metres in diameter and 6.8 metres in length, was initially planned for late 2004, but the catastrophic disintegration of American space shuttle Columbia over Texas in February 2003 delayed deployment by more than three years. After being assembled in Bremen, Germany, the module was transported to the Kennedy Space Center in the USA (Cape Canaveral, Florida), on 27 May 2006, aboard a Beluga Airbus.
On 7 February 2008, Columbus was finally launched by the space shuttle Atlantis. When it neared the space station, the ISS robotic arm lifted the 12.8-tonne laboratory out of the Atlantis shuttle. Four days later, two ESA astronauts, Hans Schlegel (DE) and Léopold Eyharts (FR), finally docked Columbus with the space station and put it into operation. The laboratory is now controlled from the ground by the Space Operations Centre in Oberpfaffenhofen, Germany. The European laboratory cost € 880 million, excluding the launch, of which Germany is funding 51%, Italy 23%, France 18% and the USA and Canada 8%.
Science on Columbus
The projected lifespan of this third ISS laboratory (after the United States and Russian laboratories) is 10 years. “After this period, Columbus will be taken out of orbit and will burn up when it re-enters the Earth’s atmosphere over the Pacific” (1). From Earth, researchers will be able to conduct thousands of microgravity experiments from user centres, or even their own offices. With an internal capacity of 75 m3, the laboratory can contain three people, as well as 10 International Standard Payload Racks (ISPR), which resemble fitted cupboards, to accommodate laboratory equipment for scientific experiments (five ISPR for NASA and five for ESA). “NASA is supplying Columbus with energy, telecommunications, robotics and cooling systems. In exchange, NASA is entitled to use 49% of the laboratory.”
Which experiments will the European ISPR be conducting? The first is a laboratory for studying the behaviour of fluids in a microgravity environment. Gravity usually causes convection, sedimentation and stratification effects in fluids, masking dynamic phenomena such as mass transfer in crystal growth. This research is expected to lead to improvements in the manufacture of products such as semiconductors. A second ISPR will study human physiology. If humans are to venture beyond the moon, we need to know how our bodies will react to prolonged weightlessness. This experiment will also add to our understanding of age-related problems like muscle loss and osteoporosis.
The third ISPR will be used to conduct experiments on micro-organisms, small plants and invertebrates. The aim is to find out more about the effects of microgravity across the whole complex spectrum of life, from a single cell to a human being. Results are expected in immunology and cell biology, for the process of cell repair, for example. The fourth ISPR, the European Drawer Rack, is a carrier system for a large number of experiments housed within standardised drawers and lockers. The fifth ISPR will serve as a workbench and storage facility. In addition to the ISPR, two further payloads have been externally mounted on the module, one to observe the sun and to measure solar radiation levels at different wavelengths, and the other to expose experiments to the space vacuum.
In spite of these exciting scientific prospects, critics argue that the experiments conducted aboard the ISS could just as easily be done on Earth at a much lower cost, using parabolic trajectory flights that reproduce microgravity for a few seconds, or even ordinary rockets. “Columbus does not replace such ground-based resources, but supplements them. Certain experiments call for stable microgravity conditions or a space vacuum. No airplane or rocket could provide the same experimental conditions. How is it possible to study human adaptation to microgravity anywhere other than in space?” Franco Bonacino’s arguments are just as convincing: “The ISS accounts for only 15% of the ESA’s annual budget and there are already more requests for experiments than we can probably handle. At least most of the scientific community seems to be satisfied.”
ATV, a lifeline
Of course, astronauts and experiments could not survive without a lifeline to connect the space station with Earth. This lifeline is the ATV. The automated transfer vehicle is Europe’s contribution in kind to ISS operating expenditures. “It is a 100% European project that gives us the sort of independence we have never had before. We are now autonomous in space – but willing to collaborate whenever needed.”
The ATV also enables Europe to provide its own industry with work instead of transferring money to its partners. “Thanks to the ATV, we have acquired and developed key technologies such as space rendezvous and automated docking. This places Europe at the forefront of the world space industry and enables it to create and maintain a skilled workforce for decades to come. Applications for these technologies exist on Earth, too, in the telecommunications or robotics sectors, for example. This also makes them a driver of non-space sectors.”
The ATV prime contractor is EADS Astrium Space Transportation. Nicolas Chamussy, ATV programme manager at Astrium clarifies the company’s role: “Following a call for tender, ESA commissioned Astrium to develop and manufacture the ATV vehicle, as well as to test the first model. In compliance with ESA specifications, this consists of designing a vehicle concept, drawing up detailed plans and forming an industrial consortium which we have entrusted with developing and producing autonomous subparts (equipment or subsystems). All that remained was to complete the final operations on the vehicle at Kourou spaceport to make it ‘flight ready’ and to provide ESA with the necessary expertise for the flight. This operational experiment can be reused for more ambitious projects in the future, such as travelling to the moon or Mars.” All in all, 30 firms from 10 European countries, together with eight Russian and American firms, will be involved in the ATV project.
The ATV is a white cylindrical craft measuring 10.3 metres in length and 4.5 metres in diameter, equipped with solar panels in the shape of a cross. On board, it can carry 7.7 tonnes of freight to the space station orbiting at an altitude of 400 kilometres, to back up the Russian space freighter Progress, which has only half that capacity. The ATV’s freight can include up to 100 kilograms of air (oxygen and nitrogen) for the ISS atmosphere, 840 kilograms of drinking water for the crew and propellants for the space station’s propulsion system, as well as 4.7 tonnes of fuel, all stored in tanks. Added to this are 4.5 tonnes of payloads enclosed in a pressurised module.
With its four main engines and 28 smaller thrusters, the ATV also has the job of raising the ISS orbit every 10 to 45 days. The space station is constantly being dragged down by the Earth’s atmosphere, which causes it to lose several hundred metres of altitude per day, so the ATV uses its engines to propel the ISS up to its correct orbit. Also, it occasionally has to manoeuvre the ISS to dodge free-floating space debris.
Jules Verne in space
The first ATV was launched by an Ariane rocket on 9 March 2008 from the Kourou base in French Guiana. Four further models will be built, so a new one will be launched in roughly 17-month intervals. After the ATV detaches itself from the launcher, its engines are fired and its navigation systems activated. To enable it to approach the space station, the ATV has an ultra-precise guidance system supplied by Russian firm RSC Energia. After three to five days in orbit (or 15 in the case of Jules Verne), the resupply spacecraft comes into sight of the space station and attempts to approach it by following two supplementary orbits.
Even though the space station and the ATV are travelling at a speed of 28 000 kilometres per hour, their relative speed is only a few centimetres per second. In the event of a collision risk, an emergency procedure is triggered, either from the ground or automatically. The engines are then switched on for three minutes to engage the emergency braking system before removing the vessel to a location outside a 200-metre radius around the space station. This system was tested successfully on 14 March 2008 with Jules Verne. The latter docked with the space station on 3 April 2008, according to plan. The resupply spacecraft will remain attached to the ISS for six months, after which it will be loaded with up to 6.4 tonnes of waste from space station. After closing its hatches, it will automatically detach itself from the space station and its engines will position it to enter the Earth’s atmosphere at a very sharp angle so that it burns up over a predetermined area of the Pacific Ocean.
ATV of the future
Apart from the planned five models, the ATV has great potential for conversion. For instance, it could be turned into an automated laboratory where microgravity would be even better than in the space station, given its comparatively smaller mass. It could dock with the ISS for maintenance operations, a concept not unlike that of the MTFF. As it is pressurised, the ATV could serve as a safe haven for the ISS crew in the event of an accident whilst they await assistance from a space shuttle or Soyuz. An even bolder idea is to attach a string of ATVs together to form a mini-space station. However, perhaps the most compelling idea yet is to turn the ATV into a transport vehicle for space exploration. As it is the most powerful space tug ever built, it could transfer tonnes of supplies to the moon or Mars’ orbits. “Our participation in the ISS is teaching us a lot about collaboration, an important aspect of future international space exploration missions, and gives us a chance to demonstrate our reliability to our partners.” All in all, its contribution to the ISS in the form of the Columbus module and ATV is a good deal for Europe. Apart from the many microgravity experiments that it will be conducting on Columbus on a continuing basis, building the ATV will endow Europe with capabilities it does not currently have, such as sending humans into space. All that remains is to apply enough resources to ensure that Europe is successful in this long-distance race to conquer space and that it takes full advantage of all that space offers.
- All unattributed quotes are from Markus Bauer.