ESA's Astrolab Mission: Making Space a Safer Place
Astrolab is deeply embedded in the effort to prepare humans for safe long-duration space travel in the future. Bringing the permanent ISS crew up to three for the first time in three years, Reiter will increase the time that can be devoted to scientific research on the station. His scientific programme has been contributed by institutions across Europe.
As part of the Astrolab mission, Reiter will carry out scientific experiments in the areas of human physiology, biology, physics and radiation dosimetry. This will help Europe to develop experience of long-term scientific utilisation of the ISS, in preparations for the arrival of the European Columbus Lab to the station in 2007. Columbus will contain research facilities that will enable thousands of experiments to be carried out in life sciences, materials science, and fluid physics. It is ESA's largest single contribution to the ISS. It is also the most expensive project in Europe's entire history in space.
Radiation Dosimetry Experiments
Astronauts encounter such high levels of radiation in their work that they are classified as radiation workers. Outside of the Earth's protective atmosphere, highly energetic cosmic rays and solar particles can cause serious damage to human cells. From the digestive system going haywire to genetic mutations and cancer, the effects of radiation exposure are a serious concern for crewed space missions. Dosimetry is the measurement of the dose of ionizing radiation that is absorbed by tissues or materials. It is a vital part of experiments onboard the ISS to help work out how crew radiation exposure can be minimized.
Marco Casolino is a researcher at the INFN (National Institute of Nuclear Physics) in Italy, and a member of the science team for the ALTCRISS experiment. He says, "Results from the experiment are particularly important in the design of new shielding materials for spacecraft and habitats for expeditions outside Low Earth Orbit. Hydrogen and hydrogenous materials seem to be the best shields, and other materials such as Kevlar are being considered for inflatable habitats. Bolder designs call for active shielding using superconducting magnets to deflect harmful particles."
Thomas Reiter and his fellow cosmonauts will be testing Kevlar and other materials including Polyethylene, which is currently used in the sleeping quarters of the US section of the ISS. A novel composite material called Nextel/Kapton will also be investigated for its mechanical and shielding properties. Developing effective shielding will be crucial in space agencies' plans to send astronauts back to the Moon, and eventually to Mars (one of the long-term goals of ESA's Aurora programme).
The microgravity conditions of long-duration spaceflight act to suppress the immune system of astronauts, making them more susceptible to infection and disease. Since the Apollo missions, astronauts have been returning to Earth with weakened immunity, and many of the early astronauts developed bacterial or viral infections that a healthy person should have been able to fight off easily.
The LEUKIN experiment, jointly devised by Swiss, Italian, and US scientists, aims to provide a better understanding of how this immune suppression occurs. The experiment will use T-lymphocytes, a type of white blood cell that plays a central role in the body's immune response. In patients with HIV it is these T-cells which are attacked by the virus, eventually leading to serious illness.
Astronaut Thomas Reiter will activate samples of the cells, taken from human blood, on board the ISS. By injecting cell samples with a chemical mixture, he will simulate what would happen in the bloodstream of a body infected by a virus or bacteria. Reiter will then prepare RNA from these cells, to show which genes have been turned on during activation. Scientists back on Earth will later analyse the expression of almost 9000 different T-cell genes using new gene-chip technology, to find out which ones worked normally, and which ones were inhibited by the microgravity conditions.
Two different NOA (Nitric Oxide Analyser) experiments will be carried out by Thomas Reiter during his mission, using new improved techniques. He will carry out NOA 1 experiments on a weekly basis to assess his airways for inflammation by measuring his exhaled nitric oxide and comparing it to pre-flight measurements. NOA 2 will involve Reiter carrying out the same inhalation-exhalation procedure just before and after a space-walk. It is known that scuba divers often have gas bubbles in their blood following a dive, without experiencing any symptoms of decompression sickness. The occurrence of gas bubbles without symptoms in astronauts following an EVA is not currently known. This experiment will try to establish whether the decompression process following a spacewalk is totally safe, or whether it needs adapting to prevent gas bubbles forming in the bloodstream of the astronauts.
The ISS is providing a unique opportunity to study the long-term effects of microgravity and space radiation on the human body and other biological systems. Understanding the short and long term impact of the hazardous space environment is a necessary and important part of preparations for future long-duration missions. A lot of the basic research has already been done, and the Astrolab mission will build on this knowledge step by step, paving the way to a safer future in space.