The space shuttle Atlantis blasts off later today, carrying with it two Irish experiments that will measure radiation exposure risks faced by orbiting astronauts. Ireland plays a major role in this research thanks to several decades of work by scientists at the Dublin Institute for Advanced Studies.
Emeritus professor Denis O'Sullivan has years of experience in studying ionising radiation exposures for flight crews and astronauts caused by naturally occurring cosmic rays. He has conducted studies for the EU and also a number of experiments for the US National Aeronautics and Space Administration (Nasa).
"I have been at this for 39 years. I am one of the few survivors of the Apollo [ spacecraft] era," says Prof O'Sullivan. "We are considered world experts on this issue," he says of the Institute (Dias) and his work there.
Cosmic rays come streaming in from beyond our solar system, high energy particles that have the potential to do harm. They pose no health risk for those of us on the ground because the atmosphere dissipates all their energy.
Yet flight crews flying at high altitudes receive significant radiation doses and orbiting astronauts face still higher exposures because there is no atmosphere to protect them.
Prof O'Sullivan led an EU study that showed flight crews received as much radiation as nuclear power plant workers.
He has also been involved in many Nasa studies to measure exposures to crews in the shuttle and the International Space Station (ISS). One key mission saw "Matroshka" put into orbit, a mannequin packed full of electronics and measuring devices which mimicked 24 different tissue types in the body to gauge radiation exposures. "We had a huge contribution to make [ on Matroshka] because of the amount of experience we have on this," he says.
This work continues with today's launch of Atlantis on mission STS122, due to lift off at about 7.45pm Irish time. It will see the delivery of the Columbus Laboratory module to the orbiting ISS and on board the lab will be two experiments with significant Irish involvement.
One will seek to map the radiation field inside the Columbus module and will start by assessing the external field that surrounds the laboratory.
Radiation exposures can reach significant levels inside the ISS, with astronauts typically receiving the equivalent of five to 10 chest x-rays a day. For example, exposures when outside on a "space walk" are typically double this, Prof O'Sullivan adds.
The second experiment involves a collaboration with scientists in Belgium and the Czech Republic and will study how cosmic ray radiation effects bacteria. "The whole idea of that experiment is there is very little work done on the effects of radiation on bacteria," says Prof O'Sullivan.
Nasa is planning manned flights to Mars and wants to know whether long-term radiation exposures can change otherwise harmless bacteria into dangerous bacteria. The change would arise due to mutations triggered by the radiation exposure.
"Nasa are putting a lot of thought into it because it is a major worry. Both the astronauts and the bacteria will be hit by radiation and we are trying to assess the danger," Prof O'Sullivan says.
The experiment will use soil and water bacteria that are harmless to humans. Dublin will measure exposures and the Belgian group will study any impact on bacterial DNA, damage that could cause mutations.