Dark side of the Northern Lights

Sir, – Dr Peter Gallagher (January 25th) reminds us of some of the negative consequences of solar events with regard to humans…

Sir, – Dr Peter Gallagher (January 25th) reminds us of some of the negative consequences of solar events with regard to humans on earth. In deep space they also cause significant problems for astronauts and will continue to be a serious factor in space travel when missions to Mars and other planets take place in the future.

Along with cosmic radiation which originates outside the solar system, the radiation associated with solar events constitutes one of the most serious hazards for humans participating in long-term space missions, particularly outside the Earth’s geomagnetic field.Missions to low Earth orbit such as the International Space Station, are not exposed to the full radiation intensities because of the protection provided by the Earth’s magnetic field and the shielding of the spacecraft structure. However, a human exposed outside a spacecraft during an activity like walking on the Moon or undertaking some extravehicular activity in space could be severely affected. For instance, during August 1972, between the Apollo 16 and 17 missions a major “solar storm” occurred which could have had very serious consequences if astronauts had been on the surface at the time.

A roadmap to enable human future space exploration is now being prepared by an international team of scientists (including the Dublin Institute for Advanced Studies) and covers a wide range of topics including space radiation, habitat management, psychology and human/machine systems and health care. – Yours, etc,

Emeritus Prof DENIS O’SULLIVAN,

Dublin Institute for Advanced Studies,

Fitzwillian Place, Dublin 2.