The Challenges of Space Exploration in the 21st Century
Tarek Nassar
Cost, radiation, space debris and long journeys: the obstacles between us and the next giant leap.
Space exploration is enjoying a revival, with new missions to the Moon and Mars and private companies launching more often than ever. The challenges, however, remain enormous.
Keeping people safe
Long missions expose astronauts to radiation and the effects of weightlessness on muscles and bones. Engineers are designing better shielding and exercise systems, but there are still many unknowns.
A crowded orbit
Thousands of satellites and fragments of debris now circle the Earth, raising the risk of collisions. International agreements on cleaning up orbit are still in their early stages.