Spring has arrived and thousands of schoolchildren are stretching their muscles and brains to reach the finishing line of Mission-X. After six weeks of activities inspired by astronaut training, these future space explorers will celebrate their achievements with special events all over the world. Each school follows its own pace in this competition which combines fitness, healthy eating and problem-solving. Around 15 000 students from over 20 countries built their own model satellites, conquered a martian mountain or worked in teams to solve puzzles.