Nowadays£¬ people have become accustomed to space travel. If Neil Armstrong hadn’t set foot on the Moon in 1969£¬ much discovery of space wouldn’t have been done. Following his Moon landings£¬ space travel soon became unexceptional to the public. When theChallengerspace shuttle took off in 1986£¬ the world seemed to have lost its wonder at the amazing achievements of the astronauts involved and forgotten how hazardous space travel could be. Tragically£¬ the space shuttle exploded and the crew on board were killed. As the Challenger disaster cast a big shadow on the public£¬ many reports were submitted requesting that space shuttle flights should be suspended for a few years. It took nearly three years before our enthusiasm was rekindled and the Discovery was launched successfully. The sacrifice of the Challenger reminds us that we must continue to reach for the stars no matter how distant they might seem.