The first earthling to orbit our planet was just two years old. her name was laika, and she was picked up in the streets of moscow in 1957, just a few days before the launch of sputnik 2. laika was a terrier mutt, and her flight aboard sputnik 2 paved the way for space exploration during a time when scientists weren’t sure if spaceflight was safe for living organisms. since then, humans have orbited earth and even walked on the moon. currently nasa is planning a mission to send astronauts to a nearby asteroid, and commercial companies are planning civilian missions to the moon. unmanned space probes have traveled past neptune and pluto to the outer edge of our solar system and entered interstellar space. space travel has come a long way since laika, but there are still many celestial bodies waiting to be explored. what do you think will be the biggest space mission of the twenty-first century? what challenges do you anticipate that the humans or space probes will experience on this journey? what specific accommodations or technological advancements will be needed to make the mission successful?