The Next Steps in Space Exploration
Advocates of manned space flight have long argued that propelling people into orbits has a public appeal unmatched by robotic missions. That was true when astronauts were racing to the moon, but since the Apollo program ended 40 years ago unmanned exploration has provided almost all of our extraterrestrial excitement â€“ at a far lower cost than crewed flights.
NASAâ€™s $2.5 billon Curiosity rover has at least prompted a follow-up US mission; a new life-seeking Mars rover will be launched in 2020. But after that NASAâ€™s cupboard for interplanetary exploration is bare. More ambitious proposals are needed to keep the excitement up during the 2020s. At the very least, NASA should be planning to visit the giant planets â€“ Jupiter, Saturn and their fascinating moons â€“ to follow on from the successful Galileo and Cassini missions. Another project with huge popular appeal would be an advanced planet-hunting space telescope, able to detect extrasolar worlds capable of hosting life. This would go far beyond the present generation of observatories which detect exoplanets by their effect on the parent star, slightly dimming its light when they pass in front of it or inducing a tiny gravitational wobble in its movement.