Brilliant Spacemissions End
Late this month NASA will attempt to land another high-tech robot on Mars, this time to drill deeper than ever into the soil to learn more about the planet’s origins and evolution. Meanwhile, NASA is observing the conclusions of two missions that took on the much bigger picture — how planets form, grow and become different; and the biggest question of all, whether Earth alone can accommodate life. Dawn, which was launched in 2007 and traveled by ion propulsion to the distant asteroid belt, established an array of firsts while orbiting the two largest objects in the belt, the asteroid Vesta and the dwarf planet Ceres. It discovered that they are vastly different objects with vastly different origins and histories, providing astronomers with enormous insights into the formation of our solar system. Dawn has exhausted its supply of maneuvering fuel and will remain in orbit around Ceres, 4.3 billion miles from Earth. The Kepler space telescope also has exhausted its maneuvering fuel and will remain in orbit around the sun. Kepler discovered 5,580 potential planets orbiting stars in the Milky Way galaxy, about 3,000 of which have been confirmed. Its findings demonstrate nothing less than that there are far more planets than stars, raising the tantalizing possibility that Earth is not alone as a habitable planet. Natalie Batalha, a Kepler mission scientist at the University of California, Santa Cruz, told The New York Times that Kepler’s data suggests the existence of 10 billion potentially habitable planets within our galaxy alone — which is the all the more extraordinary because scientists could not confirm the existence of any planet outside our solar system less than a generation ago. Both projects returned incalculable long-term value at modest cost. Dawn cost about $450 million; Kepler about $550 million. As scientists continue to feast on the data, the projects should inform members of Congress that such science is a sound investment.