Tiny satellites could be “guide stars” for huge next-generation telescopes
There are more than 3,900 confirmed planets beyond our solar system. Most of them have been detected because of their “transits” — instances when a planet crosses its star, momentarily blocking its light. These dips in starlight can tell astronomers a bit about a planet’s size and its distance from its star. But knowing more about the planet, including whether it harbors oxygen, water, and other signs of life, requires far more powerful tools. Ideally, these would be much bigger telescopes in space, with light-gathering mirrors as wide as those of the largest ground observatories. NASA engineers are now developing designs for such next-generation space telescopes, including “segmented” telescopes with multiple small mirrors that could be assembled or unfurled to form one very large telescope once launched into space. NASA’s upcoming James Webb Space Telescope is an example of a segmented primary mirror, with a diameter of 6.5 meters and 18 hexagonal...