Masking out the intense bright light a star so that the dim reflected light of its planets, especially small earth-like ones, can be seen is no easy task. As mentioned in an earlier post, a starshade is a specially designed occulter that blocks a star’s light in a way that greatly reduces the diffraction around its edges. A starshade would be placed in space so that a telescope thousands of kilometers from it could observe planets around a distant star.
New Worlds Mission is a starshade project that has done early studies but has not been funded for implementation of an exoplanet observation system. This article provides more details on starshades: Incredible Technology: Giant Starshade Could Help Find an Alien Earth | Space.com
As it stands now, the assumed $1 billion mission would be able to target about 55 bright stars in a three-year span. [Sara Seager], the chair of NASA’s science and technology definition team for the starshade project, thinks it’s possible to find Earth-like planets orbiting 22 of those 55 stars targeted by the mission.
One major advantage to the starshade is that astronomers won’t need to couple it with a large, extremely expensive space telescope. By blocking out the light of a star before that light ever reaches the telescope, the starshade eliminates the need for a huge telescope, Seager said.
“You don’t need a very fancy telescope that’s highly thermally and mechanically stable,” Seager told Space.com. “You can use any old space telescope. We can buy a telescope. That’s what we’re thinking of. … It sounds a little funny, but any telescope will do.”
- Flower power: NASA reveals spring starshade animation – PlanetQuest/JPL
- Flower power: NASA starshade petal prototype – PlanetQuest/JPL