TheNew Worlds Mission is a proposed project comprising a largeocculter flying in formation with aspace telescope designed to block the light of nearbystars in order to observe their orbitingexoplanets. The observations could be taken with an existing space telescope or a dedicated visible lightoptical telescope optimally designed for the task of finding exoplanets. A preliminary research project was funded from 2005^[1] through 2008 byNASA Institute for Advanced Concepts (NIAC) and headed by Webster Cash of theUniversity of Colorado at Boulder in conjunction withBall Aerospace & Technologies Corp.,Northrop Grumman,Southwest Research Institute and others. Since 2010 the project has been looking for additional financing from NASA and other sources in the amount of roughly US$3 billion including its own four-meter telescope.^[2][3] If financed and launched, it would operate for five years.

Currently, the direct detection ofextrasolar planets (or exoplanets) is extremely difficult. This is primarily due to:

• Exoplanets appearing extremely close to their host stars when observed at astronomical distances. Even the closest of stars are severallight years away. This means that while looking for exoplanets, one would typically be observing very small angles from the star, on the order of several tens ofmilli-arcseconds. Angles this small are impossible to resolve from the ground due toastronomical seeing.
• Exoplanets being extremely dim compared to their host stars. Typically, the star will be approximately a billion times brighter than the orbiting planet. This makes it nearly impossible to see planets against the star's glare.

The difficulty of observing such a dim planet so close to a bright star is the obstacle that has prevented astronomers from directly photographing exoplanets. To date, only a handful of exoplanets have been photographed.^[4] The first exoplanet to be photographed,2M1207b, is in orbit around a star called2M1207. Astronomers were only able to photograph this planet because it is a very unusual planet that is very far from its host star, approximately 55astronomical units (about twice the distance ofNeptune). Furthermore, the planet is orbiting a very dim star, known as abrown dwarf.

To overcome the difficulty of distinguishing more Earth-like planets in the vicinity of a bright star, the New Worlds Mission would block the star's light with anocculter. The occulter would block all of the starlight from reaching the observer, while allowing the planet's light to pass undisturbed. The starshade would be tens of meters across and probably made out ofKapton, a lightweight material similar toMylar.^[5]

Traditional methods of exoplanet detection rely on indirect means of inferring the existence of orbiting bodies. These methods include:

• Astrometry – watching a star move slightly due to the gravitational influence of a nearby planet
• ObservingDoppler shifts of the star's spectrum due to the star's movement
• Observing the amount of light from a star change as an extrasolar planettransits the star, preventing a portion of the light from reaching the observer
• Pulsar timing
• Gravitational microlensing
• Observing radiation from circumstellar disks in theinfrared

All of these methods provide convincing evidence for the existence of extrasolar planets, but none of them provide actual images of the planets.

The goal of the New Worlds Mission is to block the light coming from nearby stars with an occulter. This would allow the direct observation of orbiting planets. The occulter would be a large sheet disc flown thousands of kilometers along the line of sight. The disc would likely be several tens of meters in diameter and would fit inside existingexpendable launch vehicles and be deployed after launch.

One difficulty with this concept is that light incoming from the target star woulddiffract around the disc and constructively interfere along the central axis. Thus the starlight would still be easily visible, making planet detection impossible. This concept was first famously theorized bySiméon Poisson in order to disprove the wave theory of light, as he thought the existence of a bright spot at the center of the shadow to be nonsensical. HoweverDominique Arago experimentally verified the existence of thespot of Arago. This effect can be negated by specifically shaping the occulter. By adding specially shaped petals to the outer edge of the disc, the spot of Arago will disappear, allowing the suppression of the star's light.

This technique would make planetary detection possible for stars within approximately 10parsecs (about 32light years) of Earth. It is estimated that there could be several thousandexoplanets within that distance. The starshade is similar to but should not be confused with theAragoscope,^[6] which is a proposed imaging device designed to use the diffraction of light around a perfectly-circular light-shield to produce an image. The starshade is a proposedsunflower-shapedcoronagraph disc that was designed to block starlight that interferes withtelescopicobservations of other worlds. The "petals" of the "sunflower" shape of the starshade are designed to eliminate the diffraction that is the central feature of anAragoscope.

The starshade is aspacecraft designed by Webster Cash, anastrophysicist at theUniversity of Colorado at Boulder's Center for Astrophysics and Space Astronomy.^[7] The proposed spacecraft was designed to work in tandem withspace telescopes like theJames Webb Space Telescope, which did not use it, or a new 4-meter telescope.^[5] It would fly 72,000 km (45,000 mi) in front of a space telescope (between the telescope and a targetstar) and approximately 238,600 miles (384,000 km) away from Earth, outside of Earth'sheliocentric orbit.^[8] When unfurled, the starshade resembles asunflower, with pointed protrusions around its circumference. The starshade acts as a very largecoronagraph: it blocks light of a distant star, making it easier to observeassociated planets. The unfurled starshade could reduce collected light from bright stars by as much as 10 billion-fold. Light that "leaks" around the edges would be used by the telescope as it scans the target system forplanets. With the reduction of the harsh light, astronomers will be able to check exoplanet atmospheres tens of trillions of miles away for the potential chemical signatures oflife.^[1]

The New Worlds Mission aims to discover and analyzeterrestrial extrasolar planets:

1. Detection: First, using the space telescope and 'starshade', or occulter, exoplanetary systems will be directly detected.
2. System mapping: Following detection, system mapping would involve the direct mapping of planetary systems through the detection of the planetary light separate from the parent star. In a sufficiently high-quality image, planets would appear as individual star-like objects. A series of images of the planetary system would allow measurements of planetary orbits, and the brightness and broadband colors of the planets would provide information about their basic nature.
3. Planet studies: At this stage, detailed study of individual planets would take place. With a low noise level and a modest signal,spectroscopy andphotometry can be performed. Spectroscopy allows scientists to perform chemical analysis ofatmospheres andsurfaces, which might hold clues to the existence oflife elsewhere in theuniverse. Photometry will show variation in color and intensity as surface features rotate in and out of the field of view, allowing for the detection of oceans, continents, polar caps and clouds.
4. Planet imaging: A large increase in capability is needed to achieve true planet imaging. However, techniques ofinterferometry show that, in principle, this is possible to achieve. Fifty to one hundred percent of a planet's surface could theoretically be mapped, depending on the planet'sinclination.
5. Planetary assessment: The final step in extrasolar planet studies would be the ability to study these distant worlds in the same way that Earth-observing systems study the Earth's surface. Such a telescope would need to be extremely large, to collect enough light to resolve and analyze small details on the planet's surface. However, these kinds of studies do not lie in the foreseeable future, for it takes square kilometers of collecting area to capture the needed signal.

In addition to finding and analyzing terrestrial planets, it can also discover and analyzegas giants. The New Worlds Mission will also findmoons andrings orbiting extrasolar planets. This technique will involve direct imaging of planets by blocking the starlight with a starshade. It will study the moons and rings in detail and find whether moons can also support life if gas giant planets orbit in thehabitable zones of parent stars.

There are many possibilities for various New Worlds Missions, including

• New Worlds Discoverer proposed to use an existing space telescope (like the James Webb telescope), to find exoplanets. The size of the starshade could be optimized for the observing telescope.^{[citation needed]}
• New Worlds Observer would use two spacecraft, one that has a dedicated telescope and one with a starshade to find exoplanets. The possibility of two starshades is also a consideration. One starshade to point towards the desired target while the other moves into position for the next target. This would eliminate some of the time delay in observing different systems and allow for many more targets to be observed in the same timespan.^[2]
• New Worlds Imager would use many spacecraft/starshades. This would allow observers to resolve the planet and obtain true planetary imaging.^{[citation needed]}

• Aragoscope
• Coronagraph, a telescopic attachment to block out the light from a star so that nearby objects can be resolved
• Space sunshade

• New World's official website at University of Colorado, Boulder
• Pinhole Camera to Image New World
• Finding planets through a pinhole
• Biggest Pinhole Camera Ever
• Alien Planets to Pose for Giant Pinhole Camera in Space