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The New Worlds Mission is a proposed project comprising a large occulter flying in formation with a
space telescope A space telescope (also known as space observatory) is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO ...
designed to block the light of nearby
star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
s in order to observe their orbiting
exoplanets An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detec ...
. The observations could be taken with an existing space telescope or a dedicated visible light
optical telescope An optical telescope gathers and focus (optics), focuses light mainly from the visible spectrum, visible part of the electromagnetic spectrum, to create a magnification, magnified image for direct visual inspection, to make a photograph, or to co ...
optimally designed for the task of finding exoplanets. A preliminary research project was funded from 2005 through 2008 by
NASA Institute for Advanced Concepts The NASA Innovative Advanced Concepts (NIAC), formerly NASA Institute for Advanced Concepts (NIAC), is a NASA program for development of far reaching, long term advanced concepts by "creating breakthroughs, radically better or entirely new aerospa ...
(NIAC) and headed by Webster Cash of the
University of Colorado at Boulder The University of Colorado Boulder (CU Boulder, CU, or Colorado) is a Public university, public research university in Boulder, Colorado, United States. Founded in 1876, five months before Colorado became a Federated state, state, it is the fla ...
in conjunction with Ball Aerospace & Technologies Corp.,
Northrop Grumman Northrop Grumman Corporation is an American multinational Aerospace manufacturer, aerospace and Arms industry, defense company. With 97,000 employees and an annual revenue in excess of $40 billion, it is one of the world's largest Arms industry ...
,
Southwest Research Institute Southwest Research Institute (SwRI), headquartered in San Antonio, Texas, is an independent and nonprofit applied research and development (R&D) organization. Founded in 1947 by oil businessman Tom Slick, it provides contract research and deve ...
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.
-
arcseconds A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...
. Angles this small are impossible to resolve from the ground due to
astronomical seeing In astronomy, seeing is the degradation of the real image, image of an astronomical object due to turbulence in the atmosphere of Earth that may become visible as blurring, twinkling or variable Distortion (optics), distortion. The origin of this ...
. *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. The first exoplanet to be photographed,
2M1207b 2M1207b is a planetary-mass object orbiting the brown dwarf 2M1207, in the constellation Centaurus, approximately 170 light-years from Earth. It is one of the first candidate exoplanets to be directly observed (by infrared imaging). It was disc ...
, is in orbit around a star called
2M1207 2M1207, 2M1207A or 2MASS J12073346–3932539 is a brown dwarf located in the constellation Centaurus; a companion object, 2M1207b, may be the first extrasolar planetary-mass companion to be directly imaged, and is the first discovered o ...
. Astronomers were only able to photograph this planet because it is a very unusual planet that is very far from its host star, approximately 55
astronomical units The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to . Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its mode ...
(about twice the distance of
Neptune Neptune is the eighth and farthest known planet from the Sun. It is the List of Solar System objects by size, fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 t ...
). Furthermore, the planet is orbiting a very dim star, known as a
brown dwarf Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main sequence, main-sequence stars. Their mass is approximately 13 to 80 Jupiter mass, times that of Jupiter ()not big en ...
. 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 an occulter. 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 of
Kapton file:Kaptonpads.jpg, Kapton insulating pads for mounting electronic parts on a heat sink Kapton is a polyimide film used in flexible printed circuits (flexible electronics) and space blankets, which are used on spacecraft, satellites, and variou ...
, a lightweight material similar to
Mylar BoPET (biaxially oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical stability, dimensional stability, transparency reflectivity, an ...
.


Methods

Traditional methods of exoplanet detection rely on indirect means of inferring the existence of orbiting bodies. These methods include: *
Astrometry Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other Astronomical object, celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, th ...
– watching a star move slightly due to the gravitational influence of a nearby planet *Observing
Doppler The Doppler effect (also Doppler shift) is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. The ''Doppler effect'' is named after the physicist Christian Doppler, who described ...
shifts of the star's spectrum due to the star's movement *Observing the amount of light from a star change as an extrasolar planet transits the star, preventing a portion of the light from reaching the observer *
Pulsar A pulsar (''pulsating star, on the model of quasar'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its Poles of astronomical bodies#Magnetic poles, magnetic poles. This radiation can be obse ...
timing *
Gravitational microlensing Gravitational microlensing is an astronomical phenomenon caused by the gravitational lens effect. It can be used to detect objects that range from the mass of a planet to the mass of a star, regardless of the light they emit. Typically, astronom ...
*Observing radiation from circumstellar disks in the
infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
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 existing
expendable launch vehicles An expendable launch system (or expendable launch vehicle/ELV) is a launch vehicle that can be launched only once, after which its components are destroyed during reentry or impact with Earth, or discarded in space. ELVs typically consist of se ...
and be deployed after launch. One difficulty with this concept is that light incoming from the target star would
diffract Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the propagating wav ...
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 by Siméon 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. However
Dominique Arago "Dominique" is a 1963 French language popular song, written and performed by Belgian singer Jeannine Deckers, better known as Sœur Sourire ("Sister Smile" in French) or The Singing Nun. The song is about Saint Dominic, a Spanish-born priest an ...
experimentally verified the existence of the spot 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 10
parsecs The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (AU), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and ...
(about 32
light years A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astro ...
) of Earth. It is estimated that there could be several thousand
exoplanets An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detec ...
within that distance. The starshade is similar to but should not be confused with the
Aragoscope An Aragoscope is a telescope design based on diffraction around the edge of an occluding disc, named after French scientist François Arago. Concept The light diffracted around the edge of a perfectly circular occluder interferes constructively at ...
, 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 proposed
sunflower The common sunflower (''Helianthus annuus'') is a species of large annual forb of the daisy family Asteraceae. The common sunflower is harvested for its edible oily seeds, which are often eaten as a snack food. They are also used in the pr ...
-shaped
coronagraph A coronagraph is a telescopic attachment designed to block out the direct light from a star or other bright object so that nearby objects – which otherwise would be hidden in the object's bright glare – can be resolved. Most coronagr ...
disc that was designed to block starlight that interferes with
telescopic A telescope is an instrument designed for the observation of remote objects. Telescope(s) also may refer to: Music * The Telescopes, a British psychedelic band ** The Telescopes (album) * ''Telescope'' (album), by Circle, 2007 * ''The Telescope' ...
observations Observation in the natural sciences is an act or instance of noticing or perceiving and the acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the perceptio ...
of other worlds. The "petals" of the "sunflower" shape of the starshade are designed to eliminate the diffraction that is the central feature of an
Aragoscope An Aragoscope is a telescope design based on diffraction around the edge of an occluding disc, named after French scientist François Arago. Concept The light diffracted around the edge of a perfectly circular occluder interferes constructively at ...
. The starshade is a
spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...
designed by Webster Cash, an astrophysicist at the
University of Colorado at Boulder The University of Colorado Boulder (CU Boulder, CU, or Colorado) is a Public university, public research university in Boulder, Colorado, United States. Founded in 1876, five months before Colorado became a Federated state, state, it is the fla ...
's Center for Astrophysics and Space Astronomy. The proposed spacecraft was designed to work in tandem with
space telescope A space telescope (also known as space observatory) is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO ...
s like the
James Webb Space Telescope The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, Lis ...
, which did not use it, or a new 4-meter telescope. It would fly in front of a space telescope (between the telescope and a target
star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
) and approximately away from Earth, outside of Earth's
heliocentric Heliocentrism (also known as the heliocentric model) is a Superseded theories in science#Astronomy and cosmology, superseded astronomical model in which the Earth and Solar System, planets orbit around the Sun at the center of the universe. His ...
orbit. When unfurled, the starshade resembles a
sunflower The common sunflower (''Helianthus annuus'') is a species of large annual forb of the daisy family Asteraceae. The common sunflower is harvested for its edible oily seeds, which are often eaten as a snack food. They are also used in the pr ...
, with pointed protrusions around its circumference. The starshade acts as a very large
coronagraph A coronagraph is a telescopic attachment designed to block out the direct light from a star or other bright object so that nearby objects – which otherwise would be hidden in the object's bright glare – can be resolved. Most coronagr ...
: it blocks light of a distant star, making it easier to observe associated 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 for
planets A planet is a large, rounded astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets by the most restrictive definition of the te ...
. 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 of
life Life, also known as biota, refers to matter that has biological processes, such as Cell signaling, signaling and self-sustaining processes. It is defined descriptively by the capacity for homeostasis, Structure#Biological, organisation, met ...
.CU Proposal To Image Distant Planets Is Funded For Second Round Of Study


Objectives

The New Worlds Mission aims to discover and analyze terrestrial extrasolar planets: #Detection: First, using the space telescope and 'starshade', or occulter, exoplanetary systems will be directly detected. #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. #Planet studies: At this stage, detailed study of individual planets would take place. With a low noise level and a modest signal,
spectroscopy Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectro ...
and
photometry Photometry can refer to: * Photometry (optics), the science of measurement of visible light in terms of its perceived brightness to human vision * Photometry (astronomy), the measurement of the flux or intensity of an astronomical object's electr ...
can be performed. Spectroscopy allows scientists to perform chemical analysis of atmospheres and
surfaces A surface, as the term is most generally used, is the outermost or uppermost layer of a physical object or space. Surface or surfaces may also refer to: Mathematics *Surface (mathematics), a generalization of a plane which needs not be flat * Sur ...
, which might hold clues to the existence of
life Life, also known as biota, refers to matter that has biological processes, such as Cell signaling, signaling and self-sustaining processes. It is defined descriptively by the capacity for homeostasis, Structure#Biological, organisation, met ...
elsewhere in the
universe The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...
. 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. #Planet imaging: A large increase in capability is needed to achieve true planet imaging. However, techniques of
interferometry Interferometry is a technique which uses the ''interference (wave propagation), interference'' of Superposition principle, superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important inves ...
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's
inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...
. #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 analyze
gas giant A gas giant is a giant planet composed mainly of hydrogen and helium. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" was originally synonymous with "giant planet". However, in the 1990s, it became known that Uranu ...
s. The New Worlds Mission will also find
moons A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are colloquially referred to as moons, a deriva ...
and rings 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 the
habitable zone In astronomy and astrobiology, the habitable zone (HZ), or more precisely the circumstellar habitable zone (CHZ), is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressu ...
s of parent stars.


Architecture

There are many possibilities for various New Worlds Missions, including *New Worlds Discoverer proposed to use an existing space telescope (like the
James Webb Space Telescope The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, Lis ...
), to find exoplanets. The size of the starshade could be optimized for the observing telescope. *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. *New Worlds Imager would use many spacecraft/starshades. This would allow observers to resolve the planet and obtain true planetary imaging.


See also

*
Aragoscope An Aragoscope is a telescope design based on diffraction around the edge of an occluding disc, named after French scientist François Arago. Concept The light diffracted around the edge of a perfectly circular occluder interferes constructively at ...
*
Coronagraph A coronagraph is a telescopic attachment designed to block out the direct light from a star or other bright object so that nearby objects – which otherwise would be hidden in the object's bright glare – can be resolved. Most coronagr ...
, a telescopic attachment to block out the light from a star so that nearby objects can be resolved *
Space sunshade A space sunshade or sunshield is something that diverts or otherwise reduces some of the Sun's radiation, preventing it from hitting the Earth and thereby reducing its insolation, which results in reduced heating. Light can be diverted by diff ...


References


External links


New World's official website at University of Colorado, BoulderFinding planets through a pinhole
{{Exoplanet search projects Diffraction Exoplanet search projects Proposed spacecraft Space telescopes Articles containing video clips NASA programs