Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




SPACE SCOPES
NASA Designs New Space Telescope Optics to Find a New Earth
by Staff Writers
Moffett Field CA (SPX) Feb 19, 2013


The PIAA system uses two specially designed non-spherical optics to reshape the light in the pupil of the telescope into a new "high-contrast" pupil pattern. Image credit: Dominic Hart.

Although hundreds of planets orbiting other stars have been discovered in the past 15 years, we cannot yet answer the age-old question of whether any of these planets are capable of sustaining life.

However, new NASA technology may change that, by giving us our first look at distant planets that not only are the right size and traveling in the temperate habitable zone of their host star, but also show signs of potential life, such as atmospheric oxygen and liquid water.

Research scientists at NASA's Ames Research Center, Moffett Field, Calif., are developing new space telescope optics that won't just detect planets similar to Earth, but actually take photos of them. To take photos, called "direct imaging," a new technology will be used called phase-induced amplitude apodization (PIAA).

In development since 2003, it is a proof-of-concept and technology tested prototype that is a strong candidate for NASA's upcoming direct imaging exoplanet missions expected to launch in the 2020 decade and beyond.

"By blocking the glare and diffraction from the star, we can start seeing planets that would otherwise be obscured. With this technology, direct imaging confirmation of a habitable zone exoplanet would happen for the first time," said Ruslan Belikov, a NASA astrophycist and technical lead for the coronagraph technical experiment at Ames.

Today, scientists use primarily indirect methods, such as the "transit method," to detect extra-solar planets. This method measures the dimming of a star as the planet passes between it and the telescope's line of sight.

By observing the changes in starlight, scientists can determine a planet's size, its distance from the host star, and the orbital period. This method is currently used by NASA's Kepler mission, which was launched in 2009 to find Earth-size, planets in the habitable zone.

In the future, however, a different approach in design and concept may be used to detect common biomarkers of life, such as oxygen and liquid water, on planets similar to Earth orbiting sun-like stars.

PIAA is a "direct imaging" technique, which means it takes actual photos of exoplanets. The difficulty in taking such photographs is that the star's brilliance causes diffraction and glare to overwhelm dim planets in orbit around it. To solve this problem, a telescope needs to suppress the diffraction of the starlight.

The PIAA system uses two specially designed non-spherical mirrors to reshape the light in the pupil of the telescope into a new "high-contrast" pupil pattern. This new high-contrast pupil has the special property of confining all diffraction and glare from the star into a small spot, which virtually blocks all the starlight without appreciably affecting the light from the planet.

This is typically done with instruments that block starlight and are called "coronagraphs" (originally invented to block our sun's brilliance, so we can see its outer gaseous envelope or corona). PIAA is a particularly powerful type of a coronagraph, approaching fundamental physics limits.

Telescopic optics have tiny imperfections, called aberrations, that cause unclear images of the star. Optics completely free of aberrations presently cannot be made, but can be corrected by separate mirrors that can actively change shape. "These mirrors are called deformable mirrors. They counteract the existing distortions of the telescope optics," explained Belikov.

PIAA, or coronagraphs in general, block the brilliance of starlight, but only can work sufficiently to reveal Earth-size planets if telescope optics are perfect, which they never are. The deformable mirrors correct these imperfections with their wavefront control system. This system "fixes" the imperfect telescope optics to enable the coronagraph to work properly.

At the Ames coronagraph experiment facility, the deformable mirror, built by Boston Micromachines Corp., Mass., is a one-by-one centimeter square that employs a grid of 32-by-32, or 1024 actuators, which can generate any shape desired on the mirror. By controlling the shape of the surface of the error-compensating deformable mirror, the aberrations in the telescope can be sufficiently reduced to allow Earth-size planets to be directly imaged.

"The surface of these deformable mirrors can be set to such high precision that we are incapable of measuring it," said Belikov.

Although PIAA is approved for further development, it still is awaiting a mission. It is designed for two classes of missions: one for small telescopes, the other for very large telescopes. A small telescope proposal, called Exoplanetary Circumstellar Environments and Disk Explorer (EXCEDE), was selected in September 2011 by NASA's Explorer program for evaluation as potential future science missions.

Led by the University of Arizona, Tucson and in partnership with Ames and Lockheed Martin SSC, Sunnyvale, Calif., EXCEDE will directly image circumstellar dust and debris, and large planets in habitable zones, but not planets similar to Earth. "EXCEDE will do amazing science and may be a precursor to a larger mission, but won't quite capture exoEarths," said Belikov."

To see Earth-like planets, a much larger telescope is needed. While the current focus of the Ames Coronagraph Experiment (ACE) team is on the EXCEDE mission, they also are collaborating with NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., to develop coronagraph technology for larger telescopes, capable of observing exo-Earths. Currently, there are two vacuum testbeds at JPL developing different kinds of coronagraph technologies.

Coronagraph technologies are typically developed in ambient conditions, rather than vacuum conditions. An ambient, stable, air-controlled, environment is a cheaper and faster development path than operating in a vacuum. Testing in vacuum conditions, however, is desirable because they are similar to conditions in space. Once these coronagraph technologies are tested in ambient conditions, they then are ready to be tested on vacuum testbeds.

"The ACE testbed is in air, not in a vacuum. Our team has advanced the technology for the EXCEDE mission to the point where it is ready for vacuum testing," said Belikov.

So what are its prospects?
Recently, the National Academy of Sciences produced a 2010 decadal survey that endorsed the Wide-Field Infrared Survey Telescope (WFIRST) mission as its large mission in the 2020 decade. NASA accepted this recommendation.

"Presently, it does not include a coronagraph to do direct imaging of exoplanets. But things can change," predicted Belikov.

It also seems promising that two 2.4 meter Astrophysics Focused Telescope Assets (AFTA) telescopes were given to NASA last year by another federal agency. If one of these telescopes becomes the WFIRST mission, its telescope size will be larger than originally planned. If this happens, and the mission has a powerful enough coronagraph, it may be able to survey the nearest stars for habitable exoEarths, according to Belikov.

"With sustained funding, NASA will be capable of launching a telescope large enough to find and characterize basically all the habitable planets around our galactic neighborhood, say the nearest hundreds of stars, within the 2030 decade," concluded Belikov.

For more information about EXCEDE, visit here and here.

.


Related Links
WFIRST
Space Telescope News and Technology at Skynightly.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





SPACE SCOPES
Dichroic Beamsplitter Directs Telescope Stargazing
La Palma, Chile (SPX) Feb 12, 2013
Optical Surfaces has manufactured and supplied a 180mm diameter dichroic beamsplitter that will form a key component of the adaptive optics currently being integrated with the Gran Telescopio de Canarias (GTC). The Gran Telescopio de Canarias is a 10.4m reflecting telescope with a segmented primary mirror. It is located at the Roque de los Muchachos Observatory on the island of La Palma, o ... read more


SPACE SCOPES
Building a lunar base with 3D printing

US, Europe team up for moon fly-by

Russia to Launch Lunar Mission in 2015

US, Europe team up for moon fly-by

SPACE SCOPES
Bleach could hamper Mars life search

At the mouth of the red valley

NASA's MAVEN Mission Completes Assembly

Rover Walkabout Continues at Cape York

SPACE SCOPES
NASA Spinoff 2012 Features New Space Tech Bettering Your Life Today

Orion Lands Safely on Two of Three Parachutes in Test

Supersonic skydiver even faster than thought

Ahmadinejad says ready to be Iran's first spaceman

SPACE SCOPES
Welcome Aboard Shenzhou 10

Reshuffle for Tiangong

China to launch 20 spacecrafts in 2013

Mr Xi in Space

SPACE SCOPES
Low-Gravity Flights Will Aid ISS Fluids and Combustion Experiments

Progress docks with ISS

NASA to Send Inflatable Pod to International Space Station

ISS to get inflatable module

SPACE SCOPES
Another Sea Launch Failure

ILS Concludes Yamal 402 Proton Launch Investigation

Ariane 5 delivers record payload off back-to-back launches this week

Eutelsat and Arianespace sign new multi-year multiple launch services agreement

SPACE SCOPES
Earth-like planets are right next door

Direct Infrared Image Of An Arm In Disk Demonstrates Transition To Planet Formation

Kepler Data Suggest Earth-size Planets May Be Next Door

Earth-like planets may be closer than thought: study

SPACE SCOPES
Researchers strain to improve electrical material and it's worth it

Explosive breakthrough in research on molecular recognition

Indra Develops The First High-Resolution Passive Radar System

ORNL scientists solve mercury mystery




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement