NASA Moon Dust Probe Begins Lunar Science Mission

NASA's newest lunar probe has officially begun its mission to study the moon's tenuous atmosphere like never before, as well as track how dust moves across the lunar sky.

The Lunar Atmosphere and Dust Environment Explorer, nicknamed LADEE for short, entered its science orbit on Wednesday (Nov. 20). The spacecraft now circles the moon once every two hours in an orbit, approaching within a mere 8 miles (12 kilometers) at its closest point and soaring 37 miles (60 km) overhead at its highest point, NASA officials said.

The $280 million LADEE spacecraft launched from a Virginia spaceport Sept. 6 and is expected to spend about 100 days probing the structure and composition of the thin atmosphere of the moon. 

"A thorough understanding of the characteristics of our lunar neighbor will help researchers understand other small bodies in the solar system, such as asteroids, Mercury, and the moons of outer planets," said LADEE program scientist Sarah Noble, at NASA Headquarters in Washington, in a statement Thursday (Nov. 21).

LADEE's orbit carries the car-size spacecraft around the moon's equator, allowing the probe repeatedly see the moon during lunar day and night. Scientists hope it will be able to see strange, glowing "rays and streamers" in the moon's atmosphere that were first seen in early unmanned lunar photographs and reports from Apollo lunar landing astronauts.

The spacecraft also carries a novel laser communications system to test high-speed data transmission technology for future space missions.

The LADEE spacecraft's low orbit around the moon requires meticulous attention to keep the probe from falling victim to the strange, lumpy lunar gravity.

"Due to the lumpiness of the moon's gravitational field, LADEE's orbit requires significant maintenance activity with maneuvers taking place as often as every three to five days, or as infrequently as once every two weeks," said Butler Hine, LADEE project manager at NASA's Ames Research Center in Moffett Field, Calif., said in a statement. "LADEE will perform regular orbital maintenance maneuvers to keep the spacecraft’s altitude within a safe range above the surface that maximizes the science return."

Source of Article: Space.com

How Humanity Could Deflect a Giant Killer Asteroid

Humanity has the skills and know-how to deflect a killer asteroid of virtually any size, as long as the incoming space rock is spotted with enough lead time, experts say.

Our species could even nudge off course a 6-mile-wide (10 kilometers) behemoth like the one that dispatched the dinosaurs 65 million years ago. We'd likely have to slam multiple spacecraft into a gigantic asteroid over a period of several decades to do the job, but the high stakes would motivate such a strong and sustained response, researchers say.

"If you can hit it with a kinetic impactor, you can hit it with 10 or 100 of them," former NASA astronaut Ed Lu, chairman and CEO of the nonprofit B612 Foundation, which is devoted to protecting Earth against asteroid strikes, said during a news conference last month.

"And I would submit to you that if we were finding an asteroid that's going to wipe out all life on Earth, or the majority of life on Earth, that funding is not an issue for launching 100 of them," Lu added.

Undiscovered asteroids

Lu and four other spaceflyers spoke Oct. 25 at the American Museum of Natural History in New York City. A primary purpose of the event was to draw attention to the danger asteroids pose to human civilization and life on Earth, and to discuss ways to mitigate the threat.

Earth has been pummeled by space rocks repeatedly over the eons and will continue to get hit, a reality that was reinforced in February when a 55-foot-wide (17 meters) space rock exploded in the atmosphere over the Russian city of Chelyabinsk, injuring more than 1,000 people.

The Russian meteor came out of nowhere, evading detection by the various instruments that are scanning the heavens for potentially hazardous objects. And there are many more such space rocks out there, gliding through deep space unknown and unnamed. 

To date, scientists have discovered about 10,000 near-Earth objects, or NEOs — just 1 percent of the 1 million or so asteroids thought to come uncomfortably close to our planet at some point in their orbits. So the top priority of any asteroid-defense effort should be a stepped-up detection campaign, Lu said.

"Our challenge is to find these asteroids first, before they find us," he said. "You cannot deflect an asteroid you haven't yet found."

To make progress on the detection front, the B612 Foundation is developing a privately funded infrared space telescope called Sentinel, which will search for asteroids from a Venus-like orbit. The group aims to launch Sentinel in 2018 and says it will likely find 500,000 NEOs in less than six years of operation.

Deflecting dangerous space rocks

Scientists hope Sentinel and other asteroid-hunting instruments will spot dangerous NEOs several decades before they could potentially slam into Earth.

That's enough lead time to mount a successful deflection effort, which would likely involve launching two separate space missions, former Apollo astronaut and B612 co-founder and chairman emeritus Rusty Schweickart told SPACE.com earlier this year.

The first mission, he said, would send a robotic probe on a collision course with the asteroid, knocking it off course via kinetic impact. The second would follow up, launching a "gravity tractor" spacecraft to fly along with the space rock, nudging it further via a tiny but consistent gravitational tug.

Such a strategy would probably work on asteroids up to 1,300 feet (400 m) wide, Schweickart said at the Oct. 25 press conference. Anything bigger than that likely demands a different response, he added, such as a series of kinetic impacts or blasting the asteroid with a nuclear bomb.

Infrequent events

Colossal asteroid impacts that cause mass extinctions are extremely rare events. For example, strikes like the one that killed off the dinosaurs (and roughly 80 percent of all Earth's species) 65 million years ago happen roughly once every 100 million years, Schweickart said.

But smaller (and much more frequent) strikes can still be devastating. In 1908, an object thought to be just 130 feet (40 m) wide, or perhaps even smaller, exploded above the Podkamennaya Tunguska River in Siberia, flattening roughly 770 square miles (2,000 square km) of forest.

Impacts like the "Tunguska Event" — which would have destroyed New York City, Tokyo or any other metropolis if they had been in the asteroid's crosshairs — occur once every 300 years on average, Schweickart said.

So it makes sense to focus on city-killers and other relatively small asteroids rather than the behemoths when thinking about how to deflect space rocks — especially since the true giants are so easy to spot.

"We're not going to be surprised by something that large," Schweickart said of asteroids like the dinosaur-killer. "We will have lots of time to worry about it, or mix our martinis, or whatever we're going to do."

Source of Article: Space.com

How to Photograph Comet ISON: A Skywatching Photo Guide

The incoming Comet ISON is undergoing dramatic brightening as it heads toward its Thanksgiving Day rendezvous with the sun, but if you are hoping to snap photos of the icy wanderer, you'll need to be prepared.

Officially known as C/2012 S1 (ISON), Comet ISON was discovered in September 2012 and has been billed by some as a potential "comet of the century" because of its potential to flare up into a brilliant night sky object. It is already visible to the naked eye for observers in dark-sky sites and is now sporting a long tail.

If this icy cosmic visitor survives its fiery solar encounter on Thursday (Nov. 28), when it swings within 730,000 miles (1.2 million kilometers) of the sun's surface, it could reappear in the dawn sky in early December as a potentially spectacular naked-eye object for skywatchers in the Northern Hemisphere.

But comets are notorious for their unpredictability, as shown by Comet Kohoutek C/1973 E1 in the early 1970s, which failed to meet predictions. As our good friend and famed comet discoverer David H. Levy likes to say, "Comets are like cats; they have tails, and they do precisely what they want."

This uncertainty, however, has failed to dampen the interest and excitement of the public and the media in Comet ISON. So if you want to capture your own souvenir portrait of this first-time visitor to our solar system, here are some tips to keep in mind to increase your chances of success:

• Look for a site away from city lights that offers a clear, unobstructed view of the southeastern horizon about an hour or so before sunrise. With each passing day, the comet will plunge deeper and deeper into the brightening dawn sky as it makes its closest approach to the sun, called "perihelion," on Nov. 28. After it emerges from perihelion, the comet will climb higher and higher in the dawn sky, but at the same it will start to fade as it recedes from the sun and Earth.

WARNING:Do not attempt to observe or photograph Comet ISON when it is very close to the sun or is at perihelion. Staring directly at the sun, especially through a camera, telescope or binoculars without a proper, safe filter can result in serious eye injury or permanent blindness. No comet is worth losing your eyesight, so please be very careful!

Use a digital single-lens reflex DSLR camera to photograph the comet since it gives you more control on your focus and exposure settings. It also allows you to change lenses, from wide-angle to medium telephoto, to match the length of the comet’s tail.

• Since the comet would require exposures lasting a few seconds or more, you would need a sturdy tripod or mount to steady your camera setup.
   
• Switch your camera mode from Auto (A) to Manual (M) so you’ll be able to control its focus as well as lens aperture, shutter speed and white-balance settings. Set the camera to its highest resolution (RAW mode) so you can capture as much fine details and color information as possible. Consult your camera manual on how to change settings.
   
• Comets are inherently fuzzy objects so don’t rely on them for focusing your camera. To ensure sharp images, pre-focus the camera on Mars, Mercury or Saturn, or the bright star Spica. Use your camera's Live View feature, if it has one, to achieve accurate focus.
   
• You can minimize vibrations that can blur your images by using your camera’s mirror lock-up feature before each shot. You should also operate the shutter with an electronic cable release to eliminate camera shake.
   
• Boost your camera’s sensitivity to ISO 800, or higher. You would want to keep your exposures relatively short, especially if you are using your DSLR on a plain, fixed tripod. This will not only prevent the images of the comet and background stars from trailing due to Earth’s rotation, but it will also keep the brightening dawn sky from washing out the scene.
   
• Don’t forget to "bracket" your exposures — that is, take a series of shots of the comet at various shutter speeds and/or apertures. This will increase your chances of getting the correct exposure.
   
• Make sure your camera battery is fully charged, and put your spare battery in your jacket's inside pocket to keep it warm — cold temperatures at dawn can cause your battery to quickly lose its charge.
   
• When composing your shot, try to include some interesting visual elements in your foreground, such as a person, a tree or a monument silhouetted against the horizon.

If you want to capture detailed shots of the comet and record the full extent of its tail, you will need to use a more elaborate tracking system than the simple camera-on-tripod setup we just described, and may need binoculars or a telescope:
 

• Use a zoom or telephoto lens with a focal length of 400 millimeters or more to give you a fairly large image of the comet and its tail in the camera frame.
   
• The long-focus lens will magnify the comet's movement in the sky so you will have to mount your setup on a polar-aligned, motor-driven equatorial mount. The motor drive will “track” the comet and keep it centered in your camera’s field, allowing you to take exposures lasting several minutes.
   
• Alternatively, you can use a ball-head mount or a bracket to mount your camera/lens setup securely to a hefty telescope on a heavy-duty mount. In this "piggyback" mode, the telescope serves as a stable tracking platform for the camera.
   
• Use the camera’s Bulb (B) setting to take exposures longer than 30 seconds.
   
• Depending on your sky brightness, you can shoot a single long exposure or take a series of short exposures that you can later “stack” together digitally using an image-editing program, such as Adobe Photoshop, to create effectively one long exposure.
   
• For really close-up views of the comet’s head and tail structure, you need to shoot through a long-focus telescope on an equatorial drive. Attach the DSLR camera body securely to the telescope using a T-threaded adapter and a T-ring that is appropriate for your camera brand. Check your local camera supply store for these handy accessories.
   
• At such high magnification, any inaccuracies in the telescope’s drive system or polar alignment will be evident. That is why deep-sky astrophotographers use an "autoguider," an automated electronic guiding system that attaches to the telescope’s off-axis guider or guidescope. The autoguider can "lock" onto the comet’s head or selected guide star, and it will make automatic adjustments to the telescope’s drive system continuously throughout the exposure to ensure accurate tracking.

Assuming Comet ISON doesn't disintegrate before reaching the sun, the comet will continue on its outbound journey into deep space, never to return again for a long, long time. So don't miss this once-in-a-lifetime opportunity to catch Comet ISON now.

Source of Article: Space.com

New US Space Transportation Policy Stresses Private Spacecraft, Heavy-Lift Rocket

The Obama administration has outlined its strategy for maintaining what it describes as the United States' global leadership role in spaceflight and exploration.

The White House's new national space transportation policy, released Thursday (Nov. 21), reinforces several previously stated administration priorities. It calls on federal agencies to continue supporting the development of private American spaceships to carry astronauts to and from low-Earth orbit, for example, and directs NASA to keep working on a heavy-lift rocket to send people much farther afield.

This plan makes a lot of sense for NASA, allowing the agency to put its limited financial resources to the best possible use, NASA chief Charles Bolden said.

"The development of a commercial space sector for low-Earth orbit transportation is freeing NASA to develop a heavy-lift launch capability to travel further into space than ever before," Bolden wrote in a blog post about the new policy Thursday.

"NASA has already made steady progress on the development of the next-generation heavy-lift launch vehicle, the Space Launch System (SLS)," he added. "NASA is also well on its way to developing the Orion crew capsule, which will take astronauts further into deep space than humans have ever explored."

The maiden Orion test flight is slated for next year, while the SLS is scheduled to get off the ground for the first time in late 2017. NASA wants the duo to be flying astronauts together by 2021.

That would allow the space agency to meet two objectives President Barack Obama laid out for NASA in his 2010 National Space Policy — to get astronauts to a near-Earth asteroid by 2025, then on to the vicinity of Mars by the mid-2030s.

While it works on this deep-space transportation system, NASA is also encouraging the growth of an emerging private spaceflight industry. Through its commercial crew program, the agency has most recently funded the development of three private manned spaceships — those being built by SpaceX, Boeing and Sierra Nevada Corp. — and hopes at least one of them is up and running by 2017.

Leaders in the commercial spaceflight industry were pleased to see continued support for this effort in the new policy.

"We appreciate this clear delineation of policy in favor of supporting American industry, creating the most effective and efficient space program possible and ensuring the nation retains its leadership and competitiveness in space," Michael Lopez-Alegria, president of Commercial Spaceflight Federation and a former NASA astronaut, said in a statement. "We are grateful for the Obama Administration’s support for the commercial space sector and look forward to many joint successes to come."

The newly released space transportation policy, which replaces a version announced in 2004, is a wide-ranging document touching on many different aspects of American space infrastructure.

Source of Article: Space.com

Stephen Hawking Says Not Finding Higgs Boson Would Be 'More Interesting'

The discovery of the once-elusive Higgs boson particle after a decades-long hunt is widely regarded as a major breakthrough, but legendary physicist Stephen Hawking thinks the field would actually be more "interesting" if the Higgs had remained a mystery.

"Physics would be far more interesting if it had not been found," Hawking told an audience at the Science Museum in London this week, according to The Guardian.

The Higgs boson is an elementary particle that is thought to explain why other fundamental particles have mass. Its discovery in July 2012, at the Large Hadron Collider housed at CERN's physics lab in Geneva, Switzerland, represented the final piece of the puzzle predicted by the Standard Model, the reigning theory of particle physics. 

Last month, the Royal Swedish Academy of Sciences awarded the Nobel Prize in physics to Francois Englert of Belgium and Peter Higgs of the United Kingdom, for their research in 1964 on the theory of particle masses, which established the foundation for the discovery of the Higgs particle.

But, had the Higgs not been found, physicists might have been required to rethink some of the prevailing ideas about the nature of particles, launching investigations into other "interesting" and tantalizingly unanswered questions, Hawking suggested.

Still, the search for the Higgs boson, and its subsequent discovery, received widespread attention, including early debates about whether the long-sought particle had actually been detected or not.

Hawking's initial doubts about the discovery ended up costing him. "I had a bet with Gordon Kane of Michigan University that the Higgs particle wouldn’t be found," Hawking said, as reported by The Guardian. "The Nobel prize cost me $100."

Hawking spoke at an event earlier this week to celebrate the opening of a new exhibit about the Large Hadron Collider, the world's largest atom smasher, at the Science Museum in London.

In addition to talking about the discovery of the Higgs particle, Hawking discussed some of the other theories he hopes will be probed by scientists at CERN.

One is supersymmetry, a popular theory based on the idea that all of the known subatomic particles have "superpartner" particles that have yet to be observed. If these superpartners do exist, scientists could begin to explain some of the most enigmatic riddles in physics, such as the nature of dark matter, which is an invisible substance thought to make up a quarter of the universe. Scientists think dark matter may be composed of as-yet-undetected supersymmetric particles.

"I think the discovery of supersymmetric partners for the known particles would revolutionize our understanding of the universe," Hawking said.

Source of Article: Space.com

NASA's MAVEN Mission to Mars: 5 Things to Know

NASA is all set to launch its next mission to Mars on Monday (Nov. 18), provided the weather cooperates and no unexpected glitches pop up.

The Mars Atmosphere and Volatile EvolutioN orbiter, or MAVEN for short, is slated to blast off atop an Atlas 5 rocket at 1:28 p.m. EST (1828 GMT) Monday from Florida's Cape Canaveral Air Force Station. You can watch MAVEN's launch on SPACE.com, courtesy of NASA TV.

As its name suggests, MAVEN will make detailed measurements of the Red Planet's atmosphere from orbit, helping scientists understand why and how Mars' climate has changed so dramatically over the last few billion years. It will take about 10 months to reach Mars, and arrive at the Red Planet in September 2014.

Here are some key facts to keep in mind about the MAVEN probe and its $671 million mission:

MAVEN is big

The solar-powered MAVEN spacecraft is pretty hefty. While the probe's body is a cube measuring 8 feet (2.4 meters) on a side, MAVEN spans a total of 37.5 feet (11.4 meters) with its solar panels deployed, making the craft as long as a school bus.

And MAVEN weighs 5,410 pounds (2,454 kilograms) — as much as a fully loaded sport utility vehicle.

Elliptical orbit

When MAVEN gets to Mars, the probe will insert into an elliptical orbit around the planet that brings it as close as 93 miles (150 kilometers) and reaches as far away as 3,728 miles (6,000 km).

In addition, MAVEN will make a handful of "deep dips" during the course of its mission, coming within 77 miles (124 km) of the Martian surface on five separate occasions. MAVEN will thus be able to sample the Red Planet's upper atmosphere directly and get a wider view of the entire planet from afar — a powerful combination, NASA officials say.

Solving a Martian mystery

Mars was a potentially habitable planet billions of years ago, with a thick atmosphere and large amounts of liquid water flowing across its surface. But then something happened, and the Red Planet transitioned to the cold and dry world we know today, with an atmosphere just 1 percent as dense as that of Earth.

Scientists hope MAVEN helps them get a better handle on this dramatic shift. The mission aims to determine how and why much of the Martian atmosphere was lost to space, and what role this loss played in Red Planet climate change over the last four billion years.

MAVEN will use eight different science instruments to study Mars' upper atmosphere and the solar wind, the stream of charged particles flowing from the sun that is thought to have stripped away much of the water and other volatile compounds in the Red Planet's air.

Not a Mars life hunt

While MAVEN's observations should help researchers better understand Mars' past and present habitability, the mission will not actively search for signs of life.

In fact, MAVEN is not equipped to sniff for methane, a gas that could be an indicator of extant life. (About 90 percent of Earth's methane is produced by living organisms.) MAVEN's budget could not support adding a methane-detection component, mission scientists have said.

Communications link

While NASA is most excited about the data MAVEN will gather, the spacecraft will also serve the space agency in another way — as a communications relay beween rovers on Mars and their handlers on Earth.

NASA currently has two rovers exploring the Red Planet's surface — the car-size Curiosity, which touched own in August 2012, and its smaller cousin Opportunity, which landed in January 2004. MAVEN will augment data relay from the two robots, which is currently provided by two NASA orbiters — Mars Odyssey, which launched in 2001, and the Mars Reconnaissance Orbiter (MRO), which blasted off in 2005.

This relay capability helped the MAVEN mission stay on track despite last month's government shutdown, which forced NASA to furlough 97 percent of its employees and cease most operations. While MAVEN launch preparations were halted at the beginning of the 17-day shutdown, the space agency granted the mission an emergency exception two days later, chiefly because of its importance as a communications link. (The agency has no relay orbiters on the books beyond MAVEN.)

Source of Article: Space.com

Incredible Technology: How Future Space Missions May Hunt for Alien Planets

NASA's Kepler space telescope revolutionized the study of alien worlds after launching in 2009, and a number of other missions now stand poised to carry the burgeoning field into the future.

Over the next decade, NASA and the European Space Agency (ESA) aim to launch a handful of spacecraft that should discover thousands of additional exoplanets and characterize some of the most promising — the most apparently Earthlike — new finds in detail.

These future missions are all following in the footsteps of Kepler, whose observations have revealed that the Milky Way galaxy is jam-packed with alien planets. The instrument has spotted more than 3,500 planet candidates to date; just 167 of them have been confirmed by follow-up observations so far, but mission scientists expect about 90 percent will end up being the real deal.

Kepler's original planet-hunting activities came to an end this past May when the second of its four orientation-maintaining reaction wheels failed, robbing the spacecraft of its ultra-precise pointing ability. But the instrument may continue its planet search in a modified and limited fashion, as part of a possible future mission dubbed K2.

NASA is expected to make a final decision about K2, and Kepler's ultimate fate, around the middle of next year. By then, the first member of the exoplanet new wave will already be aloft — Europe's Gaia mission.

Gaia: The billion-star surveyor

ESA's Gaia spacecraft is slated to blast off from French Guiana next month; its launch window extends from Dec. 17 through Jan. 5.

Gaia will head to a gravitationally stable spot about 900,000 miles (1.5 million kilometers) from Earth called the sun-Earth Lagrange Point 2. Over the next five years, the spacecraft will repeatedly measure the position, movement and brightness changes of more than 1 billion Milky Way stars — about 1 percent of the galaxy's total.

"This huge stellar census will provide the data needed to tackle an enormous range of important problems related to the origin, structure and evolutionary history of our galaxy," ESA officials write in a description of the Gaia mission.

Exoplanet science should be one of the fields that benefits. The Gaia mission, whose total cost is 740 million euros (about $990 million), could potentially detect tens of thousands of new planetary systems, researchers say.

Cheops: A follow-up machine

ESA will likely launch another exoplanet mission, called Cheops (short for CHaracterizing ExOPlanets Satellite), four years after Gaia gets off the ground.

Like Kepler, Cheops will watch for exoplanet "transits," gathering data when alien worlds cross the face of their parent stars from the instrument's perspective. But the similarities mostly end there. While Kepler stared at more than 150,000 stars simultaneously, Cheops will target one star at a time. And its chief aim is the follow-up study of known exoplanets, rather than the discovery of previously unknown worlds.

"Knowing when to look, and at which star, will make Cheops extremely efficient at providing first-step characterization of low-mass exoplanets by measuring accurate radii and densities," David Ehrenreich, of the University of Geneva, said Nov. 6 during a presentation at the second Kepler Science Conference at NASA's Ames Research Center in Moffett Field, Calif.

Another key goal of Cheops, Ehrenreich added, is "collecting the 'golden targets' for future in-depth characterization by, for instance, the James Webb Space Telescope."  

Cheops' total cost is about $134 million (100 milllion Euros), Ehrenreich said. Formal adoption of the mission is expected in the next few months, with launch targeted for late 2017.

The Transiting Exoplanet Survey Satellite

NASA is developing its own mission for launch in 2017. The agency'sTransiting Exoplanet Survey Satellite, or TESS, aims to look for planets crossing the face of about 500,000 stars during its planned two-year operational life.

While Kepler scanned stars 1,000 or so light-years away, the $200 million TESS mission will look much closer to home. It will focus on stars within 100 light-years of Earth, with the goal of finding planets that will be easier to study and characterize with future instruments such as NASA's James Webb Space Telescope (JWST).

And TESS should discover plenty of new worlds. Team members expect to find about 315 the size of Earth or a little larger, 710 planets a bit smaller than Neptune, 1000 Neptune-like worlds and 660 Jupiter analogs, mission principal investigator George Ricker of MIT said Nov. 6 at the Kepler Science Conference.

"It's really a bridge to the future," Ricker said of TESS. "We're really, obviously, following on from Kepler. And because of the way in which there's a focus on providing targets that are going to be optimal in place for the continuous viewing zone for JWST, there's clearly going to be a linkage between providing information that'll be useful to that mission."

Hubble's long-awaited successor: JWST

Researchers have high hopes for JWST, the $8.8 billion infrared-optimized telescope that NASA hopes to launch toward the end of 2018.

Scientists plan to point JWST at the most promising and intriguing exoplanets that have been discovered in Earth's cosmic neck of the woods, using the powerful instrument to scan these worlds' atmospheres for water vapor and gases that may have been produced by living organisms, such as oxygen, nitrous oxide and methane. 

JWST should also make contributions in many other arenas, NASA officials say, shedding light on the early history of the universe and improving researchers' understanding of the formation and evolution of stars, galaxies and planetary systems.

WFIRST-AFTA

The outlook for space-based exoplanet science gets a little cloudy beyond JWST, but both NASA and ESA have some potential projects in the works.

NASA, for example, is working on a $1.6 billion observatory called the Wide-Field Infrared Survey Telescope. In 2010, the U.S. National Research Council deemed WFIRST the top priority for the next decade of astronomical research.

The current mission design, called WFIRST-AFTA (short for Astrophysics Focused Telescope Assets), calls for the observatory to incorporate one of two spy-satellite telescopes given to NASA by the U.S. National Reconnaissance Office in 2011.

The donated scopes are similar in size and appearance to NASA's iconic Hubble Space Telescope, sporting 8-foot-wide (2.4 meters) primary mirrors. The instruments are far from flight-ready spacecraft, however; they're basically just primary and secondary mirrors with associated support structures.

WFIRST-AFTA would probe the nature of mysterious dark energy and hunt for and study alien planets using two techniques: direct imaging and gravitational microlensing. In this latter method, astronomers watch what happens when a massive object passes in front of a star; the closer object's gravitational field bends and magnifies the star's light, acting like a lens.

The mission could find thousands of exoplanets using microlensing alone, said Matthew Penny of Ohio State University. Current plans call for WFIRST-AFTA to launch in 2023 or thereabouts, but the proposed mission remains in a sort of limbo at the moment, he added.

"There's going to be no funding for [other] large missions until JWST is launched," he said Nov. 6 at the Kepler Science Conference. "After that, NASA will have to ask Congress, I think, to fund the next large mission."

Plato

ESA may launch its own large-scale exoplanet mission at about the same time WFIRST-AFTA gets off the ground. The Europeans are developing a project called Plato (PLAnetary Transits and Oscillations of stars), with a possible liftoff in the 2022-2024 timeframe.

Like Kepler, Cheops and TESS, Plato will use the transit technique. The mission's main goal is to find and characterize large numbers of nearby planetary systems, getting accurate sizes and masses of alien worlds — many of which may lie in their host star's habitable zone, that just-right range of distances where liquid water can exist on a planet's surface.

"We want to completely characterize low-mass planets out to the habitable zone, being able to know about the internal composition, the density, the age of the system," Stephane Udry of the University of Geneva said Nov. 6 at the Kepler Science Conference.

Plato is one of five proposed "medium-class" missions — whose cost to ESA is capped at 470 million euros, or about $630 million — the agency is considering for the 2022-2024 launch slot. ESA will select one of these five in February 2014, officials have said.

Source of Article: Space.com