The Giant Magellan Telescope (GMT) Consortium of 16 universities and research institutions held their first ever summit on April 14th. The summit acted as a way to update academics, the media and the public on how design and construction of the telescope is proceeding following the National Science Foundation (NSF) officially advancing the project to its final design phase in the summer of 2025.

"This is one of the final steps that the project must take before it can be considered for federal funding," Daniel Jaffe, who is the President of the GMT Consortium and a former head of astronomy at the University of Texas, Austin, said during the summit. "Over the past five years the telescope has passed every independent, federally required review. Now my immediate focus is in successfully completing the NSF's final design phase by mid-2027. Pending approval by the NSF and Congress, the Giant Magellan Telescope will enter the beginning of full-scale construction in the fiscal year 2028."

The GMT is one of three telescopes roughly in the thirty-meter (~98 feet) class that should come online in the 2030s. The Extremely Large Telescope (ELT) being built by the European Southern Observatory in Chile is already under full-scale construction and its 39-meter (128 feet) should be the first to enter service in 2029.

Complications

For the GMT and another huge next-gen telescope, called the Thirty Meter Telescope (TMT), the situation is more complex. Both are American telescopes being funded, at least in part, by the NSF. However, in 2024, the NSF had its giant-telescope budget capped at $1.6 billion, which is not enough to fully fund both observatories. This has sent both projects looking towards private and overseas donations.

Jaffe revealed that more than a billion dollars has so far been invested into the GMT project by its partners.

"These contributions, largely made possible by donors and supporters around the world, have enabled 40% of the telescope's components to be in active fabrication and assembly," said Jaffe.

On the Las Campanas mountain top, 7,870 feet (2,400 meters) above sea level in Chile's Atacama desert, which enjoys a darker, drier and more stable night sky than almost anywhere else in the world, the GMT's foundations have already been dug, and roads, utilities and support structures put in place. In Rockford, Illinois, engineers at Ingersoll Machine Tools are constructing the huge mount that will hold the seven 8.4-meter primary mirrors, the seven 1-meter secondary mirrors, and the science instruments. The mount, when finished, will stand 128 feet (39 meters) tall (coincidentally the size of the ELT's entire mirror) and weigh 2,600 tons. It's so large that the company had to construct a special 40,000 square foot (3,700 square meter) manufacturing and assembly bay just to house it.

The mirrors, meanwhile, form a unique optical design. Both the ELT and TMT are going with one huge mirror formed out of many segments joined together, but as mentioned in the preceding paragraph the GMT's primary reflecting surface is made up of seven individual large mirrors, each a little larger in size than the mirror on the Subaru Telescope in Hawaii, for example. In fact, they are the largest single telescope mirrors ever made. By contrast, the primary mirrors on the W.M. Keck 10-meter telescopes are made of segments rather than one solid single mirror.

This design, said GMT's Chief Scientist Rebecca Bernstein, has several advantages, not least how it helps the telescope's adaptive optics.

Adaptive optics describes how telescope mirrors can make minute changes in their shape to counteract the twinkling of stars by the atmosphere.

The GMT is essentially a huge version of the reflector telescope that you might use in your backyard. In the case of amateur telescopes, the light bounces off the primary mirror and is reflected by a smaller secondary mirror to a focal point at the eyepiece. In the case of the GMT, the seven primary mirrors are mirrored, pardon the pun, by seven smaller secondary mirrors that are deformable.

"They are a game changer," said Bernstein. "The secondary mirrors are complex structures, 2mm thick and 1 meter in diameter. Attached to the back of each mirror are about 700 tiny magnets that are pushed and pulled by electromagnetic coils to enable the mirrors to change their shape thousands of times per second to remove the atmospheric jitter."

Those seven primary mirrors, operating in unison alongside the secondary mirrors and adaptive optics, will bring new eyes onto the universe. Exoplanets in the habitable zone of distant stars are a key target. Giant Magellan will detect and characterize Earth-Like planets using an instrument called the GMT-Consortium Large Earth finder (G-CLEF) that taps into the transit method as well as an instrument with a coronograph called GMag-AOx.

A coronagraph can block the light of a star, isolating the light of any planets around that star, allowing spectroscopic measurements of that planet's light.

At the other end of the scale, entire galaxies in the distant universe will come under scrutiny.

"We know that galaxies, and the stars and planets within them, form from vast clouds of gas drawn together by gravity," said Gwen Rudie, who is an astronomer at the Carnegie Institution of Science in California. As massive stars go supernova they drive that gas back out again, leading to a cycle of gas falling in, forming stars and then being blown away again.

"This cycle is not yet understood because the gas has been too challenging to see," said Rudie. "The GMT will let us study galaxies at tremendous distances, which means peering back in time 10 or 11 billion years ago when galaxies were forming stars the fastest. It will revolutionize our understanding by creating the first maps of gas surrounding individual galaxies. We'll be able to peer into the hearts of these young galaxies to connect the sites of star-birth and star-death directly to these gas flows."

However, as excited as Rudie is about the potential for these observations, she is even more excited about the unexpected things that the GMT might find.

"I believe the most remarkable discoveries that the GMT will make will be the ones that we haven't even imagined yet," said Rudie. "There's no telling what we'll find."

However, all this potential will be lost if design and construction on the GMT isn't completed. Even with federal funding hopefully granted by the U.S. Congress, it won't be enough, and Jaffe says that the project is looking to enlarge the current 16-strong consortium and encourage even further private investment to fund the estimated total of over $2 billion to build and operate the telescope.

"This will bring in more resources and added brain-power to drive discovery, leading to science observations in the 2030s," said Jaffe.

With luck, all three giant telescopes will be fully funded, constructed and in operation by the mid-2030s. Between them, and working with other established observatories such as Rubin and the James Webb Space Telescope, they promise to transform our understanding of stars, galaxies and the potential for life beyond Earth.

Correction 4/22: There are two instruments that will help the Giant Magellan Telescope hunt for exoplanets: G-CLEF and GMag-AOx. Only the latter has a coronagraph. This article has been updated to reflect that.

AXIS, the Advanced X-ray Imaging Satellite, was one of two concepts selected for detailed design studies in NASA’s Astrophysics Probe Explorer program, competing alongside the far-infrared observatory concept PRIMA. AXIS could have replaced NASA's aging Chandra observatory, which has remained a powerhouse of X-ray astronomy since 1999, but the project is coming to an abrupt halt.

An internal email sent on March 9 from AXIS Principal Investigator Christopher Reynolds informed the mission's international team members that NASA Headquarters has ruled the program ineligible for selection, ending the project’s run before its concept study could undergo full technical review.

"NASA's decision was NOT a judgment of the importance of AXIS science," Reynolds said in the email, which was posted to social media. He said that AXIS’ removal from eligibility was tied to disruptions at NASA’s Goddard Space Flight Center (GSFC) in Maryland, which managed the mission during a period of sweeping workforce losses and operational instability throughout 2025.

"The mission formulation process was critically compromised by the seismic shifts occurring in NASA and the Federal government," Reynolds wrote.

One major setback was brought on by the early retirement of Will Zhang, a scientist that NASA describes as a "mirror-making whiz" for space telescopes.

"The key enabling technology for AXIS is these single-crystal silicon mirror assemblies, pioneered by Will Zhang at GSFC," a Goddard scientist familiar with the matter, but not authorized to speak on behalf of NASA, told Space.com. "Will was always intending to retire soon but he took the DRP."

"Our intent, established in the opening days of the Phase A study, was to build three medium-fidelity assemblies," Reynolds told Space.com in an email. "By the time we reached "pens down" on the proposal, we had built one such assembly," he said, but team continued taking hits.

"It seemed like every week there was an announcement that someone was leaving the AXIS team due to retirement or finding a different job, all because of the uncertainty with NASA funding and the truly chaotic environment at GSFC," the scientist said.

The project lost more than 20 GSFC personnel with key expertise as a result of NASA's Deferred Resignation Program (DRP) and reorganizations to align with the 2026 presidential budget request, according to Reynolds' email, and faced further complications caused by the government shutdown last year.

"Work was halted for almost seven weeks when the core GSFC AXIS study team, dominated by NASA civil servants, was furloughed," Reynolds said. NASA later extended the Concept Study Report deadline, but Reynolds wrote that the extension was "inadequate compensation for the disruption and lost time" to address cost and schedule adjustments that had already been identified.

According to the email, Goddard leadership ultimately gave AXIS managers a choice: submit a Concept Study Report with a non-compliant cost and schedule, or don't submit one at all. NASA also apparently rejected the AXIS' team's appeal to bring the design within compliance during discussions normally held during the review process, calling that option "unacceptable," Reynolds said.

Another Goddard scientist not authorized to speak for NASA, speaking on the condition of anonymity, told Space.com that's not how it's normally done. "It is not at all unusual for a mission concept to be off in budget and launch date after their first pass — the first run-through you ask for everything you can possibly imagine, and then you start scoping back into what is more reasonable while still fulfilling the mission requirements," the scientist said. "The 10% they were off by is not bad at all for a first pass, but they did not have time to get additional quotes to bring it down."

They said the blame sits with NASA management.

"Internally, the general consensus is that this is 100% down to Goddard leadership mismanaging this … this has absolutely nothing to do with the AXIS team, the merit of AXIS as a concept in general, and especially not the Goddard scientists, engineers, and project managers who have put their everything into this mission and were held back by management at every step of the way."

NASA said the decision followed the agency's standard science mission selection process, which includes several checkpoints at which mission concepts are evaluated for compliance with established requirements.

"NASA has confirmed the AXIS (Advanced X-ray Imaging Satellite) Probe concept was not compliant with the 2023 Astrophysics Probe Explorer Announcement of Opportunity," an agency official told Space.com in an email, adding that more opportunities for the X-ray astrophysics community will be announced in the coming weeks.

"I am, quite frankly, livid that AXIS ultimately fell victim to the programmatic chaos of 2025," Reynolds told the AXIS team, arguing that the decision did not reflect the scientific importance of the mission.

AXIS was not necessarily the front runner against PRIMA, the X-ray space telescope's competitor in the Astrophysics Probe program, though. "AXIS was always the riskier of the proposed X-ray probes and people in the community were generally surprised they selected AXIS for Phase A," one of the Goddard scientists said. "Some folks believe it was selected because it was the most Chandra-like, and Chandra is old [and] could use replacing."

Reynolds closed his message by wishing "a smooth and speedy path to selection and flight" to PRIMA, which remains under consideration. He also noted that other X-ray astronomy projects, like SMEX and MidEX, can benefit from the research already accomplished by the AXIS team.

Editor's note: This story was updated on March 13 at 10:40 a.m. ET (1500 GMT) to add a statement from AXIS Principal Investigator Christopher Reynolds regarding the completion of one of three silicon mirror assemblies.

Roman is a survey telescope, with an 8-foot (2.4-meter) mirror like the Hubble Space Telescope, but a field of view 100 times larger. Besides studying dark matter and dark energy, one of Roman's core surveys will be the Galactic Bulge Time-Domain Survey, in which millions of stars in the central bulge of the Milky Way galaxy will be studied, principally to look for exoplanets. The idea is to use gravitational microlensing as a planet-finding device. Gravitational lensing is a technique often used in astrophysics to study distant objects; due to the way spacetime warps as per general relativity, some huge objects in space (like galaxy clusters, for instance) warp light traveling nearby, therefore magnifying, distorting and duplicating the source of that light as seen through our telescopes. Gravitational microlensing refers to gravitational lensing on smaller scales, like that of a planet.

Staring at the hundreds of millions of stars in the bulge, Roman will occasionally see some flicker, brightening temporarily as the gravity of an unseen foreground planet magnifies their light before moving out of alignment. However, microlensing is not the only phenomenon that can cause a star's light to flicker. Stars are constant, writhing masses of vast convective bubbles rising to their seething surfaces. Oscillations also reverberate through their interiors, shaking them up. The frequency of these oscillations depends upon the temperature, structure and composition of a star, and when the oscillations break through to the surface they can cause a star to temporarily, subtly brighten.

The science of studying these stellar oscillations is called asteroseismology, and the frequency of the oscillations can reveal the masses, sizes and ages of the stars for which they are observed. In turn, understanding stars better can inform astronomers as to some of the properties of the planets that orbit them.

"With asteroseismic data we'll be able to get a lot of information about exoplanets' host stars and that will give us a lot of insight on exoplanets themselves," study leader Trevor Weiss of California State University, Long Beach, said in a statement.

The Kepler Space Telescope, which hunted for exoplanets by watching for transits, was able to make asteroseismological measurements of 150,000 stars. In assessing whether Roman will be able to do the same, Weiss' team applied the Kepler dataset to models of Roman's observational capabilities. In particular, they discovered that Roman will be adept at detecting stellar oscillations on red giant stars, which are both luminous (making them easier to detect) and have a high frequency of oscillation with a period ranging from hours to days. This is a good match for Roman’s Galactic Bulge Time-Domain Survey, which will keep a steady eye on hundreds of millions of stars in the Milky Way galaxy's bulge every 12 minutes over half-a-dozen 70.5-day stretches, meaning that it will be attuned to the red giants' vibrations.

"Asteroseismology with Roman is possible because we don't need to ask the telescope to do anything it wasn't already planning to do," said Marc Pinsonneault of Ohio State University. "The strength of the Roman mission is remarkable: it's designed in part to advance exoplanet science, but we'll also get really rich data for other scientific areas that extend beyond its main focus."

The bulge, which harbors the supermassive black hole Sagittarius A*, is the oldest part of the Milky Way galaxy. Many of its stars are now aging out, evolving off the main sequence (which is what we call the stage of their life when they are generating energy through the fusion of hydrogen into helium in the core).

Upon leaving the main sequence, the next stage in the evolution of a sun-like star with less than eight solar masses is to expand and become a red giant. Initial estimates of the number of red giants that Roman could observe seismic waves on was 290,000, but deeper analysis found that the actual number could be much more.

"Now that we know the survey will entail a 12-minute cadence, we find it strengthens our numbers to over 300,000 asteroseismic detections in total," said Weiss. Depending upon certain assumptions, the total number could be as high as 648,000 red giants in its field of view, with 358,000 in the bulge.

"It would be the largest asteroseismic sample ever collected," said Weiss.

Understanding the properties of the host stars will inform astronomers about the planets they find — for example, whether they are in the habitable zones. The observations will also provide clues as to the future of planetary systems when their star begins to gradually die by evolving into a red giant star, before casting off their outer layers and leaving behind a dead white dwarf. How soon this happens depends upon the star's mass. More massive stars live shorter lifetimes than less massive stars. During the expansion and casting off phase, any planets orbiting close to the star are destroyed.

In our solar system's case, Mercury, Venus and probably Earth will all be doomed. However, microlensing has an advantage by being able to detect planets that are farther out from their star, far enough out to perhaps survive the red giant stage. By detecting planets around red giants, and the orbits of those planets, it will help astronomers better understand what fate will befall the planets of our solar system, and how far out a world has to be in order to survive. Astronomers have already noticed a deficit of planets orbiting red giants, and Roman’s findings will cement our picture of evolved planetary systems.

"Our work will lay out the statistical properties of the whole population — what their typical abundances and ages are — so that the exoplanet scientists can put the Roman measurements in context," said Pinsonneault.

Roman's asteroseismic discoveries won't just teach us about planetary systems, but the ages of the stars based on the asteroseismic readings will act as a guide to the history of the Milky Way, and its bulge in particular.

"We actually don’t know a lot about our galaxy's bulge since you can only see it in infrared light due to all the intervening dust," said Pinsonneault. "There could be surprising populations or chemical patterns there. What if there are young stars buried there? Roman will open a completely different window into the stellar populations in the Milky Way's center. I'm prepared to be surprised."

For example, a young population of stars could come to light if Roman measures oscillations on more massive red giants. This is because more massive stars live shorter lifetimes and therefore would have formed more recently.

The Roman Space Telescope is currently scheduled for launch between autumn 2026 and May 2027. In the meantime, the new assessment of its asteroseismic capabilities has been published in The Astrophysical Journal.

Dark matter makes up more than 80% of the matter in the universe, yet it doesn't emit, absorb, or reflect light, making it impossible to observe directly. Now, a new theoretical study by scientists at the University of York in the U.K. suggests light passing through dark-matter-rich regions of space could pick up a faint tint — slightly red or blue, depending on the kind of dark matter it encounters.

The effect would be extraordinarily subtle, far too weak for current telescopes to detect, but potentially measurable with the next generation of ultra-sensitive observatories, the researchers say.

"It's a fairly unusual question to ask in the scientific world, because most researchers would agree that dark matter is dark," study co-author Mikhail Bashkanov of the University of York said in a statement. "But we have shown that even dark matter that is the darkest kind imaginable — it could still have a kind of colour signature."

The team likens the concept to the "six handshakes rule," the 20th-century theory that any two people on Earth are connected by a chain of, at most, six acquaintances. In a similar way, the study suggests, even if dark matter doesn't interact directly with light, it might do so indirectly through intermediate particles that both sides "know," including the Higgs boson, the so-called "God particle" that represents the Higgs field, which is responsible for giving other particles their mass.

This indirect link could allow photons, the particles of light, to scatter ever so slightly off dark-matter particles, leaving behind a whisper of color or polarization "fingerprint" in the light, the study suggests.

"It's a fascinating idea, and what is even more exciting is that, under certain conditions, this 'colour' might actually be detectable," Bashkanov said in the statement. "With the right kind of next-generation telescopes, we could measure it."

In their study, published earlier this month in the journal Physics Letters B, Bashkanov and his team carried out what they say are the first detailed calculations of how strongly light could scatter off dark matter.

The findings suggest that if dark matter is made up of Weakly Interacting Massive Particles, or WIMPs, which interact through the weak nuclear force, then light passing through a WIMP-rich region would lose some of its high-energy blue photons first, leaving the transmitted light slightly red-tinted. In contrast, if dark matter interacts only through gravity, photons would scatter in the opposite way, giving the light a faint blue shift, the study notes.

In both situations, the interactions are minute but not zero, researchers say, meaning dark matter could leave behind a detectable "fingerprint" on light that travels through dense regions of it, such as the centers of galaxies or galaxy clusters.

Their calculations show that these effects could slightly distort the light spectrum of distant objects. A galaxy's glow, for instance, might appear microscopically redder or bluer depending on the dominant type of dark matter lying between it and Earth. In principle, such differences could help scientists distinguish between dark-matter models based on whether cosmic light skews red or blue as it travels through dark-matter-rich space.

"Right now, scientists are spending billions building different experiments — some to find WIMPs, others to look for axions or dark photons," Bashkanov said in the same statement. "Our results show we can narrow down where and how we should look in the sky, potentially saving time and helping to focus those efforts."

Detecting such tiny shifts would require ultra-precise telescopes and painstaking analysis of light that has traveled billions of light-years across the cosmos. Future observatories with exceptional spectral and polarization sensitivity, such as the European Extremely Large Telescope and NASA's Nancy Grace Roman Space Telescope, could one day test these predictions.

If confirmed, the findings would open an entirely new observational window on dark matter, bringing scientists a step closer to unraveling one of the greatest mysteries in cosmology.

PRIMA, the Probe far-Infrared Mission for Astrophysics, will study the universe at the longest of infrared wavelengths, bridging the gap between what the James Webb Space Telescope (JWST) can see in the near- and mid-infrared, and what radio telescopes observe. On Nov. 8, the international PRIMA team — led by Jason Glenn of NASA's Goddard Space Flight Center and including researchers from the US and Europe — convened at the Jet Propulsion Laboratory in California for a workshop to kick-off the design study.

The mission PRIMA is going up against is AXIS, the Advanced X-ray Imaging Satellite. Led by Chris Reynolds of the University of Maryland, AXIS would be designed to study black holes within distant galaxies in the early universe discovered by the JWST, and probe how active black holes and bursts of supernova explosions can affect the galaxies around them. The mission would also watch for "transients" – flashes of X-ray light that could be from exploding stars, gamma-ray bursts, glitches on magnetic neutron stars or sporadic accretion onto black holes.

Both teams have until 2026 to make their case, having each been awarded $5 million to do so, and the selected mission will fly in 2032.

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PRIMA is being supported by the Max Planck Institute for Astronomy in Heidelberg, Germany, where researchers will build vital components for the mission, including two high-precision, actively controlled beam-steering mirrors called "two-axis focal-plane choppers." These are able to steer the light entering the telescope and reflecting off its 1.8-meter (5.9 feet) aluminum mirror toward the sensors in PRIMA's two instruments, allowing high-resolution views of any part of the sky in the 'scope's field of view.

Those two instruments are PRIMAger (PRIMA imager) and FIRESS (Far-Infrared Enhanced Survey Spectrometer), which will observe light at wavelengths between 24 and 261 microns (the JWST can see up to 28.3 microns, which is the far end of the mid-infrared band). PRIMA would be 100 times more sensitive than its precursor missions, NASA's Spitzer Space Telescope and the European Space Agency's Herschel Space Observatory, and the team behind it claim that it will have the ability to measure in detail the chemical composition of planet-forming disks around young stars.

Because far-infrared light can be easily drowned out by thermal emission from the telescope itself, PRIMA needs to be cryogenically cooled down to –269 degrees Celsius (–452 degrees Fahrenheit), which is just four degrees above absolute zero. Yet this comes with an advantage; the instruments can use superconducting sensors called Kinetic Inductance Detectors, or KIDs, which count individual photons as well as record their energy and arrival time exactly. Superconductors are exactly what they sound like: materials that are extra-efficient at conducting electrons and which utilize quantum effects, but, in order to operate, they must be at low temperature.

With concerns about the longevity of the Chandra X-ray Observatory in NASA's budget, AXIS would be a timely mission to fill any gap if Chandra is forced to shut down. AXIS would function in unison with the JWST to probe black holes that existed over 13 billion years ago. On the other hand, PRIMA covers a wavelength band that there currently is no coverage of — far-infrared astronomy can only be done in space, since Earth's heat swamps it out — and it could also work in unison with the JWST to examine star- and planet-forming regions in the universe. It's a tough decision that NASA has to make.

The opportunity for both missions came along thanks to the recommendation of the recent astrophysics decadal survey that recognized that there could be a delay of several decades for the next generation of "great observatories" to replace Hubble, Chandra and even the JWST. To help fill the gap, the decadal survey proposed a new class of medium-scale mission, with a budget capped at $1 billion (not including launch), which could blast off in the 2030s without too much development time required. These are the Probe-class missions and they will help create opportunities that might never have happened if NASA threw all its eggs into the basket of the next multi-billion dollar project like the JWST.

Whichever mission is selected, it will do valuable work and teach us new things about the cosmos.

The small group had gathered here the American Museum ofNatural History in New York City to watch a live webcast from the NationalAcademy of Sciences in Washington, D.C. on the Astro2010Decadal Survey presented. The report designates the astronomy projectsdeemed most crucial for the next 10 years.

"I don't think there were losers," said MichaelShara, an astrophysicist at Columbia University in New York. "I think theentire community really won, and won big time."

The report's big ticket item was the Wide-Field InfraredSurvey Telescope.

With an almost 5-foot (1.5-meter) mirror, the WFIRSTobservatory ranked first among other potential space-based projects and carriesa proposed launch date in 2020. The space telescope's large-scale imagingcapability would complement the targeted infrared observationsexpected from the $5-billion JamesWebb Space Telescope, which already represents a flagship NASA projectslated to launch in 2014.

That made scientific sense to the group of observers, exceptthat no one seemed to know the details behind WFIRST. According to theAstro2010 survey group, the new space telescope would settle fundamentalquestions about the nature of dark energy and search for exoplanets orbiting starsin the central bulge of the Milky Way.

In Hubble's footsteps

Both WFIRST and JWST are infrared space observatories. Someresearchers wondered why the report did not also choose a successorto the Hubble Space Telescope that could view the universe through opticalor ultraviolet light.

Yet Shara pointed out that astronomers and astrophysicistshave had a "phenomenal UV telescope, i.e. Hubble, for the last 20 years,and we're getting it for another five [years]." He added that it madesense to wait for technology development to catch up for a next-gen optical/UVtelescope.

The choice of the $465-million LargeSynoptic Survey Telescope as a top priority for the ground-basedobservatory projects pleased Morgan May, an astrophysicist at BrookhavenNational Laboratory in Upton, NY.

His group has a lead role on developing sensors for LSST,which would use optical eyes to gaze at the heavens from its site in Chile.

"I think it's wonderful," May said. "Clearingthe ground [for the telescope] is nothing compared to coming in first for therecommendations."

The ground-based observatory would provide a steady streamof snapshots showcasing the night sky through an almost 28-foot (8.4-meter)aperture. LSST is scheduled to scan each region of the sky 1,000 times over 10years to provide an unprecedented view of changes over time.

Gazing into the future

A big uncertainty still hangs over the funding for all thepriorities listed in the report. But Shara seemed confident that the report'scommittee had already made the hard, realistic choices when considering thefuture budgets of NASA, the National Science Foundation and the Department ofEnergy.

"The reason I think this process has worked so well isthat it was driven by the science first, but also by the economics, by theharsh realities, by what is ready, by what has a real chance ofsucceeding," Shara explained. "So there was a great deal of realityin all of this."

The report incorporated risks, costs and technical readinessfor the first time as the sixth decadal survey. Its long view also includedprojects considered in past decadal surveys, as well as those which mightmature for the future decadal survey.

"From new worlds to new physics, the coming decade ofdiscovery leverages not only our current space observatories — such as theHubble, Spitzer, Chandra and Fermi space telescopes — but also our plannedfacilities — especially those from previous decadal surveys, the James WebbSpace Telescope and the Stratospheric Observatory for Infrared Astronomy(SOFIA)," said NASA officials in a statement.

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The Wide-Field InfraredSurvey Telescope (WFIRST) would launch in 2020 as one of the next generation of telescopes that should target the early universe, search fornearby habitable planets and test the boundaries of fundamental physics,according to the Astro2010 DecadalSurvey by the National Academy ofSciences.

"During the last DecadalSurvey, exoplanets weren't a big element, and dark energy wasn't really a bigdeal," said Claire Max, an astronomer at the University of California inSanta Cruz and member of the Decadal Survey committee. "There are a wholelot of things that are really new."

The influential report setsa roadmap for scientific priorities and chooses the most promising telescopecandidates for 2012-2021. Space- and ground-based research projects aresplit among large, midsize and small categories, so that WFIRST with its almost5-foot (1.5-meter) field-of-view came in first within the large category ofspace projects exceeding $1 billion.

For comparison, NASA's nexthuge space observatory ? the infrared James Webb Space Telescope ? has anestimated cost of about $5 billion and is slated to launch in 2014. The iconic HubbleSpace Telescope, which was launched in 1990, has a total cost of more than $10billion including its construction, launch and 20 years of operations. Majorinterplanetary missions, like NASA's Cassini mission to Saturn and Galileomission to Jupiter, also carried billion-dollar costs.

Anew ground-based observatory that could scan the entire available sky every three nightstopped report's list of vital, large ground projects that exceed $135 million.The $465-million telescope, called the LargeSynoptic Survey Telescope, would scan each region of the sky 1,000 timesover 10 years with an almost 28-foot (8.4-meter) aperture from its location inChile. It is slated to see first light before the end of the decade.

Unlike past reports, this latest Decadal Survey considered the technologicalreadiness and cost risk of each project. It also looked at previously consideredprojects such as LSST, which had matured since the most recent survey in 2001 andhas now been dubbed the most "ready-to-go" among the ground projects.

New eyes in space

The report also found that itsExplorer program that has supported small- and medium-sized missions such as NASA'sWide- Field Infrared Survey Explorer (WISE) ranked second in priority for large-cost spaceprojects. The astrophysics component would receive an annual budget boost from$40 million to $100 million by 2015.

Third priority went to the LaserInterferometer Space Antenna that consists of three formation-flying spacecraftto detect long-wavelength ripples in the fabric of space-time. Such ripplesrepresent gravitational waves caused by events such as black hole mergers.

NASA would share $1.4billion of the $2.4 billion total cost, assuming the European Space Agencyjoined in the effort. A successful 2012 launch of Europe's LISA Pathfindermission could lead to a full-scale LISA launch by 2025.

Another internationalproject, the International X-ray Observatory, would deploy a multi-part X-raymirror with about 20 times more collecting area than any existing X-rayobservatory. Current estimates put NASA's share of the $5 billion cost at $3.1billion, with the rest split among ESA and the Japan Aerospace ExplorationAgency.

The report's committeesuggested that IXO could represent a promising top candidate for the nextDecadal Survey, but only if the cost for NASA came down below $2 billion.

Stargazers on the ground

Earth-based projects alsoreceived careful scrutiny. The Mid-Scale Innovations Program that focused onsmall- to medium-scale experiments and facilities received second priority forthe large ground projects.

Third priority went to a"Giant Segmented Mirror Telescope" in the 98-foot (30-meter) range.Such a telescope could have three times the diameter, 10 times thelight-collecting area and 80 times the near-infrared sensitivity compared toexisting telescopes, assuming that it used the adaptive optics technology whicheliminates the atmosphere's blur effect.

Several giant telescopes slatedfor development include the $1.1-billion Giant Magellan Telescope sited forChile, the $1.4-billion Thirty-Meter Telescope sited at Mauna Kea in Hawaii,and the European Extremely Large Telescope. The report's committee noted thatthe federal government can only afford to contribute to one of the two U.S.telescopes, and proposed that the National Science Foundation immediatelychoose one for future investment.

Finally, the reportdesignated an Atmospheric CerenkovTelescope Array as the fourth priority for large ground projects. Such atelescope would use large arrays of ground-based telescopes to detect blueflashes of Cerenkov radiation, which are caused by very high energy gamma-ray photons from cosmicsources smashing into the atmosphere.

A U.S. version of the arrayknown as the Advanced Gamma-ray Imaging System was considered too expensive atmore than $400 million, and so the report suggests that the U.S. join theEuropean Cerenkov Telescope Array to share in costs and operations.

Making it happen

Government funding mayremain one of the biggest uncertainties hanging over the report, despite theconsensus among astronomers and astrophysicists about their scientificpriorities.

"My concern is that ifthe federal budget remains very constrained, we won't be able to do any of thisstuff," Max told SPACE.com.

The report did include somecontingency planning about budgetary shortfalls and the projected availabilityof money from NASA, NSF and the Department of Energy. But Max pointed out thatthe numbers kept changing even as the committee worked on the report.

Still, she remainedoptimistic about not only the progress of the past decade, but also having theright instruments to make discoveries beyond what researchers know.

"This is a chance toexploit those [past discoveries] and still build enough general-purposefacilities so that you can find the big new things for the next decade,"Max said.

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