In the coming decade and beyond, new telescopes on mountaintops and in orbit will reveal the birth of galaxies, locate (possibly) habitable worlds orbiting other stars, and track asteroids that might impact Earth.
1. 2017: Transiting Exoplanet Survey (TESS)
An array of wide-field telescopes known as the Transiting Exoplanet Survey (TESS) will launch in 2017 to conduct the first space-based survey of the entire sky in the search for habitable planets orbiting other stars. TESS will search for planets that pass between Earth and their own stars, causing a change in the observed light from the star - what’s called the transit method.
Ground-based telescopes have used this method to find exoplanets in previous surveys, which have found mostly gas giants similar to Jupiter. Smaller, rocky planets like Earth and Mars are better prospects for life, but they are also harder to spot.
The Kepler space telescope, launched in 2009, has identified some smaller worlds among its 115 confirmed discoveries, such as Kepler-37b, a rocky planet about the size of Earth’s moon with an average temperature of 800 degrees F. However, Kepler is searching for planets around only 100,000 stars in a relatively small slice of the sky. TESS will cover about 400 times as much area.
"It will identify thousands of new planets in the solar neighbourhood, with a special focus on planets comparable in size to the Earth," said the project’s principal investigator George Ricker of MIT, in a release. Once it has identified those planets, TESS’s instrument package will allow it to study their orbits, masses, densities, and the chemical composition of their atmospheres.
NASA announced funding for the MIT-led project on April 8 through its Explorers Program, the goal of which is to fund more frequent science missions at relatively low cost per mission. The program imposes a US$200 million budget cap on satellite missions like TESS and a US$55 million limit on space station missions. Since 1958, the program has launched 90 missions.
2. 2018: James Webb Space Telescope
Because it takes about 13 billion years for light to reach Earth from the most distant galaxies in the universe, those images provide a glimpse into the universe's past. A million miles above Earth, the James Webb Space Telescope [JWST] will study the oldest light in the universe to understand how galaxies formed after the Big Bang.
As cosmic objects move farther away, our view of their light shifts toward the red end of the spectrum; light from very distant objects is shifted into the infrared spectrum, which makes infrared telescopes like Webb ideal for studying the oldest objects in space.
The more light telescopes collect, the more deeply they can see into the sky. Webb will collect a lot of light: Its 6.5-meter (21-foot) segmented mirror is too wide to fit on a rocket, so it will fold up like origami alongside a sun shield the size of a tennis court, both of which will unfurl once Webb reaches orbit.
Webb has a projected lifespan of five years, but scientists hope it will last up to 10. However, repairs, like those that have kept its predecessor, Hubble, flying since 1990, will be impossible for Webb. "It's four times higher than the moon, so the day that it stops operating it's just going to stay there," says Ray Villard, news director for the Space Telescope Science Institute.
Some scientists consider that a risky proposition. Webb's price tag has grown from its original US$1 billion budget to about US$8.8 billion, forcing NASA to take money from other projects, like the Wide-field Infrared Survey Telescope commercial flights to the International Space Station, to foot the bill.
In response, researchers have tried to pack Webb with as many instruments for as many studies as possible - adding further expense. With Webb, space science is putting most of its eggs in one very expensive basket that can't be repaired if it breaks. [More about JWST at Space Telescope Science Institute (STScI) and European Space Agency (ESA) official websites]
3. 2020: Giant Magellan Telescope
With a 24.5-meter (80-foot) primary mirror, the Giant Magellan Telescope (GMT), to be built in the mountains of Chile, will be able to collect more light than any existing telescope. Its primary mirror consists of six 8.4-meter mirrors arranged around a 7.7-meter central mirror. With their combined light-gathering capability, GMT will study some of the most distant objects in the universe.
GMT will look directly at planets outside our solar system for the first time. Currently, astronomers can study planets in other solar systems only indirectly by observing the way a star "wobbles" slightly when affected by a planet's gravity, or measuring the change in the chemical spectra of a star when a planet crosses it. Researchers can "subtract" the planet's spectra from the star's to draw conclusions about the planet's size and composition.
With GMT, astronomers will actually be able to see these extra-solar planets in images 10 times clearer than those from Hubble. "Once you can actually see them, you can measure a lot of interesting properties," GMT director Patrick McCarthy told Popular Mechanics, including colour and even some weather patterns.
"We chose not to enter into what would be a decades-long process that might lead to federal funding and might not, but might lead to delays in the project and probably additional costs," McCarthy told PM. Instead, the program receives funding from its institutional partners, including Australian National University, Astronomy Australia Limited, the Carnegie Institution for Science, Harvard University, the Korea Astronomy and Space Science Institute, The Smithsonian Institution, Texas A&M University, the University of Arizona, the University of Chicago, and the University of Texas at Austin.
In light of the current federal budget situation, he said, "I think we're looking fairly wise."
4. 2021: Large Synoptic Survey Telescope
From the mountains of Chile, the Large Synoptic Survey Telescope (LSST) will map the entire sky rapidly an in greater depth than existing projects, like the Sloan Digital Sky Survey (SDSS). With its 3.2-gigapixel camera's wide field of view, LSST will scan the whole sky twice a week in a series of panoramic shots. An 8.4-meter primary mirror gives it a large light-gathering area, so LSST can detect very faint objects in those panoramas; for a given area of sky, LSST's images will reveal 10 times as many galaxies as SDSS.
The rapid scans will help build a detailed map of the sky, which researchers will compare with new images to detect changes, like new transient objects. Astronomers expect to discover billions of new objects with LSST, from the most distant stars to the asteroids nearest Earth.
"It will be the first time that astronomers have catalogued more objects than there are living people on Earth," Zeljko Ivezic of the LSST project tells PM.
Such objects include potentially dangerous asteroids, most of which are currently unmapped. A federal mandate charges LSST with finding and mapping the trajectories of 90 percent of Near-Earth Objects wider than 140 meters within 10 years. Researchers hope LSST will also identify smaller - but still dangerous - objects, like the 17-20-meter asteroid that struck Chelyabinsk, Russia in February 2013.
LSST, a joint project of numerous institutions, including the Space Telescope Science Institute, several universities and national laboratories, and the government of Chile, has received a number of private donations to fund construction. These include US$20 million from software developer and space tourist Charles Simonyi and US$10 million from Microsoft founder Bill Gates, but, "We have not received our federal construction money yet. We are hopeful to be in the 2014 budget," Suzanne Jacoby of LSST says. "We're funded for most of [2013]. We're just waiting to see what happens."
5. 2030: Advanced Technology Large-Aperture Space Telescope
The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a NASA project currently in the conceptual stage, but it offers a glimpse at the next generation of telescopes. Engineers have designed several models for ATLAST with primary mirrors between 8-meters and 16-meters in diameter, the smallest of which still would be larger than the largest current space telescopes and 2000 times more sensitive than Hubble, with a resolution five to 10 times better than the James Webb Space Telescope.
Ray Villard of the Space Telescope Science Institute describes ATLAST as a "life finder." It will analyze the spectra of distant planets to detect water vapour, ozone, methane, and other possible signatures of life. ATLAST will also study the universe's origins, investigate dark matter, and probe other mysteries we haven't even discovered yet.
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Top image: James Webb Space Telescope design. Credit: NASA.
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