Watch The Launch: NASA’s TESS Blasts Off From Cape

 

TESS—NASA’s newest planet-hunter—is now in space.

Sitting atop a Falcon 9 rocket, the robotic probe launched from Florida’s Cape Canaveral Air Force Station at 6:51 PM ET.

So far, there’s not a hitch in sight.

Says Sara Seager, MIT astrophysicist and the mission’s deputy director of science: “This is a wonderful celebration.”

And only the beginning.

TESS—$337 million and about the size of a stacked washer-dryer—will see “almost the entire sky,” says NASA.

And discover more worlds than ever before.

Credit: MIT

Artist impression of NASA’s TESS spacecraft.

During the two-year mission, NASA expects TESS to find perhaps 20,000 exoplanets.

Or more. The Kepler Space Telescope looked at less than one percent of the sky—and detected nearly 5,400 planets (with about 2,700 now confirmed).

But most Kepler planets “are too distant and too dim to do any follow-up observations,” says Jeff Volosin of NASA’s Goddard Space Flight Center.

Instead, TESS will point its four cameras at 200,000 of the brightest, closest stars—30 to 100 times brighter than Kepler’s targets, and “only dozens to hundreds of light-years away,” says Volosin.

In space, that’s close—even though a single light-year equals almost six trillion miles.

Among the thousands of discoveries, NASA hopes to find hundreds of worlds reasonably near the size of Earth.

“Bigger than Earth but smaller than Neptune,” says Seager. “These planets are still a big mystery. Are they giant rocky planets? Or water worlds?”

Credit: ESO / M.Kornmesser

Artist impression of a super-Earth.

Don’t expect discoveries within days. Once in space, TESS scientists have to check out the probe. That takes two months.

Says Seager: “You have to wake up one part at a time to make sure everything works, and works together.” Detection announcements will follow, probably in a few more months.

To find a new world, TESS will look for “transits”—eclipse-like events, when a planet passes between its star and the spacecraft.

As that happens, the planet blocks a bit of the star’s light; that dip in the light, minuscule but measurable, tells scientists that something might be there.

But TESS can’t tell if the planets are life-friendly. Discerning those details will be left for future space probes.

That includes NASA’s James Webb Space Telescope, launching in 2020—and ARIEL, a new mission from the European Space Agency, slated for a 2028 liftoff.

TESS, says Giovanna Tinetti, ARIEL’s principal investigator, “will clearly provide most of our exciting targets.”

Webb and ARIEL will analyze the atmospheres of TESS planets, searching for biosignatures—gases that indicate the possibility of life, like oxygen.

“Within the next decade,” says Volosin, “we hope we can identify the potential for life to exist outside our solar system.”

Credit: NASA’s Goddard Space Flight Center / Chris Meaney

Artist impression. TESS in space.

But as NASA looks ahead, launch day is a time to look back.

Just two decades ago, many astronomers thought exoplanets were nearly nonexistent. Our solar system, with eight major worlds, was believed a quirk.

“Exoplanets were just considered silly,” says Seager. “Twenty years ago, it was insane to search for exoplanets.

“But the line between what’s considered mainstream and what’s considered crazy is constantly shifting.”

And now, TESS has launched. “And now,” says Seager, “it’s so mainstream.”

[“Source-forbes”]

 

With the launch of TESS, NASA will boost its search for exoplanets

illustration of TESS telescpope

NASA is stepping up its search for planets outside our solar system. Its next exoplanet hunting telescope, the Transiting Exoplanet Survey Satellite (TESS), is due to launch from Cape Canaveral on the evening of April 16.

Following the Kepler space telescope’s discovery of more than 5,000 possible exoplanets since 2009, TESS will continue the galactic census — flagging more planetary candidates for further study.

Astronomers expect TESS to find about 20,000 planets in its first two years in operation, focusing on nearby, bright stars that will be easy for other telescopes to investigate later. About 500 of those expected exoplanets would be less than twice the size of Earth — and therefore may be good places to look for life.

NASA’s next exoplanet hunting telescope, TESS

SMALL BUT MIGHTY NASA’s next exoplanet hunting telescope, TESS, is only 1.5 meters tall (shown here with engineers). Its size is partly due to the fact that it was designed to launch on NASA’s small Taurus rocket, but will instead launch on a larger SpaceX Falcon 9 on April 16.

ORBITAL ATK

The TESS mission is “a whole new opening for exoplanet studies,” MIT astronomer Sara Seager, TESS’ deputy science director, said during a news conference describing the upcoming launch.

TESS will be the first NASA science mission launched on the SpaceX Falcon 9 rocket. Once in orbit, the spacecraft will trace an unusual, elliptical path between Earth and the moon that will enable it to observe at least 85 percent of the sky — 350 times as much sky as Kepler saw.

Most of the planets found by Kepler orbit stars 1,000 light-years away or farther. TESS will focus on 200,000 stars that are a few hundred light-years away at most, and shine between 30 to 100 times brighter on average than Kepler’s.

The brighter the star, the easier it is to determine its planet’s characteristics, such as its mass and whether it has an atmosphere, Seager says. “Photons are our currency — the more, the better,” she says.

That follow-up will help TESS avoid some of Kepler’s pitfalls. Because Kepler’s stars were so far and so dim, some of its planet candidates were confirmed as actual planets only by statistics rather than by other telescopes. And not all those confirmations may stick. A recent paper posted at arXiv.org showed that Kepler 452b, an Earth-sized planet that orbits a sunlike star at the same distance Earth orbits the sun, may be a mirage (SN: 8/22/15, p. 16). Many of TESS’ planets won’t face the same uncertainty.

the TESS sattelite

COASTING IN SPACE The TESS satellite’s unusual 13.7-day orbit uses the moon’s gravity to stabilize it, so it needs little fuel. During the part of the orbit colored blue, TESS will observe the sky. During the part marked in orange, it will transmit data back to Earth. The gray ring marks the moon’s orbit.

NASA

But the way TESS will search for exoplanets is the same as Kepler: The satellite will watch stars for signs of dimming, which can indicate that a planet is transiting, or crossing in front of, the star. Measuring how much starlight is blocked can tell astronomers the size of the planet.

Once TESS finds a planet, astronomers will need more information to understand its qualities, such as whether it’s rocky or gassy (SN Online: 6/19/17). For that, other telescopes will follow up. Ground-based telescopes will measure the gravitational tug of a planet on its host star to learn the planet’s density, which is a clue to its composition. Astronomers plan to measure masses for at least 50 TESS planets that are smaller than Neptune in the hopes that many of them will have rocky, and therefore potentially habitable, surfaces.

Undiscovered country

Before TESS, most known planets were more than 1,000 light-years away, with a few closer than 30 light-years (a parsec is 3.26 light-years). TESS (orange circles) will fill in the gap. The size of the circles represents how easy the planets are to find.

graph showing where TESS will be able to detect planets
ZACH BERTA-THOMPSON

NASA’s James Webb Space Telescope, now scheduled to launch in 2020, will then check some of those planets for signs of life (SN: 4/30/16, p. 32).

“This is one of the major questions that TESS is intended to answer: Where will we be pointing Webb?” said the mission’s principal investigator, MIT astronomer George Ricker, at the press conference. Webb will peer at the starlight filtering through planetary atmospheres to try to detect molecules that could be produced by something living on the surface.

It will take a few months for TESS to swing into its regular orbit before it begins collecting data. At that point, it will be able to use the moon’s gravity to stabilize itself for decades in orbit without using extra fuel. The mission is set to last two years, but could continue taking data almost indefinitely.

“TESS is not going to be limited by any expendable or other aspects,” Ricker said. “It will be basically limited by how long NASA has the patience to fund the mission.”

[“Source-sciencenews”]