NASA's newest space observatory in space has begun searching for planets around other stars, while astronomers focus on worlds that can be accessed through follow-up missions such as the James Webb Space Telescope.
The Transit Exoplanet Survey Satellite officially launched a two-year science mission Wednesday, about three months after the launch of a SpaceX Falcon 9 rocket from Cape Canaveral.
"I'm thrilled that our new Planetary Hunter mission is ready to scour the neighborhood of our solar system for new worlds," said Paul Hertz, director of NASA's Astrophysics Department. "Now that we know that there are more planets than stars in our universe, I look forward to the strange, fantastic worlds that we will discover."
Equipped with four 1
TESS is a sequel to NASA's Kepler mission that is nearing its end in search of planets around other stars. Kepler – NASA's first mission dedicated to an exoplanet search – generally searched for worlds around more distant stars, yielding 2,650 new confirmed planets outside our solar system.
The TESS mission is designed to observe stars closer to the Sun. In addition, Kepler has only pointed to certain parts of the sky, while TESS will take a broader look at it.
George Ricker, head of the TESS science team at the MITS-Kavli Institute for Astrophysics and Space Research, said the exoplanet surveyor was a "finder scope" for the Webb telescope and huge ground-based observatories.
"You can go into a dark night, and you can see 6000 stars in the sky with the naked eye," Ricker said. "We will look at each one of these stars."
About 20 million stars will be visible in TESS's light-sensitive cameras, including targets that are up to a million times weaker with the naked eye, Ricker said. Around 200,000 of these stars are selected by the TESS science team for their proximity and brightness.
Each of the TESS cameras contains four specially designed red-sensitive CCD detectors developed and developed by the Lincoln Laboratory
"TESS is a surveying machine, and it will find the very best planets we can track, and to this one Category include these small rocky planets that cross small red dwarf stars, "said Sara Seager, associate scientist director of the TESS mission at MIT, in an interview before launching the mission.
Ricker said he expects TESS to find between 500 and 1000 planets between one and three times the size of the earth. Up to 20,000 planets the size of Neptune or Jupiter could be discovered by TESS.
That would increase the number of known planets beyond our solar system fivefold or more, but it's not just about expanding the exoplanet catalog
"TESS's focus is on finding systems that are bright Stars are connected, which means they are much easier to track, "Ricker said in an interview with Spaceflight Now. "Once you realize that a transit system exists, it's something you'll come back to and learn more and more as improved instruments, satellites, and telescopes become available, because that will be the benchmark for future research."  Here the James Webb Space Telescope becomes an important tool for astronomers who want to learn more about the nature of distant exoplanets. The oft-delayed Webb telescope is set to launch in early 2021 and be able to explore the atmospheres of some of these worlds, learn about their chemical composition, and seek evidence that the planet may be habitable.
The huge, expandable observatory "will be able to find characteristic atmospheres of materials in the atmospheres of these planets … and something that may be a biogenetic signature," said Ricker Spaceflight Now. "Of course, this requires a lot of care and work, and TESS can only point the way to those goals you should focus on with Webb."
TESS will scan around 85 percent of the sky during its two-year mission, starting with stars at the top southern sky. In 2019, the observatory will relocate its target to the northern sky.
The mission will primarily examine M-dwarf stars, which are smaller and cooler than the Sun and make up the majority of stars in the Milky Way. The TESS stars, also called red dwarves, have not been thoroughly investigated to see if they host their own solar systems.
Since its launch, TESS has maneuvered itself into a unique orbit in gravitational resonance with the moon taking the spaceship between distances of 108,000 kilometers and 376,000 kilometers from Earth. In this orbit TESS makes a loop around the earth about every two weeks.
NASA released the first test image from one of TESS's four cameras in May showing about 200,000 stars along the plane of our Milky Way.
TESS's first scientific data will be downloaded to Earth in August, and NASA says astronomers will begin analyzing the images immediately. Software will help scientists extract the data and detect exoplanet transit signals.
Built by Northrop Grumman Innovation Systems – formerly known as Orbital ATK – TESS fired its engines several times and used a gravitational flight from the Moon on May 17 to reach the final orbit of the $ 337 million mission, a stable perch requires no further rocket burns and reaches close enough to the earth to transmit full-screen images from the vehicle's science cameras through a high-speed Ka band downlink. The orbit also keeps TESS away from the damaging influence of Van Allen radiation belts.
The spacecraft, which weighed less than half a ton on takeoff, has enough fuel to keep working for up to 20 or 30 years, Ricker said before interviewing TESS. This assumes that NASA funding and spacecraft parts remain stable.
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