Tuesday, April 3, 2018
NASA’s next planet hunter is ready to find undiscovered worlds
Initially slated for a two-year mission, TESS will ascend to an elliptical 13.7-day orbit around the Earth. It’s a unique and extreme orbit that’s never been used before, varying as close as 67,000 miles and as far away as 232,000 miles from its home planet. According to Space.com, the stable orbit will allow TESS to stay in space for decades without any need for course corrections.
Outfitted with four wide-angle cameras, TESS will be able to observe 85 percent of the surrounding sky as it looks for exoplanets. The instruments on the spacecraft will map 26 different “sectors” of the sky over a two-year period.
Specifically, TESS will be looking for a phenomenon called a “transit,” which is when a planet passes in front of its star. The resulting decrease in brightness can be observed and measured with spectroscopy, giving astronomers a better idea of the size and composition of the planet.
“TESS is opening a door for a whole new kind of study,” said Stephen Rinehart at Goddard Space Flight Center. “We’re going to be able study individual planets and start talking about the differences between planets. The targets TESS finds are going to be fantastic subjects for research for decades to come.”
TESS is replacing the aging Kepler telescope, which is running on fumes and will soon be unable to maneuver. Unlike TESS, Kepler is in a solar orbit and can only make observations in one direction. “TESS will cast a wider net than ever before for enigmatic worlds whose properties can be probed by NASA’s upcoming James Webb Space Telescope and other missions,” said Paul Hertz of NASA.
Kepler used the same methods to discover more than 2,600 exoplanets, but it was always observing the same area of space and most of the planets were more than a thousand light-years away. TESS will set its sights on more nearby stars that are within 300 light-years of Earth.
The discoveries made by TESS may invite further study with the upcoming $8.8 billion James Webb Telescope planned for launch in 2020. “With those larger telescopes, we’ll be able to look for telltale signs in the atmospheres of those planets that might tell us what the planets are made of, and perhaps even whether they have the kinds of gases in their atmospheres that, on Earth, are an indication of life,” Hertz said at a news conference.
TESS may even moonlight at times to investigate other cosmic phenomenon it encounters besides exoplanets. Researchers will be invited to use the spacecraft as part of a “guest investigator” program, NASA said.
“I don’t think we know everything TESS is going to accomplish,” Rinehart added. “To me, the most exciting part of any mission is the unexpected result, the one that nobody saw coming.”