Ushering in a new age of exoplanet discovery, NASA's TESS, or the Transiting Exoplanet Survey Satellite, is scheduled to launch aboard a SpaceX Falcon 9 rocket on April 18. The space telescope, a successor to the aging and soon-to-be-decommissioned Kepler space telescope, will scan an area of the night sky nearly 400 times larger (roughly 85 percent of the sky) than that covered by its predecessor.
"Kepler was all about doing a census: How common are planets in general? What is the size distribution of planets like? Are Earth-sized planets common?" Stephen Rinehart, the project scientist for TESS at NASA, told The Verge. "TESS is really optimized for knocking on doors in the neighborhood and saying, 'Hi, how are you? What is this planet actually like?'"
Much like Kepler, TESS will search for exoplanets using something called transit photometry. A transit occurs when a planet passes in front of its host star. This in turn slightly decreases the brightness of the star, creating a signature that TESS's four wide-field CCD cameras will be able to detect. Over the course of its two-year prime mission, TESS is expected to study over 200,000 of the brightest dwarf stars (similar to our own sun) in the closest 300 light-years around Earth.
"We're going to look at every single one of those stars," mission's chief scientist George Ricker of the Massachusetts Institute of Technology, told Phys.org. "All astronomers for centuries to come are really going to focus on these objects. This is really a mission for the ages."
With so much real estate out there to examine, NASA expects that TESS may discover as many as 20,000 exoplanets, with at least 50 Earth-sized planets and up to 500 planets less than twice the size of Earth. Once NASA has identified objects of interest, they will have future telescopes like the James Webb –– set to launch in May 2020 –– probe their atmospheres to see if they might host conditions suitable for life.
Big tech, small package
Unlike other spacecraft NASA has punched into orbit to study the cosmos, TESS is relatively small. In fact, as shown below, its 12-foot wide, 5-foot-tall frame is tiny when compared to the payload fairing it will launch in aboard the Falcon 9.
SpaceX intends to launch the spacecraft on April 18 from Cape Canaveral, Florida. Once successfully clear of the rocket, TESS will complete five independent burns that will eventually place it into what's called a "lunar flyby orbit." This super elliptical orbit, never before used for a spacecraft, will give TESS the ability to maintain a stable view of the cosmos with minimal fuel burn for many decades.
You can learn more about TESS and its mission to survey our closest neighboring star systems below.