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E'er since it debuted in 2009, NASA'due south Kepler spacecraft has redefined our agreement of other star systems. Just Kepler is in crude shape, and it won't final forever. Now TESS, the Transiting Exoplanet Survey Satellite, is ticking along on schedule to launch in 2017. While the upcoming James Webb Space Telescope (JWST) is set to be a partial replacement for the Hubble telescope, the JWST will as well be a sort of spiritual successor to Kepler, in that it volition team up with TESS to hunt for exoplanets in the visible and IR bands.

Like Kepler, TESS volition utilise the transit method, searching for exoplanets past watching hundreds of thousands of stars for the telltale dimming. But where Kepler must bandage its eyes to a pocket-size patch of distant space, peering securely merely narrowly into the skies, TESS will brand a shallower whole-heaven survey of stars within a few hundred light years of Earth. Most of Kepler's exoplanet discoveries came from one relatively small patch of the sky. But NASA officials say that TESS should exist able to await at over 200,000 stars.

To make things easier for mission scientists, TESS breaks up its spherical viewfield into 26 "tiles" that overlap nigh its due north and south poles. "The spacecraft's powerful cameras will look continuously at each tile for but over 27 days, measuring visible lite from the brightest targets every 2 minutes," NASA officials said in a statement. Based on the characteristics of those picayune dips in brightness, TESS scientists will exist able to tell how large the newly discovered exoplanets are, and how long they accept to orbit their parent stars.

Left: The combined field of view of the four TESS cameras. Middle: Division of the celestial sphere into 26 observation sectors (13 per hemisphere). Right: Duration of observations on the celestial sphere. The dashed black circle enclosing the ecliptic pole shows the region which JWST will be able to observe at whatever time. Image and caption via GSFC/NASA

Now, TESS is an Explorer-class spacecraft, so it isn't like Hubble or the other Corking Observatories. A ameliorate comparison might exist the Explorer-course Swift spacecraft, which is watching for gamma ray bursts. If information technology seems like 2 minutes isn't very long to await at a star, it isn't; TESS will take relatively brief glances, because it'south looking at a greater total surface area of the sky. But since the camera's viewfields overlap at the poles, some places will be under almost constant observation. The idea is to follow up on TESS'south discoveries of potentially habitable worlds using the Observatory-grade JWST, slated to launch in 2018 for actually existent this time.

Paradigm via GSFC/NASA

That'southward not all TESS has up its sleeve, though. While it will exist a planet hunter first and foremost, scientists and other "guest investigators" will also have the opportunity to take fourth dimension on TESS to observe blackness holes, supernovas, and a variety of other cosmic objects and phenomena.

I of the other major goals of TESS is to examine short-menses objects and transient phenomena, like the visible low-cal energy that accompanies a gamma ray flare-up. The spacecraft's glancing gaze might pose difficulties for asteroseismologists, considering while transits might accept some days or weeks, starquakes tin can happen in seconds, then TESS's sampling rate might bump into the Nyquist limit. Simply that kind of data loss is obviously a niche enough problem that project scientists were willing to brand the compromise.

TESS also has unique orbital characteristics. It's designed to survey both the northern and southern hemispheres and will use a new lunar orbit, dubbed P/2, to exercise so. This highly elliptical orbit will permit the spacecraft to survey its target range while simultaneously remaining balanced between the gravitational effects of the Moon and those of the Earth. NASA has published an article with more details on the spacecraft's orbit and its characteristics, if you're curious.

TESS's never-before-used P/2 orbit. Image: GSFC/NASA

TESS'due south never-before-used P/2 orbit. Image: GSFC/NASA

Betwixt TESS and the JWST, our understanding of other solar systems should continue to advance for years to come, fifty-fifty as monuments similar Hubble and Kepler are taken offline. The toolkit of astronomers continues to aggrandize as technology gets thinner, lighter, stronger, and more durable. When TESS makes it to space aboard a Falcon 9 FT rocket, it will fill a gap in information collection and, no doubt, present new bug to be overcome. But if we can beat gimbal lock, jammed reaction wheels, and broken rover artillery while still making practice nether an endless funding drought, believe information technology, we'll get some skilful science out of TESS.