NASA Launches the Transiting Exoplanet Survey Satellite

On Wednesday, April 18, 2018, NASA launched the Transiting Exoplanet Survey Satellite (TESS), its newest telescope to search for planets beyond the Solar System, and astronomers from the University of Hawaiʻi Institute for Astronomy and Maunakea telescopes will be a part of the adventure.

Artist’s impression of NASA’s TESS satellite. UH astronomers lead several projects which will combine TESS data and ground-based observations from Hawaiʻi to hunt for nearby exoplanets and study stars. Image credit/copyright: NASA/GSFC

A SpaceX Falcon 9 rocket lofted TESS into an elliptical orbit from which it will survey most of the sky over the next two years. The MIT-led TESS mission follows in the path of NASA’s successful Kepler Space Telescope, which discovered that planets are common around other stars. The goal of TESS is to find planets around closer and brighter stars, allowing scientists to study them with telescopes like those on Maunakea.

“TESS will be a game-changer for our understanding of planets and the stars that they orbit.” said Daniel Huber, astronomer at Institute for Astronomy (IfA) at the University of Hawaiʻi at Mānoa, and lead of two TESS programs funded by NASA. “The sheer number of stars for which TESS will provide data—10 to 100 times more than Kepler—is bound to yield some very exciting surprises.”

Huber is particularly interested in using TESS data to detect oscillations in stars—tiny “starquakes” causing stars to vary in brightness.

“Using these oscillations we can precisely measure fundamental properties of stars, such as their sizes and masses,” said Huber. “This also provides vital clues to better understand the planets that orbit them.”

TESS will detect tiny dips in the light from a star as orbiting planets block some of the star’s light from reaching us. Different observations are need to confirm that these signals are produced by planets, and IfA astronomers plan to obtain many of these with the telescopes on Maunakea and Haleakalā. TESS will survey both the northern and southern sky, and the observatories of Hawai’i are uniquely situated to observe many stars in both hemispheres.

“Maunakea provides some of the best conditions in the world to observe TESS targets” said Christoph Baranec, astronomer at IfA’s Hilo office, and lead of a National Science Foundation-funded program to build a robotic adaptive-optics system on the UH 2.2m telescope on Maunakea. “By taking high-resolution images of thousands of stars observed by TESS, we can confirm whether the planets indeed orbit these stars.”

In addition to planet discoveries, TESS data will be a goldmine to study the behavior of stars themselves. Jennifer van Saders, IfA astronomer, will lead another TESS program to study how the rotation periods of stars change as they age. “Stars age exceptionally gracefully for most of their lives, changing very little, and we often can’t determine their ages to within billions of years. The observation that stars spin slower as they age gives us one of the few tools we have to do better.”

TESS will even play an important role studying the deaths of stars, called supernovae, with precise observations moments after their explosion. IfA astronomer Benjamin Shappee was awarded a Mt. Cuba Astronomical Foundation grant to expand the global network of the All-Sky Automated Survey for Supernovae, headquartered at the Ohio State University.

“We will monitor the same direction TESS is looking many times per day from Haleakalā and our other sites around the world to discover TESS supernovae as early as possible,” explained Shappee.

TESS not only has strong scientific connections to Hawaiʻi, but parts of the satellite were built right here on the islands. The sensors of the four cameras TESS will use to image the sky were manufactured by the Hawai‘i Aerospace Corporation (formerly GL Scientific), based in Honolulu. GL Scientific was founded by Gerry Luppino, an astronomer at IfA for 18 years, who passed away in 2016. “Gerry would have really loved to see this launch. Working with the TESS team and contributing to a project that will enhance our understanding of the universe has been incredibly rewarding,” said Ryan Bradley, president of Hawai‘i Aerospace.

As TESS settles into its orbit, it will undergo a calibration phase, with the first scientific data expected to be delivered later this year. If successful, TESS should continue to provide data for many years to come. UH astronomers and students are standing ready to combine data from NASA’s newest satellite with the powerful telescopes in Hawaiʻi to explore the mysteries of stars and planets in our galaxy.