SpaceX launches TESS spacecraft in quest to discover other Earths

Conceptualized artist’s illustration of TESS in space. Image Credit: MIT

Note: this article was first published on AmericaSpace as a preview to the now-successful launch, and has been updated accordingly.

The discovery of thousands of exoplanets in recent years is one of the most exciting developments in space exploration, and the future promises the detection of thousands more. Many of those have come from the Kepler Space Telescope, including Earth-sized planets in the habitable zones of their stars, but that mission will soon be coming to an end as the telescope runs out of fuel. But not to worry, it will be replaced by the next generation of planet-hunting space telescopes. The next one of these, the Transiting Exoplanet Survey Satellite (TESS), launched much sooner than Kepler ends – yesterday in fact, on April 18. TESS will further revolutionize our knowledge of these far-off worlds.

The mission launched launch atop a virgin SpaceX Falcon-9 rocket from Cape Canaveral AFS Launch Complex 40 in Florida at 6:31pm EDT. Virgin as in the rocket is not flight-proven and therefore did not launch any missions previously, something SpaceX has been doing more and more over the last year. The company does however intend to land the booster on their offshore drone ship shortly after liftoff, with the intent to reuse it for the upcoming NASA CRS-15 Dragon resupply mission to the ISS as soon as June 2018.

TESS pre-launch. Photo Credit: NASA

Orbital ATK designed, manufactured, integrated and tested the planet-hunting spacecraft, which was awarded to them by NASA in 2013.

So just why is TESS so important? Kepler focused on a small patch of the sky, detecting exoplanets very far away. TESS, however, will conduct a sky-wide survey, looking at the nearest and brightest stars; TESS stars will be 30-100 times brighter than those surveyed by Kepler, and can cover an area 400 times larger than what Kepler covered. In doing so, TESS aims to discover not just exoplanets, but specifically seeks to identify habitable, Earth-like worlds.

Over at least two years, TESS will survey more than 200,000 stars, and will be able to find many new exoplanets orbiting these stars, including Earth-sized and super-Earth-sized (larger than Earth but smaller than Neptune), which are now known to be the most common in our galaxy. Later upcoming space telescopes, such as the James Webb Space Telescope (JWST), will be able to then study these planets further and analyze their atmospheres for possible signs of life.

“TESS is opening a door for a whole new kind of study,” said Stephen Rinehart, TESS project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “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. It’s the beginning of a new era of exoplanet research.”

Artist’s concept of a super-Earth exoplanet orbiting the Sun-like star HD 85512 in the southern constellation of Vela. TESS and other follow-up telescopes will be able to study the compositions and atmospheres of such intriguing worlds. Image Credit: ESO/M. Kornmesser
Overview of the TESS mission. Image Credit: NASA/Orbital ATK
Like some other telescopes, TESS will look for exoplanets by watching them transit in front of their stars. Image Credit: NASA/Goddard Space Flight Centre

The main objective of the mission is to find smaller rocky planets, like Earth, orbiting closer stars in the solar neighborhood. It is anticipated that TESS will discover more than 3,000 planetary candidates and about 500 Earth-sized or super-Earth-sized worlds.

“TESS should discover thousands of new exoplanets within two hundred light years of Earth,” said TESS Principal Investigator George Ricker of the Massachusetts Institute of Technology in Cambridge, Mass. “Most of these will be orbiting bright stars, making them ideal targets for characterization observations with NASA’s James Webb Space Telescope.”

Although Kepler and other telescopes have discovered over 3,500 exoplanets so far, most of them are very distant, making it difficult to learn more about their compositions, atmospheres, etc. TESS, however, will be able to study the planets’ mass, radius, orbit, planet-planet interactions, mutual inclinations, moons, tides and atmospheric composition and structure, including transmission spectrum, emission spectrum, albedo, phase function, clouds and winds.

TESS will complete two orbits around Earth every time the Moon orbits once, allowing its cameras to monitor each patch of sky continuously for nearly a month at a time. TESS will reach its final orbit about 60 days after launch.

TESS in the clean room at Kennedy Space Center. Photo Credit: Jeff Seibert/AmericaSpace

“That’s our first Falcon from the East Coast, for our program,” said Chuck Dovale, deputy manager of NASA’s Launch Services Program at Kennedy Space Center. “It’s a big step for us.”

Picking up where Kepler leaves off, TESS will begin a new era in exoplanet science, perhaps helping to answer the age-old question – “Are we alone?”

“This unique new data will comprise a treasure trove for astronomers throughout the world for many decades to come,” Ricker said. As TESS Project Manager Jeff Volosin at NASA’s Goddard Space Flight Center in Greenbelt, Md. also eloquently noted, “I’m still hopeful that in my lifetime, we will discover the existence of life outside of our Solar System and I’m excited to be part of a NASA mission that serves as a key stepping stone in that search.”

This article was first published on AmericaSpace.





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