TESS to search the stars for exoplanets

April 20, 2018
by Mark Ollig

Don’t worry, mom, NASA is not sending you on a mission into outer space to find planets orbiting stars.

Let me explain; my mother’s name is Therese. My father began calling her Tess before they were married, and ever since, the local community has known her as Tess.

However, I digress.

Today’s column headline refers to NASA’s new Transiting Exoplanet Survey Satellite (TESS).

TESS will be on a two-year mission, monitoring 200,000 preselected nearby stars less than 300 light-years away from Earth.

It will look for conditions indicating planetary transits – a planet orbiting a sun as our Earth does.

Onboard cameras will be searching for temporary drops in a star’s brightness, which would be caused by a planet orbiting/passing in front of it.

Ground-based telescopes are unable to search this way; they instead look for a star’s “wobbling” effect caused by the gravity of an orbiting planet.

“The principal goal of the TESS mission is to detect small planets with bright host stars in the solar neighborhood so that detailed characterizations of the planets and their atmospheres can be performed,” stated NASA on its TESS webpage.

Positive, detailed findings from specific stars can then be followed-up for additional study by ground-based telescopes.

Wednesday, a 224-foot-tall, two-stage SpaceX Falcon 9 rocket fired its nine Merlin 1D engines and launched TESS into space.

The rocket’s powerful engines produced 1.7 million pounds of thrust at liftoff.

Falcon 9 lifted off from Space Launch Complex 40 at Florida’s Cape Canaveral Airforce Station.

Approximately 50 minutes after launch, the nearly 800-pound exploratory satellite emerged from the 43-foot-tall, 17.1-foot-diameter, payload carbon fiber-enclosed shell and obtained an elliptical transfer Earth-orbit.

May 16, TESS, using its propulsion system, will be in what NASA calls “an observing orbit in resonance with the moon.”

Its multiple Earth orbital paths will range from as close as 120 miles, to as distant as 168,000 miles.

TESS will remain in an elliptical high-Earth orbit, focusing its array of telescopes at stars and looking for exoplanets for the duration of its two-year mission.

TESS is more than just a satellite. It is a well-equipped spacecraft with thermal blankets for protection from the sun’s heat, and solar arrays producing 390 watts of electricity to power all of its systems.

The spacecraft includes a hydrazine-filled propulsion fuel tank, four charge-coupled device cameras with various lenses, a sunshade for protecting the cameras, and a star-tracker camera for maintaining its orientation.

TESS contains five orbital thrusters and a master computer, which controls all operations of the satellite/spacecraft.

NASA reports its antenna will transmit the exoplanet data it collects back to Earth at a speed of 100 Mbps.

TESS team partners include the Massachusetts Institute of Technology, Goddard Space Flight Center, Ames Research Center, and Harvard-Smithsonian Center for Astrophysics; Orbital ATK, and the Space Telescope Science Institute.

The NASA website for the TESS mission is https://tess.gsfc.nasa.gov.

The official Twitter handle for updated information about the Transiting Exoplanet Survey Satellite is @NASA_TESS.

Visit my weblog at www.bitscolumn.blogspot.com.

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