NASA and SpaceX say they’ll take more time to launch the Transiting Exoplanet Survey System, or TESS, just to make sure the $337 million mission will be on the right track to hunt for planets beyond our solar system.
TESS’ liftoff aboard a SpaceX Falcon 9 rocket had been scheduled for today, but in an online update, NASA said “launch teams are standing down today to conduct additional guidance, navigation and control analysis.”
The launch was retargeted for Wednesday, with an anticipated liftoff time of 6:51 p.m. ET (3:51 p.m. PT).
NASA emphasized that the satellite, which is a little smaller than a subcompact car, was in “excellent health and remains ready for launch” from Cape Canaveral Air Force Station in Florida.
Guidance, navigation and control is always important for a space mission — but for TESS, the task is particularly complex.
The spacecraft is meant to be maneuvered into an unusual Earth orbit that ranges in altitude from roughly 63,000 to 200,000 miles. From that vantage point, TESS will keep tabs on 200,000 of the brightest stars in our celestial neighborhood, looking for the telltale changes in brightness that result when a planet crosses over the star’s disk.
That transit detection technique was pioneered by earlier probes such as NASA’s Kepler telescope, which was launched in 2009. Kepler stared at 250,000 distant stars in a cross-shaped area equal to 0.25 percent of the sky, and identified the signatures of more than 5,000 confirmed planets and candidates.
TESS’ four wide-field telescopic cameras will survey an area hundreds of times as wide, adding up to 85 percent of the entire sky. The mission will focus on planets circling bright stars that are less than 300 light-years from Earth.
After TESS identifies its candidates, scientists around the world will make further observations to confirm that they really are planets, and determine whether they’re gas giants like Jupiter and Neptune, or rocky planets like Earth and Mars.
“Not only scientists will be following up these planets, but also amateur astronomers can use their own smaller telescopes to help confirm which planets are true, and which are not,” said Diana Dragomir, a researcher at the Massachusetts Institute of Technology.
Based on Kepler’s statistics, the science team expects to detect more than 1,500 transiting exoplanet candidates over the course of a two-year primary mission, including roughly 500 Earth-sized and “Super Earth” planets.
“These are the exoplanets that will be easiest to follow up, so that we can study the planets in great detail and learn more about their characteristics,” Paul Hertz, who heads NASA’s astrophysics division, said during a pre-launch briefing.
Further follow-ups on potentially habitable planets could be done using more powerful telescopes, such as NASA’s yet-to-be-launched James Webb Space Telescope, which is designed to analyze alien atmospheres and help scientists look for potential signs of life.
Researchers might even consider sending swarms of tiny probes to sweep by the most promising candidates — a strategy that the Breakthrough Starshot initiative is already working on for the Alpha Centauri star system.
“Fifty, sixty, 100 years from now, you could use those same techniques to thoroughly explore the solar neighborhood,” said MIT’s George Ricker, principal investigator for the TESS mission. “The thing that we can imagine is that there’s this armada of nanosatellites that’ll be sweeping out from the Earth to send back information.”
Ricker and other scientists said the planetary catalog generated by TESS could well become the guidebook for that armada.
“TESS is just the first step in that journey,” said Stephen Rinehart, TESS project scientist at NASA’s Goddard Space Flight Center. “But I want to add that we care about all the planets that we find, not just the habitable ones — because for a variety of reasons, all the planets matter.”
Like Kepler, TESS will serve as a planetary population census giving astronomers a better idea as to the origin and evolution of planetary systems — including our own.
This is an updated version of a report first published at 8 a.m. PT April 16.
