MIT satellite is off to search for planets outside our solar system
A new satellite built by MIT researchers will launch Monday evening. Its two-year mission is to look for exoplanets, or planets outside our solar system, particularly those that might be able to support life.
Researchers have spent the past five years building the NASA-funded Transiting Exoplanet Survey Satellite, or TESS. The spacecraft will launch at 6:32 p.m. Monday.
“Mankind has always been searching for its origins,” said MIT scientist Roland Vanderspek, who has worked on the project for five years. “We want to understand where we came from and what else is out there. This is a way of determining that.”
TESS carries four small cameras with 150-millimeter lenses. The cameras have a big field of view, will capture a lot of light and a broad range of color, Vanderspek said.
The cameras will take snapshots of one large piece of the sky for 27 days, then move to another piece for the next 27 days, until they capture the entire sky, he said. Within the first year, the cameras will cover the sky over the entire Southern Hemisphere. During the second year, they’ll capture the Northern Hemisphere’s sky.
And because it’s the entire sky, the scientists expect to see a lot. Vanderspek estimated the team would find 50 Earth-sized planets, 500 super-Earths — which are up to twice the diameter of our planet — and thousands even bigger.
“The real good stuff is in the Earths and the super-Earths because any larger planets are more gassy,” he said. “We want to find stuff like us.”
This means that even though researchers are on the lookout for all types of planets, they’re most interested in rockier ones, which might be more likely to provide habitable environments, he said.
But in order to find any planets, the team first has to focus on the stars.
“One of the best ways to find [planets] is to look at a star and hope the planet passes between your eyes and the star, like a mini-eclipse,” he said. “And when that happens, the brightness of the star drops by a fraction of a percent, so if we see that multiple times, we know that, yes, it’s a planet.”
They rounded up 200,000 of the nearest, brightest stars and have programmed TESS to take photos of them every two minutes. The satellite will also snap full images of the entire field of view every half-hour, Vanderspek said.
Once they have those photos, the researchers will sift through them and measure the light curves of each star. By looking for repeated dips in the curves, they’ll be able to identify which stars are being crossed by planets.
Bigger ground-based telescopes will then do more detailed examinations of each planet to find its mass, radius, and density, Vanderspek said.
“I’m really looking forward to seeing some of the data, and seeing these cameras perform in real life,” he said. “I’m hoping we get some really beautiful images . . . and enable good science all around the world.”