Ellen Phiddian
Cosmos science journalist
NASA is about to launch a helium balloon carrying a telescope, to test its ability to see exoplanet atmospheres.
The Exoplanet Climate Infrared Telescope (EXCITE) is eventually destined to fly around the poles, collecting data above much of the Earth’s atmosphere, but its first test flight is due to happen from the USA in the next few months.
It will be launched for the first time from the Columbia Scientific Ballooning Facility in New Mexico.
“EXCITE can give us a three-dimensional picture of a planet’s atmosphere and temperature by collecting data the whole time the world orbits its star,” says principal investigator Peter Nagler, from NASA’s Goddard Space Flight Center.
“Only a handful of these types of measurements have been done before. They require a very stable telescope in a position to track a planet for several days at a time.”
From a vantage point of 40km above the Earth’s surface, the telescope will be above 99.5% of the Earth’s atmosphere, and so able to get a clearer view of the stars.
It’s going to study “hot Jupiters”: gas giants that orbit very closely and quickly around their stars.
Using infrared spectroscopy, EXCITE will be able to tell how heat is distributed around these worlds.
“The telescope collects the infrared light and beams it into the spectrometer, where it kind of goes through a little obstacle course,” says EXCITE team member Lee Bernard, a graduate research assistant at Arizona State University.
“It bounces off mirrors and through a prism before reaching the detector. Everything must be aligned very precisely — just a few millimetres off centre and the light won’t make it.”
While existing space telescopes, like the James Webb Space Telescope, have generated a lot of data on hot Jupiters, they have a variety of other demands on their observation time.
If the test flight goes well, EXCITE will be launched for its first scientific mission – a flight of about a dozen days over Antarctica.
“At the pole, the stars we’ll study don’t set, so our observations won’t be interrupted,” says EXCITE team member Kyle Helson, a research scientist at the University of Maryland, Baltimore County.
“We hope that the mission will effectively double the number of phase-resolved spectra available to the science community.”
