Nasa has launched the Pandora satellite to help the James Webb Space Telescope accurately detect atmospheres on distant exoplanets by accounting for stellar interference. The small spacecraft, deployed on a SpaceX rocket from California, will observe stars and planets simultaneously over its one-year mission. This $20 million project aims to refine data on potential habitable worlds.
The Pandora mission blasted off early Sunday from Vandenberg Space Force Base in California, hitching a ride on a SpaceX Falcon 9 rocket alongside about 40 other payloads. It reached a polar Sun-synchronous orbit at roughly 380 miles (613 kilometers) altitude, entering a "twilight orbit" that keeps its solar panels sunlit during observations.
At a fraction of the James Webb Space Telescope's scale and cost—Webb launched in 2021 for over $10 billion—Pandora's 17-inch (45-centimeter) mirror is modest, yet vital. Webb excels at capturing light from far-off planetary systems to identify molecules like water vapor, carbon dioxide, and methane, key indicators for habitability. However, stars' variability, including spots and flares, contaminates these signals, mimicking or masking planetary atmospheres.
"This is something that we always suspected as a community," said Daniel Apai, a University of Arizona scientist on the Pandora team. "But it was not recognized how serious a problem that is until, I would say, about 2017 or 2018."
Pandora addresses this by staring at 20 selected exoplanets and their host stars for 24 hours per visit, up to 10 times each during its prime year-long mission. This will map stellar changes in visible and infrared light, allowing corrections to Webb's data. For instance, observations of GJ 486 b, a super-Earth orbiting a red dwarf star, have struggled to confirm water due to stellar spots.
"We want to be really sure it's not coming from the star before we go tell the press," noted Elisa Quintana, Pandora's lead scientist at Nasa's Goddard Space Flight Center.
Developed under Nasa's Astrophysics Pioneers program, Pandora leverages affordable small-satellite tech from firms like Blue Canyon Technologies and a telescope from Lawrence Livermore National Laboratory. Weighing 716 pounds (325 kilograms), it benefited from SpaceX's rideshare options, slashing launch costs.
Team members, including Tom Barclay and Ben Hord from Goddard, emphasize Pandora's role in unlocking Webb's potential. "It's filling a really nice gap in helping us calibrate all these stars," Quintana added. As astronomers have confirmed over 6,000 exoplanets, this mission chips away at uncertainties, paving the way to confirm Earth-like worlds.