Pandora, NASA's newest exoplanet mission, is one step closer to launch with the completion of the spacecraft bus, which provides the structure, power and other systems that will allow the mission to carry out its work. Pandora's exoplanet science working group is led by the University of Arizona, and Pandora will be the first mission to have its operations center at the U of A Space Institute.
The completion of the bus was announced Thursday during a press briefing at the 245th Meeting of the American Astronomical Society in National Harbor, Maryland.
"This is a huge milestone for us and keeps us on track for a launch in the fall," said Elisa Quintana, Pandora's principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The bus holds our instruments and handles navigation, data acquisition and communication with Earth – it's the brains of the spacecraft."
Pandora is a small satellite poised to provide in-depth study of at least 20 known planets orbiting distant stars to determine the composition of their atmospheres – especially the presence of hazes, clouds and water. The data will establish a firm foundation for interpreting measurements by NASA's James Webb Space Telescope and future missions aimed at searching for habitable worlds.
"Although smaller and less sensitive than Webb, Pandora will be able to stare longer at the host stars of extrasolar planets, allowing for deeper study," said Pandora co-investigator Daniel Apai, professor of astronomy and planetary sciences at the U of A Steward Observatory and Lunar and Planetary Laboratory who leads the mission's Exoplanets Science Working Group. "Better understanding of the stars will help Pandora and its 'big brother,' the James Webb Space Telescope, disentangle signals from stars and their planets."
Astronomers can sample an exoplanet's atmosphere when it passes in front of its star as seen from Earth's perspective, during an event known as a transit. Part of the star's light skims the planet's atmosphere before making its way to the observer. This interaction allows the light to interact with atmospheric substances, and their chemical fingerprints – dips in brightness at characteristic wavelengths – become imprinted in the light.
The concept of Pandora was born out of necessity to overcome a snag in observing starlight passing through the atmospheres of exoplanets, Apai said.
"In 2018, a doctoral student in my group, Benjamin Rackham – now an MIT research scientist – described an astrophysical effect by which light coming directly from the star muddies the signal of the light passing through the exoplanet's atmosphere," Apai explained. "We predicted that this effect would limit Webb's ability to study habitable planets."