SPHEREx Mission Selected to Uncover Origins of the Universe

NASA’s Astrophysics Explorers Program and associated divisions are moving ahead with a new space mission designed to help astronomers understand both how our universe evolved and how common the ingredients for life are in our galaxy’s planetary systems.

The collective NASA team selected SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) from a collection of proposed instruments for the planned two-year mission funded at $242 million (not including launch costs) and targeted to launch in 2023. The instrument’s optics and detector will generate heat, but have been designed to cool passively to 80 K by radiating heat to space with a three-stage V-groove cooler. Lightweight deployed photon shields will additionally protect the cooler and optics from radiation emanating from the sun and Earth.

“I’m really excited about this new mission,” says NASA Administrator Jim Bridenstine. “Not only does it expand the United States’ powerful fleet of space-based missions dedicated to uncovering the mysteries of the universe, it is a critical part of a balanced science program that includes missions of various sizes.”

SPHEREx will survey the sky in optical as well as near-infrared light that serves as a powerful tool for answering cosmic questions not visible to the human eye. Astronomers will use the mission to gather data on more than 300 million galaxies, as well as more than 100 million stars in our own Milky Way.

“This amazing mission will be a treasure trove of unique data for astronomers,” says Thomas Zurbuchen, associate administrator for NASA’s science mission directorate. “It will deliver an unprecedented galactic map containing ‘fingerprints’ from the first moments in the universe’s history. And we’ll have new clues to one of the greatest mysteries in science: What made the universe expand so quickly less than a nanosecond after the big bang?”

NASA plans to use SPHEREx to survey hundreds of millions of galaxies, some so distant that light has taken 10 billion years to reach Earth. In the Milky Way, the mission will search for water and organic molecules—essentials for life, as we know it—in stellar nurseries, regions where stars are born from gas and dust, as well as disks around stars where new planets could be forming.

Every six months, SPHEREx will survey the entire sky using technologies adapted from satellites and spacecraft, creating a map of the entire sky in 96 different color bands and far exceeding the color resolution of previous all-sky maps. It also will identify targets for more detailed study by future missions, such as NASA’s James Webb Space Telescope and Wide Field Infrared Survey Telescope.

NASA’s Astrophysics Explorers Program requested proposals for new missions in September 2016. Nine proposals were submitted and two mission concepts were selected for further study in August 2017. After a detailed review by a panel of NASA and external scientists and engineers, NASA determined that the SPHEREx concept study offered the best science potential and most feasible development plan.

NASA’s Jet Propulsion Laboratory will manage the upcoming mission, though its principal investigator will be James Bock from the California Institute of Technology. The Caltech team is additionally set to develop the mission payload, while Ball Aerospace provides SPHEREx spacecraft/mission integration and the Korea Astronomy and Space Science Institute in Daejeon, Republic of Korea, contributes test equipment and science analysis.