Summary in Seconds: NASA’s SPHEREx mission, is a new space telescope designed to conduct an all-sky infrared survey of the universe. It will map the entire sky in 102 infrared colors every six months. Its goals are to study galaxy formation, cosmic inflation, and to search for icy organics that could explain life’s origins on Earth. SPHEREx will complement other missions like JWST and OSIRIS-REx.
“We are literally mapping the entire celestial sky in 102 infrared colors for the first time in humanity’s history.” (2)
In late February, a new space telescope called SPHEREx will join NASA’s collection of space exploration tools, if all goes to plan. SPHEREx is a conical, eggshell-white spacecraft, and its full name stands for Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer. Unlike the James Webb Space Telescope (JWST), which focuses on observing specific areas in great detail, SPHEREx uses infrared light to explore a much broader picture of the universe.
“Taking a snapshot with JWST is like taking a picture of a person,” said Shawn Domagal-Goldman, acting director of NASA’s Astrophysics Division, during a press briefing on January 31. “What SPHEREx and other survey missions can do is more like using panorama mode on a camera to capture a big group of people and everything around them.”
The SPHEREx mission is set to launch no earlier than February 27 aboard a SpaceX Falcon 9 rocket, and it will not be alone. SPHEREx will share the launch with NASA’s PUNCH mission, a group of four small satellites that will study the sun. They will both lift off from Launch Complex 4E at Vandenberg Space Force Base in Central California.
The Promise of SPHEREx
Over the course of two years, SPHEREx will map the universe by detecting two kinds of cosmic light: optical and infrared. While optical light is visible to the human eye and studied by many telescopes, infrared light is invisible to us and provides valuable information about the farthest reaches of space, star formation, and galactic structures. The JWST specializes in infrared, which is why it has been so revolutionary in revealing parts of the universe previously hidden from us.
However, unlike the JWST, which can focus on specific regions in great detail, SPHEREx will conduct an all-sky survey. This means it will scan the entire sky from Earth, unlike the JWST, which focuses on smaller sections like specific nebulas or distant galaxies.
“We are literally mapping the entire celestial sky in 102 infrared colors (3) for the first time in humanity’s history, and we’ll see that every six months,” said Nicky Fox, associate administrator for NASA’s Science Mission Directorate. “This has never been done before at this level of color resolution.”
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To be fair, SPHEREx will not rival the JWST’s ability to observe highly localized regions of the universe that are confined to the infrared section of the electromagnetic spectrum. However, unlike the JWST, it is an all-sky survey. Whereas the $10 billion JWST is great at observing things like specific nebulas and relatively narrow but tremendously dimensional deep fields, SPHEREx is intended to image the entire sky as seen from Earth.
“We are literally mapping the entire celestial sky in 102 infrared colors for the first time in humanity’s history, and we will see that every six months,” said Nicky Fox, associate administrator for NASA’s Science Mission Directorate. “This has not been done before on this level of color resolution for our old sky maps.”
“In terms of all-sky survey missions,” Jamie Bock, principal investigator of SPHEREx at the California Institute of Technology in Pasadena, said during the briefing, “generally, these have been done in photometry, looking at the sky in broad bands and handfuls of broad bands — not this complete spectrum.”
SPHEREx’s Objectives
SPHEREx’s mission is vast and includes many goals. One of its primary objectives is to map galaxies at different points in their evolution, which will improve our understanding of how galaxies form and change over time. SPHEREx will also look into the space between stars to search for icy organics that could provide clues about the origins of life on Earth.
“We’re trying to understand how life on Earth may have started,” Domagal-Goldman said.
Another goal of SPHEREx is to capture three-dimensional images of hundreds of millions of galaxies, helping scientists’ study cosmic inflation—the theory that the universe expanded incredibly rapidly just after the Big Bang.
“Just a trillionth of a trillionth of a billionth of a second after the Big Bang, the universe expanded tremendously,” said Jamie Bock, principal investigator of SPHEREx. “We still don’t know what caused that expansion or why it happened.”
Collaborations with Other Missions
SPHEREx’s work will complement other space missions. The JWST’s infrared capabilities will help guide SPHEREx in its all-sky survey by providing a detailed infrared map that the JWST can study further. SPHEREx will also work with NASA’s OSIRIS-REx mission (4), which is collecting samples from asteroids.
In addition, the Vera Rubin Observatory, a ground-based telescope, will start operating later this year, offering another layer of data for scientists.
“No single instrument or mission can answer all the big questions about the universe,” Domagal-Goldman said. “The answers will come from combining observations from different missions and observatories.”
SPHEREx’s Design
Despite its important role, SPHEREx is relatively small and cost-effective compared to other space missions. The spacecraft weighs about 1,100 pounds (slightly less than a grand piano) and uses only 270-300 watts of power, which is less than a refrigerator. It is powered by a solar array similar to those found on residential rooftops.
One of the biggest challenges for SPHEREx is keeping its instruments cool. Since infrared observations can be affected by heat, the telescope must avoid direct sunlight. To protect it, SPHEREx will be placed in a special orbit that keeps it shielded from the sun.
“The spacecraft has three concentric cone-shaped shields to protect its instruments from the sun’s warmth and Earthshine,” explained Beth Fabinsky, deputy project manager of SPHEREx. “The heat is also radiated away using a V-shaped radiator.”
Once SPHEREx is in space, fully deployed, and operational, the team will begin its first six-month sky survey. The first images from the telescope are expected to be released within two months.
“I’m excited for the moment when we take the lid off the telescope and see the first image. That will tell us if everything is working as planned,” said Bock.
Sources
1. Ravisetti, Monisha. “NASA’s New SPHEREx Space Telescope to Launch in February – it can do what the JWST cannot.” Space.com, 31 January, 2025.
2. NASA. “SPHEREx, Spectro-photometer for the History of the Universe.” NASA-Explore, 31 January, 2025.
References
(1) The James Webb Space Telescope (JWST), also known as Webb, is a space telescope that observes in infrared light. It will work alongside the Hubble Space Telescope, but with the ability to see longer wavelengths of light and much better sensitivity. This will allow it to make new discoveries and expand on the knowledge Hubble has already provided.
(2) Nicky Fox, associate administrator for NASA’s Science Mission Directorate.
(3) “Infrared.” Wikipedia, 30 January, 2025.
https://en.wikipedia.org/wiki/Infrared
(4) NASA. “OSIRIS-REx.” NASA Newsletter, 30 January, 2025.