NASA's new space telescope SPHEREx has sent its first images from space to Earth. Although not yet fully calibrated, the images captured over 100,000 light sources—each a star or galaxy—generating excitement in the scientific community.
SPHEREx detects infrared light invisible to the human eye and aims to uncover secrets ranging from the origins of cosmic water to galaxy distances. All systems are reportedly functioning perfectly, and the telescope is ready to begin its mission of repeatedly scanning the entire sky.
Following its launch on March 11, NASA's SPHEREx telescope (short for "Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer") entered observation mode. The first sky images show that the system is operating flawlessly.
Though these early images are not yet suitable for scientific analysis, they offer a powerful preview of the telescope's remarkably wide field of view—each bright dot representing a light source from a star or galaxy. More than 100,000 such sources were detected in each frame.
Each SPHEREx observation includes six images from six detectors, covering a rectangular sky area about 20 times wider than the Moon's diameter. During routine observations set to begin by late April, SPHEREx will capture around 600 exposures daily.
"SPHEREx has opened its eyes to the universe and is performing exactly as designed," said Olivier Doré, SPHEREx project scientist at Caltech and NASA's Jet Propulsion Laboratory (JPL).
SPHEREx detects infrared light, assigning a visible color to each wavelength band to make the data viewable. Each detector uses 17 wavelength bands, resulting in 102 color tones per image.
This color separation allows scientists to analyze the structure of celestial bodies or determine galaxy distances. With this data, researchers can investigate topics from the physics of the universe's first second to the origin of water in the Milky Way.
"This is t pinnacle of our mission prep—the big moment we've been waiting for. And wow… just wow," said Deputy Project Manager Beth Fabinsky.
To clearly detect infrared light, SPHEREx's sensitive detectors are cooled to about -210°C. This extreme cold is crucial for image clarity. Tests show the telescope's focus is excellent—pre-adjusted on Earth and unchangeable in space.
"We can see from the images that our hardware team did a phenomenal job," said Principal Investigator Jamie Bock of Caltech.
Unlike telescopes like Hubble or James Webb, which zoom into small sky regions, SPHEREx will scan the entire sky with a wide-angle lens. The data will be combined with detailed observations from other telescopes to create a comprehensive cosmic map.
SPHEREx will complete four full-sky surveys during its two-year mission. Using spectroscopy, it will examine light from hundreds of millions of stars and galaxies across dozens of wavelengths.
Incoming light is channeled through two paths onto detectors, each covered with special filters that act like colored glasses—except they pass a wide range of wavelengths like a rainbow. This allows for gathering far more information than traditional filters.
"I'm literally speechless. Reaching this point took incredible effort. Our engineering team has done an extraordinary job," said Project Manager Jim Fanson.
SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) is NASA's next-gen infrared telescope designed for full-sky surveys. The mission is led by NASA's Astrophysics Division and managed by JPL. The principal investigator is based at Caltech.
The telescope and spacecraft were built by BAE Systems (formerly Ball Aerospace). Caltech's IPAC center will handle data processing and archiving. All data will be publicly accessible via the NASA-IPAC Infrared Science Archive.
