Pasadena’s JPL Leads NASA’s SPHEREx Mission as Observatory Captures First Images

NASA’s newest infrared observatory, SPHEREx, has successfully captured its first images of the cosmos on March 27, confirming that all systems are functioning as designed, according to scientists and engineers at NASA’s Jet Propulsion Laboratory in Pasadena.

The space observatory, which launched on March 11 aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base, is expected to map hundreds of millions of galaxies across the entire sky during its 27-month primary mission.

Jet Propulsion Laboratory, which manages the SPHEREx mission for NASA’s Astrophysics Division, reported that initial tests show the telescope’s detectors and other components are performing to specifications.

“Our spacecraft has opened its eyes on the universe,” said Olivier Doré, SPHEREx project scientist at Caltech and JPL. “It’s performing just as it was designed to.”

The observatory’s name stands for Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer. While the images released are uncalibrated and not yet ready for scientific analysis, they provide an early glimpse of SPHEREx’s wide-field capabilities. Each of the six detectors captured imagery showing more than 100,000 light sources, including stars and distant galaxies. To make these first images visible to the human eye, science team members assigned visible colors to represent the infrared wavelengths captured by the observatory.

There are six images in every SPHEREx exposure — one for each detector. The top three images show the same area of sky as the bottom three images, representing the observatory’s full field of view, a rectangular area about 20 times wider than the full Moon.

Unlike telescopes such as Hubble and James Webb that focus on small areas of space in great detail, SPHEREx is a survey telescope designed to map the entire celestial sky four times during its primary mission. The observatory uses spectroscopy to collect light from celestial objects in multiple wavelengths, with each of its six detectors capturing 17 unique infrared wavelength bands, for a total of 102 hues in every six-image exposure.

“This is the high point of spacecraft checkout; it’s the thing we wait for,” said Beth Fabinsky, SPHEREx deputy project manager at JPL. “There’s still work to do, but this is the big payoff. And wow! Just wow!”

The observatory’s detectors and other hardware have been cooling down to their operational temperature of approximately minus 350 degrees Fahrenheit (about minus 210 degrees Celsius), a necessary step as heat can interfere with infrared light detection, which is sometimes called heat radiation. Engineers confirmed the telescope is correctly focused – a critical milestone since focusing adjustments cannot be made once in space.

“Based on the images we are seeing, we can now say that the instrument team nailed it,” said Jamie Bock, SPHEREx’s principal investigator at Caltech and JPL.

When light enters SPHEREx’s telescope, it’s directed down two paths that each lead to a row of three detectors. The observatory’s detectors are like eyes, and set on top of them are color filters, which are like color-tinted glasses. While a standard color filter blocks all wavelengths but one, the SPHEREx filters are more like rainbow-tinted glasses: the wavelengths they block change gradually from the top of the filter to the bottom.

The mission represents a collaborative effort across multiple institutions. BAE Systems (formerly Ball Aerospace) built the telescope and spacecraft bus, while Caltech managed and integrated the instrument. Data analysis will be conducted by scientists from 10 institutions in the United States, two in South Korea, and one in Taiwan. All data will be processed and archived at IPAC at Caltech and will be publicly available through the NASA-IPAC Infrared Science Archive.

Currently in a sun-synchronous orbit about 700 km above Earth, SPHEREx can be tracked in real-time using NASA’s 3D visualization tool, Eyes on the Solar System.

“I’m rendered speechless,” said Jim Fanson, SPHEREx project manager at JPL. “There was an incredible human effort to make this possible, and our engineering team did an amazing job getting us to this point.”

The mission is expected to begin routine science operations in late April, taking approximately 600 exposures daily. By breaking down infrared light into multiple wavelengths, SPHEREx will help scientists study a range of topics from the physics of the early universe less than a second after its birth to the origins of water in our galaxy.

More information about the SPHEREx mission is available at https://science.nasa.gov/mission/spherex/.