22.03.2025
The telescope on NASA’s SPHEREx observatory was protected during launch by its dust cover — the oval metal plate shown here at the center of the three photon shields.
Credit: BAE Systems/NASA/JPL-Caltech
NASA’s SPHEREx space observatory, which launched into low Earth orbit on March 11, has opened its eyes to the sky. On March 18, the mission team commanded the spacecraft to eject the protective dust cover that shielded the telescope opening. Once science operations begin several weeks from now, SPHEREx (short for Specto-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) will map the entire celestial sky to answer fundamental questions about the universe.
Measuring about 25 inches by 16 inches (64 centimeters by 40 centimeters), the cover kept particles and moisture off key pieces of hardware, including three telescope mirrors. To complete the ejection, engineers at NASA’s Jet Propulsion Laboratory in Southern California sent a command to SPHEREx that activated two mechanical release mechanisms on the protective lid, and springs helped push it away from the observatory. After being ejected, the cover began to float away and will eventually burn up in Earth’s atmosphere.
The mission won’t power on the spacecraft’s camera until it has cooled to its operating temperature, which is colder than minus 300 degrees Fahrenheit (about minus 190 degrees Celsius). So to confirm the cover’s removal, team members observed a change in SPHEREx’s orientation — essentially, a slight jiggle of the observatory after each mechanism release. Shortly after the second jiggle, the telescope’s temperature began to drop, indicating it was exposed to the cold of space as planned.
The SPHEREx spacecraft is about the size of a subcompact car. The telescope is the portion of the observatory that collects light from distant stars and galaxies. Only about the size of a washing machine, it is nestled inside three cone-shaped photon shields that protect the instrument from light and heat from the Sun and Earth.
During its two-year prime mission, the observatory will use a technique called spectroscopy to create four all-sky maps featuring 102 wavelengths, or colors, of infrared light. This information can help scientists measure the distance to faraway galaxies, identify chemicals and molecules in cosmic gas clouds, and more.
Quelle: NASA
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Update: 3.04.2025
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NASA’s SPHEREx Takes First Images, Preps to Study Millions of Galaxies
NASA’s SPHEREx, which will map hundreds of millions of galaxies across the entire sky, captured one of its first exposures March 27. The observatory’s six detectors each captured one of these uncalibrated images, to which visible-light colors have been added to represent infrared wavelengths. SPHEREx’s complete field of view spans the top three images; the same area of the sky is also captured in the bottom three images.
Credit: NASA/JPL-Caltech
Processed with rainbow hues to represent a range of infrared wavelengths, the new pictures indicate the astrophysics space observatory is working as expected.
NASA’s SPHEREx (short for Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) has turned on its detectors for the first time in space. Initial images from the observatory, which launched March 11, confirm that all systems are working as expected.
Although the new images are uncalibrated and not yet ready to use for science, they give a tantalizing look at SPHEREx’s wide view of the sky. Each bright spot is a source of light, like a star or galaxy, and each image is expected to contain more than 100,000 detected sources.
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. This is the observatory’s full field of view, a rectangular area about 20 times wider than the full Moon. When SPHEREx begins routine science operations in late April, it will take approximately 600 exposures every day.
Each image in this uncalibrated SPHEREx exposure contains more than 100,000 detected sources, including stars and galaxies. The two insets at right zoom in on sections of one image, showcasing the telescope’s ability to capture faint, distant galaxies. These sections are processed in grayscale rather than visible-light color for ease of viewing. Credit: NASA/JPL-Caltech
“Our spacecraft has opened its eyes on the universe,” said Olivier Doré, SPHEREx project scientist at Caltech and NASA’s Jet Propulsion Laboratory, both in Southern California. “It’s performing just as it was designed to.”
The SPHEREx observatory detects infrared light, which is invisible to the human eye. To make these first images, science team members assigned a visible color to every infrared wavelength captured by the observatory. Each of the six SPHEREx detectors has 17 unique wavelength bands, for a total of 102 hues in every six-image exposure.
Breaking down color this way can reveal the composition of an object or the distance to a galaxy. With that data, scientists can study topics ranging from the physics that governed the universe less than a second after its birth to the origins of water in our galaxy.
“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!”
During the past two weeks, scientists and engineers at JPL, which manages the mission for NASA, have executed a series of spacecraft checks that show all is well so far. In addition, SPHEREx’s detectors and other hardware have been cooling down to their final temperature of around minus 350 degrees Fahrenheit (about minus 210 degrees Celsius). This is necessary because heat can overwhelm the telescope’s ability to detect infrared light, which is sometimes called heat radiation. The new images also show that the telescope is focused correctly. Focusing is done entirely before launch and cannot be adjusted 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.
How It Works
Where telescopes like NASA’s Hubble and James Webb space telescopes were designed to target small areas of space in detail, SPHEREx is a survey telescope and takes a broad view. Combining its results with those of targeted telescopes will give scientists a more robust understanding of our universe.
The observatory will map the entire celestial sky four times during its two-year prime mission. Using a technique called spectroscopy, SPHEREx will collect the light from hundreds of millions of stars and galaxies in more wavelengths any other all-sky survey telescope.
Track the real-time location of NASA’s SPHEREx space observatory — in polar orbit about 404 miles above Earth — using the agency’s 3D visualization tool, Eyes on the Solar System. The spacecraft will complete four all-sky maps in its 27-month primary mission. Credit: NASA/JPL-Caltech
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, like yellow- or rose-tinted glasses, the SPHEREx filters are more like rainbow-tinted glasses: The wavelengths they block change gradually from the top of the filter to the bottom.
“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.”
More About SPHEREx
The SPHEREx mission is managed by JPL for the agency’s Astrophysics Division within the Science Mission Directorate at NASA Headquarters. BAE Systems (formerly Ball Aerospace) built the telescope and the spacecraft bus. The science analysis of the SPHEREx data will be conducted by a team of scientists located at 10 institutions in the U.S., two in South Korea, and one in Taiwan. Caltech managed and integrated the instrument. Data will be processed and archived at IPAC at Caltech. The mission’s principal investigator is based at Caltech with a joint JPL appointment. The SPHEREx dataset will be publicly available at the NASA-IPAC Infrared Science Archive. Caltech manages JPL for NASA.
Quelle: NASA