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