NASA is set to launch SPHEREx space observatory from Vandenberg Space Force Base in California by the end of February. 

Key points:

• Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) will provide astronomers with a big-picture view of the cosmos like none before.

• It will map the entire celestial sky in infrared colours, illuminating the origins of our universe, galaxies within it, and life’s key ingredients in our own galaxy. 

• Shaped like the bell of a trumpet, it is as big as a subcompact car.

• SPHEREx will enter a polar orbit around Earth and create a map of the entire sky in 3D, taking images in every direction, like scanning the inside of a globe. The map will contain hundreds of millions of stars and galaxies, showing them in 102 colours (each a different wavelength of light).

• Over a two-year planned mission, the SPHEREx Observatory will collect data on more than 450 million galaxies along with more than 100 million stars in the Milky Way in order to explore the origins of the universe.

• It will survey the sky in optical as well as near-infrared light which, though not visible to the human eye.

• Using a technique called spectroscopy, the telescope can split the light into its component colours (individual wavelengths), like a prism creates a rainbow from sunlight, in order to measure the distance to cosmic objects and learn about their composition. With SPHEREx’s spectroscopic map in hand, scientists will be able to detect evidence of chemical compounds, like water ice, in our galaxy. 

• In the Milky Way, the mission will search for water and organic molecules — essentials for life, as we know it — in stellar nurseries, regions where stars are born from gas and dust, as well as disks around stars where new planets could be forming.

• Every six months, SPHEREx will survey the entire sky using technologies adapted from Earth satellites and interplanetary spacecraft. The mission will create a map of the entire sky in different colour bands, far exceeding the colour resolution of previous all-sky maps. 

Three main goals of the mission:

1) To shed light on a cosmic phenomenon called inflation, a brief but powerful cosmic event when space itself increased in size by a trillion fold less than a second after the big bang. The observatory will measure the distribution of hundreds of millions of galaxies to improve understanding of what drove inflation and of the physics behind this event.

2) To measure the collective glow from galaxies near and far, including light from hidden galaxies that haven’t been individually observed. This data will provide a more complete picture of all the objects and sources radiating in the universe.

3) To search the Milky Way galaxy for icy granules of water, carbon dioxide, and other essential building blocks of life. The mission will help scientists discover the location and abundance of these icy compounds in our galaxy, giving them a better sense of how likely they are to be incorporated into newly forming planets.

The spacecraft’s cone-shaped design: The mission’s infrared telescope and detectors need to operate at around -210°C. This is partly to prevent them from generating their own infrared glow, which might overwhelm the faint light from cosmic sources. To keep things cold while also simplifying the spacecraft’s design and operational needs, SPHEREx relies on an entirely passive cooling system — no electricity or coolants are used during normal operations. Key to making this feat possible are three cone-shaped photon shields that protect the telescope from the heat of Earth and the Sun, as well as a mirrored structure beneath the shields to direct heat from the instrument out into space. Those photon shields give the spacecraft its distinctive outline.

SPHEREx is managed by NASA’s Jet Propulsion Laboratory for the agency’s Astrophysics Division within the Science Mission Directorate at NASA headquarters in Washington.

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